Invertebrates
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Tunicates
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“Amphitrite’s
beads” (Doliophora amphithritae)
Order: Doliolids (Doliolida)
Family: Colonial doliolids (Doliophoridae)
Habitat: Indian Ocean and Tanganyika Passage, top layers of water.
Salps, pyrosomas and doliolids are close relatives of vertebrate animals.
But it is difficult to believe in it to unsophisticated observer. At the first
sight at these creatures it can seem, that they are nearest relatives of jellyfishes:
they are fragile and transparent too. But features of embryonic development
evidently show that they are representatives of chordates (Chordata).
The body of these animals has turned to true pomp which tirelessly pumps over
water through filtering device of huge gullet. Due to it animals can move in
thickness of water, similarly to rockets. Some representatives of invertebrate
chordates form colonies numbering from two zooids up to several thousand ones
at the bottom of ocean or in thickness of water.
“Amphitrite’s beads” is original colonial species of doliolids order, usually
including species, existing as singles in adult condition. For usually single
animal transformation into the whole colony is very hard process. But invertebrate
chordates have one special feature, permitting to carry out such transition
easily. In life cycle of these creatures there is the alternation of generations:
sexual, breeding by egg laying, and sexless one, breeding by gemmation. It
is enough for the individuals developing from gemmas “to be late” in this condition
longer and also to become adults quicker and the colony is ready in general.
So, obviously, it also had taken place at ancestors of doliolid “Amphitrite’
beads”.
This colonial animal has not lost features of ancestral appearance: it is also
ephemeral, watery and transparent. The colony of this species consists of several
types of zooids (individuals being as though “bricks” of colony) having had
partly lost independence. In the top part of colony six large mover individuals,
gathered in one “block” settle down. This is the posterity of initial zooid
developed from eggs. “Founder” is at top of all colony.
When the colony was young, mover zooids had well advanced filtering device
and could support their own existing. But in due course the colony expands,
and the speciality to move colony is “laid on shoulders” of these individuals.
In due course at mover zooids filtering device is reduced, but powerful ring
muscles, strengthening jet push, develop. They strongly increase in size in
process of colony development. Besides on external (concerning to other zooids)
surface of each mover zooid the special keel develops, permitting to keep direction
of movement.
Long double chain of eating zooids numbering up to fifty individuals branches
off from the bottom mover zooid (bottom zooid does not have keel, and runner
with zooids of other type branches off from its back side inverted downwards).
Due to it all colony is similar to hanging down string of beads. Eating zooids
have well advanced filtering device: their duty includes supplying by food
of all colony. By common channels of blood system all individuals in colony
are supplied with nutrients acquired by these zooids.
For breeding at the basis of eating zooids from special gemmas strongly reduced
fertile individuals grow. At them the digestive system is reduced, filtering
device is underdeveloped, and they completely depend on nutrients delivered
by other members of colony. But at them ovaries, in which some large eggs ripen,
are advanced.
Inside eggs larvae develop, right in eggs turning to single sexless individuals.
These future founders of colony hatch and also live solitary life for some
time. Then on the bottom surface of single individual some gemmas appear, from
which additional mover zooids grow, and single individual turns to basis of
the future colony. Such “underdeveloped” colonies can be mistaken for separate
species of live creatures, but it is only special stage of development. On
the bottom side of body of the bottom mover zooid special outgrowth starts
to develop, and in body a plenty of gemmas, migrating to this outgrowth, is
formed. They settle down on it in two longitudinal lines and turn to eating
individuals. And later to this outgrowth new generation of gemmas migrates,
turning to breeding fertile individuals.
In rest the colony of “Amphitrite’s beads” dangles in water almost vertically:
mover zooids by rhythmical contractions of ring muscles slowly move colony
in water, and thick runner on which other members of colony sit, hangs downwards.
In case of need other members of colony may be included in movement. “Amphitrite’s
beads” is inhabitant of top layer of water: colony keeps in layer of water,
rich in phytoplankton. But, having felt beginning of storm, fragile colony
swims down to depth up to 50 meters. Storm and sea inhabitants frequently tear
this fragile colony to pieces, but it does not harm to “Amphitrite’s beads”:
colony easily regenerates. Usually the colony is broken off in area of runner.
Then on that part where there are mover zooids, simply the formation of new
gemmas begins, and the colony is restored till the initial size. On torn off
runner eating zooids sitting closely to place of break, gradually turn to mover
zooids. Such recycled colony differs from initial only that on its top part
there is no initial zooid from which the development of colony had began. And
function of formation of gemmas for growing colony at once two bottom zooids
have turned to movers incur.
In Tanganyika passage where strong gales are rather rare, intact colonies of
these creatures frequently may be met, but in Indian Ocean approximately two
thirds of colonies have signs of damages.
This species of doliolids has ability to light: at all members of colony, except
for fertile zooids, organs of luminescence develop. These are small sacs, located
near ring muscles, and containing inside luminous bacteria. The colony of “Amphitrite’s
beads” can shine greenish and bright blue light.
Whale salpa (Titanosalpa crystallocetus)
Order: Salps (Salpida)
Family: Giant salps (Titanosalpidae)
Habitat: cold subpolar waters of Southern hemisphere, circumantarctic species.
Primitive chordates represent the original transitive group between invertebrates
and vertebrates. There is an opinion, that vertebrate animals had descended
as the result of loss of adult stage by larva of lower chordates (this phenomenon
is named pedomorphosis). Adult individuals of lower chordates may appreciably
differ from larvae of the same species, and during the life cycle two completely
unlike against each other generations may be replaced.
Lower chordates of Tunicata subtype are very similar to jellyfishes and their
relatives – at them there is the same transparent body, which significant part
is made of water. But this similarity is only external – tunicates essentially
differ from jellyfishes by features of structure and development.
Pelagic tunicates are active filtrating organisms passing through the body
hundreds of litres of water per day. During the extinction of cetaceans and
large sea fishes, in crisis epoch at the boundary of Holocene and Neocene,
these invertebrates had got the advantage in impoverished ecosystems of open
ocean. Primarily among them many large species of filtrating organisms evolved.
But the majority of them had become extinct later, when in seas true pelagic
fishes had appeared again. But nevertheless some species of giant tunicates
had survived in subpolar areas, rich in plankton.
Whale salpa is one of such huge species of solitary tunicates, a relict of
early Neocene. It represents an animal up to 4 meters long at deep of body
about 2 meters and width a little bit more one meter. By its appearance whale
salpa resembles more the case of ancient sailing ship without masts: its sides
are slightly compressed, bottom part of animal is extended, and on it gristle-like
“keel”, helping to keep stability, is developed. The consistence of body of
whale salpa is rather fragile, and covers are translucent; therefore animal
seems made of glass. Ring muscles constantly and rhythmically contracting,
passing water through the body of animal, are visible through covers of body.
Such large animal could not survive, not having even any similarity of skeleton.
At whale salpa the half rings of dense tissue, covering body from sides, develop.
From above they are strapped with easily extensible ligament, and the bottom
ends of these formations merge with keel.
Due to rather fragile body consistence for this animal ability to feel approach
of storm is vital. Long before approach of bad weather whale salpa submerses
to depth and motionlessly hangs in thickness of water. This animal is the sluggish
swimmer, and its covers are frequently injured by various animals. But whale
salpa, similarly to the majority of relatives, can easily repair injured by
storm or predators parts of a body. The surface of tunica of this species is
overgrown with small symbiotic polyps. They slow down movement of whale salpa
in water, and partly compete to it for forage, overtaking a part of plankton,
but there is a considerable benefit to whale salpa from such union: polyps
protect animal from enemies with the help of burning tentacles. Some pelagic
fishes and invertebrates lay eggs on covers of body of animal, because of what
old individuals of whale salpa turn to true swimming “kindergarten”. In oral
siphon of whale salpa small crustaceans – symbiotic scuds – frequently lodge;
in cloacal siphon parasitic isopods frequently live.
As at all tunicates, at whale salpa there is an alternation of generations
in life cycle. Single individuals of whale salpa represent sexless generation
hatching from eggs. These giants reach the maximal size approximately for two
years, and after the attainment of full physiological maturity make the colonial
generation sharply distinguishing from single individuals externally. On the
bottom side of body of whale salpa, on front edge of keel the runner develops
– the outgrowth on which the colonial generation of this species is formed.
On runner some whorls of gemmas are formed, from which young individuals of
sexual generation develop. The young growth is formed and matures in “clusters”
of 2 – 3 pulled together whorls of 6 – 8 individuals in every one. Runner reaches
the length about one meter. When young individuals on its tip reach the size
of plums, runner is broken off right above them, and young ones swim out from
adult individual. Within several months they reach the length about 20 cm (the
length of colony of such individuals may be up to half meter), and become able
to breeding. The colony of sexual generation of whale salps makes up to 20
large eggs per one week. In the common cavity of colony eggs develop, and already
generated young individuals up to 15 cm long, the single sexless generation,
leave the colony. They grow to giants which have determined the name of this
species of animals.
Whale salps reach the utmost size in cold, rich in plankton waters of Subantarctic
region. Sometimes currents flowing to the north along the coast of Antarctica
and South America, carry away individuals of this species in tropical latitudes.
In warm water this animal does not breed and lives not for a long time. In
tropical latitudes whale salpa quickly grows old, but even faster it becomes
prey of heat-loving pelagic predators. More often these salps are eaten by
huge bat turtles.
Insects
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Stinky cave cockroach (Cavernoblattula foetida)
Order: Cockroaches (Blattoidea)
Family: Cockroaches (Blattidae)
Habitat: caves of the Balkan and the Alpes.
Cockroaches existed always and everywhere, up to times of dinosaurs – having
appeared on the Earth in Carboniferous, they strongly kept their place in ecosystems
of all subsequent geological epoch. They always rustled under legs of larger
creatures, eating various organic dust and dross. Before human epoch cockroaches
prospered in areas of warm climate, and only few small species had penetrated
far to the north. Expansion of communication and trade since Middle Ages has
allowed to cockroaches of some species to expand considerably the area and
to settle almost on global scale.
Despite of it, synanthropic cockroaches had not become rather hardy insects,
and at the extinction of people as a biological species cockroaches had receded
from temperate warm and cold areas too. Nevertheless, Holocene epoch and human
domination had not passed without results for cockroaches: they managed to
stay at the south of Europe, having evolved to some specialized species. In
caves of the Balkan formed after receding of glaciers, some underground species
had appeared, one of which is stinky cave cockroach. Its ancestor was, obviously,
oriental cockroach (Blatta orientalis) – the species widely settled in human
epoch.
Stinky cave cockroach is rather sizable insect: sometimes there are individuals
of this species up to 6 centimeters long. It has flattened oval body of brown,
black, or grey colouring, covered with oily liquid, plentifully secreting by
special gland. Regularly secreting a small amount of liquid, this cockroach
pounds it on the top part of body by back pair of legs. Oily liquid is its
most important protection, especially if the cockroach can not be escaped from
the enemy by another way. This liquid smells very unpleasantly and has bad
taste; the scared insect secrets it in plenty. Therefore the majority of rather
large predators living in caves prefers not to eat cockroaches. And from small
enemies the disturbed cockroaches usually seek safety in flight – they run
quickly and dexterously swarm up walls of cave. Stinky cave cockroach does
not have wings. Sight sense at adult insects is very bad, but young cockroaches
have well advanced large eyes, which are reduced with each subsequent moult.
But instead of them long antennas develop, which exceed body length at adult
insect.
This is unpretentious insect developed a special way of surviving in winter
colds – when winter comes, cockroaches are dug in layer of bird and bat guano,
and run into anabiosis till spring. It has allowed them to settle in systems
of caves far to the north – to the area of seasonal climate. In caves of the
Balkan located in area of rather warm climate, these insects keep activity
the year round.
Cave cockroaches can not dispense for a long time without water – it is used
for secretion of liquid covering their body. Therefore they should run out
from cave at night to drink from pools, if the rain took place recently, or,
on the contrary, to go down to the depth of cave, if there is an underground
reservoir there.
Stinky cave cockroaches are not fussy – they are ready to eat any organic material,
including each other. Usually they eat dung of bats, small worms eating dung,
sprouts of seeds belched by birds nesting in cave, and dead animals of any
species.
Some times per one year the female lays up to 20 eggs made in special capsule,
an ootheca, and carries them on its abdomen till about two weeks. Then it leaves
an ootheca in secluded place where young cockroaches leave it one week later.
In northern parts of area this cockroach makes no more than two clutches per
one year. Development from the bursting from egg up to adult individual lasts
about three months. The majority of cave cockroaches perishes in youth, when
they yet have not reached the size of adults, and their chitinous covers is
much softer. They produce less amount of odorous liquid, and rely more in their
self-protection to speed of legs; the main enemies of cockroaches are other
cave insects, like beetles and soothsayers.
Young cockroaches settle from caves, creeping out to the forest. But they frequently
use “services” of birds and bats living in their native cave. Clinging to their
body, young stinky cockroaches have an opportunity to appear in other cave.
Sometimes they appear in forest, and can live any time like usual cockroaches
living there. But they search by smell for entrances in caves and cracks, and
occupy them.
This species of insects was discovered by Bhut, the forum member.
Bromeliad dragonfly (Hyleoanax bromeliophilus)
Order: Dragonflies (Odonata)
Family: Aeshnidae (Aeshnidae)
Habitat: rainforests of South America, forest canopy.
The rainforest of northern part of South America forms unite with huge river
system – basin of Amazon and Hyppolite rivers. It is the largest forest area
of the Neocene Earth. Overflowing banks, rivers flood forest over tens kilometers
in sides from channel, and water level changes may reach ten meters and more.
This circumstance favours to passing to life in forest of some aquatic lifeforms.
Plants of bromeliad family (Bromeliaceae) represent the original “advanced
post” of water animals in forest canopy. These epiphytic plants form special
mini-reservoirs of their leaves. Leaves may be curved like a spoon and then
in each of them the tiny reservoir is formed. Or densely pressed to each other
leaves form one reservoir in the centre of the crown. These reservoirs in forest
canopy are full of life. Frogs and other small animals live in them, and also
in full safety from fishes mosquitoes breed.
In Neocene among inhabitants of similar reservoirs one more creature had appeared
– it is a large larva of dragonfly. It is flat-bodied with short wide abdomen
and strong tenacious legs. Green colouring permits the larva to hide from sights
of various predators – usually birds or predatory insects are its enemies.
The length of larva reaches approximately 4 cm. This species of insects lives
exclusively in leaf axils of bromeliads and consequently is named bromeliad
dragonfly. In such reservoirs larva avoids the dangers usual for its relatives
in river. The larva of bromeliad dragonfly is protected from beaks of birds
by its habitat. Mini-reservoir in leaf axil of bromeliad is small, but too
deep. At danger larva simply moves down to the bottom of its dwelling.
Because many inhabitants of forest canopy are interested in presence of such
reservoirs, larva of bromeliad dragonfly does not endure lack of food. It basically
eats larvae of mosquitoes regularly laying eggs in water in bromeliad leaf
axils. Also this insect can eat tadpoles of tiny frogs and catches the insects
had casually got in water. At larvae of bromeliad dragonflies cannibalism is
usual.
When in mini-reservoir, where larva lives, food sources come to an end, it
can leave it. With the help of strong legs larva simply creeps into the next
leaf, and eats all animals living in it, including its own relatives.
Many insects live in forest canopy. Here various winged predators hunt them,
among which there is remarkable large (up to 9 cm long) dragonfly of metallic
red color with black cross stripes on wings. It is the adult bromeliad dragonfly.
It constantly lives in forest canopy and does not move down to the river. During
courtship displays large male keeps near thickets of bromeliad plants, driving
competitors away from them, and involving females to plants.
This insect lays eggs in crowns of bromeliad – some ones stuck in unite slimy
mass in each leaf. Clutches are small – no more than 20 eggs to one plant.
During the life one female lays eggs in leaves of several tens bromeliads.
The incubation lasts about one week, and eggs are left by transparent tiny
larvae. They are very active, and at once start to eat small animals. After
several molts, when they become larger, relations between larvae become aggravated,
and they start to devour each other. Some of them succeed to survive and to
creep to next reservoirs of bromeliads. After furious struggle for survival
in one plant one or two larvae of bromeliad dragonfly stay. At such density
of setting they normally grow and four – five months later pass metamorphosis
successfully.
Butterfly dragonfly (Papilianax multicolor)
Order: Dragonflies (Odonata)
Family: Butterfly dragonflies (Papiliopterygidae)
Habitat: Antarctica, fresh water.
Till millions years Antarctica was the continent absolutely lack of terrestrial
lifeforms. Last ice age at the boundary of Holocene and Neocene had completely
destroyed all forms of terrestrial life at this continent. When climate started
to change and warm currents from the north had warmed coasts of Antarctica,
the surface of continent had exempted from ice cover. The areas exempted
from ice gradually began to be settled. But isolation of continent had resulted
to the fact that only swimming and flying animals, and plants which seeds
could
be moved by wind, could settle there. Free ecological niches were distributed
among these animals by the most unexpected image.
Fresh waters of Antarctica belong to dragonflies. These insects gave surprising
variety of species – from small up to very large ones. Some dragonflies of
Antarctica surpass in size the largest dragonflies of Neocene tropics of
the Earth. And in Neocene among the Antarctic dragonflies one completely
unusual
species not having of analogues anywhere in the world, Antarctic butterfly
dragonfly, had evolved.
This species of dragonflies differs from the relatives living in the neighbourhood
in many respects. The butterfly dragonfly belongs to the number of damselflies
and differs in flitting flight and very thin prolonged body. It is the largest
species of damselflies of Neocene – the length of its body from head up to
the tip of abdomen amounts 15 cm at wingspan up to 25 cm. But the size is
not the most remarkable feature of this insect. When butterfly dragonfly
flies
above the swamp, it is very difficult for not noticing. This insect has motley
colouring of wings; they have soft blue color with black mesh pattern in
the basis, and on tips of wings there are oculate spots with iridescent play
of
colours from lilac up to pink. The flying butterfly dragonfly sparkles in
light of poor Antarctic sun like a brilliant. The body of this dragonfly
has strict
black color with golden cross stripes on each segment of abdomen. Such bright
colouring appreciable from apart permits individuals of this species to distinguish
each other. These dragonflies gather for pairing in flights numbering some
tens individuals. Adult dragonflies should hasten to find each other for
pairing – at this species of insects imago does not feed and lives only due
to stocks
of nutrients had been accumulated by larva. The maximal life expectancy of
adult dragonfly is no longer, than one week.
Time of the adult life given out to dragonfly passes very roughly. Males
actively compete to each other for the right to couple to the female, and
push each
other aside from it, arranging air maneuvers and actively displaying itself
to the female. As against to the male, female saves vital resources - at
the moment of male rivalry it perches on stalk of grass and waits for the
ending
of their duel. When the winner is defined, he clings to the body of female
and insects make courtship flight together. Having fertilized the female,
male protects her for some time, not admitting to her other males. Next day
after
fertilization, when in organism of the female eggs start development, male
lets her off and perishes soon.
For egg laying the female of butterfly dragonfly chooses coastal plants with
thick stalks rich in air-containing tissue. It immerses an abdomen in water
and makes vertical cuts on integumentary tissues of stalk by sharp ovipositor.
In each cut female places one egg, and can lay about 400 eggs in total. The
laying of eggs proceeds a very long time – about some hours. This process
exhausts the female so much, that it perishes soon after laying of last eggs,
and its
body becomes prey of water predators. Frequently the female perishes from
exhaustion, having not laid last portion of eggs.
The larva of butterfly dragonfly, as opposed to peaceful adult individual,
is gluttonous and ruthless predator. It lives in thickness of water, is a
good swimmer and has wide flattened body supplied by rounded outgrowths on
edges
of each segment. Branchial outgrowths on back end of abdomen are wide and
have leaf-shaped form. When larva moves in water with the help of vertical
waves
of body, they work as a tail fin. If it is necessary to swim slower, the
larva of butterfly dragonfly uses walking legs covered from two sides by
bristles
and acting like oars.
The larva of butterfly dragonfly eats various small animals. The young larva
eats larvae of two-winged flies, scraping them by its lower lip from substratum.
The larva of advanced age reached the length of 18 cm at width of body about
2 cm eats larvae of other species of dragonflies and attacks larger prey:
freshwater shrimps and small fishes. Frequently larvae of butterfly dragonflies
attack
the adult females of their own species laying eggs, or gather their dead
bodies from surface of water. The larva of this insect develops rather slowly,
and
spends under water five years before it will be ready to metamorphosis and
will turn to sparkling fragile insect.
Aquatic soothsayer (Dimorpomantis semiaquaticus)
Order: Soothsayers (Mantoidea)
Family: Soothsayers (Mantidae)
Habitat: China, cane thickets at riverbanks.
From the moment of the origin at Earth insects became one of prospering groups
of live creatures. Features of respiratory and blood system do not permit them
to grow up large size (to become larger, rather than crabs, for example), but
among tiny inhabitants of Earth insects are in the lead unconditionally. They
easily adapt to changes of environment and among them new species evolve very
quickly. At rather small morphological reorganization insects can develop new
habitats easily. One of such species had appeared in marshy plains of China.
In Neocene the climate began more humid, and the plain part of China represents
a circuit of rivers, lakes and swamps constantly changing the outlines. Winds
bring rains from Pacific Ocean, and in plains flooding often happen. And after
flooding the part of water inhabitants may be trapped in shallow ponds drying
up quickly. In such conditions inhabitants of water environment develop adaptations
for life on land, and ground inhabitants study to develop water.
As a rule, soothsayers, insects having very ancient origin, were inhabitants
of woods and dry habitats. But in swamps of China one species of these insects
till the evolution process had got ability to live in water, at least, half.
Among water insects water bugs and beetles are very characteristic. These creatures
differ in predating behavior and eat any animals they can catch. For prey catching
modified front legs working as claws serve to bugs. These insects spend life
in thickness of water, regularly emerging to the surface for the portion of
air. In comparison with them aquatic soothsayer looks “amateur”, but its habit
of existence has the certain grace.
Aquatic soothsayer is completely not able to swim. Nevertheless this insect
is not less successful hunter, rather than armed and quickly swimming water
bugs. Aquatic soothsayer applies traditional tactics of the ambuscader for
hunting. This insect simply sits among water plants upwards an abdomen, having
immersed the forward part of body in water. Thus respiratory apertures of insect
remain above water, and soothsayer does not risk sinking.
Because aquatic soothsayer actually lives simultaneously in two environments,
in air and in water, it seems made of two halves of completely different insects.
This feature has determined the generic name of this insect – Dimorphomantis,
“the soothsayer of two shapes”. The length of this creature exceeds 15 cm:
it is rather large species of soothsayers though its larger congeners live
in tropical rainforests.
Forward part of body of the aquatic soothsayer is colored yellowish, very much
lengthened and thin. It makes approximately two thirds of general length of
insect. Forward pair of legs of aquatic soothsayer is well advanced and very
strong. Segments of forward legs are expanded and also resemble a pair of leaves
growing on thin stem. From outside they are colored bright green, and their
internal surface is grayish-white. Head of this insect is flat and triangular;
spherical eyes are very big. It is very mobile, and eyes provide the full circular
field of view. Aquatic soothsayer catches prey using sight and chemical feeling.
Usually it perches motionlessly at the surface of water, waiting while catch
of suitable size will swim up to it closely enough. This soothsayer catches
fry of fishes and various water insects. Sharp thorns on internal surface of
legs permit it to kill even dangerous insect like water bug quickly.
Abdomen of aquatic soothsayer, on the contrary, is wide and flat. It imitates
leaves of marsh plant sticking up from water rather good. Wings folded on back
and having pattern of light nerves on green background strengthen the accuracy
of this imitation. Walking legs at this insect have usual for soothsayer structure,
but are only more tenacious. Aquatic soothsayer frequently masks among water
plants, having perched on the bottom side of leaf. So it becomes invisible
to predators from air, and protective colouring masks insect from sights of
underwater predators. Wings of aquatic soothsayer are very short, and this
insect can not fly. But even if wings would be advanced enough, the structure
of body would not permit this insect to fly up. Therefore wings of aquatic
soothsayer had lost initial function of flight, and serve for masking. At males
second pair of wings has bright strips and spots – bases of wings have small
brown spots on yellow background, edge of wing is bright yellow. Opening wings
and flapping them, male shows to the female readiness for pairing. Also the
male of aquatic soothsayer is “musical”: calling the female, it rubs jags on
forward pair of legs against each other. The sound is well audible in water,
and the ear at soothsayers is located between forward legs. Therefore female
reached the maturity and ready to breeding hears courtship calls of the male
well. It answers them with short clicks even more stimulating “musical” abilities
of the male.
Similarly to all soothsayers, aquatic soothsayer breeds once in life. During
the pairing female devours the male. The stock of sperm received by it till
the pairing is sufficient to make some clutches. Female lays among reed few
ootecas (clutches packed into common dense environment), and then quickly perishes
of the exhaustion.
Approximately after 8 – 10 days from eggs larvae very similar to adult insects,
but wingless, burst. Young growth of aquatic soothsayer is also connected to
water in life, but it occurs differently, rather than at adult individuals.
Young aquatic soothsayers are very tiny; therefore it is difficult for them
to break through the surface tension film. But it not the obstacle for them:
larvae of aquatic soothsayer settle on surface film of water and live in places
protected of wind. Aquatic soothsayers settled in other reservoirs mainly at
the larval stage, often migrating on floating plants. Adult insects lead settled
life.
Larvae have hairs on tips of walking legs with which help they keep on surface
tension film. Hairs are covered with wax-like substance that makes them hydrophobous.
This substance is emitted from glands on the tip of abdomen, and insect not
occupied with hunting serially greases legs with it. Thill first days of life
young aquatic soothsayers catch springtails (Collembola) living on water surface,
then start to gather small insects fallen in water. Water bugs become catch
of larvae of advanced age. Gradually growing up larvae start to hunt fish fry
hiding among water plants, applying the same mode, as adult insects.
At later stages of development (after the penultimate moult) young insects
start exclusively underwater hunt. At this time wax gland starts to produce
much larger amount of wax, and insect starts to grease with it an abdomen.
Such feature of behavior helps to immerse in water deeper in searches of catch,
and rescues when the insect casually falls in water – in this case aquatic
soothsayer has some minutes to get out of water.
The aquatic soothsayer is successfully protected from predatory fishes, striking
impacts by spiny forward legs. In ponds of China it has the dexterous imitator
– one local frog species.
Super-longest archobaculum (Archobaculum prelongissimus)
Order: Walking sticks (Phasmoptera)
Family: Baculids (Baculidae)
Habitat: rainforests of Meganesia, a forest canopy.
In the world of insects it is difficult to be a giant. Insects have certain
features of physiology which impose essential restrictions to opportunities
of size increasing. Those ones are tracheal respiring and loss of ability to
transfer oxygen by blood (hemolymph). Therefore even largest species of insects,
living in atmosphere with low contents of oxygen, can not become giants. Epoch
of Carboniferous with the high contents of oxygen in air and absence of competition
to flying vertebrates gone irrevocably. Therefore in Neocene the largest species
of insects all the same have small weight and represent the unique phenomenon
among small relatives. Walking stick species super-longest archobaculum, living
in tropical forests of Meganesia, evidently shows the restrictions connected
to body weight. This is one of the largest insects of Neocene: the length of
its body reaches 40 centimeters. But thus its thickness does not exceed 15
mm. This giant has lost ability to fly, and its wings are strongly decreased
in size; at the female of this insect wings are completely reduced.
Archobaculum is, in fact, the huge variant of small walking sticks. Its body
has cylindrical form, and head is short and almost spherical, with short antennas.
Legs of this insect are very long and thin – they are only a little shorter
than the body. The grayish-colored body of archobaculum with knobs and dark
spots imitates tree bark texture. On head and thoracal segments knobs are numerous,
and covers of abdomen are smoother. Only on terminal segment of abdomen there
are some small outgrowths helping to male and female to fix stronger during
the copulation.
At archobaculum sexual dimorphism is well expressed. Males of this insect are
smaller and more movable, rather than females – their maximal length is no
more 30 centimeters. Male also differs from the female in presence of the small
outgrowths, imitating parts of leaf almost completely eaten by caterpillars,
on shins of forward pair of legs. These sites of body are dark green with bright
green longitudinal line on shin imitating middle nerve of leaf. This adaptation
serves for courtship combat – males push each other away from the female by
front pair of legs. Demonstrating itself to the female, male displays to it
courtship ritual: it spreads legs of front pair and opens bright reduced wings
of back pair – they are yellow with black border and several spots at the root.
These wings can not lift this insect in air, and are used only for courtship
display. In rest they are covered, as if by covers, by narrow front wings.
This species is almost defenseless to predators. A plenty of young ones perishes
from small insectivorous birds, larger individuals are eaten by reptiles and
mammals. The basic protection of super-longest archobaculum is the protective
similarity to branch of tree. Having felt danger, insect clings to branch and
extends forward front pair of legs pressed together. Thus the walking stick
seems the continuation of branch. The disturbed insect emits unpleasant smell,
but can not give even any repulse to predator at all.
Males of super-longest archobaculum meet less often, than females, but such
disproportion does not interfere with breeding of insects. At absence of males
females simply lay parthenogenetic eggs from which normal viable young ones
hatch – but only females do. On some islands this species of insects is presented
only by females.
The success of this species in settling is caused by two important features
of these insects. First, super-longest archobaculum is herbivorous species
consuming wide spectrum of vegetative food. At other species of walking sticks
the number of fodder plants species may be strongly limited, and it interferes
with their settling.
The second component of success of this insect is the feature of eggs structure.
The majority of walking sticks lays eggs with dense dry shell, which fall on
the ground and can rest during very long time. The female of super-longest
archobaculum lays eggs on the bottom side of leaves with the help of mobile
tip of abdomen. The egg of this insect is placed on long threadlike stem and
has shell sticky because of slime not drying up for a long time. It endures
gusts, but is easily pasted to feathers of birds and wool of mammals. Vertebrate
animals have considerably larger abilities to settling, than these insects,
therefore due to their “services” super-longest archobaculum is very widely
settled in rainforests of Meganesia. Besides if the egg will fall on the ground
from forest canopy, it will be very difficult for larva bursting from it to
rise back to forest canopy to find fodder plants. Eggs at the female of super-longest
archobaculum are produced, as if on the conveyor. It can lay no more than 15
– 20 eggs per day, but keeps such daily fertility during the whole adult life
(after last moult).
Larvae of super-longest archobaculum differ from adult individuals only in
smaller size and smoother body. Outgrowths and knobs characteristic for adult
insect appear at them only after penultimate moult. Development of the larva
proceeds till about 15 months, and life expectancy of adult insect seldom exceeds
half-year.
Saw-legged
dragon grasshopper (Serratipodus dracocephalus)
Order: Orthopters (Orthoptera)
Family: “Awful grasshoppers” (Horrodecticidae)
Habitat: woods at the islands of Pacific Ocean.
Islands are fairly named as “hearth of evolution”. Here there is a fastest
rate of new species formation, and here life gets the most fantastical forms.
As a rule, at the islands never been a part of continent, the fauna consists
of species able to flight, or lost this ability already after island settling.
At islands there are no representatives of many groups of animals and plants,
characteristic for continents. And at islands there are many free ecological
niches which sometimes are occupied with species completely unexpected in this
role. At islands of Pacific Ocean the place of small predators was occupied
with the huge representative of insects - the distant relative of common grasshoppers,
the saw-legged dragon grasshopper.
On contrary to popular belief, the significant part of grasshoppers is predators
(and herbivorous locusts belong to other family). The saw-legged dragon grasshopper
is the huge representative of grasshoppers: the length of its body reaches
20 cm, and because of long antennae and wings he seems even larger. Among the
impoverished fauna of islands it occupies an ecological niche of small predators,
attacking large insects and small vertebrates - birds and rodents. This species
also eats carrion: after storm or during outflow saw-legged dragon grasshoppers
wander along ocean coast, eating dead sea animals or gathering inhabitants
of the ocean has got in pools at the coast.
Adaptation to predating is visible in appearance of insect: forward legs of
saw-legged grasshopper are very long (they are equal to back legs by length),
on their internal side there are sharp thorns: this is the adaptation for catch
seizing. Powerful mandibles of insect easily crush both armour of beetle, and
bones of small vertebrates. Frequently saw-legged dragon grasshopper swarms
up trees searching for bird nests: it equally willingly eats eggs and nestlings
of small species of birds.
Back legs of this insect as at the majority of representatives of order, are
rather long, but because of large weight this insect is not able to hop. But
this huge grasshopper swarms up trees well: on its paws tenacious claws, permitting
to heavy insect to cling to slightest jogs of bark, are advanced.
On large head of saw-legged dragon grasshopper there is a plenty of knobs and
outgrowths especially advanced at males. They give to this insects fantastical
appearance, and serve for tournament fights in breeding season. antennae of
saw-legged dragon grasshoppers are very long too: they are equal to body by
length. On thorax at males two bent horns are advanced sticking up upwards
and in sides.
Colouring of this insect quietly sitting on tree seems modest: body is gray-brown
with small black speckles. The brightest part of body of saw-legged dragon
grasshopper, the back pair of wings, at this moment is latent. But during courtship
duels or at caring for the female males open them, showing bright pattern:
black “grid” of nerves on yellow background; near the basement of wing there
is big red spot. Top wings of insect are reddish-brown with grey cross strips,
on edge nerves the sound device is advanced: a line of tiny denticles. During
chirring the insect rubs one wing against another, uttering sounds heard at
the distance of one hundred meters.
Despite of size, this insect is able to fly, and even can make distant flights
between islands, especially at good fair wind. Such way saw-legged dragon grasshoppers
had settled practically at all in slightest degree suitable for life islands
in tropical zone of Pacific Ocean. The unique limiting factor for them is the
presence of fresh water. But at small islands these insects find enough moisture
in puddles accumulating after rain in bases of palm leaf petioles.
These large insects can breed all the year round. The female differs from the
male with fuller abdomen, long saber-like ovipositor and pale colouring of
wings. Males find females ready to breeding by smell. During acquaintance male
creeps up to the female from the side of head, widely opening and planting
in sides bright wings. Thus it moves by antennae, touching by them to antennae
of the female. When the female reciprocates, male closes wings and starts to
chirr loudly, rubbing one wing against another. Thus it declares the rights
on the female. If near one female some males gather, they begin original “tournament”
in which the strongest one is displaying. Males up to the last moment avoid
to enter direct collision which can be finished by death of one of them, and
superiority is defined by loudness of chirring and brightness of coloring of
wings. Males start to chirr, to short time interrupting warbles with demonstration
of unwrapped wings. Weaker males at once leave a place of competitions, and
gradually near the female only one or two contenders stay. If it is impossible
to define the strongest one in the peace way, and not any male wish to concede,
between them fight is possible. Strong forward legs are in use, with which
contenders grip each other by bases of antennae and try to push aside from
the female. Fight is accompanied with menacing chirring and demonstration of
opened wings.
Pairing lasts not for long, then the male loses interest to the female and
crawls out. With the help of long ovipositor female places portion of two -
three tens large eggs in friable, well warmed up ground, and does not care
any more about them. For all life she can make up to ten clutches.
All orthopters are insects with incomplete metamorphosis: from eggs larvae
similar to an adult insect excluse. Young saw-legged dragon grasshoppers about
5 millimeters long eat different delicate insects - plant lice and tiny caterpillars.
At half-year age they grow up to the size of adult insect, and become able
to breeding. At the lack of forage they will turn to “scanty” ones with thin
long body and wide wings. Such individuals fly perfectly, and easily move from
island to another one searching of favorable conditions for life.
Scorpio earwig (Scorpiforficula cervicera)
Order: Dermapters (Dermaptera)
Family: Earwigs (Forficulidae)
Habitat: Balkan, southern and western coast of Fourseas.
Forests of temperate latitudes differ from tropical rainforests in presence
of thick layer of soil. In tropical forest soil layer is very thin, and under
it there is a layer of infertile mineral substratum. In forests of temperate
latitudes and subtropics ground layer is considerably thicker. Ground of these
forests is rich in various live beings which process dying off organic substance
to the condition easier absorbing by plants.
Among ground animals of temperate latitudes earwigs (order Dermaptera), the
insects changed externally a little from Paleozoic era, are characteristic.
Separate species of these insects had successfully survived till the ice age
at the boundary of Holocene and Neocene, and had given rise to several interesting
species of Neocene epoch. In subtropical forests of Balkan and coastal areas
of Fourseas there is one very large species of this group, the scorpio earwig.
The body length of scorpio earwig reaches 5 – 6 cm; it is the largest representative
of order in Neocene. This is heavy-built wingless insect with strong long legs
which is able to run quickly – escaping from the enemy, scorpio earwig accelerates
momentum up to 20 cm per one second.
Scorpio earwig looks very impressively – its covers have black color with faint
metal shine. This insect is not able to fly, and its wings had undergone the
reduction – the back pair of wings had vanished completely, and two small outgrowths
on thorax remain from forward wings. Cercuses at this insect are large, reddish-brown,
differing in shape at insects of different genders. At males they have the
additional outgrowth directed inside – hence the specific epithet meaning “deer-horned”.
At females cercuses are wider and lack an additional outgrowth. The difference
in cercuses shape is connected to their different role in life of insects of
different genders. Males use cercuses for courtship combat, and female hatches
posterity on them.
In human epoch at earwigs various forms of care of posterity were recorded.
Scorpio earwig is not exception here. It differs in strongly advanced parental
instinct and original care of posterity. The laying of this species totals
about fifty large eggs. It is covered with the common foamy environment which
dries up and forms a semblance of porous cocoon. Female constantly carries
clutch in cercuses, having bent them above head (at this moment it is similar
to scorpion, hence the name).
Common earwig (Forficula auricularia) which, most likely, was an ancestor of
this species, perished right after bursting of young ones and the posterity
ate remains of their own mother. The female of scorpio earwig does not perish
after the bursting of posterity, because before it had led almost habitual
way of life. It continues to carry the hatched young growth on back, and additionally
feeds young ones with belched semidigested food. For this reason the survival
rate of posterity of early age at this species is very high. During the feeding
of young growth female raises head upwards, and belches a part of food. Young
insects (similar externally to adult individual, but translucent) creep right
on its head and eat belched food.
Scorpio earwig is a predator. Its prey includes slugs and sot-bodied insects
(caterpillars and grubs). Also this insect eats carrion.
Rabbit earwig (Graciliforficula cuninculiphila)
Order: Dermapters (Dermaptera)
Family: Earwigs (Forficulidae)
Habitat: New Zealand, colonies of castle rabbit, caves.
Species of animals, widely settled at the Earth due to human activity, occupied
ecological niches in new ecosystems. Frequently it proceeded to the detriment
of local flora and fauna, but occasionally such process passed not so sharply.
After extinction of mankind species of animals and plants introduced to habitats
unusual for them began to evolve and to survive in equal conditions with
native species. Species got advantage because of ability to live in anthropogenous
landscape died out, as a rule. Other species adapted to life in natural environment
and became a part of new ecosystems.
In New Zealand common earwig (Forficula auricularia) was one of numerous
introduced species. Its descendants had adapted to life in forests of islands
and differ
from the ancestor a little, but one species had chosen absolutely special
inhabitancy.
For fauna of Neocene mammals of New Zealand castle rabbit is characteristic.
It is a social species of herbivorous mammals building strong and long-term
constructions in which all colony lives. Many species of invertebrates being
symbiotes, commensals and parasites of rabbits live in system of tunnels
and chambers of these animals. The descendant of common earwig living in
nest litter
is completely blind rabbit earwig.
This insect is perfectly adapted to life in warm and humid holes of rabbit,
but hardly can survive at the ground surface. Its covers are thin and soft,
as if at termite, colored yellowish-white, even translucent on the bottom
side of abdomen. The length of insect does not exceed 25 millimeters. A constitution
of this earwig is very fragile and delicate – it has long flexible body with
short legs, and thin cercuses bent on tips. Wings at rabbit earwig are reduced
– it never leaves rabbit holes and spends the whole life in litter of their
nests.
Head and cercuses are the firmest parts of body of this insect. Despite of
delicate constitution, rabbit earwig is an active predator. Its prey includes
various insects living temporarily or constantly in dwellings of rabbits.
More often flea larvae living in litter of nest fall prey of this insect,
but occasionally
rabbit earwig eats larvae of crickets and cockroaches.
For breeding this insect chooses burrows not visited by rabbits for a long
time. In friable walls of holes it digs a short tunnel ending by nest chamber.
In chamber the female of this earwig lays up to 50 eggs and protects them
right to bursting of young ones, having turned around of them. Frequently
females
of rabbit earwig form small colonies, arranging holes near each other. Larvae
and adult individuals at overpopulation of colony move in new habitats. For
this purpose they use “services” of castle rabbits – insects simply creep
in their wool.
This species of insects can live not only in colonies of castle rabbits.
Rabbit earwig can form small populations in caves populated by bats. In caves
they
hunt cockroaches and larvae of flies settling in dung of bats.
Vinegar ground beetle (Deinocarabus acetiferus)
Order: Beetles (Coleoptera)
Family: Ground beetles (Carabidae)
Habitat: Southwest Europe, North Africa, Atlas Mountains.
Insects are one of the most successful groups of terrestrial inhabitants. Features
of anatomy of respiratory system do not permit them to turn to large animals,
but in small-sized class they are out of competition among other groups of
terrestrial animals by variety and abilities to adaptation. Huge number of
populations, wide spectrum of variability and fast alternation of generations
successfully allow them to adapt to various changes of environment. Among insects
there are species having interesting adaptations for survival.
In Neocene strait of Gibraltar was closed for ever because of movement of Africa
to the north, and Mediterranean Sea had turned to circuit of salt lakes and
swamps with few islets of land. The western Europe and North Africa in Neocene
became unite land where rather dry climate dominates. On grasslands overgrown
with dry light forest, there is penetrating heat in summer, and the majority
of animals hide in shadow places, or at all pass to underground way of life.
However heat is not dangerous to insects, and they become even more active
when sun is almost in zenith.
Large predatory beetle, the vinegar ground beetle lives in grasslands of Western
Europe and North Africa. The length of this insect reaches 7 – 8 cm: it is
the largest representative of ground beetles living beyond the area of tropical
forests. Vinegar ground beetle is not able to fly (it is the common feature
of all ground beetles), but runs very quickly. Elytrums form strong armour
on its body, protecting insect from birds. However, the main protective adaptation
of this beetle is not armour. Colouring of insect is dark blue with metal shine.
Elytrums are covered with set of knobs forming longitudal lines. Prothorax
of vinegar ground beetle is smooth, with white oculate spots. Long legs of
insect strongly contrast with body colouring – they are bright red, covered
with shining shell. Such colouring is warning – vinegar ground beetle easily
defends from small predators belong to vertebrates.
Sight of vinegar ground beetle is good; eyes are large and spherical. Strong
mandibles of the beetle with sharp cutting edges can bite through even skin
of vertebrate animals, therefore vinegar ground beetle has very few enemies
among animals of size comparable to it. But its main protective adaptation
is the chemical weapon, able to stop an attack even of large predator. Ground
beetles of Holocene epoch differed in ability to emit caustic chemical substances
with unpleasant smell. Hit of liquid of large species on skin could cause painful
chemical burns in aggressor. Vinegar ground beetle has even more succeeded
in chemical war leading: it has transformed the poison inherited from ancestors
to offensive weapon. This insect can be dangerous to rodents and other inhabitants
of holes – the beetle emits poisonous easily evaporating substance having suffocating
action. This way vinegar ground beetle quickly kills small animals in closed
space of holes, where the ventilation is insufficient. Especially frequently
cubs of rodents and others burrowing animals become prey of vinegar ground
beetle. Secretions of the beetle strongly smell as vinegar – hence its name.
On the ground surface vinegar ground beetle also attacks small vertebrates
– frogs and small lizards. As the chemical weapon on ground surface influences
less effectively, vinegar ground beetle chases them. Also this beetle eats
large insects and spiders. Having killed prey large in comparison with itself,
beetle stays near to it while it starts to spoil. Thus the insect furiously
protects catch from congeners. If near dead animal two beetles of this species
meet, between them severe fight is fastened.
Holes of mammals are not only hunting territory, but also an incubator for
eggs of vinegar ground beetle. This insect lays eggs one by one and leaves
them slightly dug in top layer of ground inside the tunnels dug by rodents.
Fertility of the female makes up to 300 eggs for 6 – 7 months (imago of this
beetle lives so much time). In conditions of constant humidity and good aeration
eggs of vinegar ground beetle incubating successfully, and after 9 – 12 days
from them small worm-like larvae burst. They quickly dig in ground, and till
first some weeks of life eat ground invertebrates. Development of larvae of
vinegar ground beetle is delayed for two years. The larva of advanced age shortly
before metamorphosis is frightening creature in shining armour of black color,
up to 15 cm long, with advanced legs. It lives in friable ground where digs
a system of its own tunnels and hunts digging insects and their larvae. In
droughty districts larvae of vinegar ground beetles meet mainly under stones,
where ground is rather damp, or in deep layers of ground, in holes of mammals.
Larvae of vinegar ground beetle are creatures on which well-being the set of
animals in extensive territory in Western Europe and North Africa depends.
These creatures eat clutches of locusts dug in the ground, and thus adjust
number of these gluttonous orthopters.
Narrow-sided fur beetle (Pellibius compressipleurus)
Order Beetles (Coleoptera)
Family Leather-winged beetles (Cantaridididae)
Habitat: South America, moderate and cool areas, commensal at large animals.
Large species of animals are an extensive habitat for various parasites. On
each species the unique community of parasitic animal’s species (parasitocenosis)
is formed – some of their species are strict special for the present species
of large animals. Abundance of parasites involves various predators. Some of
them only incidentally meet on large parasitocenosis host animals, and others
spend on them at least all life. Usually these predators are insects though
among parasite hunters there are even bats living on body of obda – the huge
herbivorous animal of Eurasia. On groundsloth
rodents living in Neocene epoch
in Patagonia, the separate species of tiny
marsupial mammals lives. But the
original beetle – narrow-sided fur beetle – shares with this mammal places
of inhabiting. For quite explained reasons the doctor caenolestes does not
settle in feathering of large birds, but this beetle can live even there though
it obviously prefers for life mammal wool.
Narrow-sided fur beetle had not changed predating habits of representatives
of its family, but it hunts specific catch: mites, trichodecteses and other
parasites plentifully inhabiting wool of large mammals. Strong chewing jaws
permit this beetle easily crack even firm shells of mites.
The beetle is perfectly adapted to movement among hair – as at the flea, its
body is strongly compressed at sides, short and deep. Elytrums of the beetle
have the specific shape: they do not cover body from above, but cover it from
sides, adjoining along the bottom side of abdomen. Narrow-sided fur beetle
has not lost ability to fly. Moreover, this ability is vital for it – having
exterminated parasites on any animal, this beetle simply flies to another one.
In flight wide elytrums are stretched sideways, creating some elevating force
similarly to plane wings.
This species of beetles ise poisonous, as well as many representatives of its
family – in body of this insect the small amount of cantharid poison is accumulated.
Colouring of elytrums of the beetle is bright and warning: it is orange with
faltering longitudinal black strips. Usually birds or mammals do not search
this beetle specially, but can injure it, cleaning themselves. In case of danger
(for example when the animal is scratched or cleans wool by claws) the beetle
simply draws legs in and slips out from wool or feathers of the host on the
ground, and then flies up and returns to the body of the host.
At the fur beetle there are short tenacious legs, and this insect can quickly
run among wool or feathers of the host animal.
Eyes at this beetle are well advanced, because it leads an active habit of
life and can fly. With the help of sharp sense of smell the beetle easily finds
parasites sitting on large animal among wool. antennae of this beetle are feather-like
(it is an attribute of well advanced sense of smell) and short. When the beetle
creeps on body of the host animal, they are wrapped and hided under head.
This beetle lives in conditions of seasonal climate. It spends winter in shelters
on the ground, but in northern (warmer) parts of the area it occasionally spends
winter on animals.
Fertility of narrow-sided fur beetle is not so big: the female lays for all
life no more than thousand eggs in small fine portions. It pastes eggs one
by one on covers of the host animal. The larva bursts in one week. It develops
right on the body of host animal within approximately two months (larvae bursted
later, spend winter on the body of host animal). Larva is active, worm-looking,
with well advanced legs. Covers of its body are rather soft, but head capsule
is firm, and mandibles are well advanced. It also is a predator and attacks
parasitic and blood-sucking insects. While the larva is small, it feeds with
mortifying particles of host animal skin. Larva pupates in ground. Duration
of metamorphosis is about two weeks.
Menthol
leaf beetle (Menthodoromela chemica)
Order: Beetles (Coleoptera)
Family: Leaf beetles (Chrysomelidae)
Habitat: Southern and South-Eastern Asia, thickets of mint tree.
At each species of plants numerous species of animals feed. Sometimes the plant
protects itself from numerous eaters, accumulating in leaves and stalks various
chemical substances frightening off the majority of herbivores. But evolution
develops the absolute weapon seldom: for some animals chemical protection of
plants is not a problem, and due to the adaptation produced by plant, they
practically lose competitors.
Among shades of greenery of tropical rainforests silvery “caps” of crones of mint
tree (Menthoxylon leucophyllum) are remarkable. This plant accumulates
in foliage plenty of menthol giving to greenery of plant characteristic smack.
But not all insects bypass its foliage. Many leaves of this tree are perforated
by holes, and their edges are gnawed.
Originators of damages openly feed on leaves of tree. They are big-bellied
beetles of emerald-green color about 1 cm long. At them there are thin short
antennae and tenacious legs. They lazily creep on branch, or motionlessly sit
on leaves, gnawing their edges. Near to adult insects larvae feed. They gnaw
soft pulp of leaves, leaving from them only net of nerves. It is menthol leaf
beetle - one of few insects eating leaves of mint tree.
By the habit of life these beetles differ only a little from other leaf beetles.
But in connection with specific diet at this insect the special protective
adaptation has appeared. For protection against enemies many insects accumulate
various liquids having unpleasant taste. Menthol leaf beetle is not exception
here. But it has ability to accumulate in special glands menthol from plant,
and adds it in pungent liquid secreting for protection. The principle of action
of the chemical weapon of this beetle is, that menthol irritates flavoring
receptors of predator and by that strengthens action of poison.
Menthol leaf beetles lay eggs on bottom side of leaves where they will not
dry up right in the sun. Larvae in first days of life keep on the bottom side
of leaves, then creep to top one. They are light green, but through translucent
cuticle interior and intestines, filled with chewed greenery are visible. Development
of larvae proceeds about one month. For one year the menthol leaf beetle can
produce up to 4 generations.
Shepherd beetle (Dolichocurculio pastor)
Order: Beetles (Coleoptera)
Family: True weevils (Curculionidae)
Habitat: Mediterranean deserts, plants of leafless
paunchstem invaded by water-bearing
plant louse.
Symbiosis is very favourable life strategy: mutually helping to each other,
representatives of different species get ability to survive in extreme conditions
and to form productive communities. Examples of this benefit are represented,
accordingly, by lichens and coral polyps. Besides them, in nature there is
a set of other species of live beings forming symbiotic connections and receiving
success in survival due to it.
In desert at the edge of ultrahaline Mediterranean swamps sources of food are
poor, but some species find an opportunity for specialization and exist due
to it successfully even in extreme conditions. Among plants of this area there
are many succulents reliably protecting stocks of water from herbivores with
the help of poisons. One of these plants is leafless paunchstem, a succulent
umbellate plant with thick leafless stalks. This plant is a habitat of various
species of invertebrates. One of inhabitants of this plant is a large species
of weevil beetles about 3 cm long, named shepherd beetle. This insect has ash-grey
color with black legs and bottom part of body.
Adult insect of this species is omnivore. Shepherd beetle feeds on nectar of
paunchstem, which is plentifully secreting at the inflorescences, but receives
additional protein food, eating various small insects flying to inflorescences
of paunchstem. The plant does not receive from its presence of any benefit,
but there is one species of insects, for which the union with shepherd beetle
has a vital importance.
In desert water is a biggest value for animals. Sap of paunchstem contains
a plenty of alkaloids and is not suitable for drinking almost for all species
of animals, except for small species of sucking insects, the water-bearing
plant louse. In colonies of this plant louse shepherd beetle has found a plentiful
source of drinking water. Each individual of plant louse from time to time
secrets a drop of almost clean water not containing poisons and suitable for
drinking. With the help of head extended as a proboscis this beetle easily
gathers water in colony of plant lice, and due to it survives in hot desert.
The head of shepherd beetle is extended to very long proboscis exceeding in
length thorax and abdomen in total. The proboscis is arc-like bent from top
to bottom, the mouth and short antennae are located on its tip. On the top
part of proboscis two or three pairs of acute spikes develop, sticking upwards
and in sides. Neck of this insect is very mobile. Due to its movements head
may be turned in under body and be curved forward by sharp movement – this
way beetle strikes a blow by proboscis, armed with spikes. By such impacts
of proboscis shepherd beetle drives away from plant lice of large insects which
can injure them – predatory beetles, solitary wasps and grasshoppers. However,
at food shortage it also can eat a small amount of water-bearing plant lice
from preserving colony. But this casual damage is not comparable with the benefit,
brought by this beetle to colonies of water-bearing lice, preserving them from
enemies.
Legs of this beetle are very long – they are longer than a body of insect.
Usually shepherd beetle cautiously walks in colony of plant lice, gathering
liquid secreted by them. By short antennae and tentacles of lower lip this
beetle tickles plant lice, and licks off their secretions.
It is able to fly, but makes it reluctantly and flies slowly because of massive
head. Shepherd beetle flies at night and in the morning, while birds have not
woken up. Being attacked by bird it folds wings or turns in legs, and falls
on the ground, and then is hidden in cracks of ground under the plant.
When paunchstem plants begin blossoming, beetles move to their inflorescences
and eat nectar. Inflorescences of paunchstem, reaching one meter in diameter,
serve as a place of meeting of beetles of opposite sexes, and also as arena
for determine of relations between contender males.
Fertilized female of shepherd beetle searches for egg laying for absolutely
other species of plants – roots of paunchstem contain not less alkaloids, rather
than its overground part, and larvae of this species do not eat them. Due to
keen sense of smell the female of shepherd beetle searches for tubers of other
deserted plants, located deeply in ground. It is dug in the ground above the
tuber, and at the ground surface only a part of proboscis is visible. Having
extended an abdomen, the beetle female lays eggs in ground as deep, as possible,
and as close, as possible to the surface of tuber. The larva bursts from eggs
and at once searches by smell for a tuber of fodder plant. It gnaws through
the tuber and develops in its pulp during dry season. The larva keeps activity
in winter – it is necessary to have time to pass the metamorphosis. The next
year in spring it leaves tuber and pupates in the top layer of ground near
to sprouts of fodder plant. Within one month it turns to adult beetle and flies
out to search for fodder plant. Adult shepherd beetles perish at the end of
an autumn.
Bird-eating
wasp (Ornithosphex ornithophagus)
Order: Hymenoptera (Hymenoptera)
Family: Digger wasps (Sphecidae)
Habitat: Great Antigua, tropical forests.
During evolution solitary wasps had turned to extremely specialized predators
with complex behaviour. At these insects female specially prepares for the
posterity insects or other invertebrates of certain species – it paralyzes
them by sting, pulls to specially prepared nest and lays egg on the body of
prey. The larva of wasp devours the paralyzed prey alive, protected by nest.
In Neocene separate species of parasitic Hymenoptera had made original “breakthrough”
in development of parasitism. They passed to parasitizing on vertebrate animals.
In Southeast Asia doctor
wasp (Hygeiosphex antibioticus) lays eggs in hypoderm
of small mammals, and its larva develops in body of animal, releasing it from
other parasites. The species imitating it, the special kind of ichneumons,
killer wasp (Pseudohygeia
placebo), also attacks mammals. Its larva even breeds
parthenogenetically in host organism. At Great Antigua Island some kinds of
wasps parasitizing on vertebrates live. Frog-devouring
wasp (Batrachovespa batrachovora) infects tadpoles of local frogs, and develops for a long time
in body of animal, leaving it when host animal has undergone metamorphosis
and has settled on land. And one more species of wasps from Great Antigua had
passed to parasitism on birds independently of these species, and makes it
by very complex way.
Antiguan bird-eating wasp is rather large insect. Length of its body is about
35 mm. It differs in fragile and graceful constitution: it has a long thin
body, and short drop-like abdomen is located on long pedicle. The female of
bird-eating wasp is covered with velvety grey hairs, giving to its body silky
shine. The tip of abdomen at this insect is black and hairless, and has bright
metal shine. Male differs from female in smaller size and more expressed silvery
shine.
This wasp lays eggs in incubating eggs of medium-sized birds – pigeons, small
parrots, passerines and other forest birds. Wasp searches a clutch with the
help of sense of smell, and easily penetrates even into the spherical nests
or nests made in hollows. The ovipositor at this species of wasps is very strong;
it easily pierces egg-shell near the air chamber. During the egg laying special
glands produce substance, sticking on the spot an aperture from prick of sting
and thus the development of bird's egg is not broken. In egg of bird tiny larva
finds a developing bird embryo, creeps into its digestive path and sticks to
wall of intestines. Modified legs turned into suckers with small claws on edges
and semicircular sucker on the back end of body work as organs an attachment
at this one. The larva of bird-eating wasp feeds on blood of developing embryo.
Usually from the eggs, infected by this wasp, weaker nestling having more chances
to die hatches. If it happens, larva turns to active scavenger: in body of
dead nestling wasp larva starts to eat meat, growing up to size necessary for
further development much faster. If the nestling survives, the wasp larva continues
eating of its blood and grows slower. In this case development of larva lasts
till about six weeks. To the moment of preparation to metamorphosis it reaches
length of about 10 cm. The body of larva at this stage is very long and flat,
therefore bird in which body it parasitizes, continues rather normal existence.
The larva ready to metamorphosis leaves body of host bird over intestines,
and pupates in ground, in litter of nest of host bird, in forest litter or
in moss thickets.
Mole
wasp (Talposphex terrestris)
Order: Hymenoptera (Hymenoptera)
Family: Burrowing fossores (Terrasphecidae)
Habitat: Great Antigua, ground in rainforests.
During evolution the species can get advantage in struggle for existence, having
changed habit of life. As the stimulus to it the free ecological niche, or
the big competitiveness of the beginner in comparison with species, that occupied
this habitat earlier, can serve. At the island Great Antigua which separates
Atlantic Ocean and Caribbean Sea, one of species of solitary wasps has gone
such way of evolution. From the mobile flyer this insect has partly turned
to digging creature which does not see sunlight. The new species of insects,
the mole wasp, differs from neighbours by original habit of life: males look
as usual wasps, hide in various shelters in daytime, and fly at night; females
are not able to fly, burrow in ground and creep out to the surface only before
pairing.
Mole wasp is a small insect. The shape of male and female sharply differs in
connection with difference in way of life.
Length of body of the female is up to 3 cm. Body is lengthened, flexible, covered
with strong chitinous armour. Wide shovel-like head is the main instrument
of ground digging. Eyes of the female are small, hided in small holes on edges
of head and protected by “eyebrows” composed by bristles. The upper lip is
well advanced, serving for ground digging. Wings of the female have lost function
of flight – they are dense and skinny, covering body of insect similarly to
elytrums of beetle. On edges of wings small hooks grow, due to which wings
are densely linked with each other. All legs of the female are rather short,
with wide paws. The forward pair of legs is supplied with small thorns on edge
– the wasp loosens ground by them, burrowing and repairing holes.
Male strongly differs from the female: it is a long-legged wasp about the same
size, but of more graceful constitution with short rounded abdomen sitting
on long stem. At it there is mobile head with sensitive feather-like antennae
and big eyes. At the male there is very keen sense of smell – its success in
breeding depends on how soon it will find out the female and will couple with
her. The body of the male is colored black with violet metal shine. Wings of
male are narrow and translucent, with black basic nerves.
Male and female eat different kinds of food: male sucks nectar of colors and
wood sap flowing down from damaged bark, and female is a predator. Her catch
is small digging insects and their larvae, and also small soil worms.
This species of wasps is parasite of invertebrates. Usually single wasps lay
eggs on caterpillars of butterflies and other insects living openly, and also
on spiders. Frequently they paralyze prey by poison, and larva simply eats
alive “canned food”, reserved in nest. Mole wasp avoids competition to them
due to that its larvae develop in completely other species of invertebrates.
This species of wasps parasitizes on earthworms and other digging invertebrates
– larvae of cicadas and beetles, root scale insects and other sedentary insects.
For pairing at night female creeps out on ground surface and hides under leaves.
She involves males with smell which is emitting out from the special gland.
Having felt it, male starts to run on leaves, as if a police dog, trying to
find its source. Having found out the female, he rakes leaves above her, quickly
fertilizes her and departs for searches of new females.
Fertilized female digs in the ground. One pairing is enough for her to lay
normal eggs all next life. The female of mole wasp moves under ground in its
own tunnels, but more often it uses burrows dug by its potential prey – worms
and other insects.
For egg laying the female searches by smell holes have been dug by suitable
species of animals. This species has some ecological races preferring for development
different species of host animal: some races prefer worms, others like larvae
of beetles, third race is not so legible in choice of host insect. The form
parasitizing on cicadas is especially rare: it is connected with the circumstance
that at some cicadas there is very long term of development (much longer, than
at the wasp), and their larvae meet not so frequently as at other species.
Having found prey, the female wasp chases it and gets to it’s back. Supporting
against ceiling of hole, it presses prey to the ground and deprives with an
opportunity to move, then wasp puts to it sting, laying egg in body of chosen
animal. Larvae of insects and worms on which this species parasitizes, in some
cases many times over surpass the adult mole wasp in weight. In some hours
from eggs thin translucent larva bursts immediately starting to eat from within
their alive cradle. Sooner or later it puts to the host animal damages incompatible
to life. Worms on which the wasp parasitizes, are in best condition, rather
than insects - they even can tear itself half-and-half and to be released in
such a way from the parasite, and regenerate after that. After destruction
of the host animal larva very quickly eats everything, that it is possible
to have eaten, and pupates under protection of remains of the had eaten animal.
For all adult life (approximately 2 months) the female can lay up to 20 - 30
eggs.
If the larva turns to male, difficult travel upward to ground surface is necessary
to it. Many males can not make it and perish. But it is quite enough the number
of survived males to fertilize females. Female right after emerging appears
in native habitat. It eats various soil animals for some days, accumulating
in body the fat necessary for formation of eggs. Only after that at hot tropical
night it digs burrow to the ground surface, and waits for the male.
Snail
diving wasp (Aquavespilla helicivora)
Order: Hymenoptera (Hymenoptera)
Family: Diving wasps (Aquavespidae)
Habitat: rivers and lakes of South America.
South America of Neocene epoch, as well as in human epoch, has an extensive
circuit of rivers and lakes. The huge river of the past, Amazon, had divided
to two rivers flowing almost in parallel each other, but their basins nevertheless
remain biggest ones in the world. For inhabitants of these places it appears
very favorable to adapt to life in water: here it is possible to find a lot
of food, and the competition is sometimes lower, than on land or in wood crones.
Therefore in rivers of Amazon region it is possible to meet representatives
of various groups of animals, at times of rather unexpected ones.
In shallow, but rather wide forest river, which banks are overgrown with set
of plants, it is possible to see small insects sitting on leaves above water.
Their bodies are colored grey; therefore such insect is clearly visible at
the background of green and reddish leaves. Being frightened off, insect immediately
jumps off in water, turning as if in quicksilver ball, and quickly swims between
plants and driftwood. In some minutes it emerges to the surface of water, clings
to petiole of leaves, and stops for some time. Having convinced, that danger
has passed, this insect creeps on leaves and then it can be distinguished in
full details.
It is obviously not the beetle: it does not have characteristic smooth elytrums.
Narrow “waist” indicates that it is not a fly. This insect is snail diving
wasp, the fossore, the representative of Hymenoptera. In New World these insects
have adapted to aquatic life, having formed the separate family which has reached
certain success.
Length of body of this insect is about 2 cm. The body has features of adaptation
to swimming: it is short and rounded. Abdominal stem at this species is rather
short and thick. Colouring of body is metallic – grey; wings are transparent.
Legs of snail diving wasp also are adapted to aquatic way of life. Two forward
pairs of legs have kept the universality, but the hind pair became larger;
shin and last segments on it are flat and wide, forming oar-like structure.
The main adaptation to aquatic way of life is at the surface of body of this
insect: the wasp is covered with water-repellent hairs, and glands on abdomen
secret paste-like wax substance. Under water this wasp is similar to water
spider (Argyroneta): due to hairs and greasing its body is surrounded with
layer of air; that’s why the body of insect seems silvery, as if quicksilver.
Only rowing hinder pair of legs juts out from air bubble.
The unusual habit of life of the diving wasp is connected with the special
circumstance: this species of hymenopters parasitizes on numerous snails inhabiting
rivers and bogs of Amazon region. Wasp searches under water snails by smell,
feeling by antennae trace of slime leaving by mollusk at movement. Wasp finds
snail and cautiously swims up to it. Having felt approaching of insect, snail
hides in shell, but wasp is able to wait. It cautiously clings to shell of
snail, and stands motionless. When the snail, deceived by imaginary calmness,
creeps out from shell, wasp pricks it by sting, laying egg in creeping sole
of mollusk. In some days from it small larva bursts. It parasitizes in creeping
sole of snail, gradually eating away its muscles. Also the larva eats part
of liver and sexual glands of mollusk. It eats gradually, and mollusk has time
to restore partly injured organs. Except for direct physical harm larva influences
life of host snail with the help of biologically active substances emitting
with it. Had reached the certain age, the larva with the help of secreted hormones
is forcing snail to leave water. Actually it is the death sentence to snail.
When the mollusk creeps out to damp ground of riverbank, it still can live
any time. But the larva of the wasp will not permit it to make: it starts to
eat actively, and for any some hours eats everything, leaving from a snail
only empty shell. During this time larva grows up larger then adult wasp. Having
to had eaten snail, wasp larva blocks shell fauces with mix of dung and secretions
of special rectal glands, forming some kind of partition. Under its protection
larva pupates in empty shell. About one week after the partition bursts, and
from behind it the young wasp creeps out. Having dried, the insect spreads
wings, and flies for searches of the male. Young females emit odorous substances
by which they are found by males. Fertilized females fly to bogs and begin
life of the swimming hunter, searching for snails. For the short life the female
wasp may lay up to 20 eggs.
The genus of diving wasps includes some species; each of them parasitizes on
certain species of mollusks:
Tiny
diving wasp (Aquavespilla minimissima) is tiny wasp about
4 mm long at all. It differs in coal-black colouring with metal
shine; by proportions it is similar to winged ant. This species
parasitizes on small orb snails (Planorbidae). Because of very
small size is not able to swim, creeping under water. To remain
under water longer, the insect has developed an interesting way
to update a stock of air: wasp gnaws by mandibles leaves of aquatic
plant, and simply rises above bladders of gas rich the oxygen formed
at photosynthesis, emitting from plant. Wasp shakes surplus of
gas from body by legs. Due to such adaptation the insect can remain
under water all the day.
Lung
diving wasp (Aq. pulmovora) is the internal parasite of
the snails, breathing by lung. It meets in vicinities of savanna
rivers and others partly or completely drying up reservoirs. It
is small (length of a body about 6 mm), metallic green wasp with
reduced wings. It swims and dives very well, similarly to the whirligig
beetle (Gyrinus). It parasitizes in large snails, settling in their
lung cavities. Wasp lays only one egg in wall of respiratory tube
of snail. Further in development the embryo divides to some parts,
and as a result from one eggs it appears at once about ten larvae
(similar feature was known at some representatives of ichneumons
(Ichneumonidae), close relatives of wasps). They settle in walls
of lung cavities, rich in blood vessels, and eat blood of snail.
In dry season when reservoirs dry up, and snail digs in silt, larvae
of the wasp start to develop roughly. Soon they devour the struck
snail, and wait a dry season under protection of its shell. In
the beginning of rain season they abandon shell and depart to searches
of new prey.
Frog-devouring
wasp (Batrachovespa batrachovora)
Order: Hymenoptera (Hymenoptera)
Family: Diving wasps (Aquavespidae)
Habitat: rivers and lakes of South America and the south of Northern America.
In family of water wasps not only the species infecting small animals had appeared.
In shallow rivers and ponds usual in selva of South America and the south of
Northern America, the set of frog species lives. And one species of water wasps
has adapted to parasitize in them.
Frog-devouring wasp is appreciably larger and more massive than its relatives
parasitizing in snails. Its body reaches length 2.5 - 3 cm (male is smaller
than female). This wasp differs in very thin body, its abdomen sits on long
stem. The body is colored black with red cross band on stem and spot on thorax
between wings. Males of this species have more red color in coloration, than
females, sometimes all abdomen of the male is colored red.
Back legs at males are usual, and at females they are modified to swimming
ones. Shins at them are wide and flat, and at external edge of shin there is
a line of hairs increasing rowing surface. The frog-devouring wasp also has
glands emitting water-repellent greasing. As against snail wasps, it does not
grease all body, limiting only with abdomen (where at insects respiratory apertures
open) and wings. In case of need, for example, rescuing from fish, this wasp
can, having gathered speed under water, jump out in air, and at once depart.
This species differs in some features of life cycle connected with parasitizing
in vertebrate animals.
For breeding female ready to lay eggs, dives and searches for flight of tadpoles.
It correctly defines by smell among tadpoles of some species of frogs representatives
of the necessary species. The wasp chooses tadpoles of largest species of frogs
and toads. Usually wasp creeps to flight of tadpoles on floating plants, having
turned over upwards by abdomen. Having tracked down prey of the necessary species,
wasp does not wait, while it will come closely to it. Insect puts all forces
to one successful throw. In case of successful throw the wasp grasps the tadpole
in two forward pairs of legs, and lays egg in its body. Then it lets it off,
and slowly emerges to the surface of water.
The tadpole in which wasp had injected egg, practically does not differ in
rate of growth from neighbours. The matter is that the larva of wasp develops
very long and slowly, therefore its presence does not lie down excessive loading
to the organism of amphibian. Moving in blood vessels, the larva of the wasp
is fixed in bladder of the host animal. The tadpole continues the life, and
in necessary time turns to frog. All this time in its bladder larva of the
wasp sits, gradually growing up. At last, when the frog becomes adult (at one-year-old
age, and even later), larva finishes the development, and begins metamorphosis.
The young wasp abandons body of the frog through cloaca. Because traumas, put
to the frog at this moment, are minimal, the frog survives in most cases. And
wasps flying above pond or river bank are not so terrible to it.
The adult wasp lives not for long time, as against its larva: only 2 – 3 months.
But for this time it has time to lay in tadpoles about 250 - 300 eggs: 2 -
3 eggs per day.
Ñontravirgo ichneumon (Micrevirator contravirginus)
Order: Hymenoptera (Hymenoptera)
Family: Ichneumons (Ichneumonidae)
Habitat: Siberia. The area coincides with the area of contravirgo moths.
In human epoch ichneumons were one of prospering groups of insects. They had
safely gone through epoch of global ecological crisis – among them only some
endemic and highly specialized species had died out. But as a whole in Neocene
the specific variety of ichneumons is comparable with the situation in human
epoch.
Intensive speciation of host insects (in reality each species of insects is
the host of any ichneumon) had caused the occurrence of parasites at which
life cycle was coordinated with host development. Some kinds of moths of bears
family, contravirgo and antivirgo, live in Siberia. These insects are remarkable
by the feature of breeding; at them individuals of one gender reach sexual
maturity being in larval stage. Poison protects them against large predators
from among vertebrates, but it does not save them from parasitic insects. One
species of ichneumons living in Eurasia, parasitizes on caterpillars of moths
of Contravirgo genus, which turn to males.
Contravirgo ichneumon is tiny insect with thin body and long legs. The length
of adult female does not exceed 1 cm, but its ovipositor is three times longer
than the body of insect. Male is considerably smaller, than female is – its
length is about 5 mm. Covers of this species of insects are colored black with
metal shine. By its shape contravirgo ichneumon differs only a few from ichneumons
of other genera, including ones known in human epoch.
The female of contravirgo ichneumon searches for caterpillars of contravirgo
moth by smell. It attacks caterpillar promptly and is not late near it for
a long time. The female makes fast sting by ovipositor to last segments of
caterpillar, almost not causing anxiety to it. Due to long ovipositor ichneumon
female avoids a prick of poisonous hairs of contravirgo caterpillar. It lays
tiny egg to friable connecting tissue of body of caterpillar. Some hours later
from egg the microscopic underdeveloped larva hatches and starts to eat caterpillar
gradually. At early stages of development it almost does not harm to the host,
and the infected caterpillar practically does not differ from healthy individuals
by rate of growth and appearance. However hormonal signals of maturing caterpillar
change the direction of development of parasite larva. At last stages of metamorphosis
of contravirgo caterpillar the development of ichneumon larva becomes more
active, and it starts to grow roughly. The growing larva of parasite moves
into testicles of contravirgo male. After that event instead of sperm liquid
in male organism the larva of ichneumon matures, eating growing tissue of testicles
of caterpillar (hence the scientific name meaning “small castrator”).
The larva of contravirgo ichneumon starts in turn to influence to the development
of host caterpillar. Secretions of ichneumon larva block the development of
smell glands at the male caterpillar of contravirgo at late stages of development.
Also colouring of infected contravirgo male is dimmer, than at healthy males.
As a result it less visible not only for contravirgo females, but also for
insectivorous birds. Obeying an instinct, contravirgo male creeps on leaves
and starts to wait for females. But it does not emit smell involving females,
and they are not interested in infected male. Such male exists for a long time
“in waiting mode”, imperceptible neither for females, nor for predators. In
such way the larva of contravirgo ichneumon prepares to itself an opportunity
of successful end of development. In some days a body of contravirgo male caterpillar
gradually mummyficates alive and it falls on the ground. The significant amount
of mummified bodies of such males is hidden among forest litter, and they are
not found by insectivorous animals. Inside a mummy of contravirgo male the
larva of ichneumon successfully passes metamorphosis. In spring the contravirgo
ichneumon leaves the shelter. Pairing at this species takes place on flowers,
and adult insects eat mainly nectar, licking it off from opened flowers. Approximately
in one week after fertilization in organism of the female eggs start to develop,
and it searches for young contravirgo caterpillars suitable for infection.
Cunning spider miner (Arachnomina arguta)
Order: Hymenoptera (Hymenoptera)
Family: Spider miners (Arachnominidae)
Habitat: temperate and subtropical climatic zones of Europe, Atlas Mountains;
deciduous forests and bush.
In Neocene among hymenopters various species, which larvae parasitize in other
animals, had appeared. Some species of ichneumons and solitary wasps had adapted
to parasitizing in vertebrates: mammals, birds and amphibians. Others had remained
“faithful” to former food source – invertebrates. The special family of Neocene
hymenopters specialized in parasitism exclusively at spiders. For features
of individual development these insects are called “spider miners”. These insects
are the specialized branch of ichneumons.
These insects are extremely tiny – the length of largest tropical species hardly
exceeds 5 millimeters, but usually they are twice lesser. Spider miners are
similar externally to small fruit flies, but their thick abdomen is placed
on clearly visible pedicle as at wasps and is very mobile. The ovipositor of
female differs in durability and can pierce covers of body of various insects.
On narrow head of spider miners there are big eyes consisting of set of facets,
and short plumose antennae. Jaws of spider miners are gnawing, and the lower
lip is mobile and covered by hairs on the tip. Wings of these insects are short,
rounded, covered by hairs on edge.
Males of spider miners are smaller, than females. Adult insects of this group
are long-term and eat flower nectar. They are fed on liquid food with the help
of lower lip, dipping its tip into liquid. In spring spider miners gather on
trees and lick the tree sap flowing down from cracks in a bark.
Ichneumons lay eggs directly in animals become food of their larvae. At spider
miners this process proceeds in two stages. First the fertilized females of
spider miners search for web of spider of suitable species, and constantly
“are on duty” near it. As patiently, as spiders, they wait, while prey will
get in web. When any insect appears in web, the female of spider miner rushes
to it, trying to get to it before spider, lays some eggs to its body and flies
at once. The spider seizes prey, bites it and injects enzymes diluting contents
of exoskeleton of prey. Digestive enzyme dissolves tissues and organs of prey,
but has no influence on eggs of spider miners. And at the second stage of infection
the spider soaks up in common with dissolved tissues of prey eggs of spider
miners. They are tiny, but covered with dense environment. Enzymes of spider
make an environment of eggs more permeable and stimulate development of the
larva. The larva of spider miner is very small. It penetrates into the wall
of intestines of spider and moves to its body cavity. Here larva eats tissues
of spider and develops. At this time it additionally pedogenetically breeds.
During the term of development one larva gives rise to several ones – in body
of one large spider it can develop in total up to ten larvae.
The significant part of term of development larva harms to spider a little,
and it continues normal life. At them differentiation of organs and tissues
proceeds, but they grow very little – they increased in length approximately
three times in comparison with the initial size. Shortly before the ending
of development larvae start to influence stronger to the life of spider in
which they parasitize – it is a part of preparation to their metamorphosis.
With the help of chemical substances they change behaviour of spider and force
it to bury itself alive in literal sense. Under influence of substances secreting
by larvae of spider miner the spider stops usual way of life. It leaves web,
finds shelter in forest and makes in it the similarity of cocoon for itself.
Soon it perishes here, because larvae begin to grow and eat its tissues. In
its mummificated body larvae finish development. They quickly devour soft tissues
of prey, grow intensively and soon undergo metamorphosis inside the exoskeleton
of spider.
At spider miners fertilized females winter. At species living in the north
of area of family, pupae winter right in shelter which is made by spider before
its death.
Cunning spider miner belongs to widespread European species and parasitizes
in the majority of species of European spiders except for wolf spiders (Lycosidae)
and other species not making web for prey catching. Females of this species
differ in grey colouring of abdomen; head and thorax are black.
The idea about existence of this group of animals is proposed by Nem, forum member.
Revolutionary ant (Formica comandante)
Order: Hymenoptera (Hymenoptera)
Family: Ants (Formicidae)
Habitat: Central and East Europe, deciduous and coniferous forests.
Between ants of different species, as a rule, there are antagonistic relations.
In rare cases ants of various species can enter relations of symbiosis, for
example, recruit ant (Recrutoformica
latrunculus). In human epoch so-called
slave-making ants were rather usual: these species had no their own caste of
workers, and for updating the number of working individuals in ant hill they
simply grasped pupae of other species of ants, from which new working individuals
appeared.
Such tactics brings to slave-making ants the great benefit, therefore species
leading such way of life are kept in Neocene. But constant “military actions”
between different species of ants resulted in formation of new defensive tactics
during the evolution process. One of species of ants, which ancestors had been
exposed to attacks of aggressive neighbours, had developed most interesting
tactics of protection, because of which it is named revolutionary ant.
Appearance of revolutionary ant is quite usual for these insects. The size
of adult fertile female reaches 14 mm; working individuals are much smaller
– up to 9 mm. This species has one unusual caste of large workers which are
only a little bit smaller, than “queen” – about 12 mm long.
These insects are colored reddish-brown color with white “mask” of short hairs
on forward part of head.
Colonies of revolutionary ant lead life standard for ants of Formica genus.
They build ant hills about 30 cm high around of mouldering stubs, and penetrate
stub through with their tunnels, transforming it to well fortified “palace”.
Under roots of stub there is a large chamber where some fertile foundress females
live. Working individuals drag various small insects to ant hill, clearing
a site of forest from pests.
In posterity of revolutionary ant it is possible to see clear difference of
larvae and pupae into castes by size. Working individuals protect the posterity
from predators, but are not always able to resist to impact of slave-making
ants, which steal many pupae of this species for updating the number of “slaves”
in their own ant hills. In this situation that property, for which revolutionary
ant has received the loud name, is expressing.
Slave-making ants steal pupae of this species of ants, and pupae, from which
large working ants develop, frequently get to their ant hills. But it becomes
the original “biological bomb” for a colony of slave-making ants. Large working
individuals of revolutionary ant have a special feature: they are females turning
to parthenogenetic “queens”. Slave-making ants do not perceive these individuals
as threat, because they have a smell peculiar to all members of colony. Being
in safety, parthenogenetic “queens” of revolutionary ant at good feeding (if
the colony with captured ants prospers) start to lay eggs actively; working
ants care of them as of eggs of slave-making species. In this case number of
individuals of revolutionary ant in mixed colony gradually grows and soon exceeds
number of the former oppressor. Actually, revolutionary ant simply biologically
supersedes the slave-making ant from its own ant hill, and gradually forms
a normal colony of this species. In it winged females, which normally couple
with males of this species, develop and settle.
Hawaiian
shell ant (Cochleoformica ostracophila)
Order: Hymenopters (Hymenoptera)
Family: Ants (Formicidae)
Habitat: Hawaii, rainforests.
During the human colonization of Hawaiian Islands intentionally or casually
the set of species of animals had been imported there. When large species of
vertebrates (pigs, deer, domestic cattle, mongooses) had been introduced purposefully,
small ones, especially insects, mostly got to islands casually, as “unbidden
visitors”: in the ground with exotic plants, or with any cargoes. So the set
of species of insects had settled at Hawaii and among them more than 40 species
of ants has appeared there. Being mainly natives of tropical countries, not
all these species had gone through the ice age, but survived ones had received
a prize – an opportunity of settling of islands. At these islands evolution
had caused set of unique species of ants distinguishing by interesting features
of habit of life.
Among tens of ant species inhabiting Hawaii, shell ants belong to smallest
ones. The length of working ant at this species is about 5 millimeters, and
only queen reaches length about one centimeter. These ants are colored rather
dim: at them there is brown body with metal shine and only at working individuals
(“combining” this occupation with the speciality of “soldiers”) head is colored
bright orange with black mandibles. This colouring is warning: sting of this
species of ants is poisonous, despite of their tiny size. The sting of ten
adult ants of this species may kill pigeon-sized birds, and the solitary ant
of this species can kill the beetle or the soldier ant of larger species.
Poisoness of this species of ants is the defensive weapon, rather than hunting
adaptation. Shell ants eat small insects, gathering them on the ground, and
seldom keep in big groups, gathering food. Such food predilections are partly
connected to habit of life of this species: their dwellings are arranged so,
that large catch simply does not place in them.
This ant is connected in life with some local birds: most frequently shell
ant arranges nests under “dining rooms” of Hawaiian hookbill – the local bird.
It lodges in shells of the snails had eaten by bird, therefore many features
of its way of life are dictated by opportunities of its dwelling. The colony
of shell ants occupies some empty shells of snails. One of these shells, the
largest one, is occupied with the queen-foundress. Queen chooses this shell
once per life, during the breeding flight, and never leaves it more. Queen
sits in the most distant curl of shell, surrounded with set of workers which
carry off the eggs laid by it to “kindergartens” located in next shell, and
bring to it food – fresh insects. Workers preserve their queen, clear her body,
remove dust, and every time are ready rush to its protection if somebody disturbs
“imperial” shell. The majority of workers lives in the next bowls, in the same
place there are warehouses of food.
About two times per one year at shell ants breeding flight takes place: one
month prior to this event female starts to lay large eggs, and workers, obeying
her chemical signals, rear from them the generation of future “kings” and “queens”
– fertile males and females. For this purpose they clear one of best shells
in vicinities of colony, and care of larvae very attentively. Larvae, from
which fertile individuals of new generation will develop, receive the increased
feeding. If they hatch before time of the common fly of young insects from
the next colonies, they stay in shelter shell, and working ants continue to
care of them. But usually different colonies synchronize breeding fly, and
young insects, founders of new colonies, direct to breeding flight simultaneously.
After pairing which occurs in air, before the fertilized female there is a
difficult task: it must find empty shells of snails which collect under “dining
rooms” of hookbills. Sometimes the instinct “misfires”: the insect finds and
occupies a single shell of snail had perished from any casual reasons. Then
growth of colony slows down: it is limited only to this shell, and the place
for expansion of ant settlement is absent. Such colonies quickly become victims
of ants of other species, or perish from casual reasons.
The fertilized female gets into depth of shell and there lays the first portion
of eggs – about ten ones largest of ever laid by it. From them larvae hatch,
and the female any time feeds them. They receive partly cut down diet though
turn to normal working individuals: development follows due to stocks of nutrients
in egg. After they develop, queen female leaves “household chores”, and starts
to lay eggs only.
The colony exists, while the queen-foundress is alive – till three years.
Monstrous ant (Horromyrma pestis)
Order: Hymenopters (Hymenoptera)
Family: Ants (Formicidae)
Habitat: Hawaii, mountains, light forests.
Before the people occurrence at Hawaiian Islands many groups of animals, characteristic
for continents, had been abscent there. One of such group were ants, which
are numerous and various all over the world. They had an opportunity to settle
at islands as a result of human economic activity, and due to the opportunities
of adaptation they had successfully outlasted their “benefactor”. Many species
of ants distinguished by various interesting features live in Neocene at Hawaii.
And in conditions of island isolation among them the true monster, one of the
most dangerous inhabitants of these islands – monstrous ant had appeared. It
is the descendant of fire ant (Solenopsis heminata), introduced from North
America. It has kept a migrating habit of life and has even more strengthened
predatory behavior of the ancestor.
This insect is the largest species of ants of Neocene world: length of working
individual is over 3 cm, and queen surpasses 5 cm lenght. Monstrous ant has
silver-gray body with black cross strips on abdominal segments and black legs.
At ants of “soldier” caste there are black head and contrasting with it large
white mandibles, therefore “soldiers” are well distinguishing on the background
of other ants of this species. “Queen” has black colouring and differs from
workers in larger abdomen with very wide black cross strips. Its head is silvery
and also has lighter shade, rather than at working individuals and “soldiers”.
By size of thorax and head queen does not differ from working individuals.
Monstrous ant is heat-loving insect: it lives at sunny and well warmed up slopes
of islands; also it does not like dampness and does not go down in marshlands
and lowlands. Till the morning these insects are very languid, but become active
and very dangerous in the afternoon.
It is one of the most dangerous predators of Hawaii. Monstrous ants attack
any animals which could not escape from them for any reasons, including rather
large vertebrates. This species does not lodge for a long time in any certain
place, and leads vagrant life. In day time the colony of this ant moves in
wood stretched to long columns, and for lodging for the night uses holes and
others shelters. During the movement queen is protected by plenty of “soldiers”
with hypertrophied mandibles, and the most part of a colony is made by workers
keeping ahead and behind the queen. Once a week in abdomen of the female up
to 200 small eggs develop, and the colony is compelled to stop movement till
some time to hatch the next generation of ants. For cultivation of posterity
the colony searches for suitable shelter – hole of any vertebrate (frequently
thus the owner of hole or its posterity appears had eaten), in which working
ants train vegetative rests. If in vicinities there are no holes, workers gather
vegetative dust in heap and build of it a friable temporary nest. Having organized
a settlement, the colony of ants stops in it approximately for three weeks.
For this time the female lays eggs, and from them larvae hatch. Working ants
in support of some “soldier” ants hunt small animals, devastating vicinities
of nest to the moment of metamorphosis of young generation.
When all posterity undergoes a metamorphosis (within approximately three weeks),
the colony abandons shelter and continues wandering in the forest. Only birds
able to catch these insects not sitting on the ground represent the potential
danger to monstrous ants. Frequently colonies of these insects are accompanied
with large omnivorous birds which cause some damage to ant colony, and provide
to themselves constant, though also dangerous food source.
Recruit ant (Recrutoformica latrunculus)
Order: Hymenopters (Hymenoptera)
Family: Ants (Formicidae)
Habitat: moderate and subtropical areas of Europe – from Atlantic coast up
to Three-Rivers-Land steppes; woods and bushes.
Ants are one of most typical groups of forest insects. Due to their activity
some plants settle, and number of pest insects restrains in reasonable limits.
Among ants there are no solitary species, though colonies of some species of
Holocene epoch could include some tens individuals. In colonies of ants more
or less expressed division to castes exists. Relations of ants of different
species show the variety though more often they may be reduced to interspecific
antagonism. Among ants of Holocene epoch there were species having “slaves”
were known: they took larvae of other species of ants from which then individuals
carrying out functions of workers in colonies of the aggressor ant grew. In
Neocene one species of ants had developed this form of relations with other
species in other direction – it had turned to the original “mercenary” living
in colonies of other ants. This feature has determined its name: the recruit
ant.
This insect has only two castes: fertile queens living in colonies of other
species of ants, and furious “soldiers”, which replace own “soldiers” of host
species and protect its colony on equal terming of high-grade inhabitants.
The shape of representatives of these castes considerably differs.
During the top expression of breeding function the queen resembles the fertile
female of termites. At this time it reaches the length of 35 – 40 millimeters,
from which only about 10 mm falls to head and thorax, and strongly swollen
abdomen makes other lenght. The adult female of recruit ant is completely helpless
and can not move independently. It lives in most protected bottom part of ant
hill, in special chamber. It is fed and cleaned by working individuals of host
species, and all cares of larvae of recruit ant are completely their duty.
Such way of life transforms the female to true “factory” of egg producing.
In summer when all ants are most active, the recruit ant queen lays one egg
each minute. Working individuals of host species immediately carry eggs away
and look after them the same way as after eggs of their own species.
The most part of summer from eggs larvae hatch, turning to individuals of other
caste – furious “soldiers”. “Soldiers” of recruit ant are absolutely not similar
to queen. These ants are easy for detecting in colonies of other species: recruit
ants differ in black colouring with metal shine, and white mandibles. The length
of these insects reaches 20 – 25 millimeters: these ones belong to the number
of largest ants of Eurasia. They concede in size only to some tropical species.
But this feature also imposes the certain restriction to opportunities of existence
of recruit ant. It can live only in colonies of ants of size comparable to
them. Smaller species of ants will have not enough food resources to support
giant “soldiers”, and also large “soldiers” simply can not move normally in
too narrow passages. Recruit ant can settle in colonies of various species
of ants, including ones having their own “soldiers”. The colony protected by
recruit ants develops more successfully, rather than other colonies of the
same species of host ants. Sting of “soldier” of recruit ant is very painful:
in addition the insect injects in wound the poisonous liquid containing ant
acid. Efficiency of protection of nest by recruit ants is very great: mouse-sized
mammal perishes from ten stings of such ants. And joint attack of recruit ant
“soldiers” can turn into flight even large mammal.
In second half of summer queen of recruit ant lays eggs from which winged individuals
taking part in breeding develop. These insects are similar to winged ants of
other species, but appreciable metal shine of body covers, and also larger
mandibles distinguish them. They fly off from populated ant hills of various
species of ants almost simultaneously, pair quickly, and males perish soon
after that. Females of recruit ant must carry out the important mission just
after pairing: to find the colony of other species not populated with congeners,
and to settle in it. The female of recruit ant produces special pheromone which
reduces aggression of ants of potential host species. Having found a colony,
the female of recruit ant defines by smell, whether individuals of its species
are present in colony. If the smell of congeners is weak, or it is not present
absolutely, the female enters into ant hill, surrounding itself by pheromone
smell. It searches for the chamber suitable by size, and settles in it. First
time young female of recruit ant is very cautious: it does not lay eggs, and
emits pheromones actively. Gradually it starts to smell similarly to environmental
ants, and moves in ant hill galleries more freely. When ants of host species
“recognize” the female of recruit ant and start to feed it under its requirement,
it settles in chosen chamber and starts to produce eggs. After several weeks
of intensive feeding its abdomen hypertrophies, and female becomes similar
to “queen” of termites.
If the smell of recruit ants is present in ant hill chosen by the female, but
is rather weak (that means in colony there is a little number of ants of this
species), the female also settles in such ant hill. The large colony of any
host ants may feed up to five recruit ant females, using their “soldiers”.
Life expectancy of the female of this species is about three years.
The idea about existence of this species of insects was proposed by Momus, the forum member.
Housebreaker ant (Pachycephalomyrma destructor)
Order: Hymenoptera (Hymenoptera)
Family: Ants (Formicidae)
Habitat: North Africa, arid areas – savanna, woodlands.
In history of terrestrial fauna there are two large branches of social insects
between which severe war without an armistice lasts for millions years. These
are termites known from Permian period, and ants, the representatives of Hymenoptera
evolved in Mesozoic. Both groups of insects passed to social way of life independently
from each other, and lead completely differing habit of life. Termites are
tireless converters of organic substance, decomposing even such stable substances,
as cellulose is. Ants are predators able to attack animals, much larger, than
they are, and to kill them. Termites are compelled to protect themselves from
enemies and dry air, and for this purpose they erect termitaries of smart structure
remarkable by exceptional hardness. Heat does not harm to ants, and they are
ready to attack any creature which will want to destroy their nest. And some
ants do not build constant nests at all.
Termites represent usual inhabitants of tropical zone of the Earth. In Africa
their nests may be met practically everywhere. And one species of ants had
adapted to attack on well fortified buildings of termites. This species
is named housebreaker ant.
The most part of colony of housebreaker ant is presented by small working individuals.
Their length is no longer 10 – 12 millimeters. But in colony there are also
“soldiers” reaching the length 15 – 18 mm. And their strong mandibles add 5mm
moreover to their length. Housebreaker ants differ by large head and rather
aggressive behaviour - even the average working individual may be aggressive,
and easily wins “soldiers” of other species of ants attacking nest of housebreaker
ant. And stings of “soldier” caste ants are enough to frighten off large herbivorous
mammals, which may represent danger to the colony of these ants.
Colouring of these ants is obviously warning: abdomen is white with reddish
tip, and thorax and head are coal-black. This colouring is shown at all castes
of housebreaker ant. But at individuals of “soldier” caste abdomen is brighter
– it is almost entirely reddish, except for two first segments.
Slave-making ants attack nests of other ants with the purpose of capture of
pupae from which in their own nest “slaves” develop. Housebreaker ant uses
colonies of termites only as a food source. The siege of termitary is very
difficult problem: sun dries up the external layer of their nest up to stone
hardness. But housebreaker ant had adapted to an attack on termitaries by special
way. In colonies of this species there is a special caste of “breakers” with
strong mandibles and head protected with armour; the length of such ants reaches
25 mm. The head of ant of “breaker” caste reaches almost 40 % of the general
length of insect. Mandibles of “breakers” are not similar to long mandibles
of “soldiers” jagged on internal edge. “Breaker” has short thick mandibles
with one small dens on internal edge. On its head the chitinous cover reaches
sizeable thickness and forms a semblance of shield – edges of armour cover
eyes and the bases of antennae, and mandibles jut out from under its front
edges. Such heads are practically impregnable for stings of termites protecting
their nest. The task of “breaker” caste in attack is the widening of entrances
to termitary. “Breakers” bite off with mandibles the top layer of termitary,
opening the way to “soldiers” and foragers. Besides they form similarity of
mobile shelter for “soldiers” at defense against the termites protecting their
colony.
These large individuals are tetraploids, but they develop from usual eggs.
At housebreaker ant the first divisions of oocyte are incomplete frequently
enough, and only a doubling of chromosomal complement takes place. From such
eggs larvae burst, reaching larger size, rather than usual working individuals
and “soldiers”. They grow faster, but need more food. However, expenses for
rearing of “breakers” pay off by successful end of the most part of attacks
to termitaries.
The own nest of housebreaker ant is not complex and firm architectural masterpiece.
These insects arrange ant hill in the basis of trunk of large tree with core
rotted through. If such trees are not present, they can use ready holes of
various animals for arranging of nest – any animal prefers to abandon the burrow,
if these insects will settle in it. Ants arrange in burrow some simple chambers
in which females and larvae are placed, or minimally convert available sites
of burrow, expanding or narrowing entrances. Colonies of ants which have a
choice of food source – some colonies of termites, even of various species,
develop better. In this case colonies have time to restore after housebreaker
ant attacks. If the termitary degraded and the population of termites had lost
after regular attacks of army of ants, housebreaker ants can move to new place.
Their “queens” have kept the ability to move normally, and the colony of ants
is quite able to move till some days, searching for new place for life. Thus
they move larvae and even eggs. During the resettlement “soldiers” and even
“breakers” protect the colony.
Lantern ant, twilight lanternomyrma (Lanternomyrma
crepusculina)
Order: Hymenoptera (Hymenoptera)
Family: Ants (Formicidae)
Habitat: rainforests of Meganesia; the symbiote of lamplighter
bird.
In tropical forest live beings receive the set of opportunities for evolution
– abundance of various food sources and habitats. But the inhabiting in such
ecosystem has an underside – strict competition. As a result various species
of live organisms during the evolution develop the oddest and keen life strategies
permitting to use effectively an opportunity given by nature and to avoid
unnecessary competition. One of effective forms of survival is symbiosis.
One of mysterious and secretive inhabitants of rainforests of North Meganesia
is lamplighter bird, the nocturnal species of bowerbirds. This bird builds
for courtship displays simple constructions – heaps of pieces of rotten wood.
But on them special pileate fungi
of Mycolanterna genus grow; these ones
have ability to glow. In their illusive light male of this bird arranges
courtship
displays.
Male of lamplighter bird constantly renews the construction, dragging on
it new pieces of rotten wood, which it gathers in forest. And such activity
of
bird is very favorable for constant settler of these constructions – small
ant named twilight lanternomyrma, or lantern ant.
Twilight lanternomyrma is a species of ants a little distinguishing externally
from the majority of these insects. It is an ant of red-brown colouring with
rather large head and mandibles extended forward and forming similarity of
tweezers. Working individuals of twilight lanternomyrma are no more than
4 millimeters long, and the adult “queen” female grows up to 8 – 9 mm. In
colony
of twilight lanternomyrma there are some breeding “queens”.
Life of colony begins from the important event – fertilized winged female
finds a heap of pieces of rotten wood suitable to life which the male of
lamplighter
bird started to gather. If such opportunity is not present, the female can
lodge in already existing, but weak colony which had already rendered habitable
construction of lamplighter bird. First days the female leads a secretive
way of life, but gradually gets smell characteristic for colony, and working
individuals
accept her.
The colony of twilight lanternomyrma leads nocturnal habit of life. Ants
of this species turn more active in twilight, and hide in nest soon after
dawn.
For night these insects have time to gather enough forage for feeding of
colony. They should not care of repairing and expansion of nest - all work
on delivery
of “building material” is incurred by lamplighter bird, certainly, not understanding
its role in life of this ant.
Nevertheless lamplighter bird receives the certain benefit from presence
of such symbiote. When parasitic insects start to annoy bird male vastly,
it simply
digs a hole on the construction, and lays in it. Ants creep into bird’s plumage
and carefully clear it of parasites. Besides stings of ants cause in bird
the behavioural reaction similar to euphoria. And ants receive food – parasitic
insects and mites.
Male of lamplighter bird would not achieve only by its activity even a half
of success in cultivation of glowing mushrooms without these ants. The second
species of live organisms with which these insects had entered symbiosis
is the glowing mushroom settling on heaps of lamplighter bird. Working individuals
of lanternomyrma create conditions for prosperity of these mushrooms – they
destroy other species of fungi settling on constructions of lamplighter bird.
The saliva of ants contains the substances overwhelming growth of some species
of fungi, particularly mold ones. Besides working individuals of lanternomyrma
creep on fruit bodies of mushroom and exterminate insects which damage them.
Certainly, all this activity is selfish – ants eat a part of mycelium. The
mycelium of glowing mushroom forms original galls in places of stings of
these
ants, and ants from time to time gather a rich “harvest” which serves as
addition to usual food consisting of insects and other invertebrates.
Flight of lanternomyrma also takes place in twilight. Males of this species
differ in good sense of smell – they can feel the presence of the female
for some tens meters, that is too good result for tiny insects. Pairing occurs
in air, and then the female at once flies to search the suitable place for
future colony. Female is guided by sense of smell in choice of settling place
– it searches for mycelium of glowing mushrooms by its smell. Frequently
females
settle simply on rotten tree trunks decomposing by mushrooms. But such colonies
live not for long and degrade after 1 – 2 years.
Water-bearing plant louse (Toxiaphis aquifera)
Order: Homopters (Homoptera)
Family: Plant lice (Aphidiidae)
Habitat: deserts of Mediterranean Lowland, plants of leafless
paunchstem.
Plant lice are tiny and delicate insects living in huge amount on whole Earth.
As against the majority of insects, the body of plant lice is covered with
very thin cuticle. It makes plant lice very vulnerable for any predators who
will want to attack them. But protection of these insects is not in the reliable
reservation at all. Fast rate of development and the highest fertility save
them. Plant lice enter symbiosis with other animals, for example, with ants,
and use their protection in exchange for drops of sugary secretions.
Ability to increase number quickly, ease of settling and high adaptive ability
easily had permitted plant lice to go through changes in biosphere at the boundary
of Holocene and Neocene. Their specific variety had not changed almost, and
in Neocene increased even more. Among plant lice the specialized species distinguished
by interesting adaptations to inhabitancy had appeared.
It is possible to meet plant lice everywhere. Even at the border of severe
saline desert of former Mediterranean these insects find house and food. The
most important condition for life of plant lice is the presence of fodder plant.
In places, where small streams flow in spring, thick not branchy trunks of
leafless paunchstem plant stick up from ground. This unpretentious plant is
a food source for one Neocene species of plant lice. Insects form white, as
if powdered colonies on tops of trunks of this plant where covers of stem still
thin, and sap flows more actively.
On surface of colony of plant lice drops of their secretions gleam. It is not
dense sugary syrup, but something more valuable in desert – almost clean water.
For this feature plant louse living on paunchstem is named water-bearing plant
louse.
This insect is the stenophagous species feeding strictly on paunchstem plants.
Paunchstem is poisonous, but this plant louse during the evolution had adapted
to neutralize its chemical protection. It even defends from enemies, accumulating
poisonous substances from plant sap in body. Except for predatory insects,
water-bearing plant louse has other enemy – the drying up sun. To escape from
it, the insect produces wax, protecting itself from drying. Colouring of body
of water-bearing plant louse is light grey, and wax gives to its body whiteness.
It does not form continuous cover, and lays on body of plant louse by friable
flakes, creating isolation from overheat.
Similarly to all species of plant lice, water-bearing plant louse is inactive
insect. It almost constantly stays immovable, having pierced by proboscis covers
of plant. From paunchstem sap the insect receives all substances necessary
for life. Secretory glands are well advanced; their tips stick up from wax
coating as two tubules. Plant lice known in human epoch entered symbiosis with
ants. They “bribed” ants, secreting sugary liquid at stimulation. Water-bearing
plant louse lives in desert, and secrets substance more valuable to inhabitants
of desert – clean water. Ants of various species live in desert, and some of
them simply can eat these plant lice. But this plant louse has entered relations
of symbiosis with other insect. Plant lice are protected by shepherd
beetle of true weevils family. It preserves plant lice, attacking other
insects appearing in colony of plant lice. The beetle receives appreciable
benefit
from mutual
relations with these plant lice: it drinks water secreted by them. The paunchstem
plant contains a plenty of water, but not many animals can use it, because
the plant is poisonous. Plant lice serve as original natural filter, supplying
the beetle with water.
For plant lice the phenomenon of alternation of generations is typical. Depending
on conditions these insects form various intraspecific forms – winged and wingless,
parthenogenetic and breeding with fertilization. In hot summer water-bearing
plant louse forms only parthenogenetic generations. They settle on surface
of chosen plant of paunchstem and actively breed. In autumn, when weather becomes
cooler, and at night fogs form, in colonies of water-bearing plant lice winged
males and large mobile females of sexual generation appear. Males find and
fertilize such females, and they lay hibernating eggs covered with dense shell.
Using cracks in the ground such female penetrates under ground. It creeps on
the surface of rhizome and lays eggs on buds, from which in spring new stalks
will grow. After the laying of all eggs the female perishes. In winter eggs
of water-bearing plant louse are in inactive condition. In spring the stalk
of plant starts to grow and takes eggs of plant louse out on ground surface.
From them larvae, which settle on tips of sprouts, burst. In process of stalk
growth larvae creep higher. The part of larvae turns to generation of small
winged settling females. They fly out from the plant where they were born,
and search for new fodder plants. The majority of them perishes: winds carry
them away in salt desert of former Mediterranean, or in Alps. But those few
individuals succeeded to find fodder plant start to give rise to larvae from
which the colony develops soon. For one summer season the water-bearing plant
louse gives more than twenty generations, and fertility of one female can reach
fifty larvae. They quickly grow, and in one week can rise posterity.
Sea wax scale (Thalassorthezia cereifera)
Order: Homopters (Homoptera)
Family: Scales (Ortheziidae)
Habitat: Atlantic coast of Europe; the parasite of leafless
sea asters.
Various insects of homopters order – scales, plant lice and bark lice – are
among the most specialized parasites of plants. The parasitic habit of life
has resulted in simplification of way of life at simultaneous complication
of breeding ways. Some insects of this group had lost mobility at adult stage
of development, and live, having constantly stuck to fodder plant. Frequently
the parasite is highly specialized species, and evolution of host plant results
in occurrence of surprising adaptations in its parasite.
In salt marshes of littoral zone of North Europe leafless sea asters grow.
These ones are flowering plants enduring regular flooding by tidal waves. This
species of plants is a fodder plant for one species of parasitic insects which
had also adapted to existence in tidal zone. It is the sea wax scale living
on succulent stalks of leafless sea aster. Similarly to all relatives, this
is inactive insect almost constantly sitting on plant and sucking its sap with
the help of long proboscis.
Males and females of sea wax scale strongly differ by appearance. The female
of this species is wingless one about 1 centimeter long. At it very short legs
are kept. Because this insect leads motionless way of life, legs do not serve
for walking any more. Two forward pairs of legs are reduced and weak. The back
pair of legs is longer, than the others; they are mobile, with wide paws. These
legs serve for the vital process: using them insect smears over the body wax
secreted by special glands. Around of body of the female the scute of wax serving
for protection against sea water develops. This scute protects not only the
female, but also its posterity, forming brooding chamber in back part of body
of the female. For fertilization of the female the male creeps up under her
scute.
The male of sea wax scale is tiny – about 2 – 3 mm long. At him wings are advanced,
and it flies from one plant to another in searches of females. For the short
life males eat of nothing. They have two overall purposes in life – to fertilize
female and to settle posterity. However, females easily breed without fertilization.
Fertilizing the female, the male involuntarily takes away on itself tiny larvae
from her brooding chamber, and carries them in vicinities. Larvae also easily
settle with the help of wind and sea water. They weight so little, that do
not break a film of surface tension, and are carrying by currents to long distances
along the coast. But they survive only in places, where the fodder plant grows.
This insect receives feed from unique source – from sap of leafless sea asters.
The sea wax scale in adult condition constantly sucks sap of plant with the
help of very long proboscis three times exceeding the length of body of insect.
As sap is not balanced ideally for feeding of insects, the sea wax scale is
compelled to remove the substances received in superfluous amount from the
organism. Relatives of this insect, plant lice, secret surplus of sugars entering
to the organism, with the help of special glands. Sea wax scale emits with
their help not only sugar, but also surplus of salt: in sap of fodder plant
there is much more salt, rather than in sap of ground plants. Secretory pores
on the top side of sacciform body of the female look like two tubules. Through
them sweetish brine from time to time is secreting. Salt dries up atop of wax
coating and falls off from wax cover of insect as translucent scales. Sometimes
butterflies fly to the colony of these scales and suck liquid secreted by them.
Salt dissolved of sea water is a main problem for animals, compelled to develop
life in sea. Sea wax scale solves it very simply: insect does not suppose contact
of water with its own body. This insect produces plentiful wax coating, and
the top part of its body is covered with hairs. Due to such adaptations the
insect can endure flooding – around of its body the thin film of air protecting
the organism of insect from influence of salt and serving for breath is kept.
But air surrounding the body of insect, would not suffice for stay under water
during the inflow. However this insect has practically unlimited source of
oxygen for breath, and sea wax scale is able to use it. Stigmas on abdomen
of insect are shifted downwards and pulled together. They are protected by
special kind of scales, which compose the peaked tube. Due to this feature
the insect does not choke during inflow: the scale simply sticks tube through
thin skin of stalks of plant and respires the gases formed in parenchyma of
plant. The gas mix inside the plant is rich in oxygen formed at the photosynthesis,
and thus, the plant serves to the insect not only as “dining room”, but also
as “aqualung”.
This species can maintain stay in sea water and settle on floating branches
of leafless sea aster. Therefore sea wax scale is settled almost in all places
where the leafless sea aster grows at the Atlantic coast of Old World. This
insect does not live only at New Azora and in Iceland – these islands are too
far from the coast of Europe and Africa.
Gold-winged
metal swallowtail (Metallopapilio chrysopterus)
Order: Butterflies (Lepidoptera)
Family: Swallowtails (Papilionidae)
Habitat: rainforest canopy of South-Eastern Asia.
Butterflies of swallowtails family were among the most remarkable insects of
Holocene epoch. Large size and bright contrast colouring draw attention to
these insects when they promptly fly by above flowers somewhere at the meadow
of temperate zone of Earth or above trees of tropical rainforest. After
ecological accident and mass extinction carried away to non-existence tropical
woods of Holocene epoch with all inhabitants, some species of swallowtails
managed to survive. When the climate became warmer and soft, they had occupied
again formed habitats, having given rise to set of effectively looking species.
Among descendants of common swallowtails (Papilio) butterflies of separate
genus of metal swallowtails (Metallopapilio), distinguished with the special
structure of wing scales are especially remarkable.
At metal swallowtails light-reflecting properties of wing scales have amplified;
that’s why representatives of this genus flash in various metal shades: from
cold silvery steel up to gold and green and reddish metal of amazing beauty.
Metal shine is combined at these butterflies with velvety matte blackness at
edges of wings. At all species at back wings there are characteristic “tails”.
Shine of wings permits insects to find out representatives of species at large
distance.
The body of metal swallowtails is usually covered with thick short hairs of
grey and black color. At some species at the middle line of body there passes
white or yellow strip. Metal swallowtails differ in large size of body: the
length of body of the butterfly is about 5 cm, and wingspan at some species
exceeds 15 see.
These swallowtails have very long proboscises - up to 10 cm being unwrapped.
It is the specialization to feeding at trees with long tubular flowers. Adult
insects practically never leave forest canopy.
Caterpillars of these swallowtails feed on trees of other species, rather than
adult butterflies. Especially frequently it is possible to meet caterpillars
on plants which leaves are rich in essential oils. Caterpillars of metal swallowtails
are large (length is up to 10 cm), thick, and they have bright colouring. Usually
in their coloring green color is combined with red and white spots and strips.
Behind the head of caterpillar there is a repugnatorial gland, which in case
of danger turns out as bubble and emits unpleasant smell.
Gold metal swallowtail is one of the most impressive species of genus: its
wingspan reaches 18 cm. Wings of this insect are covered with brilliant scales,
playing in all shades of gold. On edge of wings there passes narrow black border,
corners of forward wings are black too. At every back wing there are two “tails”
with the expanded end and rounded tip. The border on back wings is wider, than
on front ones.
Caterpillars of this species are about 12 cm long; they are almost entirely
black with narrow longitudinal green strips. They feed on trees of family of
labiates (Lamiaceae).
Other species of this genus live in woods of South-Eastern Asia:
Mourning
metal swallowtail (M. hypochondricus) lives at former Sumatra Island
(in Neocene it is a part of Jakarta land). Its wingspan is up to 10 cm. Wings
are almost entirely black, with several lines of silvery scales along main
ribs and large site of silvery color near a root of forward wing. At every
back wing there is one pointed “tail”.
Copper
swallowtail (M. chalcopterus) inhabits islands of
Indonesia near Australian-New Guinean continent. It is very
large species: wingspan is up to 20 cm. Wings are colored copper-red
with rust-colored shade; only corners of forward wings and
narrow border at back wings are black. At back wing there is
one big “tail” with rounded tip.
Steel
swallowtail (M. ferrum) lives at the south of islands
of Indonesia and at the north of Australian-New Guinean continent.
Wingspan is about 10 cm. The basic colouring is grey with bluish
shade; black border on back wings forms characteristic indented
pattern, on front wings there is only narrow black strip. On
back wing there are three very thin “tails” with pulled together
bases.
Urushi swallowtail (Necropapilio urushiphilus)
Order: Butterflies (Lepidoptera)
Family: Swallowtails (Papilionidae)
Habitat: Japan islands, humid mountain woods.
Between plants and animals continuous “race of arms” always proceeds. Plants
put forward acute spikes against four-footed herbivores, and edible parts are
penetrated with rigid fibres. Protecting from eating, plants developed various
poisons, pitch and lacteal sap. But the answer to these adaptations of plants
is the next coil of evolution of herbivores. Uniquitous insects have especially
succeeded in counteraction to plants: any kind of plants protected from the
majority of herbivores, appears a forage for any species of insects. As the
consequence of such evolutionary transformations, these insects are very highly
specialized species. It can result adversely in perspectives of their further
evolution, but while nothing threatens to species of fodder plants, they prosper
and appear out of competition.
In warm and humid mountain woods of Japan Islands the plant had reached the
great successes in chemical war against herbivores prospers. All its parts
are literally impregnated with poison (hence its name: “death
tree”), and in
air the bitterish smell warning possible lovers of greenery about danger is
felt. Around of this tree only few insects hover, and on the ground under roots
of this tree dead and dying butterflies lay – they all belong to the same species.
Their number is too large to explain their presence in such place as simple
accident.
Actually large bright butterflies, whose life comes to an end at roots of “death
tree”, appeared here quite naturally – they had finished their life cycle.
Besides, it is quite possible, that they began life on the plant of this species.
And this is one of few insects successfully coexisting the “death tree”. The
butterfly is named urushi swallowtail (“urushi” is the Japanese name of poison
dogwood (Rhus vernix), the ancestor of “death tree”, and urushiol is one of
poisons of “death tree”).
The urushi swallowtail is rather large species of swallowtails: the wingspan
at this species reaches 15 cm. Colouring of wings is bright and contrast –
orange background with red edges of wings and black nerves especially well
expressed at the basis of wings. On tips of back wings there are some “tails”
among which the middle one is largest. The basis of this “tail” has round black
spot with white “eye”. Male of urushi swallowtail is colored contraster, rather
than female – it has more black color in coloring, and at separate ones even
narrow black border on wings appears. Body of this butterfly is black with
red longitudinal strips on sides. The abdomen of female is greater, rather
than at male.
Caterpillars of urushi swallowtail feed on leaves of “death tree”: usually
damages on leaves of this tree are left by them. Gluttonous caterpillars of
advanced ages leave from leaves of “death tree”only thick middle nerve.
The caterpillar of this butterfly is very big – right before the metamorphosis
it reaches the length 12 – 15 cm. Colouring of caterpillar is black with big
red spots on each segment. On prothorax there are two white oculate spots which
help the caterpillar to imitate a head of small snake or lizard. For additional
protection at them smell gland of two outgrowths is advanced – at danger it
turns outside and emits unpleasant smell. Tissues of this gland are colored
orange and contrastly allocate on the background of caterpillar’s back.
Such colouring of adult butterfly and its larva has the large biological sense
– it is warning one. In fat tissue of insect a lot of poison is accumulated:
the caterpillar receives it from leaves of “death tree”. Even after the metamorphosis
poison remains in body of imago in amount enough to make the butterfly completely
inedible. Development of caterpillar of urushi swallowtail lasts approximately
5 weeks, and for one year at this species up to three generations may develop.
Last generation of insects hibernates in pupal stage. The pupa of urushi swallowtail
also has warning colouring: it is cross-striped red-and-black.
The adult butterfly eats nectar of flowers of various plants, avoiding, however,
flowers of “death tree”. Poisonous substances in its body are accumulated in
fat organ and are reliably isolated from organs and tissues. Its immunity to
poison of plants in which its caterpillar is fed, is much below, rather than
at caterpillar. Adult urushi swallowtails often feed at flowers of Urushiphla
orchid parasitizing on roots of sumach and “death tree”.
Males ready to pairing gather in well lighted places among tree crones. They
fly in sunlight by dense flight seen from apart. Males emit pheromones involving
females from the long distance.
Female of this butterfly lays eggs once a life. It finds a fodder tree and
sits on foliage, choosing young sprouts. At this time the substances evaporating
from leaves of plant start to influence an insect. Development of eggs in body
of the female demands a lot of energy, and exhausts an organism of insect.
Thus ability to resist to poisonous substances of “death tree” is reduced,
and the insect appears poisoned.
Female leaves eggs by some ones on leaves of tree. Common fertility of this
species reaches half a thousand eggs and more, therefore laying of all eggs
takes a lot of time. Up to the finish of egg laying the female appears fatally
poisoned with evaporations of plant and perishes. Dead or poisoned insect falls
on the ground under tree. At mass flight of urushi swallowtails the ground
under trees appears interspersed with dead butterflies. Males overlive females
not for a long time – after pairing they stop eating and perish in some days.
Grieving swallowtail (Funestopsyche necrophagus)
Order: Butterflies (Lepidoptera)
Family: Swallowtails (Papilionidae)
Habitat: savannas and woodlands of North Africa and southern Europe.
At top of food pyramid of the ecosystem there is a large predator. In savannas
of North Africa and southern Europe bordering a hollow of dried up Mediterranean
sea, such apex predator is deadlynetta
(Necrogenetta deima) – huge saber-toothed
species of viverrids. Its prey includes large local animals: flathorns and
ndipinotheriums, huge giraffe
ostriches, and also very large rodent mighty
grasscutter. In addition to deadlynetta in savanna there is a set of other
predators, from small up to rather large. When such predators eat prey, near
them various scavengers wait for their share. They understand that if they
will hurry, they may draw upon themselves the aggression of predator. But some
impudent ones easily receive the share of forage – they do not demand too much,
therefore predators do not drive them away. One of such impudent scavengers
is a snow-white butterfly with black border on wings. Long “tails” on wings
specify its belonging to family of swallowtails. This species never meets on
flowers, but gathers in great number on dead animals. For this feature this
butterfly is named grieving swallowtail.
Adult butterflies of this species never meet on flowers – they had completely
lost ability to eat vegetative food. But these butterflies fly by tens to smell
of blood and meat. They literally stick round the prey tormented by predator,
and are not afraid to sit on the muzzle of animal soiled with blood. Having
unwrapped long proboscis, butterfly licks off blood and meat juice which make
food of this insect. Besides of fresh prey of predators, this butterfly is
able to feed on decomposed corpses of animals.
Wingspan of grieving swallowtail makes about 15 cm. Flight of this butterfly
seems slow and majestic, but it is deceptive impression – butterflies fly very
quickly, and already literally in some minutes gather on prey of various predators
in tens. Colouring of wings of this butterfly confirms somewhat the name of
species – on white background of wing the black border is brightly visible,
and some large nerves in wing basis also may be black. On back wing there is
long “tail” near which there are some other shorter shoots.
On prey of predators butterflies not only eat, but also pair. Only time when
these insects are interested in plants is a larval stage. The caterpillar of
grieving swallowtail eats on leaves of trees – more often it can be met on
leaves of acacias in the top part of crone. The caterpillar of this swallowtail
is colored dark brown with grey longitudinal strokes on sides. It keeps on
bottom side of leaf, escaping from hot sunlight. Development of caterpillar
lasts about four months, and for one year the grieving swallowtail can give
two generations. This insect goes through driest months in pupal stage and
finishes metamorphosis in the beginning of rain season.
Altjira (Aepypapilio altjira)
Order: Butterflies (Lepidoptera)
Family: Swallowtails (Papilionidae)
Habitat: Meganesia, rainforests.
In human epoch New Guinea was known as a motherland of the largest butterfly
of the Earth – Queen Alexandra’s birdwing (Ornithoptera alexandrae) from swallowtails
family (Papilionidae). This species alongside with a plenty of bright tropical
insects had become extinct in epoch of global ecological crisis which had come
at the end of human epoch. In Neocene tropical rainforests had covered equatorial
areas of the Earth again. And there new species of insects had evolved, many
of which do not concede in beauty and size to the most known species of human
epoch. One of such species – is swallowtail butterfly altjira from rainforests
of the north of Meganesia. The adult butterfly of this species has wingspan
over 30 centimeters, and caterpillars reach the length of about 20 centimeters.
Such insects had evolved due to stable conditions and an abundance of food
in places of their inhabiting. The name “altjira” descends from mythology of
one tribe of Australian aborigenes – it is the name of the mythical lord of
sky.
Caterpillars of altjira feed on leaves of forest species of leguminous plants.
They are rather easy for seeing on the background of vegetation: the caterpillar
has black colouring due to which it is quickly warmed up after cold night and
has higher speed of metabolism. On the second thoracal segment caterpillar
has a pair of large oculate spots of orange color with short vertical stroke
in the middle. These spots imitate eyes of small reptiles. The first thoracal
segment is orange-red, and head is black, as the rest of body. The disturbed
caterpillar draws head in thorax, and thus the forward part of its body becomes
similar to head with opened mouth. In such way it frightens off birds. Also
it has one more way of defense: on thoracal segments odorous glands of bright
yellow colouring stuck out, emitting disgusting smell. With the help of such
smell caterpillar frightens off animals searching for food with the help of
sense of smell – reptiles and mammals. If both ways do not work, the caterpillar
shoots at the enemy by partly digested food, adding to it a secretion of modified
salivary glands, stiffening on air in gum-like mass.
Development of the caterpillar, having so numerous protective adaptations,
lasts about 3 months. The adult butterfly of this species looks very impressive
– long peaked front wings give to it the remote similarity to swallows. Forward
nerves on wings are thicken and very strong. Back wings are rounded, and at
their external and back edges some tails grow. Back pair of tails is very long
– at males they reach length up to 15 cm and extend on tips. Adults males of
altjira are colored blue with green metal shine and black front edge of the
wing. In the basis of back wing they have some small black spots. Females of
altjira are green with slight metal shine. On their front wings the thin cross
strokes are scattered, forming faltering mesh pattern, varying at different
individuals. Tails on back wings at representatives of both sexes are colored
black. At males on larger tails of back pair along the middle line the narrow
silvery strip stretches. The bottom side of wings at butterflies of both sexes
is colored similarly – it has yellowish-brown tone, imitating colouring of
dried leaf. In rest these butterflies hang on bottom side of branches and among
foliage, hiding in such way from predators. Body at butterflies of both sexes
is black with greyish-white longitudinal strip stretching from head up to tip
of abdomen.
Altjira flies quickly, and in flight tips of wings clap against each other
from above and from below of the body of butterfly with rather loud sound.
In courtship season male, displaying itself to the female, hangs before her
in air, loudly flapping wings. After courtship season tips of wings at males
look shabby, and their colouring fades up to semi-transparency.
Altjira feeds on flowers of various trees and lianas, not giving preference
to any separate species. Due to a long proboscis (up to 12 cm long) this species
can feed even on flowers inaccessible to metal
swallowtails – distant relatives
of this species. The maximal life expectancy of imago makes about 3 – 4 weeks,
but usually it is less. For the life the female has time to make up to five
clutches of 300 – 400 eggs in each one. The greatest death rate at caterpillars
falls to the first weeks of life, while at them all means of protection are
not advanced to the full.
Ribby
flower pierid (Petalopterina flosculimima)
Order: Butterflies (Lepidoptera)
Family: Pierids (Pieridae)
Habitat: dry woods and semi-deserts of Southwest Asia.
In wild each species of plants coexists with various species of animals, directly
or indirectly dependent on it. It happens, that any species of insects, for
example, lives on one plant, feeds on next one, and its larvae eat greenery
of third species. It happens on the contrary, when two species, plant and animal,
adapt only to each other, and evolve together.
In semi-deserts surrounding the dried up Mediterranean Sea, there are groups
of thick-trunk low true cabbage
trees (Brassixylon crassus) belonging to crucifers family (Brassicaceae).
For some animals these plants are unique source of moisture and food, and sometimes
the unique house.
In spring and in the beginning of summer when clouds from Indian ocean and
Tanganyika passage reach this droughty district and humidify ground, the true
cabbage tree begins to blossom: its crone is crowned by set of large inflorescences
with bright pink flowers. They will bloom not for long, and wind breaks them
from tree and carries away. It looks, however, that not all petals agree to
leave a tree so easily: some of them rather confidently fly against a wind,
and sit back on branches. At the nearest acquaintance it becomes completely
evident, that they are not flowers, and not plants at all, but animals – butterflies,
skillfully imitating by shape and colouring of body flower of cabbage tree.
This species of butterflies is named ribby flower pierid, and belongs to family
of pierids among which there are species, rather not indifferent to plants
of crucifers family. In human epoch some species of these insects were considered
as plant pests, but the nature had put the situation to rights when people
have disappeared and huge plantations, where one or two species of plants were
cultivated have become a thing of the past follow them.
Ribby flower pierid is rather large butterfly: the length of its body is up
to 5 cm, and wingspan reaches 8 – 9 cm. Rounded wings of this insect are colored
pinkish with dark red nerves. The body and antennae of the butterfly are yellowish,
covered with downiness of short hairs. In case of danger this butterfly imitates
flower of the true cabbage tree, on which it lives: it plants wings forward
and back as a cross, slightly raises them (it is the imitation of petals),
lifts up and bends on back the abdomen, lifting head with antennae (imitating
stamens and pestle). Its similarity to flowers is so great, that even in the
beginning of dry season when the tree has already faded, birds do not peck
butterflies sitting among drying up rests of inflorescences of cabbage tree.
The caterpillar eats leaves of the same tree, and for masking is colored green.
Usually these caterpillars sit on edges of leaves, eating soft tissues. After
them only “skeletons” of thickest ribs remains from leaves. Disturbed caterpillars
bend the forward end of body as letter S and belch swallowed and semi-digested
greenery, from which the disgusting smell emits. It is their unique protection,
and the part of them perishes in beaks of birds and teeth of lizards. But fertility
of butterflies of this species giving up to two generations during short rain
season, permits to compensate these losses. Butterflies of the first generation
are “early”: they are small, grow and perish quickly. From their eggs caterpillars
excluse, which gather weight during first half of droughty season, eating withering
leaves of tree. They pupate in cracks of ground and among vegetative dust.
The second generation of butterflies survives dry season at the stage of pupa,
and emerges after first rains of the next year.
“Winged guard” (Pugnatonymphalis lord-protector)
Order: Butterflies (Lepidoptera)
Family: Nymphalids (Nymphalidae)
Habitat: Far East, subtropical and warm-temperate areas, forests.
Forests are rich in various species of butterflies. Nature gives them a generous
choice of forages at any stage of development – from caterpillar to imago.
In tropical forests extremely specialized species of butterflies frequently
meet, connected in life cycle to unique species of fodder plants. And in temperate
and cold areas of the Earth butterflies may be very unpretentious in choice
of food. Besides of nectar, diet of adult butterflies includes other kinds
of food: tree sap (even fermenting), liquid of decomposed bodies of animals,
dung of large animals. However, some butterflies not feed in adult condition
at all.
Evolution does not stay, and frequently live beings can develop odd and unexpected,
but effective ways of survival. At the Far East one species of butterflies
had completely stopped to feed on flowers. This small (wingspan is about 6
cm) bright butterfly meets on large grassy plants where colonies of plant lice
have settled. This butterfly constantly keeps near the colony of plant lice
and drives the congeners away from it. For this feature it is named “winged
guard”.
The sugary liquid producing by plant lice is needed for “winged guard”. It
quite replaces nectar to the butterfly, and “winged guard” only occasionally
may be seen on flowers. Most likely, these ones are “tramps” at which the fodder
colony of plant lice was lost. Within several days such butterflies search
for new colony and continue to lead habitual way of life.
Similarly to ants, “winged guard” stimulates a plant louse to secret sweet
liquid. The butterfly sits in colony of plant lice and cautiously tickles insects
by short antennae. Replying to stimulation plant lice secret sweetish liquid
which “winged guard” licks off by short mobile proboscis.
Such food source is not as accessible, as flower nectar, therefore “winged
guard” is very territorial. Butterflies of this species leave on plants the
odorous marks warning congeners that the territory is occupied. Colouring of
top side of wings is very bright and clearly visible from apart: they are yellow
with black border on edge of wing. Black color of border is shaded with blood-red
strip. On bottom surface of front wings of “winged guard” has bright labels
– on grey background big there are white spots with grayish scales scattered
on them. Scales reflect ultra-violet part of solar spectrum, making the butterfly
especially visible for congeners. The back pair of wings has brownish bottom
side and brown external edge. When the butterfly hides from predators, it closes
bottom side of forward pair of wings by back ones, and light shine does not
give out its presence. The butterfly is very cautious: having noticed a flying
bird it closes wings, covers shining spots and simply falls in grass.
If the congener interferes to the fodder territory of “winged guard”, the owner
of territory protects colony of plant lice from strangers. Driving competitors
away, the butterfly arranges bloodless, but active “duels” in air, pushing
congeners aside from the chosen colony of plant lice. If the contender flies
at the edge of territory, the lawful owner of colony of plant lice flies up
and makes some circles along borders of territory. From time to time butterfly
stops in air for some seconds, trembling wings and showing ultra-violet “flashes”
on inside of wings. Other contenders of “winged guard” are ants. This butterfly
can make of nothing against them, and is content with feeding on plant lice
colonies located at the distance from ants colonies. If such colonies are not
present, butterfly makes a strike on colonies of plant lice occupied by ants,
and feeds while ants had not gathered for protection of plant lice.
At “winged guard” male has dimmer colouring, than female – on top side of its
wings there is no red strip, black strip is narrower, and background color
of wing is paler. It has no constant fodder colony of plant lice and leads
“vagrant” life, searching for females. Pairing at these butterflies lasts more
than one hour. Thus the female sits vertically on plant stalk, and male hangs
headfirst, having closed wings and having drawn legs in. Such position does
not cause inconvenience in him: pairing male simultaneously “plunders” fodder
colony of the female, actively licking off secretion of plant lice. It is its
basic source of food.
After pairing the female leaves for a short time the territory to lay eggs.
Caterpillars of “winged guard” feed on leaves of hazel grove and birch, therefore
fertilized female flies to the forest for searches of fodder tree. It makes
it in evening, in order to prevent congeners to occupy its territory. After
egg laying the female flies back, being guided by smell of its own labels.
For the life the female has time to make 3 – 4 layings numbering 200 – 300
eggs in each one. Caterpillars have not striking green colouring with brown
longitudinal strip on the top part of body. They keep on the bottom side of
leaves and skeletonize them.
For summer this species of butterflies gives two generations. Pupae of the
second generation hibernate. In spring their metamorphosis is finished, and
they turn to butterflies lead a way of life typical for this species.
Summer contravirgo (Contravirgo aestiva)
Order: Butterflies (Lepidoptera)
Family: Bears (Arctiidae)
Habitat: Siberia, areas overgrown with grass vegetation and bushes.
In Neocene Eurasia has remained huge landmass where the severe continental
climate dominates. Therefore in central part of this continent the period favorable
for active life of invertebrates is rather short. Evolution of insects in such
conditions frequently appears directed to development of adaptations permitting
as soon, as possible, to develop and to use resources of the environment more
economically.
In this sense among Neocene insects of Siberia moths from Arctiidae family
forming the separate genus Contravirgo are interesting. At these insects development
was sped up so, that they partly even have got ability to breed, remaining
in larval stage. The most common species of this genus is summer contravirgo.
The moth of this species flies in middle and in second half of summer.
For contravirgo the expressed sexual dimorphism is characteristic. The female
of summer contravirgo develops in usual order, turning from caterpillar to
winged imago up to 4 cm in wingspan. The female of this species of insects
is poisonous – it synthesizes poisonous substances, being a caterpillar, and
keeps them in the body after metamorphosis. Colouring of wings of summer contravirgo
is warning: front wings are white with clear black nerves. The bases of front
wings and thorax of moth are covered with rich black hairs. Back wings of summer
contravirgo are bright red with mesh pattern of shining dark blue nerves. Usually
adult insect is rather inactive: in day time the moth hides in grass and sits
on bottom side of leaves, having put wings V-shaped. The disturbed moth stretches
front wings and shows bright coloring of back wings. But in the evening adult
females of summer contravirgo fly, feed and search for males.
There is one more feature of shape of contravirgo – at females of these moths
feather-like antennae, fluffy because of additional hairs increasing sensitive
surface of antennae, are strongly advanced. Usually males of moths differ in
advanced antennae and sharp sense of smell, but at contravirgo the shape of
male is completely other, rather than at usual moths.
The male of moths of genus Contravirgo is actually reduced up to larva able
to pairing. Usually the survival rate of males at larva stage is higher, than
at females – they are smaller and keep secretively, therefore at larval stage
the number of males is more, than females. The male caterpillar of contravirgo
has dim grey colouring with greenish strip along the back and black strokes
on sides. It grows slower, than females, and undergoes less number of moults.
After last moult at it sexual glands roughly develop, and the body strongly
changes externally: the male caterpillar becomes bright orange, starts to creep
out on top side of leaves of fodder plant and emits the special smell attractive
to females. At this stage sexual glands filled with sperm liquid occupy about
the half of body volume of the male caterpillar. At it tenacious walking legs
similar to legs of adult butterfly of other species develop, but abdominal
false legs, characteristic for caterpillars, do not disappear. The head of
such male also gets separate features of shape of adult insect – eyes become
larger, and pectoral segments from above four small shoots appear – these ones
are reduced wings. Mouth parts of the male at this stage degrade, and from
them only nonfunctional rudiments remain. The oral aperture completely grows
out. In such condition the unique applicability of the male is to fertilize
the female.
The female flies involved by smell of the male, sits near to it and turns to
pose of pairing, having slightly stretched wings and having extended an abdomen
aside the male. The male creeps on the female, and goes with her to courtship
flight, having clung to her abdomen from below. The male keeps on body of female
by walking legs, enters in sexual ducts of the female all seed liquid which
was formed at him, and quickly perishes after pairing. Frequently it simply
falls down from the flying female on the ground.
Spermatozoids keep viability in sexual ducts of the female for a long time.
As against the male, after metamorphosis she can eat and lives for a long time
– about two weeks. For the stayed life she makes some clutches numbering 200
- 300 eggs each after the single pairing. Also for this time she can fly tens
kilometers, settling to new places of inhabiting. The female finds suitable
fodder plants, lays eggs and perishes usually after the first light frost.
Caterpillars of summer contravirgo are unpretentious regarding a feeding: they
eat leaves of various evergreen bushes wintering under snow. This species has
some externally indiscernible ecological races, feeding on different plants.
Eggs of contravirgo hibernate in dormant condition, and start to develop after
snow thawing. Caterpillars burst from eggs in early spring, and at once start
to eat. They are very hardy: during light frosts they simply remain on foliage
of fodder plant, easily tolerating freezing. After night light frost caterpillars
easily thaw and continue feeding. Being frozen and motionless, they could become
easy catch of various insectivorous animals, but they are protected with poisonous
bristles richly covering the body. At first stages of development caterpillars
of summer contravirgo of both sexes are similar in colouring to the male caterpillar
of advanced age.
Female caterpillars of advanced age have typically warning colouring – they
have black color with cross white strips. Besides the female caterpillar is
richly covered with hairs. These hairs easily break off and stuck in skin of
aggressor, causing irritation. Also they easily get in respiratory ways and
lungs, causing strong burning. Colouring of caterpillar is precisely remembered
by insectivorous birds or small mammals, and they leave alone dangerous larvae.
But in places of inhabiting of summer contravirgo there are some species of
birds able to eat caterpillars protected in similar way. Also ichneumons are
natural enemies of these moths.
In Siberia there is the close species of moths: hibernating contravirgo
(Contravirgo hibernata). This insect eats narrower set of forages, than summer contravirgo.
Fodder plants for hibernating contravirgo are poisonous species of buttercups
family. Therefore hibernating contravirgo more often lives in damper district
where there fodder plants necessary to it grow usually. This species differs
from summer contravirgo in larger size – the caterpillar of this moth feeds
for longer time and pupates later. Female caterpillars at this species are
much larger than males, grow faster and moult more often. They pupate an early
autumn, for some days before males. But the basic difference from summer contravirgo
is that the male in condition of caterpillar is more active. It finds by smell
and fertilizes females being at the pupa stage. Males of these moths also do
not turn to imago, but live longer, than at summer contravirgo, and perish
after fertilization of several females. The pupa of this species is protected
by poison which is received from fodder plants and is accumulated in hemolymph.
The female pupa hibernates and in spring the moth undergone the metamorphosis,
already lays fertile eggs on suitable plants. The female of hibernating contravirgo
has wingspan of about 6 – 7 cm. It also is colored very brightly – front wings
have black color with dark blue shade and slight metal shine. On back wings
of the female dark red irregular-shaped spots are scattered on white background.
The female of hibernating contravirgo does not search for males by smell; therefore
its antennae are rather short and only a little hairy. The imago of this species
eats nectar of spring flowers and lives for rather long time – up to three
– five weeks. The female lays eggs in several portions of 400 – 500 ones within
two weeks, and then perishes.
Two-shaped antivirgo (Antivirgo dimorpha)
Order: Butterflies (Lepidoptera)
Family: Bears (Arctiidae)
Habitat: Siberia, areas of landscape overgrown with grassy vegetation and bushes.
Some moths of bears family living in Neocene at the territory of Siberia had
developed expressed sexual dimorphism as a result of adaptation to rigorous
continental climate. At moths of genus contravirgo
(Contravirgo) males in fact
remain in condition of caterpillar and do not turn to normal imago stage. Very
sharp sexual dimorphism also had developed at moths of other close genus –
antivirgo. At this genus the female matures, remaining a caterpillar, and small
winged male does not differ by features of development from moths of other
species. It finds sexually mature caterpillar females and fertilizes them.
During the life male succeeds to fertilize several females. At non-fertilized
caterpillar females eggs also develop. During the first division chromosomes
in such cells do not separate and new cellular wall is not formed. From such
eggs females hatch exclusively. From eggs of fertilized female both females
and males excluse. Besides in ovoduct of growing caterpillar female eggs continue
to form some time after fertilization. Last portions of eggs in clutch of fertilized
female are unfertilized, and from them small haploid males develop.
Fertilized caterpillar normally undergoes metamorphosis and turns to imago.
Imago of antivirgo serves only for settling of species – it finds trees suitable
for development of caterpillars, lays eggs and perishes. Imago of antivirgo
of both genders does not feed, oral parts of these butterflies are underdeveloped.
Eggs of antivirgo winter, and in spring when growth of plants begins, from
them caterpillars burst.
Caterpillars and moths of genus antivirgo are protected from predators by poison.
7 – 8 cm long caterpillars of this species are covered in rich black hairs.
On black background the white longitudinal strip on back side of body is clearly
visible. It is warning colouring supported with effective way of protection.
Hairs of antivirgo caterpillars are poisonous and easily break off at the basis.
Sticking to mucous membranes they cause strong irritation and hypostasis. Caterpillars
of antivirgo produce poison by themselves. They feed on nonpoisonous plants
of various species – dogrose, hazel grove and large grassy plants. Male caterpillars
grow slower, rather than female ones.
Imagoes of this genus also are poisonous. Male and female of two-shaped antivirgo
sharply differ externally (hence the specific name of this moth). Male represents
small insect (wingspan is no more than 3 cm) of red-brown color with black
tip of abdomen and white spot on thorax. Wing nerves are a little darker, than
the basic background of wing colouring. The female is much larger, than male
– its wingspan reaches 7 cm. Front wings of female have cross-striped black-and-white
pattern; strips are irregular-shaped. Back wings are colored bright blue with
metal shine, contrasting with strict colouring of forward wings. The body of
female is covered with rich velvety hairs of cherry-red color. The disturbed
female opens front wings and displays shining of back wings. It supports the
warning of inedibility, emitting sharp bitter smell in air.
Antivirgo males fly in August, and imago females appear at the end of August
and in beginning of September. They fly till only some days, but appear simultaneously
in plenty. Females of antivirgo are most active within midday hours when their
body is well warmed by sun. Flight of antivirgo females marks the end of Siberian
summer.
Crab botfly (Carcinotaba vorax)
Order Two-winged flies (Diptera)
Family Horseflies (Tabanidae)
Habitat: South-Eastern Asia, Jakarta Coast, Sunda Land and nearby islands.
Among insects of two-winged flies order parasitism is widely spread. Some of
these insects suck blood (mosquitoes, midges, some flies), others parasitize
in body of large vertebrates (larvae of botflies). In tropics of Asia one of
species of horseflies has adapted to parasitizing on ground crustaceans. Adult
flies of this species suck blood of crabs and ground hermit crabs. Larvae are
predators as at the majority of horseflies. But their catch is not soil animals,
but eggs and young growth of the same crabs.
Externally crab botfly only a little differs from other flies. But at this
insect the sexual dimorphism is advanced. The male of this species eats of
nothing, and lives not for long time. It is colored white with the silvery
shine reflecting ultra-violet rays, and its eyes are emerald-green. It “displays”
on the lighted place on tree trunk, uttering characteristic buzzing and involving
females by specific smell. The female is colored grey with black longitudinal
strip; its eyes are brown. Right after hatching from pupa females search for
“displaying” males, pair with them and depart away. At females organs of smell
sense are very much advanced: it is necessary for search of the specific host
animal on which this species parasitizes. Right after pairing the female quenches
blood, and in its organism… not eggs, but at once alive larvae start to develop.
Having got to the host animal, they at once start to grow and develop.
For cultivation of posterity the adult crab botfly finds the female of crab
had recently laid eggs. Fly cautiously flies up behind, and sits on carapace
of crab. Having waited some minutes while the animal will calm down, the insect
strongly extends an abdomen, and postpones in cavity between cephalothorax
and abdomen of crab the live larva covered only with thin film. If the crab
is large (this insect frequently parasitizes on huge “mangrove
robber” crab (Archocancer mangrophilus), some larvae can get at once to
it. The larva of crab botfly at once starts to eat eggs of crab, and frequently
destroys them
almost completely. If it does not suffice eggs for feeding, larva can bite
through covers of crab and lick off flowing out blood. In case of shortage
of forage one larva can to have eaten other ones if they appear together on
one crab. Having fattened up to the necessary size, the larva abandons a body
of crab, and falls in wood litter. Having buried in the ground, it pupates,
and in one week turns to adult insect.
This species was discovered by Arseny Zolotnikov.
Bird leechfly (Bdellomusca ornitina)
Order: Two-winged flies (Diptera)
Family: Leechflies (Bdellomuscidae)
Habitat: temperate, subtropical and tropical areas of Old World: Eurasia (except
for Siberia and Beringia), Africa, Zinj Land.
Two-winged flies represent successful group of insects in evolutional aspect.
They are cosmopolites and occupy great amount of various ecological niches.
Some species had developed even hyperhaline reservoirs of Mediterranean hollow,
and others became predators in this inhospitable area. But nevertheless the
majority of two-winged flies lives in less extreme conditions.
Among two-winged flies there are many parasites of other animals, including
vertebrates. These insects parasitize at various stages of development: some
ones at larval stage and others in adult condition. In Neocene in Old World
representatives of new family of two-winged flies, leechflies, had widely settled.
These insects are adapted to parasitism on vertebrate animals of various species.
Some species of these flies are highly specialized parasites of separate species
of vertebrates, and others use wide set of species for feeding. Leechflies
bear live larvae which destiny at different species develops differently. Some
species leave them directly on skin of the host (usually it is characteristic
for highly specialized species); at such species fertility is small, but larvae
are larger, and also survival rate of posterity is higher. Other species leave
larvae in places of most probable occurrence of possible hosts, and do not
care of posterity any more. At such species larvae are small, and their survival
rate is lower, because they not always succeed to find suitable host in time.
High fertility of such species (up to 200 – 300 larvae from one female) compensates
death rate of posterity. Right before metamorphosis the length of leechfly
larva 2 – 2,5 times exceeds length of adult individual. Imagoes at all species
of leechflies eat other food, rather than larvae: rotten organic material,
dung of animals, nectar. Depending on breeding way the shape of these insects
differs. At leechflies leaving larvae directly on body of host, the sexual
dimorphism is sharply expressed. Males of such species have bright and beautiful
colouring, and females have ordinary-looking grey or black colouring, and differ
from other species of flies only a little. The species which simply leave larvae
in suitable places, have bright colouring with metal shine at both genders.
The way of breeding is precisely connected to the size of adult individual:
more prolific species are larger, than specialized ones. On tips of wings of
leechflies there are dark spots; at males they are larger, than at females.
Females of leechflies also have the feature connected to gender: on their back
pair of legs special attaching hooks and suckers are advanced, permitting to
keep on the body of the host.
Larvae of leechflies differ from larvae of other species of flies in few features
of anatomy. They have worm-like segmented legless body and lack the expressed
head capsule. But, as against larvae of other flies, larvae of leechflies have
a special sucker with hooks on forward end of body. Having searched the suitable
host, larva of leechfly sticks to its body and drinks its blood. The larva
sticks to skin where it is thin or where there are wounds. It keeps on skin
of host with the help of attaching hooks. At some species there are additional
hooks on body segments. Larvae of flies lack mandibles with which help it is
possible to gnaw through or to pierce skin of host. Therefore they solve a
problem of feeding rather simply: larvae produce active digestive enzymes which
dissolve the top layer of skin of host animal and stick to the wound. Due to
action of digestive enzymes of leechflies larvae wounds made by these larvae
do not get inflammation and do not fester, and after striking off of the parasite
heal rather quickly. The saliva of leechfly larva contains the substance interfering
blood fibrillation and rendering local anesthetizing effect.
Larval stage is limiting part in settling of these insects. The adult insect
is well protected from drying by chitinous armour, but larva has thin covers
and rather quickly loses moisture in dry air. Therefore leechflies meet mainly
in areas, where air is damp – in forests and near reservoirs.
Bird leechfly parasitizes on various birds living in forest canopy, and is
the typical representative of family. Its length does not exceed 5 – 6 millimeters.
The female of this species has grey colouring with darker thorax, and reddish-brown
eyes. Male strongly differs from the female in appearance – it is larger and
has golden-yellow colouring with metal shine. This insect meets in forests
of Southern and Southeast Europe. It attacks small birds, mainly passerines,
but occasionally meets on birds of other taxonomic groups.
Males of this species are easily appreciable: during the most part of summer
they arrange courtship flights. Males display themselves to females, flying
in forest canopy. Involving the female, male can stop for a long time in air
in ray of sunlight appear through forest canopy. If the competitor appears
near, male rushes to it and drives it away. If the female moves nearer to male,
it arranges chase for it, from time to time stopping in air and uttering special
hum of higher tone. Pairing occurs in air and lasts for some seconds.
After pairing in ovoduct of female larva starts to develop. It eats secretions
of walls of ovoduct, and quickly reaches the weight of approximately one third
of weight of adult female. When the larva is ready to independent life, the
female searches for host bird of suitable size. Usually the female of leechfly
leaves larvae on skin of birds in the evening or in the morning when bird is
less active. The insect creeps under plumage of bird, and tries to find by
smell the injured site of skin of bird. When suitable place is found, the leechfly
female gives rise to the larva which at once starts to feed. Newborn larva
attaches to skin of bird by viscous secretions of special glands on the bottom
side of body and starts to suck blood.
Development of larva lasts about five weeks. Thus, till the summer bird leechfly
can give three, and in warm years even four (at the south of area up to five)
generations. At leechflies pupae winter.
The stuck larva eats almost continuously. Nevertheless, it adequately reacts
to world around. When bird cleans feathers or searches for parasites, larva
unfastens from wound and starts to creep between feathers quickly, escaping
from beak of bird. When conditions become quieter, it finds by smell the place
of feeding, and continues blood sucking. When development of larva comes to
end, it leaves the host and pupates in moss growing on branches. Larvae of
other species of leechflies pupate in wood dust, forest litter, or in soft
ground.
This genus includes many species differing by habit of life:
Hollow leechfly (Bdellomusca alveophila) lives in forests of Europe from Atlantic
up to Three-Rivers-Land steppes and parasitizes on wide spectrum of species
of animals – its larvae feed on bats, small carnivores, various birds. This
species is easily distinctive from other leechflies by reddish-brown colouring
with faint shine, and by bright orange eyes at insects of both genders. Hollow
leechfly belongs to largest species of genus – the length of adult insect reaches
10 – 12 mm. Fertility of this species makes up to 30 – 40 small larvae for
one laying. The female leaves them not on skin of the host animal, but in hollows
of trees where the probability to meet suitable animals for feeding is more.
Larvae not constantly live on animal, but only temporarily stick to it for
feeding. They prefer to attack bats at which wing membranes are plentifully
penetrated by blood vessels. Adult individuals eat fermenting tree sap and
fruits of plants beginning to rot: yeast are the main component of food of
imago. For one year this leechfly gives only two generations.
Burrow leechfly (Bdellomusca subterranea) lives in Three-Rivers-Land steppes,
at Balkan, at the edges of Mediterranean swamps and in savannas at the north
of Africa. It parasitizes strictly on burrowing animals – digging mammals and
their neighbours (usually on birds). Very seldom larvae of this species may
be met on lizards and toads. Adult insect is about 8 mm long and has grey color
with metal shine. On each segment of body larva has a fringe of short strong
bristles permitting to keep more durable on body of host animal.
Corroding leechfly (Bdellomusca dermatolysa) is the largest species of the
genus living in Southern Europe and Southern Asia (to the south from Himalayas
mountain circuit). Length of adult female of this insect is about 15 mm; male
is about 10 mm long. Male has contrast colouring: body has copper shade, reddish
metal shine and green eyes. Female is yellowish-grey with black longitudinal
strip on abdomen. This species of flies parasitizes on large mammals. The larva
is well adapted to reach blood vessels through thick skin of host animal. It
injures skin producing active digestive enzymes. Usually the forward part of
body of larva is immersed in skin of mammal. The disturbed larva quickly gets
out from the wound and tries to hide in wool of host animal. The female gives
rise to large larvae (about 30% of weight of the female) with periodicity in
2 – 3 days, sitting on skin of large mammals. Adult individuals feed on dung
of mammals.
Predatory leechfly (Bdellomusca rapax) from North Africa and Western Europe
represents the exception among representatives of genus. Its larva is not an
ectoparasite, but an active predator. It feeds on large mammals and birds.
The adult individual of this species feeds on flowers; its proboscis is long
enough, and helps to reach nectar in deep flowers. As against the majority
of leechflies which females have dim colouring, at this species the female
is colored silver-grey with green eyes. Male, on the contrary, is coal-black
with metal shine. It also has green translucent eyes. The animals, instinctively
feeling danger of blood-sucking insects, are not afraid of this leechfly. It
freely creeps on the body of large animals, and leaves on their skin large
larvae. Young larvae of predatory leechfly exhaust parasitic insects and ticks
(especially sated of blood), and later start to swallow them entirely. Larva
pupates in ground.
Representatives of close genus of aquatic leechflies (Aquabdellomusca) are
even more adhered to humid habitats. They parasitize on various amphibians
and other water vertebrates. Their larva has the special adaptations, permitting
to receive oxygen from water - on its body segments long elastic outgrowths
penetrated with tracheal tubules develop. When larva is in water, its stigmas
close, and outgrowths extended and promote gas exchange - oxygen from water
diffuses through thin covers directly in tracheal system. Besides at larvae
of aquatic leechflies additional attaching hooks on two back segments of body
develop – it is the adaptation which permits the larva to keep on the body
of host at its movement in denser environment.
Duck leechfly (Aquabdellomusca anatina) lives on bottom part of body of waterfowl
– ducks and grebes. It has very wide area – from Fourseas and rivers of Southern
and Southeast Europe up to Equatorial Africa and South Asia. The settling of
this species is obviously connected to migratory ways of European birds. The
length of adult individual of duck leechfly does not exceed 6 mm. The female
has dark grey color with white points on thorax and the first segments of abdomen.
Male is bright green with metal shine. Eyes at individuals of both genders
are orange-red.
The imago of this species feeds on rotten parts of water plants, and frequently
meets at the coast of reservoirs in innumerable flights. Adult males and females
form the common swarm, and feed in common. After pairing when in ovoduct of
the female some small larvae start the development, it searches for the host
bird suitable for the posterity. The female cautiously sits on plumage of bird,
and waits, while the bird will calm down and the will cease to pay attention
to it. Then the female creeps in plumage of bird, and quickly bears several
larvae on its skin. Larvae creep, find blood vessels stretching close to skin
surface, and stick to it. When the bird dives, in its plumage the layer of
air which permits to larvae to breathe is kept. At larvae of this species adaptations
to inhabiting in aquatic environment are expressed in lesser degree.
Frog leechfly (Aquabdellomusca ranophila) parasitizes on frogs of various species.
It reaches length of 6 – 7 mm and lives in tropical and subtropical areas of
Old World. Females of this insect have expressed camouflage colouring varying
at different populations from sand grey up to brown and black. Eyes at females
have about the same color, as a body. Males of this leechfly sparkle golden-yellow
colouring with greenish metal shine and emerald-green eyes. They keep near
swamps and marshy areas of river channel, gathering to dense swarm. When the
female flies nearer to the male congestion, they rush to chase her, and only
after several minutes of chaotic flight one male is coupled to the female.
The female shows very big care, searching for the host animal for larvae. Having
found a frog, the female of frog leechfly flies behind where frog does not
see it, and cautiously creeps nearer to the frog. Some last steps it moves
an abdomen forward, having extended it. The female of leechfly slightly touches
skin of frog, throwing out the larva on frog skin by contraction of muscles
of abdomen. The larva at once is attached to the body of frog, and only after
that starts to search on its body for a place suitable for feeding. The body
of larva is translucent, and is poorly appreciable on the background of motley
skin of frog.
Turtle leechfly (Aquabdellomusca testudophaga) is the largest species of genus.
Its length is about 15 mm. It inhabits areas where turtles live – tropics of
Old World from Equatorial Africa up to Japan Islands. This insect has copper
red colouring, and male differs from female only in yellow color of eyes (at
females they are brown) and presence of black spots on wings. This insect leaves
larvae on bodies of various turtles - from huge African crocoturtle up to small
turtles of Southeast Asia. The female bears larvae on back part of body of
turtles, near the basis of tail and under carapace. Larvae are covered with
dense cuticle, and tracheal gills at them are advanced only on last segments
of body. The adult insect feeds on decomposed corpses of various animals.
Flat-bodied leechfly (Aquabdellomusca platysoma) is named because of body shape
of the larva, which is very wide, and resembles flat cake in rounded outlines.
On edges of larva body the additional suckers develop from plicas of integumentary
tissues, permitting it to keep on smooth skin of host animals. This species
lives in Southeast Asia and parasitizes on body of amphibians living in quickly
current mountain rivers. More often this leechfly attacks flat
toads. The adult
fly keeps in thickets of wide-leaved grassy plants, on the bottom side of leaves,
waiting while in thickets amphibian of needed species appears. Attack of the
female of flat leechfly is very fast – during a split of second it “shoots”
to flat toad the larva, and simultaneously throws out a drop of sticky secretions
which help the larva to attach to the body of host animal. Flat leechfly is
rather large insect: the length of adult individual makes about 15 mm. It has
massive constitution (the specific name is determined exclusively by the body
shape of larva) and heavy slow flight. Therefore adult flat leechflies prefer
to lead a secretive way of life. Bodies of imagoes of both genders are ruby-red
with metal shine, and eyes are bordered by thin silvery strips. The same strip
stretches along the abdomen. At males of this species wings are almost entirely
black; only back edge of wing is transparent. Imagoes of this species are active
in twilight and eat pulp of rotting fruits.
Fourseas leechfly (Aquabdellomusca tetramarina) is found in thickets of reed
and giant cat's tail at the coast of Fourseas, and is especially numerous at
the southern coast and at Caucasian Peninsula. This species is a polyphage;
larva feeds on various birds and frogs. By habit of life the larva of this
species considerably differs from other species. At the majority of species
of leechflies the female by the behaviour provides contact of larva and host
animal. At Fourseas leechfly larva leads mobile way of life and searches for
the host animal itself. It waits for approach of suitable host, having hidden
in leaf axils of marsh plants like ground leeches of tropical forest. Larvae
of Fourseas leechfly are rather large. During the life the female can give
birth up to 50 such larvae. It leaves them in leaf axils of huge cat's tail
where the small amount of water gathers.
Adult Fourseas leechfly feeds on corpses of various animals. It is rather easy
to define because of bronze colouring of body with reddish metal shine, and
of golden-yellow eyes with tiny black points. Male and female at this species
are similar to each other, and differ only in colouring wings – at male they
are darker.
The idea about existence of present group of insects is proposed by Nem, the forum member.
Millipedes
|
Tear gas millipede (Lacrimacausa irritans)
Order: Snake millipedes (Juliformia)
Family: Snake millipedes (Julidae)
Habitat: Great Antigua, underbrush of rainforest.
Millipedes are among the most ancient terrestrial animals of the Earth. Having
evolved in Devonian, they had safely gone through the time of human domination,
and in Neocene had kept their positions in ecosystems.
The main protective weapon of millipedes includes various chemical substances.
Some of them have strong poison and inject it in wounds during the sting.
Others, escaping from the enemy, secret odorous substances with addition
of hydrocianic acid vapor. Third ones leave a trace of the caustic substances
irritating skin.
In Neocene one of millipedes living at the island Great Antigua, had developed
even more effective way of protection against enemies. This species named
tear gas millipede lives in underbrush of rainforest. When this millipede
feels danger, it emits a mix of easily evaporating substances which influences
as tear gas (its Latin name literally means “the reason of crying”) and strongly
irritates mucous membranes of predator.
Presence of such way of protection is very useful for tear gas millipede
– it does not have other ways of protection against enemies. By the nature
it is peaceful sluggish animal. The length of tear gas millipede reaches
20 cm, and thickness of cylindrical body is up to 15 mm. In its body it is
totaled 60 segments. This species lives on the ground, and only if necessary
can dig in rotten foliage. Occasionally the tear gas millipede gets on trees
by thick stalks of lianas.
Tear gas millipede is herbivorous one; its diet mostly consists of fallen
leaves and mushrooms. However, tear gas millipede eats snails and carrion
equally willingly. This animal belongs to large group of snake millipedes,
and has practically all their typical features. Though on each body segment
except for first three ones at tear gas millipede there are two pairs legs
(it is the common feature of snake millipedes), it can not escape from the
enemy by flight – legs are too short. But it is no need in speed because
the chemical protection of this millipede is very reliable. It is supported
with bright orange colouring of body, and across the body on each segment
the strip of silvery color passes, that makes tear gas millipede more beautiful
and appreciable from apart. On back end of its body one more protective adaptation
is located: two terminal segments of body are colored black with two white
points on sides. They form “false head”, which distracts attention of predator
from the true head of tear gas millipede.
This species of millipedes breeds the year round. The female lays eggs by
small portions of 20 – 30 ones. For each laying it builds a special nest.
For this purpose the female digs small jug-like hole by the back end of body.
It loosens the ground by legs and densely stamps walls of nest. Thus special
secretions from glands on one of segments cement the ground and disinfect
an internal part of nest.
From eggs larvae with small amount of legs hatch. First weeks of life they
eat only mycelium of mushrooms, later start to eat foliage processed by fungi,
and only after reaching of about one third of length of adult individual
begin to eat just fallen leaves of trees, rich in cellulose.
Tiger millipede (Bradyjulius rubro-nigrum)
Order: Snake millipedes (Juliformia)
Family: Snake millipedes (Julidae)
Habitat: humid forests of Japan Islands.
Warming in Neocene had caused expansion of area of tropical climate at the
Earth. The abundance of food and rather equal temperature conditions favoured
to occurrence of large species with long cycle of development among Neocene
invertebrates. Warming had caused the development of humid tropical forests
at the southeast of Japan Islands, at mountain slopes, open to winds from
Pacific Ocean. As in any tropical forest, in wood litter of humid forests
of Japan Islands the set of invertebrates lives – beetles, cockroaches and
large snails. Also the largest ground invertebrate at the islands, large
millipede named tiger millipede, lives here. This is an animal with cylindrical
body up to 20 cm long and about 3 cm thick. In body of this millipede it
is about 100 segments.
Despite of large size, this animal does not represent danger to other inhabitants
of underbrush. It is a harmless species of ground invertebrates, the exclusive
vegetarian eating mushrooms and fallen foliage. The body of tiger millipede
is covered with strong armour. Wide and flat head helps it to dig in ground.
Such feature helps this millipede to dig out underground fruit bodies of
truffle mushrooms, which tiger millipede can sense through the 10 – 15-centimetric
layer of ground. Eating mushrooms, this millipede carries their spores. Also
tiger millipede can eat tubers and bulbs of various grassy plants. But all
the same in its diet fallen leaves of various plants prevail. These millipeds
have an important role in processes of decomposition of organic substances
in forest.
This millipede has short antennae, developing under the bottom part of head
during ground digging, and very small eyes. Eyesight at this species is very
weak: tiger millipede confidently distinguishes only light and darkness,
and can distinguish movement of large objects around of it. However, it is
not required to it of sharp sight – food is always present near it and does
not disappear anywhere. And tiger millipede is reliably protected from predators,
though is not able to bite at all. Weak mandibles are a common feature of
snake millipedes, and it is not an exception.
This large millipede is difficult for not noticing in forest: it has very
bright colouring seen from apart. Tiger millipede has red body with cross
black strips – one stripe on each segment. It is warning colouring, and any
predator, had not stopped the attack in time, in the full can test all abilities
of protection of this millipede.
Under attack tiger millipede instinctively turns body off as a spiral, having
hidden head in coils of body. It already should become the warning for predator,
because after it this animal will involve the second line of defense. Tiger
millipede is poisonous, and, being disturbed, lets out easily evaporating
liquid with the unpleasant smell, containing a plenty of formaldehyde and
organic acids. Having got on skin of aggressor, this liquid causes strong
inflammation, which lasts till some days, but seldom comes to an end in fatal
outcome. Usually only frogs and toads die from the poison of tiger millipede,
because their naked skin is very sensitive to its secretions. Due to the
effective chemical weapon of this millipede, there are some imitators at
tiger millipede – one small
species of snakes and large ground flatworm.
As they also are protected, though weaker, than this one, these three species
form a “ring”, and represent a good example of Mullerian mimicry.
This species of millipedes arranges spectacular courtship rituals. For breeding
a plenty of these millipedes gathers. The congestion may occupy up to hundred
square meters, and on each square meter it may be up to two hundreds of animals.
All of them emit a specific sharp smell which is felt from the large distance.
In such congestions individuals of opposite genders find each other and are
coupled within several hours at night. It is interesting, that smell emitting
by these millipedes involves some local birds very much. Breeding congestions
of this millipede are frequently visited by local bird forest
ronin (Roninornis mortifer). These birds usually aggressively relating to congeners do not
pay attention to each other, sitting among creeping millipedes. They fluff
feathers and try to come nearer to the greater congestion of tiger millipedes.
Obviously, birds in such way get rid of parasites living in their plumage.
The female lays eggs, having dug by back part of body in friable ground near
roots of tree. In clutch of this species there is up to 50 large eggs, and
such clutches may repeat each 2 weeks. The young animal reaches the size
of adult individual only at the second year of life.
Arachnids
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Four-legged net spider (Tetrapodarachna tetramana)
Order: Spiders (Aranei)
Family: Orb-web spiders (Araneidae)
Habitat: rain tropical forests of South-Eastern Asia, rainforest canopy.
During the evolutional history spiders had developed various ways of prey
trapping: from simple chasing up to web traps reaching sometimes a high degree
of refinement in design. The majority of spiders trap catch, having stretched
web constructions among branches. But some spiders hunt by special way, combining
features of hunting spiders and spider web builders. The Neocene inhabitant
of woods of South-Eastern Asia, the representative of orb-web spiders, four-legged
net spider is those.
It is a large spider: the length of body is about 6 – 7 cm from which big
rounded abdomen accounts about 60 per cent. The cephalothorax is wide, in
its forward part there is an eminence on which eyes are located: two large
shining eyes look forward, and six ones provide the circular field of view.
The cephalothorax is covered with rich hairs of black color. Abdomen is cross-striped,
“wasp-colored”: on black background there are yellow cross strips. Legs are
light green with longitudinal black strips on top side.
Woods of South-Eastern Asia differ in changeable weather. Here is rainy every
day, and rain is accompanied with strong winds from ocean. Therefore four-legged
net spider does not arrange huge nets: they may be frequently torn by wind.
This representative of arachnids has no constant shelter: it hunts, wandering
over branches and lianas of forest canopy in searches of catch, similarly
to representatives of hunting spiders of family Lycosidae. Each shelter happens
occupied in succession of some days, and then spider leaves it. But this
species of spiders also is not stopped weaving web, though it makes it extremely
originally.
Legs of four-legged net spider are of different length: first two pairs are
very long, approximately twice exceeding length of cephalothorax and abdomen
taken together. Two back pairs of legs are much shorter, only one and half
times longer than the body of spider. Such structure is connected to features
of web weaving. For this purpose the spider rises on two forward pairs of
legs, and begins making of web on tips of two back pairs of legs. In the
beginning it connects claws of back pairs of legs by basis strings, then
stretches between them radial basic strings, and braids them by sticky circular
string. The web of characteristic circular form, by length and width approximately
equal to body of spider turns out as a result. When it is ready, spider gradually
takes its corners by long legs of forward two pairs, changing them one by
one. At the end of this operation it stands on two back pairs of legs. When
the web appears stretched on long forward legs, it is ready for hunting.
The hunting spider moves on two pairs legs, making short dashes and jumps.
The web is always ready to prey catching: the spider holds it above eyes,
having stretched asides. Having noticed suitable catch (any small animal
from cockroach up to tiny lizard), the spider drives it by jumps, or simply
moves down from above on web string, and covers catch by web.
The female of this spider looks and behaves so. The male of four-legged net
spider is much smaller than the female similarly to males of the majority
of spiders. This creature is more similar to large ant - at it there is narrow
cephalothorax colored black. Such coloring combined with the body shape gives
him quite good chances of escape from insectivorous birds. For improvement
of masking it holds up a forward pair of legs put up before head, imitating
ant head.
In courtship season the male should be especially cautious: if it will approach
to the female too close without the appropriate ritual, she simply will “swaddle”
him by web, and will have eaten. Therefore ritual of acquaintance at this
spider begins from very cautious acquaintance of the future parental pair.
The male defines shelter of the female by smell, cautiously sneaks to it,
and leaves odorous labels. Just in case he keeps near suitable shelters,
ready to hide at the first threat from the side of female. But gradually
the female gets used to his presence, and once the male begins courtship
dance near her dwelling. During this ritual the male imitates the actions
made at prey capture. Only he holds simply plant leaf or the bird feather
in two forward pairs of legs instead of web. The male “covers” by this object
an imagined prey, but does not finish action, being limited only by “prey
capture”. If the female does not show aggression, the male “presents” her
with this object, and while the female holds it in cheliceras, quickly couples
with her. After that the male occasionally succeeds to escape, but more often
the female eats him.
The female of net spider lays up to 200 eggs simultaneously. She keeps them
in web cocoon, carefully clearing it from dust and preserving from damages.
Approximately in ten days the posterity hatches from eggs. Young spiders
first days “ripe” in cocoon then leave it and get over on back of the female.
Having got stronger, they start to lead independent life. First time young
spiders hunt plant lice and small termites, and then start to attack larger
and better protected insects: ants and beetles.
Mangrove
fishing spider (Arachnopiscatorius mangrophilus)
Order: Spiders (Aranei)
Family: Orb-web spiders (Araneidae)
Habitat: Meganesia, mangrove thickets of Eyre Gulf.
Among spiders there are only few species leading completely aquatic habit of
life – only separate species do it. For comparison, among insects representatives
of several orders had developed aquatic inhabitancy, and they spend in water
whole life, or any stage of development (usually larval one). However, the significant
amount of species of spiders leads near-water habit of life, and even has skills
of catching of water animals. One of such spiders lives in thickets of marsh
plants of Eyre Gulf in Meganesia.
Eyre Gulf represents shallow-water reservoir with variable salinity of water
in which action of ocean inflow is felt. Two times per day water of gulf directs
to the ocean over sandy shallows in mouth, and two times in day it is replaced
with tidal wave from ocean. As a result the water level in gulf strongly fluctuates.
Rivers drift in some places of gulf a circuit of small sandy shallows and islets
separating from gulf extensive sites of quieter water. At these shallows original
“mangrove forests” made mainly of Pandanus trees grow. Among sites of such forest
various animals find shelter and food – birds, insects, mollusks and other animals.
One inhabitant of Pandanus thickets in Eyre Gulf is a large spider of reddish-brown
color with white spots on abdomen. The length of its massive abdomen reaches
4 cm, and leg span exceeds 15 cm. It is mangrove fishing spider which has adapted
to inhabiting in changeable world of mangrove forest.
Mangrove fishing spider is very poisonous animal – its sting may kill pig-sized
animal in some minutes. Signaling about presence of such strong weapon, mangrove
fishing spider has developed very bright and appreciable colouring. All legs
of this spider have cross-striped colouring of wide brown and snow-white strips.
On reddish-brown abdomen of spider white strokes form a rough border, and along
the middle line of abdomen the strip of white round spots is stretched. The cephalothorax
of this spider colored white is covered with short velvety hair; pedipalps and
killing cheliceras have black colouring. The body of spider is covered with water-repellent
hair, which keep air layer on abdomen and permit the spider to breathe any time,
having plunged in water. Legs of forward pair are very long – their length is
up to 10 cm.
Eyes at this spider are large and shine green light in darkness.
Mangrove fishing spider lives in thickets of Pandanus and keeps on border of
usual level of inflow. This spider is too heavy to be able to swim. Nevertheless,
its food is made of various water animals. This spider builds webs, having the
characteristic circular form, among trunks and roots of Pandanus and other plants.
It is engaged in construction and repair of web during the outflow time. The
web of mangrove fishing spider is strong and elastic enough to sustain rather
strong tidal wave. All way of hunting of this spider is designed for rough waves
of inflow and outflow. At this time in web prey gets – fish fry and small crustaceans,
crabs and shrimps. At hunting for such prey having slow metabolism it is very
important to kill it fast; the strong poison of spider is designed for it.
Web is plaiting so that spider has convenient place above it. If there is no
firm support, spider makes for itself small web of dry strings, forming similarity
of a hammock. During inflow and outflow mangrove fishing spider keeps front legs
on web, thus its body is outside of water. Having felt presence of prey, it slips
in water (approximately up to half of abdomen length) and seizes prey by front
pair of legs. It accurately breaks off strings of web keeping prey, and kills
it by sting. During the hunting spider keeps by one of back legs for strong “safety
cable” made of web.
Male at this species is lighter than female in some tens times, but it is equally
poisonous. The most part of time it leads the same way of life as the female,
but hunts smaller prey. In courtship season male finds the female and starts
cautious courting ritual. When female catches prey, male cautiously comes nearer
to web from the side and cautiously starts to pull web in special rhythm, warning
the female about its presence. When the female replies the male with a special
signal, he cautiously comes nearer to her, keeping in sight and observing a distance.
At the slightest sign of aggression from the part of the female male hides and
begins courting all over again.
Pairing at these spiders occurs quickly, but it is preceded with special preparation
– male at first ties legs of the female together by web. After pairing he has
some minutes to leave a web of female and to survive. But approximately in one
case from four it has not time to make it, and becomes a prey of the female.
The female lays about 200 eggs in large cocoon of strong web which she always
carries in back legs. For young spiders she makes a special “children’s” web
above the maximal inflow level, and feeds posterity, bringing prey to “children’s”
web. Young spiders quickly leave parental nest and settle, flying on web thread.
Many of them perish in waves of Eyre Gulf and become prey of fishes. But the
part of young spiders survives and reaches places, suitable for life. The first
months of life they hunt small invertebrates with the help of simple web traps,
and only having reached the size of approximately one third of the length of
adult individual, start to make underwater webs.
Heraldic spider, shield-spider (Heraldarachne scutiferus)
Order: Spiders (Aranei)
Family: Wolf spiders (Lycosidae)
Habitat: Southern and South-Eastern Europe, Balkans, coast of Fourseas, Caucasus;
humid subtropical woods.
In Neocene when the significant warming of climate had taken place, borders
of natural zones had changed: the border of humid deciduous woods had moved
far to poles. It appeared especially appreciably in areas close to ocean
and seas while the central areas of Eurasia had remained a zone of sharply
expressed continental climate. In Europe the climate became warmer and humid
due to influence of Fourseas – huge brackish lake. It promoted the occurrence
of the zone of humid evergreen subtropical forests along western and southern
coasts of Fourseas. The fauna of these places is almost as rich, as in subtropics
of Holocene epoch. But it is formed mainly by descendants of European species
– from the south these woods are separated from Africa and South Asia by
mountains, and primal tropical groups of animals and plants are submitted
in them by separate species.
In warm tropics and subtropics arthropods are very diverse and often reach
large size. Among them as in the world of vertebrates, there are predators
and prey. Spiders are one of main predators among arthropods. One large species
of spiders, obviously the descendant of European wolf spiders (Lycosa), lives
in forests of Balkans. The length of its body is about 8 cm, and legspan
may reach about 12 cm. This creature lives on trunks and branches of trees,
and leads the vagrant habit of life, spending night in casual shelters. Its
appearance differs from habitual shape of spider: this is flat creature with
tenacious legs and very originally-shaped abdomen. The abdomen of this spider
is expanded, its top part is extended forward and hangs like cap peak above
the cephalothorax. The first line of abdominal shield is expanded and is
bend a little. The abdomen of animal at sight from above resembles the Medieval
French knight’s shield, and its coloring strengthens this similarity. For
it the spider is named shield-spider, or heraldic spider. At quietly creeping
spider the forward part of cephalothorax with eyes juts out from under “cap
peak”, and animal has good circular field of view. In case of danger animal
completely hides under abdominal shield, moving it on body from above. Thus
due to cryptic colouring and shape spider becomes indistinguishable from
any outgrowth on tree bark. In case of need heraldic spider can defend from
enemies by stings. Its main enemies are birds searching these spiders with
the help of sight and simply pecking them having pressed by paw against bark.
This spider has kept features characteristic for wolf spiders: it also does
not build a spiderweb, and catches prey, suddenly snatching on it by jump.
Its catch often appear moths spending day on tree trunk. Occasionally heraldic
spider catches even young frogs and lizards. Cheliceres of this animal are
long (up to half of cephalothorax length), their sting is poisonous and dangerous
to pigeon-sized birds. Heraldic spider has fine sight: it has two large forward
eyes giving the stereoimage of high quality. Four lateral eyes are small,
and the back pair of eyes is shifted upwards, enabling an animal to see everything
happening behind of it.
Legs and bottom part of body of heraldic spider are covered with hairs, and
top part of shieldis hairless with wrinkled surface – it imitates bark of
tree well. Colouring of shield of heraldic spider is cryptic: on brown background
there is a pattern of grey and yellowish spots and points, forming figures
approximally similar to heraldic figures. Under the armour this spider is
colored much brighter, rather than outside. The bottom surface of shield
at the male is covered with red hair reflecting light and giving to inner
side of shield silky shine. Bases of walking legs of the male are coal-black,
and legs are cross-striped black-and-white. At the female the inner side
of shield is colored red-brown color, and bases of striped legs are covered
with hair of bright blue color.
The male of heraldic spider is approximately 20% lighter, rather than the
female. Such small difference in weight permits it to avoid lethal outcome
after pairing which is very characteristic for many spiders. The male ready
to pairing actively searches for females, running on tree trunk. It tries
to keep in places where through forest canopy sun beams penetrate – in bright
light it looks very effectively. Having met the female, the male begins courtship
demonstration: having risen on three pairs of legs, it turns towards to the
female bright inner side of shield so, that sun light reflects from it. When
the female ready to pairing freezes (it is a part of ritual too), male gets
to it on shield, and densely pastes the female by web against bark. Certainly,
it is not enough to of it to keep the female stopped reliably, but the male
may win some seconds to escape from the female after pairing.
The female differs from the male not only in size. At it there is the special
structure of abdomen: it has asymmetric from of the bottom side forming original
“pocket” (usually from the right side). This adaptation is necessary for
carrying of cocoon, which this spider hides under the shield.
Heraldic spiders breed the most part of year, except for the coldest winter
months when their activity is reduced and they spend the most part of time
in shelters. For one year the female bears 3 – 4 cocoons numbering 200 –
250 eggs. Last clutch is usually smaller, rather than others, but eggs in
it are larger, and young spiders have chance to go through winter better.
Eggs develop within 15 days; young spiders sit in cocoon till three days,
and then get over to the bottom side of the shield of the female. Having
cast the coat, they abandon the female for ever and lead independent life.
Young heraldic spiders reach sexual maturity at the age of one year. Life
expectancy of heraldic spiders is rather great and can make up to 9 – 10
years.
All arthropods for growth are compelled to pass through hard process of molt.
Usually at molting spider the top part of cephalothorax armour is separated,
and it gets out through this aperture. At heraldic spider this process is
complicated with very large abdomen of specific shape. Therefore it molts
differently a little: at molting spider the seam separating the top side
of armour from other body bursts. When the top part on abdomen exfoliates,
animal gets out through it, as through the hatch, back to front.
Closely related species of spiders live in subtropics of Europe:
Bullhorn spider (Heraldarachne taurocornis) lives in woods of Caucasus Peninsula.
It is smaller species, rather than heraldic spider – it is 6 cm long at all.
This species lives on bottom parts of tree trunks in moss cover. The shield
outgrowth on its abdomen forms two “horns” sticking forward. The top part
of body has masking color: it is black with bright green irregular-shaped
spots and thick green hairs on edge. Bottom side of body at this spider is
bright orange; legs at males are silver-gray, at females black. In fight
for territory males “butt” each other by horn-shaped outgrowths. In the heat
of battle spider can fling the contender away or dump it from trunk down
by movement of “horns”.
Leaf-bellied spider (Heraldarachne foliomimus) lives in forests at the western
coast of Fourseas. It reaches the size of 7 – 8 cm. This species is colored
dimmer, rather than its relatives: from the bottom side of shield there are
no bright hairs, legs are colored grey with dim white cross strips, and only
on forward pair of legs at the male there are reddish-brown “brushes”. But
this spider has excellent masking: the abdomen of this species is flat and
wide, having on edges some jags with tips extended and slightly bent upwards.
Colouring of abdomen precisely imitates dry leaf: the basic background is
yellowish-brown with darker spots. Light strokes simulate leaf nerves and
form irregular mesh-like pattern. This spider eats insects and can kill spiders
of smaller species.
Eared spider (Heraldarachne auriculatus) inhabits Balkan forests. It is the
largest species in genus: its length exceeds 10 cm at legspan more than 15
cm. It differs from other heraldic spiders by the shape of shield formed
by abdomen overgrown forward: on it forward and upwards two large flat lateral
outgrowths stick. Eared spider lives in forest canopy and does not go down
on trunks. It is very poisonous, and bright warning colouring is developed
at it: shield is bright yellow with black warts on the surface; outgrowths
are black with blue oculate spots in the center. Legs of animal are black
with red tips. The sting of this spider may kill an animal weighting up to
50 kg. Eared spider eats small vertebrates – frogs, lizards and nestlings
of small birds. It also eats large insects – cockroaches and crickets.
Manure shining spider (Callolycosa coprobia)
Order: Spiders (Aranea)
Family: Wolf spiders (Lycosidae)
Habitat: Southwest Europe, savannas of North Africa.
In nature of the Earth some groups of live organisms can form extensive landscapes.
It had taken place so in Cenozoic, when the union of graminoids and hoofed
mammals had caused extensive productive communities – grasslands. In Neocene
graminoids still prosper, and numerous herbivorous mammals do not allow savannas
to turn to woodlands. Collision of Africa and Europe had resulted in occurrence
of extensive dry areas surrounding dry desert of Mediterranean lowland. Large
herbivorous mammals live in these places – harelopes, flathorns and ndipinotheriums.
Except for them, the mite in formation of landscape is brought by huge giraffe
ostriches. All these herbivorous animals devour a plenty of vegetation, producing
the appropriate amount of manure. Many species of insects feed on manure
of herbivores, and this circumstance has involved the separate species of
wolf spiders – manure shining spider – to manure heaps
Body length of the adult female of this species is about 17 mm. Manure shining
spider differs in very bright and beautiful coloring. The body is covered
with plentiful hairs having intensive metal shine. Forward part of cephalothorax
at animals of both sexes is brown with additions of black hairs, but back
part of cephalothorax, abdomen and legs are colored bright color with metal
shine. Body of the female is crimson-red and orange on the tip of abdomen.
Male is smaller, then female (length of its body is less than 1 cm), and
its body is colored blue. Hairs on the male body intensively reflect ultra-violet
beams, involving to it insects – the potential prey.
The body shape of this species does not differ any remarkable features. Legs
are partly specialized for digging: the terminate segments of back legs are
flattened, as if shovels. This spider, similarly to the majority of representatives
of family, does not build cobweb, and leads vagrant life. It keeps in heaps
of manure, and builds to itself temporary shelters – spider digs by back
legs vertical burrows in substratum. Building the burrow, spider is dug in
manure by back; therefore its bright colouring the most part of time is imperceptible
for possible predators. By forward legs the animal holds the cover of cobweb,
which closes the entrance to the burrow. On cobweb pieces of dry manure and
dust are pasted, masking the entrance to the burrow. Manure shining spider
prefers to live in places where inhabitants of savanna leave manure constantly.
Only at drying or destruction by other animals of manure heap it passes to
fresh manure.
Manure shining spider hunts insects involved with manure. More often flies
and dung beetles become its catch, but occasionally it catches even butterflies,
which receive mineral substances from manure and frequently visit manure
heaps of large animals. Usually the spider hides in burrow and expects, while
possible catch comes nearer to it itself. Having seized the moment, it jumps
out from burrow by sharp throw, seizes an insect, and hides in refuge again.
On pedipalps of this spider combs of rigid hairs are advanced – spider cleans
itself by them. Living in the environment, rich in bacteria and other pathogens,
this spider spends a lot of time, clearing body from manure.
As plentiful and constantly renewing manure heaps meet in savanna rather
seldom, manure shining spiders relate to congeners very unfriendly. Exception
is made only by the female for the male in short minutes of pairing. Declaring
about the territorial claims, spider of this species shows itself to the
contender, sparkling in sunlight by bright colouring with metal shine. But
the spider necessarily keeps by one leg for the edge of hole, ready to rush
to shelter at first sign of danger. The heap of manure usually is shared
by several females, and on edge of their territory vagrant males not building
long-term shelters gather.
Colouring of manure shining spider is also warning: its sting causes severe
pain in large animals; however it is not dangerous to life. Small animals,
however, may die from sting of this spider. But thus spiders frequently become
prey of birds, which kill them by impact of beak. Also lizards hunt these
spiders.
At the majority of spider species male is much smaller, than female, and
manure shining spider is not exception here. Therefore the male of this species
very cautiously approaches to problem of pairing. At first the spider accustoms
the female to its presence, leaving odorous marks near her hole. Then it
appears at the edge of territory of the female, cautiously trying to come
nearer to her. If the female perceives him quietly, the male resolves to
pairing. Before it he arms with piece of dry manure, and safely creeps in
hole of the female. He literally wedges her by this original weapon, braids
legs of the female with web, and quickly couples with her. Using such preparation,
after pairing the male frequently escapes from the female, and has an opportunity
to fertilize up to five females while it becomes a casual victim of one of
them.
In clutch of manure shining spider there is about 150 small eggs packed to
snow-white web. But cocoon becomes fast of dim brownish-grey color because
of specific inhabitancy of this species of spiders. The female with cocoon
leaves manure heaps – it is too brisk place dangerous to young growth. She
lives in old holes of rodents or in others shelters. The young growth becomes
sexual matured at the age of about half-year.
The close species lives in savannas of North Africa: cadaverophilous
shining spider (Callolycosa cadaverophila). This species of spiders had chosen as
an inhabitancy corpses of animals at various stages of decomposition, and
eats necrophagous insects. Colouring of this spider is equally bright: the
female is bright green with white spot on cephalothorax, and the male is
bright red with white tips of forward legs. The cadaverophilous shining spider
is less adhered to the certain place of inhabiting and can overcome long
distances in searches of suitable substratum. With the help of sense of smell
it easily finds corpses of animals. Cadaverophilous shining spider digs in
the ground near them, and catches necrophagous insects, and also gathers
larvae of flies. This spider frequently settles near lairs of large predators
like deadlynetta.
Acatou feather mite (Acatoubius plumophilus)
Order: Acariform mites (Acariformes)
Family: Syringophilids (Syringophilidae)
Habitat: South America, giant carnivorous bird acatou.
In nature any animal, large or small, represents true “zoo”: in its organism
the plenty of various parasites settles. They are protozoans, flatworms
and nematode worms, various arthropods. Among bird parasites mites are
rather
usual. Various species of these arachnids live on feathering of bird, in
pipes and in skin. Some species only temporarily live on bird and hide
in litter of its nest. Other species of mites, on the contrary, live on
the
body of bird constantly or the most part of life, excepting the short periods
of settling. Various species of parasites are strictly connected to certain
parts of body of the host animal.
When the giant bird acatou opens wings and wants to fly up, it becomes
especially appreciable, that in one wing some minor primary feathers are
deformed and
short. It almost does not prevent this bird to fly, but reduces its maneuverability
at prey chasing. Such development of feathers is the result of activity
of one acatou parasite, the acatou feather mite.
This tiny arthropod lives in shafts of primary and tail feathers of bird.
The adult female of this species represents the translucent worm-like four-legged
creature about 3 cm long at the thickness of body about 2 mm. It lives
in the basis of feather shaft and does not leave it up to the end of life.
When
the feather falls out, the female living in it perishes, but more often
it perishes before this moment when the basis of feather placed in skin
of bird,
stops the development.
The male of this species sharply differs from the female: it has typical
shape of free-living mite. It is thin-bodied eight-legged creature about
2 mm long. In essence, the male differs only a little from larvae of last
age. Larvae and males live on skin of acatou and eat exfoliating epidermis,
not harming a bird.
The male fertilizes the female out of feather before her last molt. After
fertilization in behaviour and anatomy of the female striking changes take
place: she starts to search feather papillae from which largest feathers
in acatou feathering – primary feathers in wings and quill feathers in
tail develop. The female gnaws in the tip of developing feather an aperture
and
creeps inside of it. Having found the shelter, she at once molts and turns
to inactive creature. The female loses two back pairs of legs, and its
abdomen stays covered with soft elastic cuticle. Only in forward part of
her cephalothorax
rather firm chitinous cover remains. On it there are some elastic bristles
which allow the mite to fix inside of feather shaft.
Feather shaft is filled with friable keratinous fibers, and the female
partly eats them away from within. She gradually reaches a basement of
feather.
To this moment it is not formed yet, therefore the female has access to
blood vessels surrounding the feather bursa. She pierces an environment
of developing
feather and starts to suck blood. At this moment at her in an abdomen the
development of eggs fertilized before begins. For short life the female
of acatou feather mite can form and incubate in the body over 50 thousand
eggs.
They ripen in small portions in abdomen of the female, and gradually, as
on the conveyor, move along the oviduct. From them right in oviduct hexapod
nymphs excluse. After birth they live some time inside the feather shaft,
eating dung of the female and the rests of keratinous fibers. The female
of acatou feather mite prepares for them a kind of “baby food”, only partly
digesting the exhausted blood of bird. Nymphs eat liquid dung of the female
which actually consists of semidigested blood of acatou and is rather nutritious.
Eating such food young acatou feather mites pass some molts inside the
feather. Nymphs of advanced age scrape walls of feather from within, making
it fragile.
Because of their activity the feather breaks or broken off, when the bird
cleans feathers, and mite nymphs leave it. They begin life as commensals,
crawling on the body of acatou. Nymphs of acatou feather mite settle during
the contact of adult birds, or bird and nestling. But they have one more
way of moving which they frequently use. Nymphs find larvae of Goliath
feather louse (Megalaembothrion goliath) – large parasitic insect, and
cling to them.
The nymph can not eat very long time, staying in inactive condition on
the body of Goliath feather louse larva. They expect, while the Goliath
feather
louse larva will cling itself to any flying insect and will get on body
of new host bird. The part of nymphs, however, stays on body of bird and
also
turns to adult mites.
Crustaceans
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Fish sacculina (Piscisacculina quasisymbiotica)
Order: Root-headed crustaceans (Rhizocephala)
Family: Fish sacculinas (Piscisacculinidae)
Habitat: northern part of Pacific Ocean, seas of Southern hemisphere.
In seas of Holocene one surprising crustacean was known – sacculina, the
endoparasite of crabs, developing in the infected crab as long roots in all
its body, exhausting nutrients. In Neocene this kind of parasitism had promoted
further away, practically up to a level of symbiosis. The crustacean similar
to crab sacculina infects fishes of certain species leading mainly schooling
habit of life. These fishes do not make long migrations, remaining within
the limits of zone of inhabiting of the population, near to coast of continent,
and eat seaweed, invertebrates, ground and silt inhabitants.
The microscopic larva of crustacean – the nauplius – finds young fish, is
swallowed by it with water and settles on gills. Having attached to epithelium,
it has metamorphosis. As a result of it the crustacean larva sprouts inside
of host animal body as long tissue outgrowths, and the rests of the nauplial
cover on the surface of fish gills disappear after the molt. Gradually “sprouts”
pass through all its body and organs, absorbing nutrients of the host organism.
The fish does not feel the special discomfort; the parasite has adapted to
not affect for the time being the vital centers, and also develops the connections
overwhelming unpleasant sensations. Taking root in gonads, the invader dilutes
sexual products of fish at early stages of development, and develops its
own ovo- or spermatogonies, depending on its sex, occupying all volume of
former gonads. Ripening of sexual products of crustacean coincides to terms
of egg ripening of the not invaded individuals of fishes of this species.
In required term the fish comes to spawning with other congeners. But it
can not spawn eggs any more, and generates in its gonads eggs or sperm cells
of the parasite. And soon naupliuses of the parasite appear, swimming to
searching of new hosts.
The parasite creates alternative communication system in the body of fish,
providing transport of substances, oxygen, and participating in their metabolisme.
By developed substances it interferes with development of congeners again
getting on this fish, and they perish still larvae at attempt of “sprouting”
into the fish. Except for it, thr parasite creates a chemical barrier to
all this school of fishes for other larvae, frightening them off and overwhelming
their development, and it is as stronger, as more is the rate of infected
fishes in school. If in fish school there is more than the one fifth of infected
fishes, defeats new practically do not occur and fishes receive some kind
of “immunity” from new attacks - the parasite has “an interest” to keep a
significant part of fishes healthy to permit them to breed.
Through skin of fish long hair-like outgrowths of the parasite sprout. They
are supplied with sensitive receptors reacting to the slightest signs of
food keener, than fish’s own ones, and fish through system of the mutual
biochemical communications moves there, and it is followed also by other
fishes of school. Except for it, the poisonous secret of the parasite emitting
through the same outgrowths, makes fish almost up to the end of life uneatable.
The predators had tried such fish few times, at all try to avoid catching
of fishes of this species. The infected fishes live till 5-6 years.
Only at the end of host’s life the parasite takes root into brain of fish,
and its coordination of movements is broken. The struck fish swims badly,
and larger predator usually swallows such individuals. But it will not be
infected, because its biochemistry is not the same, as at host fishes to
which the physiology of parasite is very well adapted. In digestive path
of predatory fish after digestion of catch beforehand firm formations of
the parasite similar to cysts are formed. They will be kept, and the fish
will distribute them wandering in open spaces of ocean in wider areas, than
migratory routes of the separate population of the host fish. After removing
of cysts from the organism with excrement from them plankton larvae of parasitic
crustacean will burst.
This species is discovered by Arseny Zolotnikov.
Surveyor
scud (Geocaprella geometra)
Order: Scuds, or Side-swimmers (Amphipoda)
Family: Skeleton shrimps (Caprellidae)
Habitat: shores of northern part of Pacific ocean.
Active processes of orogenesis in northern part of Pacific Ocean have resulted
to radical changes of the coastal line of Asia and Northern America in comparison
with situation known in Holocene. A plenty of new islands has appeared, and
it has permitted to some sea inhabitants to master land.
In ebb-tide strip of north - Pacific islands life has to found a convenient
place for itself. True “forests” of brown and green seaweed develop here, and
in them tens species of invertebrates crawl. In these places one equally well
feeling like both in water, and on land, survives successfully.
Among crabs scurrying among rotting thalli of seaweed at the coast, it is possible
to find strange creatures of unusual appearance: they are long-bodied, also
creep “by steps” similarly to caterpillar of geometer moth. But antennae and
well advanced legs indicate, that they are not caterpillars. The body of these
creatures is covered with firm armour and colored red - brown with dark irregular-shaped
spots. These animal are lineal descendants of crustaceans skeleton shrimps
(Caprella). For characteristic manner of movement this creature is named surveyor
scud. They are rather large representatives of order: body length of surveyor
scud is up to 10 cm.
The body of surveyor scud is covered with numerous knobs and outgrowths, and
on antennae and legs rounded scalloped outgrowths stick up. It helps this crustacean
to mask among seaweed from enemies and possible catch. During the inflow the
surveyor scud stays in thickets of brown seaweed, waiting for small animals:
fry, other crustaceans and snails. Having clung by back legs to seaweed, the
surveyor scud expects, while the prey will come nearer too close to be seized.
The caught prey is kept by forward pair of legs on which tips there are small
spikes. During walking the surveyor scud folds these legs under thorax.
Being the inhabitant of an intertidal zone, the surveyor scud is able to live
not only in sea, but also on land. In outflow tens of these crustaceans creep
in intertidal zone, eating animals cast ashore. But at this time they are endangered:
many sea birds fly above intertidal zone, and even ground predators at times
search for catch at the coast. Therefore, having remained at the coast, surveyor
scuds keep near to natural shelters - usually near heaps of seaweed. At first
signs of danger surveyor scud rushes to the nearest shelter. Due to colouring
and body shape it easily masks. When the hidden crustacean keeps in seaweed,
it may be easily mistaken for a part of plant. Like crabs and fishes surveyor
scuds rescue from small predators by jumps: having turned up the back end of
body under itself and sharply having straightened, the scud jumps at the distance
up to meter. Being overtaken at the flat area, it can escape, very quickly
having buried in sand. As a last resort seized surveyor scud easily rejects
extremities which completely restore after two molts.
The female of this species carries eggs and posterity on itself. At this species
there is direct development, and from large eggs posterity similar to adult
scuds bursts. The young growth keeps on body of the female and eats the rests
of her catch. Before the first molt the posterity abandons mother and further
lives independently.
Plankton living stick (Thalassophasma tenuissima)
Order: Scuds, or Side-swimmers (Amphipoda)
Family: Skeleton shrimps (Caprellidae)
Habitat: Pacific Ocean, top water layers.
After extinction of significant part of plankton organisms the set of ecological
niches of open ocean appeared empty. It stimulated the evolution of survived
ocean inhabitants and had permitted to some inhabitants of sea shallow waters
to make attempt to develop habitats of open ocean. At the initial stage of
open ocean settling in plankton there had been a plenty of descendants of
shallow water forms, but gradually their amount had decreased, and few lines
of new immigrants to plankton had survived only. Even descendants of one
rather specialized group of scuds – skeleton shrimps (Caprellidae) were among
them. These animals had developed pelagic habit of life rather originally:
they had left shallow water adapting to live on huge brown or green algae
floating in top layers of water. And only therefrom skeleton shrimps passed
to inhabiting in thickness of water, becoming true plankton animals. One
species of these creatures differs in very large size and characteristic
appearance. It is named plankton living stick.
This crustacean looks the real giant among scuds: it is the animal up to
20 cm long. But the large size does not mean that it is very strong and dangerous
creature. Plankton living stick quite justifies its name – it is the fragile
and graceful creature adapted to plankton life. The body of this animal is
very thin, and four forward pectoral segments are lengthened very much –
they amount approximately 80% of the general length of animal. Four forward
pairs of legs are also very long. They are covered with hairs facilitating
soaring in water. The forward pair of legs is little bit shorter, rather
than the others – it is used for prey grabbing. On tips of forward pair of
legs small pincer-like outgrowths develop, helping to keep catch.
Segments of back part of thorax appreciably differ from front ones – they
are flat; two pairs of short and strong swimming legs with dense bristles
on edge grow on them. In case of need the plankton living stick is able to
swim – for this purpose it folds long forward legs back, and rows by swimming
legs. But this animal is not so good swimmer, also is is not able to swim
for a long time. The longest moving it makes is the vertical migration. Having
a presentiment of storm, this fragile crustacean falls to the depth of about
20 meters.
The pleon of plankton living stick is reduced (this condition had been present
already at skeleton shrimps, ancestors of this animal) and is extended to
needle-shaped outgrowth.
Usually plankton living stick motionlessly soars in thickness of water, having
stretched pectoral legs in sides. Occasionally one or two swimming legs come
in movement, slowly turning animal to the necessary direction. This sluggish
creature eats small plankton animals, catching them one by one. At this animal
there are maxillipeds of cutting type – plankton living stick bites off pieces
of catch.
Fertility at plankton living stick there is rather low for plankton animals
– the female lays at all only some hundreds eggs and bears them on segments
of back part of thorax (at females these segments are wider, rather than
at males) within approximately three weeks. From eggs young animals similar
to adults hatch. They sit on body of the female about one week and catch
smallest plankton animals floating near it, then abandon the female and live
independently. The young growth is able to swim faster, rather than adult
individuals – at just passed to independent life plankton living sticks body
is shorter and swimming legs are rather long. Also at them the forward pair
of pectoral legs is longer than the others. With each molt proportions of
young animal advance to proportions of adult individual.
Mantis scud (Deinogammarus rapax)
Order: Scuds, or Side-swimmers (Amphipoda)
Family: Scuds, or Side-swimmers (Gammaridae)
Habitat: Fourseas, coastal thickets of plants. This crustacean can rise against
current of rivers and form freshwater populations.
The history of Fourseas had begun from zero, or from the size close to it.
When four internal seas at the south of Europe had dried up, all sea fauna
appeared simply destroyed. And after rigorous ice age when Fourseas had formed,
this reservoir became populated with numerous species of live creatures. They
were not descendants of representatives of the extinct fauna, but animals,
whose ancestors lived in rivers and lakes.
In geological sense Fourseas had formed very quickly: for some hundreds thousand
years thawed snow of glaciers of Northern hemisphere have filled in hollows
of dried up seas, and rains have lifted sea level even more. Tectonic processes
have closed Bosporus passage, and Fourseas actually appeared a little bit above
ocean level.
Processes of evolution of live creatures in new reservoir have gone especially
roughly. The set of free ecological niches has permitted to descendants of
few founder species to avoid the competition. Among crustaceans which have
occupied Fourseas, there were scuds. These crustaceans had survived in glacial
lakes with cold and clean water. When glaciers had started to thaw, filling
in hollows of dried up seas, scuds first of all began to develop the new world,
forming new species better adapted to inhabitancy which Fourseas could give
them. They became the most mass group of invertebrates in reservoir. Among
them both fine plankton species, and various ground inhabitants have appeared.
And one of species, the mantis scud, became the true predator.
The length of this crustacean is about 10 cm: it is one of largest species
of scuds of Fourseas. But it seems even larger because of very long antennae,
surpassing in length its body. Except for them, on head of the crustacean there
are very well advanced eyes consisting of set of very small facets. Due to
it mantis scud can distinguish tiny details of environmental district. The
body of this crustacean is lengthened and flexible, numbering set of segments.
This animal is active ambuscader eating water insects (larvae of dragonflies,
water beetles, etc.), leeches and small vertebrates (fishes, tadpoles, frogs).
Also this species willingly eats carrion. In this connection at it the adaptation
for keeping of catch and meat tearing are developed: the forward pair of legs
has increased, segments on edge are supplied with spikes and jags. In rest
these trap legs are put together, but when the animal attacks, they quickly
open and grasp catch. This crustacean can swim quickly: three back pairs of
legs are feather-like, covered with long elastic hairs. Back pairs of legs
also serve for attachment to substratum: on their tips sharp bent claws are
advanced.
Colouring is cryptic: the top side of body is olive-brown, and bottom is reddish.
It permits the crustacean to mask in thickets of pondweed, waiting for catch.
Usually this crustacean hides in plants, and expects for suitable catch. But
the hungry crustacean may chase catch, swimming to small distance from shelter.
These crustaceans, similarly to many single predators, are strictly territorial:
invisible borders share thickets of underwater grasses to set of sites, and
each of which is vigilantly protected. If the neighbour has crossed border
and does not hurry up to leave another's possession, the lawful owner warns
it. For this purpose on trap legs of the mantis scud the special knobs, to
which on the next segment small holes are opposed, are advanced. Bending the
leg, and pushing knob in hole, crustacean utters sharp clicking sound. The
click distinguished by loudness and sounding, is an alarm signal. When above
places of inhabiting of mantis scuds the large fish swims, its movement is
accompanied by alarm signals of these animals. If the neighbor or predatory
fish attacks the mantis scud, the animal is able to protect itself with the
help of spiny trap legs. Protection is accompanied by the special gnashing
sound which will be remembered by any predator, having received deep painful
wounds from the mantis scud.
The pledge of success of survival consists not only in skill of protecting
against the enemy, but also in care of posterity. This species differs in child-loving:
the female drags eggs and larvae on the body. From large eggs (up to 100 ones
in clutch) hot helpless larvae, but tiny advanced youngs – small copies of
parents, hatch. Since the first minutes they can move independently, but do
not leave mother before hardening of carapace after the first shed. They eat
the rests of mother’s catch, and successfully grow up till the size guaranteeing
their survival. Young mantis scuds are good swimmers, and can attack animals
of size equal to them.
Sea bird louse (Thalassophthirus aviphilus)
Order: Isopods (Isopoda)
Family: Idoteids (Idoteidae)
Habitat: Northern hemisphere, Atlantic and Arctic oceans. The parasite of large
sea birds.
Extinction of cetaceans and others sea mammal in epoch of ecological crisis
had carried away to non-existence the fauna of their parasites – worms, crustaceans,
and other species of invertebrates. In Neocene the place of large sea vertebrates
in Northern hemisphere is occupied by large flightless birds. Various species
of parasitic animals had settled these birds evolved in appropriate way. Some
of them descend from own parasites of birds, and others had settled newly evolving
species of huge birds from zero.
One of new settlers of huge sea birds is the parasitic species of isopod crustaceans,
externally similar to louse - because of it this species is named sea bird
louse. It settles on skin of birds under feathers and eats blood. Length of
body of this crustacean is about 7 – 11 mm. Obviously, it is the descendant
of one of species of sea crustaceans of genus Idotea – usual inhabitants of
interdial zone in Holocene epoch.
The body of sea bird louse is flattened, covered from above and from sides
with firm shell. On the bottom side of body chitinous cover is thin and folded.
Plicas increase the area of body surface, and help in respiring. And when this
animal sucks a plenty of blood, plicas are smoothed, and the body becomes slightly
bulging. Mouth feet of this crustacean are modified to thin long proboscis.
At sea bird louse five pairs of walking legs are advanced. The forward pair
of legs is similar to hunting legs of soothsayer – on their internal side there
are pointed thin denticles. These extremities serve for attachment to the host
body – sea bird louse clasps by them feather shaft of host bird, or clings
the stretched legs to its skin, sticking denticles in epidermis of the bird.
Next three pairs of walking legs are short and hook-like. On penultimate segment
of walking legs there is a sharp spike, and last segment is hooked. These two
segments form strong claw, therefore sea bird louse is not washed away from
host bird by casual wave, and even bird carefully cleaning feathering not always
can deliver from these parasites. Last pair of walking legs has changed to
similarity of flippers – they are lack of spikes, but last segment of these
legs is very wide and is bordered by rigid hairs. With the help of such legs
sea bird louse swims well, and in rest these legs cover from below very short
abdomen on which gills are located, and protect them from drying.
Though sea bird louse is able to swim, it can stay on land for a long time
and even rather quickly creeps on the ground. It settles on head of gannetwhales and
other sea flightless birds – plesioloons and laughterloons. Occasionally
this species settles on skin of other birds, but, as a rule, it lives on them
not for long: small birds clean off these crustaceans from themselves or peck
them off one from another. Sea bird louse settles at direct contact of birds,
or swims from one bird to another when birds hunt in sea. This crustacean makes
risky travels on the ground in cool foggy night when the risk to dry or to
be eaten is less.
Sea bird louse breeds, laying many small eggs – up to 2 – 3 thousands in one
clutch. When the host bird stays on land, female protects eggs from drying,
covering them by swimming legs. Term of incubating of eggs is short – about
3 – 4 days at all. When the host bird dives, tiny free-living pelagic larvae
hatch from eggs, quickly leaving egg shells. After that female within day cleans
off rests of clutch from the body, and becomes ready to breeding again. For
one year one female can make over thirty clutches.
Mouth parts at sea bird louse at any stage of development represent the proboscis.
Larvae of early age live among seaweed and eat small soft-bodied animals, exhausting
them. They are similar to adult individuals, but at them there are transparent
body and only two pairs of walking legs. Later they start to attack large invertebrates.
Gradually larvae settle closer to surface of water. Larvae of advanced age,
which has reached the size of about third of length of adult individual, pass
to amphibiotic habit of life: they creep out on surface of algae carpet, waiting
for occurrence of the host bird. Having got on the body of bird, crustaceans
pass to feeding on blood, and start to grow quickly, turning to adult individual.
“Phantomic murderer” (Vitromantella microhorrida)
Order: Stomatopods, or Mantis shrimps (Stomatopoda)
Family: Pedomantids (Pedomantidae)
Habitat: Indian Ocean, tropical and subtropical latitudes.
Pedomorphosis is the special way of evolutional transformations when the adult
stage is gradually lost and replaced by previous larval one. This phenomenon
is closely connected with pedogenesis – the aquiring by larvae of ability to
breed not turning to adult stage.
In the epoch of global ecological crisis there was an extinction of plankton
organisms and inhabitants of coral reeves. Descendants of a few survived genera
(mainly inhabitants of seas of moderate climate zone) occupied the exempted
habitats in next epoch of climate stabilization. Among them branches which
representatives developed a plankton habit of life had been separated. Such
process occured simultaneously in several groups of sea crustaceans, therefore
in Neocene plankton there is a plenty of species of “adult larvae” of various
crustaceans belonging to different groups. Among decapods the family of infantoportunid
crabs (Infantoportunidae) had appeared, and mantis shrimps had “answered” this
step of crabs with occurrence of plankton species of pedomantids.
It was easier to stomatopod crustaceans to pass to such way of life, because
all their species in development have plankton larva. The result of such evolutionary
step became the occurrence of stomatopod species which had received the name
“phantomic murderer”. This animal is a plankton predator about 4 – 5 cm long.
At it there is translucent body, poorly distinct in water – it is a common
attribute of the majority of plankton organisms. In anatomy of “phantomic murderers”
many features characteristic for a larva of benthic mantis shrimps are kept.
The main hunting weapon of the “phantomic murderer” is the pair of catching
legs, characteristic for representatives of the order. They are big relatively
to the body size – the span of completely opened and extended legs exceeds
the length of animal almost twice. Catching legs of this crustacean are very
thin; their last segment has a small hook on the tip. Thorns with which help
the animal keeps and kills catch, are thin and sharp, similar to bristles.
Food of “phantomic murderers” includes various small plankton animals with
soft and thin body covers, and it is not necessary of the big efforts for their
capture.
This predator has very good sight. Eyes of “phantomic murderer” are large,
spherical and shining; they are located on thin stems – it improves the field
of view and simultaneously facilitates soaring in thickness of water. Facets
are small; therefore the animal sees even tiny plankton inhabitants very well.
On the head of the “phantomic murderer” there is long thorn (its length is
a half of thorax lenght), directed forward. On it from both sides hairs grow,
allowing soaring in thickness of water without efforts.
Abdomen of this crustacean is very thin and rather short: its length makes
about a half of general length of the crustacean (at benthic mantis shrimps
abdomen is much larger and much wider, rather than thorax).
Not hunting animal slowly floats in thickness of water, flapping by wide fanlike
“oars” (propodits of 4-th pair of mouth feet). They are long (their length
makes about the one fifth of general length of animal), covered with hairs
on edges. With their help the crustacean turns in water, being aimed on prey.
Sometimes “phantomic murderer” passively soars in thickness of water, having
stretched propodits in sides. If necessary to swim faster (for example, attacking
the prey), the crustacean can increase speed, moving by strong abdominal legs.
Abdominal legs are covered with hairs on edges, which increase a rowing surface.
On the tip of abdomen there is a wide telson plate. Last pair of abdominal
legs is also wide and flattened. Joining the telson they form a fin having
a role of rudder of depth and turn.
This crustacean is an active predator, hunting small plankton animals – worms,
crustaceans, fish fry, larvae and young cephalopods. For “phantomic murderers”
the cannibalism is very characteristic – about a quarter of young animals of
this species become the prey of their congeners. The crustacean catches prey
by sharp throw (accelerating momentum about half meter per one second), and
seizes it by trap legs. Per one day the “phantomic murderer” eats the amount
of food approximately as much, as it weighs itself. But actually it kills much
more animals, because it eats only the richest with nutrients parts of preyed
ones body and leaves the rests.
This crustacean is the solitary animal showing interest to congeners only during
hunting and in breeding season. Pairing at the north of an area (in tropical
latitudes) occurs at any time year; at the south it takes place in summer.
Walking legs at different genders of “phantomic murderers” are advanced unequally:
it is connected to their different roles in breeding. At the female all three
pairs of walking legs are advanced though they do not participate in walking:
the crustacean lives far from coast above the big depths. The female bears
eggs (up to thousand fine eggs in one clutch) on walking legs covered with
hairs. At the male the last pair of walking legs turned into short strong hooked
appendages is advanced only: they serve for keeping of the female at pairing.
First pairs of walking legs are reduced up to thin and weak hooks.
Breeding and development of this crustacean is connected to lunar cycles. The
peak of sexual activity falls to a full moon and some days after it. The incubating
lasts about one week, and from eggs plankton larvae hatch, at once leaving
the female. The larva moults about 10 times before it will turn to adult crustacean.
The cycle of development of “phantomic murderer” lasts about 2 months, and
its life expectancy usually does not exceed half-year.
Cricket crayfish (Symbiosquilla
innoxia)
Order: Stomatopods, or Mantis shrimps (Stomatopoda)
Family: Lysiosquillids (Lysiosquillidae)
Habitat: mollusk-spongial reeves of Indian and Pacific oceans, shells of
huge bivalves.
Plancton communities of ocean form an enormous biomass. And the greatest
variety of species is concentrated at the reeves forming in shallow waters.
Reeves
of Neocene are constructed not by corals, but by other live organisms: practically
all reef-building corals had died out in epoch of ecological crisis at the
boundary of Holocene and Neocene. The reef of Neocene is formed mainly by
slowly growing and living a long time massive bivalves and sponges. But it
is as rich
in life, as coral reeves of Holocene were. Various predators, often highly
specialized are richly presented here: it indicates a variety of food resources.
At reeves of Neocene mantis shrimps of various species live. In epoch of
ecological crisis a lot of species of these crustaceans had died out: all
of them pass
a part of life cycle in plankton as a floating larva.
In majority mantis shrimps are solitary predators and active cannibals. But
among them there is a small amount of species living in breeding pairs in
common shelter. Obviously, from any of similar species one kind of mantis
shrimp living
on reeves had evolved – the cricket crayfish. It is a tiny species of mantis
shrimps – the length of adult crustacean is about 3 – 5 cm (the male of this
species is appreciably larger, rather than the female). Such creature would
have a lot of enemies on a reef. But it had adapted to inhabiting in perfectly
protected place - in huge shells of goblet-like
false rudistes, which tower
above the body of reef, as if fortifications. Pair of adult animals lives
in each such shell, but occasionally in very large shell of old mollusk one
male
and two or three females settles.
Life in safety and twilight of shell of huge mollusk has resulted at the
appearance of this crustacean. The majority of mantis shrimps living in shallow
waters
is colored very brightly or has the cryptic colouring which harmonizes with
color of environmental district. And the cricket crayfish resembles any cave
animals by the shape: at this shell inhabitant the body is depigmentated,
translucent and brownish. Eyes of this crustacean are very small, and sight
sense is much
weaker, rather than at freely living mantis shrimps. Long antennae help the
animal to orientate itself in the shell.
The cricket crayfish is, perhaps, the most peaceful species among stomatopods.
Inside shells where it lives there is no catch, characteristic for the diet
of its freely living congeners. Its trapping extremities are modified to
scrapers with which help these crustaceans gather settling suspension from
gills of
mollusk. It is the basic food of cricket crayfish. On trapping legs of this
animal many tiny denticles, not adapted to pierce and kill catch, grow. Presence
of such small symbionts renders the big benefit to mollusk: these crustaceans
clear its body of parasites, eat worms and smaller parasitic crustaceans
which injure gills of goblet-like false rudistes.
The population of shell protects the habitat from neighbours. Except for
trapping legs, in set of natural weapon of mantis shrimps there are “clubs”
on pectoral
legs with which help typical stomatopods break shells of mollusks. This crustacean
uses them in intraspecific conflicts. Cricket crayfishes living in one shell,
learn each other by smell. The number of animals living in same shell is
determined by frequency of their meetings with each other. At too often meetings
crustaceans
turn more aggressive, and start to attack against each other. Thus the weakest
animal abandons shell, or may be killed. “Indigenes” drive off from the habitat
of unfamiliar neighbours, trying to lodge in shell, and can attack larvae
of their species, getting to the shell in current of water. Avoiding an opportunity
to enter fight, these mantis shrimps show in the beginning their presence
to
unfamiliar congeners. They utter warning sounds, passing by mouth feet along
denticles of trapping legs. Such sound is similar to chirring of some orthopters
– this feature combined with long antennae and secretivity has determined
the name of the animal. Protecting the shell, these crustaceans creep out
to the
edge of shell of mollusk in which they live, keep in shadow of the closing
fold and chirr continuously. If the neighbour does not leave the shell, fight
which can be finished by fatal outcome is possible. Protecting the shell,
the cricket crayfish can leave it for a short time. It swims with the help
of abdominal
legs fast and manoeuvrably. Such small creature can put strong and even fatal
impact to small animals by “clubs” on armour or head of the opponent. It
lasts a split of second, and stuns or kills the opponent. Attacking predatory
fishes,
the animal quickly comes up from the shell, “clicks” in nose or eye of fish,
and immediately hides back.
Under the protection of shell the cricket crayfish breeds the year round.
In shell only one male can live. He fertilizes all females living in its
shell,
and even visits for this in next shells. The female has wider abdomen, than
the male, and bears some hundreds of small eggs for one clutch. The incubating
lasts about one week; at this time the female is very cautious, and does
not take place in habitat protection, because it swims much slower. The egg
laying
repeats each two weeks.
Transparent plankton larvae hatch from eggs. The larva spends the time up
to the first moult on abdomen of the female. Then the female creeps out on
edge
of shell and throws larvae off in water, intensively moving by abdominal
legs. So the plankton stage of development of young crustaceans of this species
begins.
It is reduced in comparison with time of development of freely living congeners.
The larva spends some days in plankton above the reef; at this time it is
settled and with the help of sea current may overcome the big distances between
islands.
Due to this ability the cricket crayfish is widely settled in tropical area
of Pacific Ocean and has penetrated to the eastern part of Indian Ocean.
The animal occupies pallial cavity of huge mollusk, getting in it with a
current
of water while the mollusk opens shell and lets out lobes of pallium with
symbiotic algae. If it manages to occupy the shell, after 2 moults it will
reach the
half of length of adult crustacean and will completely lose larval features.
At the age of 4 months the young animal is able to breed.
Life expectancy of cricket crayfish is insignificant and exceeds two years
seldom.
Barracuda
prawn (Sphyraenolemon serripes)
Order: Decapods (Decapoda)
Family: Palaemonids (Palaemonidae)
Habitat: rivers of Northern Australia.
In seas of Neocene crustaceans compete to predatory fishes, have got good chance
during mass extinction when the global cataclysm had carried away to non-existence
the majority of predator species and has laid down survived species in rather
equal conditions. So, at the reeves of Pacific ocean formed by large bivalve
mollusks and algae, there are large predatory mantis shrimps. In Australian
rivers there was a similar situation: the ichthyofauna of this continent was
considerably depleted during mass extinction, than decapods have taken advantage.
And here evolution showed to the world the new kind of predator – the barracuda
prawn.
It is rather large prawn – length of its flexible body is up to 30 cm. Its
cephalothorax is rather short: about a quarter of general length of animal,
but pleon is very large and muscled. In it there is plenty of muscles providing
intense work of swimming legs (pleopods). Swimming abdominal legs of this prawn
are covered with numerous hairs. During forward movement of leg hairs press
to it and do not interfere with movement, but in rowing time they form extensive
rowing surface.
Pincers of barracuda prawn are well advanced: with their help this crustacean
seizes and kills catch: smaller shrimps and fishes. Pincers of this prawn are
rather large (their size is about half of body length), serrated at the cutting
edge. Seizing fish, the barracuda prawn pierces by teeth of pincers its spinal
cord, and at the caught shrimps breaks off abdominal nerve chain. It instantly
paralyses catch and deprives it of opportunity to resist. Walking legs and
sharp serrated mouth feet help predator to kill catch.
Eyes of barracuda prawn are very large, spherical, located on long stems. Facets
making these eyes are numerous, therefore prawn can distinguish even tiny details
of environmental district. In water inhabitancy the chemical feeling has not
less important role. Organs of chemical feeling (chemoreceptors) are placed
at the barracuda prawn on antennae. antennae of this prawn are as long, as
body, feather-like due to set of hairs (it considerably increases their sensitive
surface).
Barracuda prawn spends the most part of time in ambush – among thickets of
floating plants. As well as all crustaceans, it is not able to chase prey for
a long time, therefore it has selected optimal for crustacean physiology tactics
of ambuscader. In this connection at it cryptic colouring was developed: the
basic background color of body is yellowish-green with faltering longitudinal
dark green strips at the top side of body. The barracuda prawn clings to floating
plants upside down: thus it has practically full circular field of view.
Having noticed possible catch, barracuda prawn cautiously creeps to it, having
turned pincers together: probability of their hooking for plants during solving
throw is less so. When the planned prey appears close, prawn makes throw. Having
pushed by walking legs from plants, it starts to work intensively by swimming
legs, at once developing the big speed. Usually the chase lasts no more than
ten seconds – physiological opportunities of organism of crustacean do not
permit longer chase. If the first throw was unsuccessful, the prawn stops chase
and again hides in thickets. Usually only one throw from five ones is successful.
Having caught fish or shrimp, the barracuda prawn kills it by strong compression
of pincers and starts to eat. But it is not safe occupation: involved by smell
of blood, hungry neighbours gather, and at times fairly preyed food becomes
the property of the neighbour which simply had appeared in necessary place
in necessary time. Therefore the prawn tries to drag prey off in place, where
it will not be to found at once by competitors. Usually it hides in thicket
of plants and starts to eat catch hasty, beginning to eat softest parts. Barracuda
prawn simply throws out rests of catch, and they fall on bottom, becoming food
for other lake inhabitants.
Usually barracuda prawns live solitarily, banishing neighbours from territory
which they occupy. But from time to time under influence of breeding instinct
they become much more tolerant to some neighbours.
Males of this prawn species differ from females in smaller size. But at them
pincers and very long antennae are appreciably larger. It gives them certain
advantages to larger and strong female: in time of “acquaintance” it looks
more impressive, suppressing a little by demonstrations aggression of the female.
The female lays rather small amount of eggs: about hundred ones. But each egg
is rather large: its diameter is about 4 mm. After a fortnight incubating on
abdominal legs of the female from it not helpless plankton larva, but well
advanced young prawn hatch. It differs from adult representatives of species
only in underdeveloped pincers and very small size of body. Young prawns are
predators of their weight category: they eat plankton crustaceans and fry,
gradually passing to larger prey.
Sexual maturity at barracuda prawn comes at the age of half-year at length
about 20 cm. After that growth rate of crustacean decreases, but time of intensive
breeding comes there. Each two months during almost three years the female
bears the next portion of eggs.
But barracuda prawns will never become most numerous inhabitants of Australian-New
Guinean lakes, and partly they are the reason of it. Among barracuda prawns
at any age the cannibalism is usual phenomenon, and because of it only rather
few from young prawns can live up to mature age.
Umbrella shrimp (Umbellocaris furtivus)
Order: Decapods (Decapoda)
Family: Palaemonids (Palaemonidae)
Habitat: Pacific Ocean, top water layers.
Plankton is the special community of live organisms. Here there are species
of predators and scavengers, parasites and symbionts. The competition in plankton
is very strong, and predators of different trophic levels are diverse. Therefore
various live organisms enter the unions with each other to resist to predators
in common. Often one well armed species becomes the involuntary defender to
tens species of smaller animals. Such unions are not always safe. Jellyfishes
are one of the most widespread animals in plankton. They are a food for many
larger predators, but nevertheless they are not too defenceless. Stinging cells
of jellyfishes save these animals of the majority of predators, and only few
specialized species can unpunishedly eat jellyfishes or parasitize
on them.
Animals looking for protection at jellyfishes must be cautious – the casual
touch of tentacle may transform them to easy dinner of this animal. But there
are live creatures venturing to live in dangerous affinity from poisonous tentacles
of these coelenterates.
Under the bell of jellyfishes it is possible to find often the small shrimp
keeping by thin hooked pincers for edge of the jellyfish bell. For this feature
it received the name of the umbrella shrimp: it looks like hidden from the
sun under the umbrella of jellyfish. This is small crustacean: length of its
body is about 5 cm. Body of umbrella shrimp is translucent and has bluish shade.
Therefore it is absolutely imperceptible in water. Only sometimes, when the
jellyfish emerges to water surface, the sun shine in round eyes indicates the
presence of this crustacean.
Pleon of this animal is very short and has advanced swimming legs. Walking
legs are not adapted to movement on firm surface. They are covered from edges
with rigid hairs and help the shrimp to swim. But nevertheless this crustacean
spends the most part of life having clung to the bell of jellyfish. At the
umbellate shrimp two pairs of pincers twice exceeding length of body are well
advanced. Tips of these pincers are very thin and long. The forward pair of
pincers is used more often to keep for edge of the jellyfish bell. In case
of necessity to hide from the predator, umbrella shrimp bends joints of these
pincers, and by one somersault hides under umbrella of the jellyfish. By second
pair of pincers of the same length the umbrella shrimp “handles” tentacles
of the jellyfish on which it lives. It takes off from tentacles and eats small
animals had got to the jellyfish. Hence the specific epithet of this shrimp
meaning “thievish”. Such habit of life is possible for it because this shrimp
is tolerant to poison of jellyfishes.
Umbrella shrimp spends all life on jellyfishes. If the host jellyfish perishes,
shrimp can move to other jellyfish. It swims very reluctantly and mostly soars
in water, having stretched antennae in sides. When the jellyfish approaches
to it, shrimp seizes it to the edge of bell. First time umbrella shrimp gets
accustomed to poison of new host jellyfish and develops immunity. It cautiously
touches tentacles of the jellyfish, receiving easy stings. At this time the
immune system of shrimp accumulates antibodies to poison of jellyfish. Having
got accustomed to new host jellyfish, shrimp starts to live habitual life,
taking away a part of catch right from tentacles of jellyfish.
Umbrella shrimps are strongly expressed egoists. Each individual protects the
jellyfish from contenders, getting rid them from bell and pinching by pincers.
If the opponent is stronger, the crustacean seizes edge of jellyfish bell by
all pincers waiting while the contender will leave out. Sometimes after such
passive defense the part of legs and antennae of shrimp appears bitten off,
but they quickly grow after the molt.
But for the sake of breeding umbrella shrimps are compelled to overcome individualism
and to search each other in the ocean. The female stays the homebody, but the
male should undertake risky travel to thickness of water in searches of the
female. It folds long pincers under the body and swims using walking legs.
Male searches for female by smell and leaves the jellyfish only when the female
ready to pairing is felt absolutely beside. At the male there are long antennae
at the basis with numerous hairs. They are rich in chemoreceptors; therefore
male precisely finds the necessary female at the distance of several meters
in congestion of jellyfishes. Having found the female, male as soon as possible
must couple with it. But for this purpose it should convince the female of
peace intentions. At meeting with the female it is very cautious: when the
meeting of the male and the female takes place, the male cautiously touches
the female by tip of antenna. It strokes the cephalothorax of the female in
the area of eyes and maxillipeds, accurately approaching nearer to the female.
Courtship ritual lasts till some minutes. Having convinced that the male does
not express aggression, the female supposes it to itself. Pairing proceeds
fast: male clings to female, leaves on its pleon two large spermatophores and
departs. More often it can not return back to the “own” jellyfish, and after
each pairing is compelled to search new one. But during one “wedding travel”
male has time to fertilize several females.
In some hours after pairing the female lays large eggs and bears them on abdominal
legs. At the umbellate shrimp there is direct development: tiny copies of parents
burst from eggs. This species has a little posterity in comparison with other
plankton animals, but young shrimps are very much advanced. They perch on abdominal
legs of the female till some days, then abandon the mother and begin independent
life. Since the first days of life young shrimps start to cooperate with jellyfishes.
First they live on bell of jellyfishes and clear them of parasites – infusorians
and microscopic worms – for any time. Then young umbrella shrimp move on edge
of its bell and start to eat its catch.
This shrimp grows very quickly – at three-monthly age the young shrimp reaches
the size of adult one and starts to breed. Every five – six weeks the female
makes a new clutch.
Dragonfly prawn (Libellulocaris prolongus)
Order: Decapods (Decapoda)
Family: Penaeids (Penaeidae)
Habitat: Pacific Ocean, top water layers.
Waters of open ocean represent very specific habitat. Here it is almost impossible
to find a point of support, and the majority of plankton inhabitants is adapted
to soaring or swimming in water thickness. Some sea inhabitants spend in water
thickness only a part of life cycle, and others constantly live in this world.
All of them form the special community named plankton. All plankton creatures
have one common property – they are not able to resist to current, and constantly
wander in ocean.
In plankton constant struggle for existence, not less rigid, rather than in
the world of big creatures, takes place. Peaceful vegetarians eat plants –
microscopic algae growing in top layers of water. In turn, they serve as food
to various predators. Their activity is so great, that plankton inhabitants
practically do not have chance to die a natural death. Some predators are passive,
and others chase the planned prey actively. One original prawn had received
the name dragonfly prawn for features of appearance and habits concerns to
number of active predators of plankton.
The length of this crustacean reaches approximately 10 – 13 cm. Body of dragonfly
prawn is long, thin and transparent. Through covers of its body it is visible,
as heart contracts, and in intestines the digested food moves. This creature
becomes well appreciable when it appears in day time in the top layers of water.
Then its huge spherical eyes on short stems brightly shine. Eyes of dragonfly
prawn are rather large in comparison with the size of its body, and also number
hundreds thousand tiny facets. Due to it dragonfly prawn easily distinguishes
even the slightest movement in thickness of water. By casual light shine on
body covers it finds plankton inhabitants which often are almost completely
transparent. Organs of sense of smell are located on long antennae. When this
prawn chases prey, antennae are pressed to the body.
Land dragonflies chase catch using opportunities of wings. Dragonfly prawn,
certainly, has no wings, but it does not prevent it to chase catch. This crustacean
swims with the help of strong abdominal legs. In connection with such way of
movement the body of dragonfly prawn had partly changed: the cephalothorax
of this crustacean became very short (its length is about one fifth of the
general body length), but the pleon is strongly extended. At dragonfly prawn
segmentation had changed - the number of pleon segments reaches one and half
tens. The fin formed by back pair of abdominal legs serves as rudder for sharp
turns – catch of dragonfly prawn often makes sharp jumps aside, forcing predator
to stop chasing.
Usually small plankton crustaceans and larvae of fishes become food of this
prawn, but occasionally this prawn can catch fry, large crustaceans or floating
mollusks. Walking legs of dragonfly prawn are one more feature giving to this
crustacean similarity to winged prototype from among insects. At pelagic habit
of life ability to walk appeared useless (land dragonflies can not walk too),
but legs had got other, much more useful function. On internal surface of all
five pairs of walking legs at dragonfly prawn lines of long sharp spikes are
developed. Put together, legs represent similarity of fishing-basket. For capture
of small animals dragonfly prawn simply rushes through their congestion and
catches them by some ones at once, not undertaking special efforts. Usual dragonflies
catch their prey, midges and mosquitoes, the same way. Larger animals also
can not avoid deadly “embraces” of this prawn – it grasps large animal and
strongly compresses it by legs, piercing through by spikes.
When prey is caught, maxillipeds are used. Bristles on their bottom side gather
tiny plankton animals to one clod which is swallowing by animal. The prawn
dismembers large catch with the help of cutting edges of maxillipeds. For one
day the prawn can eat up to ten rather large fish fry or smaller animals in
amount approximately equal to body weight of this animal.
The dragonfly prawn is a predator and active cannibal; therefore it does not
form congestions in plankton. Only in breeding time the male searches for the
female not having the purpose of attack. The male of this species differs from
the female in larger back pair of walking legs with which help it keeps the
female till the pairing.
The female ready to pairing emits the special substance involving males. By
odorous trace they find it – often near one female some competing males gather.
One of males (as a rule, the largest one) drives off others and pairs to the
female, and then swims away. The fertilized female stops the odorous substance
emitting, and becomes dangerous to own congeners again.
Tiniest eggs (up to 20 thousand grains of roe) are bearing on abdominal legs
because of what the female loses speed of movement and lives half-starving
for some time. Through 3 – 5 days from eggs translucent plankton larvae with
long back outgrowth facilitating soaring in thickness of water burst. They
are predators, and immediately start to eat unicellular organisms. At one month
age the larva finally turns to tiny copy of adult animal. But to this time
up to 90 % of larvas perishes of various predators including their own congeners.
Sexual maturity comes to them at the age of 7 months. After that the adult
female regularly starts to lay eggs with an interval equal to lunar month.
The maximal life duration of dragonfly prawn does not exceed one and half years.
Tentacle prawn (Furocaris toxiresista)
Order: Decapods (Decapoda)
Family: Penaeids (Penaeidae)
Habitat: warm and temperate areas of Indo-Pacific.
In Neocene plankton fauna had undergone some changes in comparison with Holocene.
The reason of it had been the mass extinction connected to global ecological
changes. In early Neocene when conditions of life had stabilized, planktonic
habit of life had been developed by plenty of new groups of animals. They had
been mainly various descendants of coastal and shallow-water forms. Shrimps
are one of typical inhabitants of plankton in epoch Neocene. Among them there
is a set of various species – from peaceful filtrating organisms up to predators.
Some species of planktonic shrimps had entered symbiotic relations with other
animals living in plankton. Generally speaking, forms of relations of shrimps
and their neighbours change from symbiosis up to predating with various variants.
One of such variants is shown by tentacle prawn living in waters of Southern
hemisphere.
It is rather large carnivorous prawn about 15 centimeters long. It keeps near
to congestions of jellyfishes, and even constantly lives in tentacles of some
species of these coelenterates. Body of this crustacean is lengthened; cephalothorax
is rather short. Tentacle prawn is a little similar to another pelagic crustacean,
its distant relative, dragonfly prawn. Antennae of tentacle prawn are very
long – they exceed body length of this crustacean. Walking legs of this prawn
are covered with small bristles and adapted to drifting in water – tentacle
prawn frequently floats, keeping for a tentacle of jellyfish by one claw, and
having freely stretched legs in thickness of water. Also with the help of such
legs shrimp easily keeps on tentacles of jellyfish on which it lives. At the
male the back pair of walking legs is larger, than others: these legs serve
for keeping on the female during pairing.
In spite of the fact that this prawn is rather large, it is difficult for seeing
in water. Armour of animal is almost transparent and has slight bluish shade.
Through covers of this prawn it is perfectly visible, as its heart pulsates
and food moves in intestines. A parameter of refraction at tissues of tentacle
prawn is almost same as at sea water, therefore small grey spots on pleon segments
and shining dark eyes are only things visible at this crustacean in water at
dim illumination.
The food of this prawn consists mainly of prey captured by jellyfish – the
main sense of its relations with jellyfishes consists in it. Tentacle prawn
constantly swims near jellyfish, inspecting its tentacles. This occupation,
however, is unsafe – tentacles of jellyfishes are poisonous. But tentacle prawn
has strong immunity to poison of jellyfishes. This immunity is acquired, and
is developed during some time. At first tentacle prawn cautiously moves nearer
to jellyfish, touching up to its tentacle by antennae. Usually at this moment
it receives weak burn of stinging cells. After attack of jellyfish the prawn
does not swim out, but stays near this animal, and even sits on its dome from
above, outside of zone of reach of jellyfish tentacles. Within approximately
one day prawn actively develops antibodies and gets immunity to poison of present
species of jellyfishes, if it had not it earlier. After that it actively creeps
in tentacles of jellyfish in searches of its prey. Immunity is kept to whole
further life, therefore the “skilled” prawn had replaced host jellyfishes of
several species becomes a universal predator. Sometimes this prawn can harm
to jellyfish: it simply bites off a tentacle in common with prey, and eats
it entirely. Poison of jellyfish accumulates in liver of prawn, and additionally
makes it inedible.
Tentacle prawn is a solitary animal. It concerns to congeners neutrally, but
at the case of lack of food it can drive them away from jellyfishes on which
it is fed by impacts of rostrum.
This prawn is the descendant of pelagic animals, and has kept a way of breeding
characteristic for them. After short courtship ritual and pairing female lays
set of tiny eggs – up to several thousand ones. 3 – 5 days later from them
tiny planktonic larvae hatch; they pass some stages of metamorphosis before
turning to tiny similarity of adult individual. Tentacle prawn breeds monthly
during half-year, and then in coldest months of year the break follows.
Young tentacle prawns lead a pelagic way of life. They gather to schools up
to several hundreds individuals, and avoid meeting with jellyfishes. At young
age their immune system is not ready to development of antibodies against poison
of these animals, and they frequently become prey of jellyfishes. Only at length
of about 5 cm young prawns become advanced physiologically enough to pass to
inhabiting on jellyfishes without danger to their own life.
Feather-legged shrimp (Baculophthalmocaris plumopes)
Order: Decapods (Decapoda)
Family: Penaeids (Penaeidae)
Habitat: northern part of Pacific Ocean (temperate and polar latitudes), top
layers of water.
In Neocene among oceanic plankton the essential place was occupied by decapod
crustaceans. In Holocene many species of these animals spent in plankton only
a part of life cycle. But in Neocene among them the true planktonic forms competing
to other groups of crustaceans had appeared. One of such species is tiny feather-legged
shrimp. This is pelagic crustacean adapted to inhabiting in water thickness.
It has translucent body, therefore it is difficult to notice feather-legged
shrimp in water. The body length of this crustacean does not exceed 3 – 4 cm.
This crustacean passively drifts in water thickness, having stretched in sides
long walking legs. The length of legs is almost equal to body length of this
crustacean. Legs from both sides are densely “feathered” with hairs – this
adaptation facilitates drifting in water thickness. Claws of feather-legged
shrimp are long: they twice exceed body length. In rest they are usually folded
along the body on its bottom side, and do not prevent movement of shrimp.
The pleon of feather-legged shrimp is short; it makes less than half of general
length of animal (not including antennae and legs). It is wide, and pleopods
are covered with hairs on edges and are adapted to drifting in water. When
feather-legged shrimp drifts in water thickness, pleopods are spread wide in
sides, increasing the common area of body.
The structure of eyes of this crustacean is remarkable. Eyes are rather big
– they are cherry stone-sized. They are located on long mobile stalks which
can move almost in any side. Eyes of spherical form give this shrimp the full
circular field of view. They are combined by set of tiny facets providing sharp
sight. Stalks of eyes also serve as the additional organs facilitating drifting
in water: the similar attribute was present at fry of deep-water fishes Idiacanthus
known to people. The animal can change position of body in water thickness,
moving by long eye stalks.
Despite of passive way of life, feather-legged shrimp is a predator. It catches
small invertebrates, seizing them by mobile claws and moving to mouth. Occasionally
it can make short throws to prey or to escape from a predator, rowing by pleon.
This species of shrimps is dioecious. Male is smaller, than female, and also
weighs almost twice less. It is able to swim actively, rowing by walking legs.
Pairing occurs quickly and is not anticipated by any ritual. In some days after
pairing the female spawns a lot of tiny eggs (up to 3 – 5 thousand ones), and
bears it on pleopods within two weeks. From egg pelagic larva (zoea) hatches,
which at once leaves the female. Within one year the female can make up to
5 – 6 clutches.
Development of larva takes about three months. Till this time it undergoes
up to 8 – 9 moults and gradually turns to tiny similarity of adult individual.
To the end of metamorphosis its length reaches about 20 mm. Two months later
it becomes sexually mature.
Ice shrimp (Cryopenaeus crystallinus)
Order: Decapods (Decapoda)
Family: Penaeids (Penaeidae)
Habitat: Antarctica, shallow rivers.
After thawing of glacier covered Antarctica during late Tertiary and Quaternary
periods, at this continent marshes, rivers and lakes had formed. The freshwater
fauna of Antarctica formed from zero – its former representatives were destroyed
by congelation. Settlers of fresh waters get to the continent in two ways –
by air (insects) and from the sea (crustaceans and fishes). In reservoirs of
Antarctica invertebrates take more significant place, rather than at other
continents – it is connected to small number of local fishes. Among local invertebrates
the species having various adaptations had appeared, permitting to survive
in extreme conditions which had developed at this continent.
In southern seas shrimps of penaeids family (Penaeidae) are usual. Usually
their representatives spend in fresh water only a part of life, and for breeding
necessarily migrate to the sea. Among freshwater animals of Antarctica these
shrimps are very usual. One of their species is ice shrimp.
Body length of this crustacean is up to 10 cm; male is smaller, than female.
The body of ice shrimp is almost completely transparent: through thin covers
internals, heart pulsation and movement of food in intestines are visible.
On armour small grey points are visible only. Such colouring provides good
masking. Only the bases of legs, mandibles and maxillipeds, and also eyes of
this shrimp are opaque. Long serrated rostrum, and also large reddish eyes
consisting of numerous facets are characteristic features of shape of the ice
shrimp. This shrimp is able to swim well with the help of pleopods. The forward
pair of walking legs is not transformed into claws, but they are thicker and
stronger, than the others. On bottom side of these legs sharp prickles, with
which help shrimp keeps food, grow.
Ice shrimp is a predator. It eats larvae of insects – dragonflies and two-winged
flies. This shrimp hunts from an ambush. Usually it hangs upside down on plants
floating on surface of water, or on stalks of water plants, and waits for occurrence
of prey. It catches small animals by throw; having seized prey, shrimp returns
to stalk and eats it, keeping by forward pair of walking legs. Having eaten
prey, ice shrimp simply lets off the rests, and they are carried away by current.
This species of crustaceans has adapted to survival in shallow reservoirs of
Antarctica completely freezing through in winter. Ice shrimp survives in winter,
having dug among rests of vegetation at the bottom. While the environment is
liquid, shrimp keeps any activity and can even slowly move in thickness of
silt impregnated with water, clinging by strong forward pair of walking legs.
When the reservoir freezes through to the bottom, this crustacean falls into
anabiosis and permits body liquids to freeze. In tissues of shrimp the substances
constraining formation of large ice crystals accumulate, and ice does not destroy
cells. In such condition ice shrimp can endure frosts up to - 40°Ñ.
In spring, when reservoirs get warm enough, ice shrimps release from winter
captivity. They start to fatten actively, searching for larvae of insects fallen
into catalepsy, and sometimes eat their own congeners. Approximately one month
after clearing of reservoirs of Antarctica from ice, having restored forces,
these shrimps start to prepare for breeding. Males compete for females, arranging
fierce, but not fatal combats with the help of forward pair of legs. They grasp
by forward pair of legs leg or antenna of the opponent, and try to turn it
and to keep in such position. But usually the amount of males in population
is less, than females – they grow slower and more often become prey of other
water animals.
Ice shrimp breeds in sea water. Fertilized females migrate downstream, gathering
to numerous schools, numbering tens thousand individuals. At this time in ovaries
of females eggs develop; they which will be laid only in water of ocean salinity,
far from coast. There are many eggs in clutch – up to 50000 ones; but they
are very small. After young ones hatch, the female dumps the rests of clutch
from pleopods and moves back to the river. Females come back upstream along
the riverbank, where current is slower, and at this time do not gather in schools.
Using well advanced sense of smell, each individual finds the river in which
it lived before breeding. The egg laying repeats 2 – 3 times per polar summer,
but the mass breeding migration takes place in late spring. Males of this species
never leave fresh water.
Development of ice shrimp includes planktonic larval stage. After the metamorphosis
(at the age of 3 months) young shrimps enter rivers and move upstream. The
first year of life young ones stay in lower reaches and central channels of
rivers not freezing completely. Strong enough and mature individuals rise upstream
farther and settle in lakes and streams. One-year-old shrimps can breed; life
expectancy seldom exceeds three years.
Badger prawn (Pedocrangon minimeles)
Order: Decapods (Decapoda)
Family: Crangonid prawns (Crangonidae)
Habitat: rivers of Pacific coast of Asia - from Big Kurils and Far East coast
of Asia up to the south of Japan.
In Holocene prawns of crangonid family had started to develop freshwater habitats;
separate species of these crustaceans passed the bigger or smaller part of
life cycle in fresh water. Among Neocene crangonids species completely passed
to freshwater habit of life had evolved, and they had settled rivers and lakes
far from seas. Transformation of life cycle of these prawns was the result
of this act – they are lack numerous larval stages and the development had
to greater or lesser extent come nearer to ametabolous development. In Asian
rivers of Pacific Ocean basin the genus of crangonid prawns had evolved, which
had a special life cycle during which the individual changes gender depending
on circumstances. It is a genus of prawns of massive constitution, which representatives
have massive short claws adapted to digging. In dense ground composing riverbanks
they dig burrows in which hide during the day time.
Dark colouring and longitudinal white strip along the middle line of cephalothorax,
and also skill of burrow digging had denominated this species as badger prawn.
At this species of crustaceans the sexual dimorphism is sharply expressed.
The female of badger prawn is massive – up to 20 cm long, with short wide claws
and strong legs. It swims not so good, but walks on the bottom much better.
The armour of this crustacean is sculptured – on cephalothorax and pleon segments
of adult prawns quaint relief of knobs and grooves is expressed. On body numerous
tiny hooks and bristles are located. It is necessary for masking – badger prawn
fastens on itself parts of plants. Antennae at the female of this species are
short.
Male sharply differs from female. It is very small – not larger than 2 cm.
It is connected to features of life cycle of badger prawn. The gender at these
crustaceans is not fixed genetically, and connected exclusively to age of animal.
Badger prawn has ametabolous development: from eggs tiny similarities of adult
individual hatch. They keep on pleopods of the female within several days.
After the first molt young individuals ready to independent life leave female’s
pleon and the first year lead independent life. The next summer they reach
sexual maturity and every one of them turns to male. Males find mature females,
and sit to bottom side of their pleon. Walking legs of males have special attaching
claws. In breeding season (in the beginning of spring) male fertilizes the
female but does not leave her after that. He lives on her body as a commensal,
eats prey of female and clears her body of parasites. When the female bears
posterity, male cares of eggs and young prawns, sitting on bottom side of body
of the female. He clears eggs of dust, moves off dead or non-fertilized eggs
and protects just hatched posterity from small predators. When posterity leaves
the female, male also leaves off. Its male life is finished in this time, and
within one year after some molts its transformation into the female takes place.
After that transformation up to the end of life this individual will be the
female, and male of new generation will look after eggs, sitting on its pleon.
At the second year of life females are able to breeding. Active growth proceeds
at them up to the seventh year of life, and general life expectancy makes till
20 years.
Badger prawn digs holes, using claws and massive rostrum. Edges of claws of
badger prawn are covered with denticles, with which help animal loosens clay
ground and even “saws” roots of plants. The hole of this crustacean is made
at the depth up to one meter. The length of hole may exceed two meters. Summer
holes of this species are horizontal; individuals from southern sites of an
area dig similar holes. In areas of seasonal climate and in cold winter badger
prawn makes deep hibernating holes directed downwards vertically to the depth
up to 160 cm.
The idea about existence of present species of crustaceans is proposed by Nem, the forum member.
Antarctic swamp false jabby (Antarctocancer palustris)
Order: Decapods (Decapoda)
Family: Antarctic false crayfishes (Pseudocancridae)
Habitat: meadows and marshy areas in Antarctica.
Antarctica of Neocene epoch is true “lost world”. It remained isolated from
other continents for a long time, and the whole terrestrial fauna of this continent
had been exterminated by glaciation held down Antarctica to millions of years.
As a result after climate warming in Neocene this continent had been settled
by terrestrial animals almost from zero.
Absence of ground mammals in New Zealand (before human colonization of islands)
had resulted in occurrence of giant flightless orthopters of Deinacridae family,
which became ecological analogues of rodents. In Antarctica the similar situation
had repeated. But insects have the limited opportunities for increase of size
because of features of anatomy of respiratory system. Therefore in Antarctica
they had lost to representatives of decapod crustaceans in struggle for existence.
In Antarctica there are no river crayfishes, fauna of sea crabs is very poor,
and ground crabs live far overseas, and their larvae can not get to this isolated
continent remarkable by cold climate. But in coastal waters of Antarctica there
are many kinds of shrimps. Some shrimps had developed life in fresh water,
and one genealogical line of these crustaceans had given rise to unique terrestrial
forms. Antarctic swamp false jabby is the largest terrestrial arthropod of
Antarctica. It is the true terrestrial species of crustaceans, the close relative
of prawns of crangonid family (Crangonidae). It is very large species not only
to measures of prawns – the length of this crustacean reaches 20 cm.
Appearance of Antarctic swamp false jabby is freakish and even grotesque. It
has rough granular armour and sharp denticles on carapace, growing in three
longitudinal lines. Pleon of this crustacean is short and wide; on each segment
a cross line of large knobs grows. Edges of carapace at Antarctic swamp false
jabby are convex, and on each side of the body extensive cavities are formed.
In them there are plicas of thin epithelium penetrated with blood vessels and
substituting lungs. The similar adaptation was present at terrestrial coconut
crab (Birgus latro) of human epoch. Due to such adaptation Antarctic swamp
false jabby well feels like on land many hours in succession. Nevertheless,
this crustacean is compelled to fill up stocks of water regularly. For this
purpose Antarctic swamp false jabby keeps near to marshes and various temporary
reservoirs where dives for wetting of respiratory cavity.
From four pairs of walking legs first pair is advanced rather poorly. These
legs are thin and mobile; with their help animal gathers food. The following
three pairs of walking legs are rather large and strong. They easily maintain
weight of body of Antarctic swamp false jabby on land. With their help animal
can even climb on bushes in searches of food – bird eggs and insects. Powerful
claws are inherited by this crustacean from ancestors – prawns of crangonid
family. Dactyl (“thumb”) is very short, and the propodus (outgrowth of penultimate
segment), forming the basic part of claw, is wide and shovel-like, with serrated
internal edge and knobby surface. With the help of claws Antarctic swamp false
jabby digs holes in which rests and molts.
Male differs from female in smaller size, narrow body and larger claws. At
females bottom side of claws is grey with white edge, and at males it is bright
pink. Besides female is colored darker, than male.
This crustacean has short antennae – their length does not exceed length of
carapace. Basal segments of antennae are thick and covered with tiny thorns.
In courtship season males of Antarctic swamp false jabby arrange combat for
females, pushing each other away with the massive antennae bases. Eyes of this
crustacean are large and located on short and thick eyestalks. The set of facets
provides good sight, but animal is short-sighted and in search of food uses
sense of smell first of all.
Antarctic swamp false jabby is a predator and scavenger. It eats terrestrial
invertebrates – insects and their larvae, and also its own smaller relatives.
It willingly eats nestlings of local flightless mousebirds
(Musornis spp.),
pulling them out from holes. In autumn and in spring, when in Antarctica day
and night alternate, at night Antarctic swamp false jabbies may creep out to
the coast of ocean in searches of sea animals cast ashore.
This crustacean has almost interrupted the connection with aquatic environment,
and does not depend on sea water in breeding season at all. After pairing the
female lays large eggs (up to 400 ones about 6 mm in diameter) staying on land.
It bears clutch on pleon up to the hatching of young ones. Only just before
the ending of incubation female searches for fresh-water reservoir. At this
time it behaves very aggressively to any congener, attacking on it and expelling
from the reservoir occupied by her. Young jabbies hatch in water, and female
with young ones lives in shallow water till some time. After 5 – 6 days young
jabbies leave the female, and she comes back to land. To the end of summer
young Antarctic swamp false jabbies reach the length of 3 – 4 cm and leave
a reservoir in searches of place for wintering.
Features of Antarctic climate had forced this crustacean to develop special
forms of behaviour permitting to survive. Antarctic swamp false jabby winters
in deep hole (its depth is up to 3 meters) dug almost vertically. In hole there
are some horizontal ells closed by friable ground fuses – it provides thermo-insulating
and the minimal air change. Along the hole, depending on weather in forthcoming
winter, this crustacean arranges up to five fuses. Young individuals winter
in casual shelters, and frequently penetrate into holes of adult individuals.
In spring nothing threatens to them: while weather is cool, at adult individuals
appetite is reduced, and they do not pay attention to young growth, leaving
a hole. But in summer, when there is a polar day and the sun shines all day
and night, in meadows of Antarctica it is warm weather, and adult false jabbies
can eat young ones. Also young jabbies frequently become prey of terrestrial
birds and bird-catching sundew (Droserophyllum ornitivorum) – large carnivorous
plant.
Young animals reach sexual maturity at the age of 3 years at length of a body
about 15 cm. Life expectancy of this crustacean seldom exceeds 15 years.
Bristle-legged
shrimp (Planctoatyopsis setipes)
Order: Decapods (Decapoda)
Family: Atyids (Atyidae)
Habitat: rivers and lakes of Northern Australia and New Guinea.
Reservoirs of Australia and New Guinea of Holocene epoch were rather poor in
true freshwater fishes. Their population developed basically from sea species,
adapted to life in fresh water, and from migratory species of fishes. Because
Australia at the moment of origin of orders and families of freshwater fishes
was separated from other continents by sea passages, it has had an effect on
its ichthyofauna which appreciably differs from ichthyofauna of near islands
and Asia.
In Neocene the fauna of seas has changed strongly: it is connected to fluctuations
of biomass of plankton and extinction of coral reeves. The fauna of fresh waters
has suffered less though species of fishes connected to sea biotopes, mostly
have died out. Therefore in Australia the nature had organized interesting
experiment: ecological niches of fishes were partly occupied with other animals,
swimming crustaceans.
Bristle-legged shrimp is one of such species occupying free ecological niches.
Absence of fishes filtering microscopic algae in reservoirs of the Australian
region has permitted this species of shrimps to reach the certain success.
This pelagic crustacean up to 5 cm long meets in big shoals in lakes at small
depth. The bristle-legged shrimp gathers food to itself with the help of filtering
device developed on forward legs. At shrimps of family Atiidae, known to humans,
at three forward pairs of walking legs the special adaptation for getting food
was developed: brushes of hairs sticking up in sides. With their help shrimp
digs out tiny edible animals, sifting through them sand, as through a sieve.
At the bristle-legged shrimp this filtering device is transformed for filtration
of plankton organisms and large algal cells from water. At the internal side
of legs brushes are especially strongly advanced.
Swimming in thickness of water, shrimp makes paddling movements by forward
pairs of legs. At the stroke brush gathers plankton from water and when the
leg makes return movement, mouth feet scrape from bristles paste of algal cells
and plankton, and push it in mouth. The basic swimming organ at this shrimp
is fourth pair of legs with wide blades (as at water beetles). At known in
Holocene representatives of this family (for example, at Malayan wood shrimp
Atyopsis moluccensis) these legs served for keeping at the bottom in stream.
In connection with transition to pelagic way of life function of these legs
had changed. Fifth pair of walking legs is thin, adapted to accurate movements.
They serve for gill clearing of silt and suspension.
Body of the bristle-legged shrimp is sharp-nosed and streamline-shaped. This
crustacean constantly keeps in thickness of water, occasionally sitting on
stalks of floating plants for rest.
Short moments of pairing at these shrimps pass in thickness of water. The female
is little bit larger than the male, but at him the claw at the tip of rowing
leg is better advanced. Male swims up to the female from below, overturning
upside down, and clasps her body by rowing legs. He injects sperm in oviducts
of the female with the help of first pair of abdominal legs, and then swims
away. Female lays about hundred large eggs and bear them on abdominal legs
during some days. Development is direct: from eggs tiny shrimps similar to
adult individual hatch.
Young shrimps do not compete to adults for food: they live near coast in thickets
of plants. Their forage is large infusorians and rotifers; growing up, they
pass to feeding by small crustaceans and algae. Shrimps had reached length
about 2 - 3 cm gather in schools and swim in thickness of water, and pass to
adult food. Having reached such length, they can have posterity.
Bristle-legged shrimp lives up to two-year-old age seldom.
In the rivers and lakes of Australia there are also close species of shrimps:
Bearded
shrimp (Pl. barbatus) is considerably more
specialized species: it eats almost exclusively algae,
competing with plankton cladocer crustaceans. At its
forward legs there are brushes of very rich thin bristles,
permitting to filter only rather tiny cells of algae,
and only smallest plankton animals - rotifers. This
shrimp is rather small - length of its body is up to
3 cm. Body of this crustacean is practically transparent
with light greenish shade: it helps to mask from possible
predators among plankton algae. Because the food source,
used by this species, differs in big efficiency, bearded
shrimp makes big congestions. But its number strongly
changes in various seasons proportionally to amount
of phytoplankton. Life expectancy of this species exceeds
one year seldom, but the young shrimp can breed already
at the fifth week of life.
Needle-legged
shrimp (Pl. spinosus) as against to relatives
is active predator eating large plankton crustaceans
(including larvae of other shrimps) and even small
fishes. Bristles on legs are hooked, large and thin
– they are adapted to hooking and keeping small catch,
instead of algae filtering. Length of this shrimp is
up to 6 cm. The body is colored green with reddish-brown
and black vertical strips; on pair of swimming legs
there are white longitudinal strips. It keeps solitarily
or in small changeable congestions in thickets of floating
plants, immediately attacking shrimps and small fishes.
At times shrimps of this species can have fights for
catch, and as a result of which crustaceans can lose
not only catch, but also pair of legs moreover. Development
is direct, eggs are very large, but not numerous: only
30 – 50 ones. Larvae at first eat algae, than start
to catch in the beginning small plankton crustaceans,
and later small shrimps and fry of fishes.
Driftwood-boring
shrimp (Xylocaris terebratus)
Order: Decapods (Decapoda)
Family: Long-armed shrimps (Macrobrachiidae)
Habitat: woods of Amazon region, shallow rivers.
Tropical rainforest and river are practically indissoluble combination. Many
forest inhabitants are connected in their life with rivers, and the wood roofs
and foods some river inhabitants. In Neocene the set of interrelations between
inhabitants of two these worlds has replenished with one more example.
Rainforests of an Amazon region from time to time are overflowing by water.
Trees have not sustained flooding, fall and lay across rivers. In their roots
and branches fishes and other inhabitants of the river find shelter, and some
fishes even rather willingly gnaw mossy moldering wood. In Neocene one more
animal has joined to set of dead wood destructors.
The tree has fallen in water about two months back, at first sight looks almost
intact. Rotten pieces of bark here and there have fallen off, and dead leaves
are carried away by river. But at close look it becomes visible, that tree
trunk obviously has traces of someone’s work: in some places wood is pierced
by apertures in which small creatures sit. Being scared, they disappear in
burrows, but being calmed, they dare to creep out. And then it becomes evident,
that they are crustaceans: at them there are long antennae and eyes sit on
stems.
It is the special kind of shrimps from tropical rivers of America – the driftwood-boring
shrimp. It serves here as the original analogue of bivalve mollusk “ship worm”
(Teredo): this crustacean drills holes in wood, destroying trees have got in
water. The driftwood-boring shrimp lives in minks by whom itself does(makes)
in wood. Sometimes this shrimp lodges even in roots of trees, for any reasons
flooded with the river and remaining in water the year round. These species
prefer a society to itself similar, therefore settle usually the whole colonies
numbering up to hundred of individuals.
Length of the driftwood-boring shrimp is about 5 cm. Body of animal at the
back edge is translucent, armour is yellow-colored with black longitudinal
strip. Pincers are white color, very short and strong, with jags along the
edge. They have turned to powerful drilling apparatus with which help this
shrimp destroys wood of the majority of tropical trees.
Eyes are large; they are placed on long stems. When shrimp sits in shelter,
from hole only eyes and antennae stick up. Occasionally the crustacean leaves
holes, but does not leave far from them. At danger this animal quickly swims
and hides into the nearest hole.
The colony occupies tree and pierces it with holes where crustaceans live and
breed, while the tree will decay finally. Holes are deep, pulling mainly in
top layer of wood. They join, forming complex system in process of colony increasing.
The driftwood-boring shrimp almost does not eat wood: it eats, scratching out
from walls of holes fungoid film and colonies of bacteria, and also eats small
animals swimming away in holes in searches of shelters. Naturally, as an addition
to food it swallows some wood dust, but it is not digested. Due to strong pincers
the crustacean easily splits shells of snails.
Development is direct, from eggs tiny shrimps similar to adult individual hatch.
In clutch it is about 30 – 50 rather large eggs. Young shrimps live in holes
of adults, but in process of growth they are gradually superseded to edge of
colony, where they start to drill their own holes.
Needle
shrimp (Acuticaris incola)
Order: Decapods (Decapoda)
Family: Tubocarids (Tubocaridae)
Habitat: reeves of Indian and Pacific oceans, colonies of tube worms.
After extinction of reef-building corals, a role of main architects of ocean
shallow waters had been undertaken by various animals, first
of all by mollusks.
But the considerable part of reeves is constructed by sedentary annelid worms both
with red algae sedimenting limestone. Settlements of worms form on sea bottom
true “towns” of numerous directed upwards straight or bent tubes. Usually from
tubes tentacles of these animals stick up, but if any large animal appears
nearby, worms immediately hide in tubes. But they will not manage to disappear
from some animals of reef thus even because that ones share “apartments”, their
own tubes. One of inhabitants of worm tubes is thin transparent shrimp with
extended legs and pincers. When it is shown at few seconds from tube of one
worm to get into the next tube, it is practically not visible in sea water
- only two black beads of eyes give out presence of this crustacean.
The needle shrimp almost constantly sits in tubes of worms. Certainly, these
animals are not always glad to meet visitors: the tube is designed only for
one worm. But they suffer presence of this shrimp not vainly: this crustacean
plays a role of cleaner, cleaning from tube every possible dust, and also gathering
from bodies of worms every possible parasites which this sedentary animal is
not able to shake out from itself.
The thin and flexible shrimp scurries in dwelling of worm, touching by antennae
to its body. By its physical condition shrimp estimates environment and chooses
the moment to get over to the tube of the next worm. If worms have quietly
opened their tentacles, shrimp can travel in colony under their covering. But
if worms are disturbed and start to fold tentacles, shrimp immediately dives
into the nearest tube. Its body is flexible and worm-like: armour covering
cephalothorax is rather short, and shrimp resembles more any primitive crustaceans.
The body of this shrimp is strongly extended (about 5 cm long at thickness
only of 3 - 4 mm), and legs are very thin. Pincers account the body length;
they are thin and sensitive: with their help shrimp gathers dust and parasites
from cautious “host”. On the forward end of a body of needle shrimp the strong
spike grows – it is unique weapon of this fragile creature. When too curious
fish shows interest to tube where this shrimp is hidden, it risks getting sensitive
sting of such spike.
Swimming abdominal legs of needle shrimp are hairless, and serve only to bear
eggs - this shrimp is not able to swim, and can only creep clumsily in a bottom
outside of worm tubes.
Because needle shrimp is the homebody, at it a breeding problem could arise:
eggs should be fertilized to make the posterity genetically various. And at
the same time populations of worms in which tubes these shrimps live, are far
from each other, and frequently are too small to settle in them many individuals
of needle shrimps. But this crustacean has to found a simple way out: the needle
shrimp is hermaphrodite, also in case of need it can be simply self-fertilized.
But it is the extreme way: more often in colony of worms there are even two
shrimps mutually fertilizing each other.
In clutch of needle shrimp it is usually up to 300 very small eggs. From them
smallest plankton larvae decorated with long needle-shaped outgrowths on sides
and back hatch. Their development passes at the reef, usually at deepest sites
of it. This shrimp breeds when for some weeks quiet weather without storm is
established. At larvae there are two main problems in life: to survive in plankton
where everybody can to have eaten them and find a colony of worms. After the
next molt larva loses “ornaments” on body and gets rather recognizable shape
of adult shrimp, only without needle on head. It finds tentacles of worm and
settles in its tube. It is a crucial stage in life of young shrimp: if it will
not to find a colony of worms, it’ll appear completely defenceless against
numerous reef predators. If the young shrimp is lucky, it starts to grow and
at the age of about 10 weeks already becomes adult. To this moment at it the
nasal needle grows.
The first contact of young shrimp and worms never passes smoothly. Worms, one
might, “mistrustfully” concern to occurrence of shrimp, and perceive it hostilely:
hide, close tube by operculum, or jet out to the shrimp the poisonous substance
at all. But persistence and care of shrimp make the business: it starts to
clear accurately the future hosts of parasites and dust, and eventually between
it and worms communication is established. Gradually the shrimp starts to get
into tube constructed by the worm, and soon grows roots in it and takes over
“trusteeship” some part of colony of sedentary worms.
Spike shrimp (Paracuticaris echinophila)
Order: Decapods (Decapoda)
Family: Tubocarids (Tubocaridae)
Habitat: reeves of Pacific Ocean, symbiote of sea urchins.
Reeves are favorable place for life, and are comparable to tropical forest
on specific variety. In Neocene the main reef-builders, madreporarian corals,
had become extinct, and the body of reef is formed by other invertebrates:
mollusks and worms. Between inhabitants of reef there is strict competition
inducing strict specialization. And the abundance of predators forces to develop
more and more effective ways of protection. Some inhabitants of reeves use
reliable means tested during millions years of evolution. Sea urchins of various
colors are armed with spikes and firm armours. It makes them impregnable for
the majority of reef inhabitants. Protection of sea urchins serves not only
to them – among spikes of these animals tiny graceful shrimps hide. Pointed
spikes with poisonous slime in grooves serve as an absolute obstacle for predators
eating crustaceans. The specific pointed body shape had determined the name
of this crustacean – spike shrimp.
This tiny (about 5 cm long) crustacean occupies the ecological niche of fishes
– shrimpfishes (Aeoliscus strigatus) and urchin clingfishes (Diademichthys
lineatus) used such shelter in human epoch. Spike shrimp constantly keeps between
spikes of sea urchins – here it finds simultaneously food and shelter. This
crustacean gathers parasites and dust from body of echinoderm, and receives
safe dwelling in return for it.
Body of spike shrimp is long and narrow. Cephalothorax is short; pleon is cylindrical
with wide fin formed by telson and back pair of pleopods. On head of this crustacean
there is pointed straight outgrowth directed forward and little bit similar
to spikes of sea urchin. If necessary, spike shrimp is able to change color
of body cover, adapting to shade of spikes of sea urchin on which it lives.
This crustacean sits among spikes directing head outside. Shrimp can move among
spikes of sea urchin in any direction, and at danger hides deeper into spikes,
closer to body of host animal.
With the help of thin claws shrimp gathers from spikes of sea urchin larvae
of sedentary animals settling on them, and kills parasites attached to it.
Thus, relations of sea urchin and spike shrimp represent mutually advantageous
symbiosis.
On each sea urchin some such shrimps live, forming breeding group. The gender
at these shrimps is not genetically determined, and depends on age of animal
and its position in hierarchy. Usually the colony is presented by females among
which one male lives – it is the largest and strongest shrimp. If for any reasons
male leaves colony or perishes, strongest female takes its place in hierarchy.
Shrimps growing alone initially develop as males.
Each female regularly lays eggs – up to 100 eggs once in four weeks (the laying
is dated for full moon), and bears them within two weeks. At this species there
is development without larval stage, and from eggs tiny similarities of adult
individuals leave. They at once leave parental colony and search new host for
themselves. Young shrimps can live on sea urchins with rather short spikes,
and larger individuals whenever possible move to long-spiked species. Spike
shrimp becomes adult at the age of about 7 months. Life expectancy of these
animals seldom exceeds two years.
Hawaiian boring crab (Terebrocancer geograpsus)
Order Decapods (Decapoda)
Family Grapsid crabs (Grapsidae)
Habitat: Hawaii, ground in tropical woods.
Islands never having connections with other land differ in big originality
of animal and plant population. The fauna of such places is impoverished by
typical continental species (especially by animals unable to fly or not suffering
salt water), but is frequently replenished due to sea species passing to overland
life. One of ways to leave the sea is to become digging creature and gradually
to pass to existing in damp atmosphere of underground burrows.
Rather small competition of soil animals at Hawaiian islands had permitted
to one of sea crabs widely settled in Pacific Ocean to pass to this inhabitancy.
This way the boring crab, the next overland descendant of sea inhabitants,
had appeared at Hawaii. It is small species of digging crustaceans – width
of its carapace is about 15 cm, and whole crab is up to 20 cm width. It could
be rather significant size for crabs of habitual constitution, but not for
this species. Hawaiian boring crab combines usual for crabs habit of movement
sideways with hole digging, therefore proportions of its body had strongly
changed. At such significant width of the body the height and length of this
crab do not exceed 5 – 6 cm: this animal is as if “stretched” in sides.
Pincers of this crab have unequal sizes (this feature is characteristic for
crabs in general), and fulfil different functions: one pincer serves as the
drill, the second is a shovel. Usually crab bores ground with the help of right
pincer which strongly differs from left one externally. On the right pincer
the penultimate segment is very big with the expanded gear edges and numerous
knobs on the external surface. “Thumb” (last segment) on this pincer is small,
but strong: with its help this crustacean easily cuts roots of plants, preventing
to dig a hole. Left pincers is lesser than right one, expanded, with smooth
edges. It rakes away ground dug by crab. Also with its help crab brings food
to mouth. If the crab had injured boring pincer, or it had been bitten off
by any predator, it has reorganization of sense organs and anatomy: the remained
intact pincer for some molts turns to boring one, and the crab turns to “lefthander”
from “right-handed one”. The restored right pincer becomes “shovel”. However,
about 10 % of population of boring crabs are hereditary “lefthanders”. The
walking legs of this crustacean located from the same side as “boring” pincer,
also fulfil the function of shovels, raking away the loosened ground back,
under “shovel” pincer. For this purpose the fringe of rigid bristles on their
edge also serves. When near of “shovel” pincer the heap of ground gathers,
crab walks to other side, raking away friable ground on the ground surface
or to burrows of other animals which contact with its holes, partly shifting
the work to them.
Sight does not play the significant role in life of Hawaiian boring crab, and
its eyes are appreciably reduced: they are very small, located on short thick
stems and at ground digging are hided in deepenings of the front edge of the
carapace. From outside they are protected from the ground by rich “eyebrows”
of bristles.
Boring crabs live in holes at the depth about half meter, at night rising to
the ground surface. They eat various invertebrates, but can eat and fruits
beginning to rot: obviously, a strong smell of fruits involves crabs. Occasionally
at night they get out on the surface of the ground and catch small ground animals.
If the dead animal (for example, the carcass of Hawaiian
forest goose – the
large local bird) lays on the ground, crabs can sap under ground the carcass
and eat it from below, and also gather larvae of flies and beetles eating carrion
and dug in the ground for pupating.
Being the ground inhabitant, this crab has not lost the connection with water.
It had left the sea, but goes to fresh water for breeding. Male differs from
female in narrow wedge-shaped pleon and in larger size. It couples with female
in specially dug wide hole, and does not accept any more participation in care
of posterity. But the female, ready to lay eggs, settles closer to water: it
digs in riverbank a hole which is filled with water filtered through ground.
In the formed reservoir female bears eggs within approximately two weeks. In
clutch it may be about 200 large eggs. When the time to hatch larvae appears,
female abandons the shelter. At late night it gets out of hole and hastens
to the reservoir where the simultaneous hatching of young growth occurs (fresh
and rich in oxygen water serves as stimulus of this process). If not all posterity
had hatched within night, female throws off the rests of eggs from the abdomen,
and always comes back in a hole to the morning.
The posterity of this species, looking like tiny transparent crabs, lives in
water some weeks similarly to other species of crabs. Having reached the diameter
about 3 cm, they leave water and pass to life in wood litter. Having got stronger
enough, they start to bore holes in ground. Half-year aged crabs having width
of carapace about 6 cm are able to breed, and they reach the size typical for
this species at 3-rd – 5-th year of life.
Azorean nocturnal crab, “night robber” (Azograpsus fur-nocturnus)
Order: Decapods (Decapoda)
Family: Grapsid crabs (Grapsidae)
Habitat: New Azora island, forests.
Terrestrial island ecosystems differ from continental ones in one feature –
recent natives of sea play rather large role in them, and many groups of terrestrial
animals, characteristic for continents, can be absent completely. At New Azora
island, which is located in tropical latitudes of Atlantic Ocean, in an ecosystem
there is a plenty of descendants of mammals, terrestrial continental animals.
This is a consequence of human activity – people had introduced some species
of terrestrial mammals to Azorean Islands. But in ecosystem had formed at the
island after extinction of mankind, there are descendants of sea animals –
various crabs of separate genus Azograpsus, or Azorean crab (Azograpsus). Various
species of these crabs occupy ecological niches of scavengers and small predators.
Among these animals the largest species is “night robber”, or Azorean nocturnal
crab – scavenger and active predator representing danger to rat-sized and smaller
animals.
“Night robber” is large crustacean – the width of its carapace reaches 12 –
15 centimeters, but because of legs and large claws it seems even larger. Its
armour is flattened from above and has rounded outlines. Claws are rather large,
have short fingers and serrated cutting edges. With the help of such claws
crab easily breaks snails shells and crushes bones of small vertebrates.
Colouring of armour of crab is black with bluish shade; bottom part of body
is grey. Cutting edges of claws are brightly visible on background of body
– they are snow-white. On claws there are some more white spots.
Azorean nocturnal crab lives in underbrush and can climb on trees, especially
at young age. Small crabs of this species spend much more time on trees, rather
than adults. Due to this feature of behaviour the probability of survival of
young ones of this species raises – this way young crabs avoid meeting with
adult individuals which frequently are cannibals. Adult Azorean nocturnal crabs
lead nocturnal habit of life and hide in holes in day time. They dig hole by
themselves, but can occupy and re-build ready hole of any small animal (frequently
the lawful inhabitant of hole is simply eaten thus). At night this crab moves
to searches of food. It easily copes with small rodents, eats eggs and nestlings
of birds nesting on the ground, and easily finds carrion and rests of prey
of local predators with the help of sharp sense of smell. Azorean nocturnal
crabs living near the ocean coast can hunt crabs of other species.
All crabs of genus Azograpsus had breaked off the dependence on the water environment
during the breeding to greater or lesser extent. Only some species of these
animals make migrations to ocean, and the majority of species is content with
temporary reservoirs for posterity hatching. At all species of these crustaceans
in clutch there is only a few sizable eggs from which well advanced young crabs,
quickly passing to independent life, hatch. Females of Azorean nocturnal crab
dig holes at the coast of reservoirs, and on bottom of such holes from ground
a lot of water filters. In formed puddle female spends all day and some part
of night, and only in darkest night hours it hunts. Last days of incubation
the female does not leave shelter at all.
In clutch of this species of crustaceans up to 70 – 80 rather large eggs is
totaled. Young crabs are translucent, colored light grey. The female does not
pay attention to the posterity, and does not feed young growth specially. First
some days of life young crabs hide in hole of the female and eat tiny ground
animals. After the first molt they leave parental hole and begin independent
life. At the age of four years young crab reaches the size, characteristic
for adult individuals, and its growth slows down. The sexual maturity at these
crabs comes at the age of about one and a half years.
At New Azora some other species of crabs of this genus live:
Azorean signaler crab (Azograpsus signalis) differs in very bright colouring.
It is medium-sized (carapace width is about 7 – 9 cm) diurnal species of crabs.
It has good sight, and large spherical eyes are located on long mobile eyestalks.
The body of this crab has dark red colouring, and claws are colored scarlet
color with white spots. Claws of this crab are very strong and serve for digging
of larvae of insects from ground. Besides with the help of such claws crab
protects itself, and bright colouring serves to defending animal for warning
signals injection. The disturbed crab rises claws and starts to click by them.
On finger of claw it has small knob which enters into hole on claw. When crab
closes claw, loud click is heard. The similar mechanism was developed at this
species independently from snapping shrimps of family Alpheidae known in human
epoch.
This species of crabs eats small invertebrates and oily fruits of palm trees
and trees of laurel family. Females bear eggs on abdomen during almost all
term of incubation. When time of posterity hatching comes, females gather in
littoral marshes and drop young crabs hatching from eggs in water. Fertility
of this species makes up to 200 eggs in one clutch.
Arboreal Azorean crab (Azograpsus arboreus) is small species of the genus.
The width of carapace of adult animal does not exceed 4 – 5 cm. It differs
in dim greenish colouring of body with dark brown legs and claws. The bottom
surface of claws is colored snow-white – crabs of this species inject signals
to each other, raising claws and showing their bottom side. This species constantly
lives in crones of trees and is able to swarm up branches in searches of fruits
and small tree invertebrates. Females of this species bear clutch, gathering
in tree hollows where rain water accumulates. Clutch of this species totals
no more 50 large eggs from which young crabs hatch. Adult animals do not attack
young growth, and the survival rate of posterity at this species is rather
great. Young crabs right after hatching from eggs start to lead independent
life. They creep away from hollow where they were born, and hide in moss or
in other places where the moisture is kept. This species of crabs does not
go down to the ground during whole life cycle.
Lemon, or frugivorous Azorean crab (Azograpsus citrinus) lives in tropical
forest litter. This medium-sized (carapace width is about 8 cm) crustacean
differs in very bright colouring – lemon-yellow with black points on tips of
claws; the bottom part of body is white. Frugivorous Azorean crab eats mainly
vegetative food; the most part of its diet is made of fruits of plants of laurel
and heathers families characteristic for forests of New Azora island. Occasionally
it eats seeds of coniferous trees.
In day time crabs of this species dig in wood litter or hide in shelters of
various kinds, and in the evening goes to search of fallen fruits. In cloudy
and damp weather they are active in day time. This species of crabs makes mass
migrations during breeding season, and females with clutch spend some weeks
in shallow waters of island while incubation of eggs proceeds.
Tiniest Azorean crab (Azograpsus minutissimus) is the most numerous crab of
the island. This tiny (carapace width is no larger than 4 cm) species of crustaceans
is the important part in ecosystem of island, because the basis of its food
is made of rotten leaves of trees and grassy plants. Such accessible forage
allows these crabs to reach great number – on the average, at each 5 square
meters of territory of New Azora forests one crab of this species lives. Colouring
of tiniest Azorean crab is dark, but is remarkable by its refinement: body
is reddish-brown, legs and claws are black, and cutting edges of claws are
snow-white. Due to activity of these crabs fallen leaves quickly turn to humus,
from which plant easily take mineral and organic substances. These crabs dig
in wood ground deep (up to 60 – 70 cm) holes in which spend the day. The female
incubates eggs on land, and right before hatching of posterity searches for
shallow reservoirs. Young crabs spend some days in fresh water, and then creep
out on land.
"Mangrove robber" (Archocancer mangrophilus)
Order Decapods (Decapoda)
Family Mangrove crabs (Archocancridae)
Habitat: mangrove thickets of South-Eastern Asia – Jakarta Coast, Sunda Land
and near islands, fresh and brackish water.
Mangrove swamps are very changeable world. Twice per day inflow and outflow
replace each other here, and the salinity of water strongly changes – from
almost fresh up to almost oceanic. Trees form continuous thickets, alternating
with sites of viscous oozy ground. Everywhere from silt respiratory roots of
trees stick up, forming almost impassable “fences”. Here it is difficult to
survive to both oceanic and freshwater inhabitants. Neither aquatic animal,
nor the ground one can not feel like as at home in this place. But animals
had been adapted to this changeable world can feel like true kings.
Largest of local inhabitants has all properties permitting it to survive here.
It has tenacious legs, and it can swarm up roots of trees. Stepping through
branches and air roots, it actively searches for food. But if it will fall
down in water, it simply will continue to move in a bottom. It easily tolerates
change of salinity of water, and its food is made almost by everything, that
it is possible to find in swamp. It surveys a surface of mangrove swamps walking
on long legs as if on stilts. Sharp twigs do not harm to it – its body is covered
with shell.
This creature looking monstrously from the point of human view is one of species
of crabs. In Neocene when number and variety of many of dominating before groups
of animals has decreased, some of “supernumeraries” had an opportunity to evolve
actively. And from one crab of Cardisoma genus, able to live both in fresh,
and in sea water, the huge crab “mangrove robber”, the largest arthropod able
to live on land, had evolved. To tell the truth, it spends on land not all
life – for breeding and gill humidifying these huge crabs are compelled to
come back to the water, but not for a long time.
The width of the armour decorated from above with “hornets” and lumps, reaches
half meter, and leg-span exceeds one and half meter. Carapace has the “angular”
shape; in front it is almost straight, hind edge is rounded. “Mangrove robber”
lives mostly in air environment therefore its branchial cavity functions as
lung. However sometimes it comes into water to humidify gills. During the rain
this huge crustacean willingly puts body to floods of the water flowing down
from leaves.
Colouring of this crustacean is rather bright. The animal is perfectly armed;
therefore it is favorable to it to warn the predator about consequences of
attack by the colouring. The trunk of crab is colored from above yellowish
- brown color with small dark speckles, legs outside are colored the same color.
But an internal surface of legs and the bottom side of flat body is ivory-colored.
Pincers of crab are wide and flat; at males they are larger than at females.
Surface of pincers is smooth and shining. They are colored outside bright red
with white strips along cutting edge on “thumb”. The bottom side of pincers
is light pink. In courtship season males show to females bottom side of pincers
to lower their aggression.
Eyes of crab are increased and placed on mobile stems: it permits an animal
to have the full circular field of view. Small facets provide rather sharp
sight, and the crab can easily define a possible predator. Though in mangrove
swamps almost nobody is danger to it, in forest predatory mammals or birds
can easily trap “mangrove robber”. They attack young growth especially frequently.
But the adult crab in intervals between molts is practically impregnable, and
it will reflect any attack by strong pincers.
“Mangrove robber” is omnivorous animal. It willingly eats any food of animal
origin: it hunts mollusks creeping in oozy shallow water, gathers fishes, shrimps,
worms and snails staying in pools during outflow, catching them by big long
pincers having on tips sharp jags and hooks. It does not squeamish also to
eat carrion: after storm such crabs frequently leave on a shore, searching
for dead animals have been cast ashore. In forest “mangrove robbers” appear
for the sake of fruits – they eat sweet and strongly smelling fruits of tropical
trees with great pleasure, being one of main distributors of seeds on tropical
islands.
This is solitary animal not having certain territory. “Mangrove robbers” meet
at the distance no more than one kilometer from the nearest sea coast, but
along the rivers they come deeper into land areas: up to 3 – 4 kilometers.
They frequently lodge on coast of brackish lakes where sea water filters from
sand. Usually the crab uses as shelter natural niches, but it also can dig
own holes or occupy and expand abandoned holes of rodents.
For breeding females of this crab right after pairing migrate to the sea: eggs
of these animals develop only in salt water (salinity must be not below the
half of oceanic one). At “mangrove robber” the development is direct: from
eggs tiny crab babies hatch. First days of their life the female carries them
under an abdomen. Gradually the young growth molts, and gets over on back of
female. At this time female shows surprising for large crustaceans care for
posterity: during meal the young growth can drag slices of parental meal, and
the female patiently waits, while the posterity will be sated. At this time
it is ready to attack any animal of size comparable to it, if it will consider
its presence dangerous to young growth. Crabs of this species breed the year-round,
giving 2 – 3 hatches of 150 – 200 young crabs.
Though “mangrove robber” has no large enemies, its life from the very beginning
is threatened by various tiny creatures. During the bearing of posterity crabs
are threatened with flies of the special kind – crab
botflies (Carcinotaba vorax). They actually are not true botflies, and belong to… horseflies. Adult
flies of this species suck blood of crab, and larvae develop among eggs, destroying
them almost entirely. The small agile coastal bird resembling nuthatch, the
crab-cleaning rattlebird
(Carcinornis crepitaculum), having the tenacious paws,
permitting to perch on carapace of crab, saves “mangrove robber” from crab
botflies. It feeds with these flies, trapping them, perching right on body
of crab. At an opportunity it also clears crab of other parasites – small ground
leeches and ticks. But sometimes these birds turn from friends to enemies:
they equally willingly eat young crabs.
This species was discovered by Arseny Zolotnikov.
Grooming crab (Hygeioportunus accuratus)
Order: Decapods (Decapoda)
Family: Swimming crabs (Portunidae)
Habitat: reeves of Pacific Ocean, tropical and subtropical regions.
Coral reeves of Holocene epoch had represented the community of live organisms,
not conceding in variability of species to tropical rainforests. In conditions
of food abundance inhabitants of coral reeves frequently showed very strict
specialization in feeding and habit of life. But this circumstance had made
them dependent on existence of ecosystem as a whole. Therefore, when at the
boundary of Holocene and Neocene reef-building corals had died out, the most
part of rich reef fauna had disappeared after them.
In Neocene instead of former reeves new ones have appeared. Not corals, but
other animals – sponges, huge bivalves and other sedentary animals form them.
At these reeves like at Holocene ones, various sea animals search for shelter
and food. In struggle for existence they also show miracles of specialization.
Among inhabitants of Neocene reeves crabs of various families are characteristic
– these animals are mainly predators and scavengers of reef. They often develop
very effective and deadly ways of food getting. But one of crabs had evolved
to other way of specialization – it had staked not on bloodthirstiness, but
on cooperation. And, of course, it is very successful from the point of view
of survival.
Around of one huge shell growing at some distance from body of reef the school
of fishes swims. They stay near the shell for rather long time, though obviously
they are not going to be fed. Fishes only replace each other above the shell,
turning in round dance. The reason of interest of fish school to this shell
is a small motley crab creeping on skin of one fish. This creature is not afraid
that fishes will eat it: crab slowly moves on fish scales, searching for parasites
attached to it. Having finished to clear the fish, crab leaves it and quickly
moves to other fish.
This animal is grooming crab, the descendant of one species of predatory swimming
crabs. It differs a little in anatomy from congeners leading predating way
of life in other parts of ocean. At grooming crab there is the same flattened
back pair of walking legs with which help it swims quickly. On the bottom side
of these legs small holes are advanced – they are suckers helping the grooming
crab to attach to smooth sides of fishes. This crab is rather small – the carapace
width of the adult female reaches 6 – 7 cm; males are a little bit smaller,
but have larger pincers.
The main hunting weapon of swimming crabs is pincers with which help these
predators kill fishes and other prey animals. At the grooming crab pincers
had turned to thin tweezers with which help animal gathers parasites from skin
and gills of fishes, and also “cuts out” sites of dying off tissues from wounds
and grazes. Sharp sight helps the grooming crab to search even for small parasites:
his eyes are spherical and placed on short mobile stems. They are supplied
with set of facets providing recognition of small details.
For “advertising” of rendering services contrast colouring serves to grooming
crab. Body of this crab is coffee-black, but the middle part of carapace is
snow-white with small round black spots. Pincers of animal are also white with
black tips and separate black spots. Swimming legs are red on tips: when crab
swims near the shelter, their movement involves fishes wishing to be cleared
of parasites.
Obviously, first time only young growth of any reef species of swimming crabs
rendered cleaning service to fishes, attacking parasites of large fishes, as
if the prey. They were too small to be prey of large fishes, but near to them
the constant protection had been provided. This vital strategy appeared favourable:
adult grooming crab, actually, eats food of animal origin, gathering it from
bodies of fishes, being well protected – its behaviour combined with bright
colouring became a signal of lowering of aggression for fishes.
Each grooming crab has the certain territory on reef zealously protecting from
congeners. As a rule, the best possession is one having any object seen from
apart – group of sponges, stone or mollusk shell. But near to them the shelter
is necessary located, in which crab hides in case of danger.
The crab constantly lives at its own territory. Only male can leave the possession
in searches of females ready to pairing. But in this case there is a danger
that it may find at the territory any stranger lodged there during its absence.
Usually such ones are “tramps” – small crabs not having constant territory
and eating casual food. Such animals are weaker in comparison with “thrifty”
crabs – they strongly concede to them in growth. To banish such animals is
easy for the male of grooming crab. Females of this species are larger and
more aggressive, rather than males, therefore their territory becoomes free
only owing to death of the animal.
The female lays some thousand eggs from which in three weeks tiny young growth
bursts. Young animals spend about two weeks in plankton above reeves, and then
fall on bottom and pass to habit of life characteristic of adult individuals.
Young crabs are transparent with several black spots on sides. They clean of
parasites shrimps and small fishes. Approximately at one-year-old age young
crab is able to breed.
On reeves of Pacific Ocean grooming crab has imitator from among fishes – the
impostor boxfish. This fish imitates colouring of crab, but does not render
cleaner services to fishes. But being attacked this boxfish emits a jet of
poisonous liquid. Such way of protection benefits not only to it, but also
to grooming crab which is also not attacking by predatory fishes.
Crystal swimming crab (Crystallonectes crystallinus)
Order: Decapods (Decapoda)
Family: Swimming crabs (Portunidae)
Habitat: Indian and Pacific oceans, thickness of water.
In early Neocene many ecological niches of plankton organisms appeared empty
after mass extinction of plankton caused by natural accidents at the boundary
of Holocene and Neocene. But the biosphere as a whole has one remarkable property:
ecosystems develop to the way of maximal use of resources given by environment.
Therefore right after extinction of plankton organisms of Holocene epoch the
thickness of water began to be settled again.
Among new representatives of plankton crustaceans are especially characteristic.
Except for myzids, scuds and shrimps, even crabs had appeared in plankton.
Representatives of swimming crabs family were one of first invaders of thickness
of water. In Neocene they had generated even the separate family which has
kept neotenic features. But in parallel to them in the ocean there are also
descendants of the basic branch – true swimming crabs of specialized species.
Benthic swimming crabs were predators, and they still live on reeves. And pelagic
swimming crabs became predators of plankton.
The crystal swimming crab is one of predatory pelagic crabs. By features of
anatomy this animal is very close to representatives of family Infantoportunidae.
It is the descendant of crabs actually became transitive forms between families
Portunidae and Infantoportunidae. Independently of true Infantoportunidae it
had got similar adaptations to life in plankton.
Body of this crustacean is transparent, flattened, about 4 cm long and about
5 cm width. For simplification of soaring in water two long spikes on each
side of body serve to crystal swimming crab. They are slightly bent back and
covered from back edge with the bristles increasing a surface of shell.
Walking legs of first three pairs are short and thin, reduced up to small hooks
keeping segmentation. They can not serve for walking any more, and animal uses
them only for catch keeping. At males legs of third pair are larger, rather
than at females. They are a little similar to trapping legs of soothsayer,
and on their internal side small jags are advanced. Such legs of the male help
it to keep the female at pairing. In rest they are fold at the bottom side
of crab body and pressed to pleon to not prevent to swimming. The male differs
from the female a little: it is smaller, but has larger pincers. For pairing
the male tries to swim up to the female behind and to seize it by third pair
of walking legs. It avoids so an attack from the part of female – at this species
the cannibalism is usual.
Back pair of legs serves for active swimming as at all swimming crabs. They
are flattened, and the terminal segment is expanded and supplemented with folding
hairs along the edge. When crab pushes by legs, they unbend, strengthening
the effectiveness of the rowing.
At crystal swimming crab there are flat and wide pincers. When it is swimming,
pincers serve as rudders of depth and turn, permitting to change fast the direction
of movement. Hunting small animals, this crab is able to make sharp rushes
and turns on the spot. Also it is very important for predator to have well
advanced sense organs. This crab distinguishes prey and danger with the help
of sight. At it there are large shining eyes numbering numerous facets. Due
to such feature of eyes crystal swimming crab is able to distinguish slightest
movements around of itself. Short antennae of this crustacean are feather-like
– they help to catch a smell of prey.
Prey of the crystal swimming crab includes others plankton animal – worms,
jellyfishes and fish fry. Usually this crustacean passively soars in thickness
of water, having stretched pincers and legs in sides. Having noticed catch,
animal instantly turns to the condition of “alertness”: it folds pincers in
front of itself and presses walking legs to pleon. When catch is too small,
crab simply waits while it will approach nearer to it. But it can chase large
catch at the distance of several meters, that it very long for so small creature.
Fertility of plankton animals usually reaches astronomical scopes. But survival
rate of their posterity is parts of one per cent. At crystal swimming crab
it is, on the contrary, rather small: no more than 200 – 300 eggs. But it is
compensated by care of posterity. Youngs of this species are tiny copies of
parents about 3 mm long. The posterity of this crab keeps for a long time on
the carapace of the female – till one week. For this time young crabs have
time to pass through two molts. Swimming legs of young crystal swimming crabs
are modified to suckers and serve for the attachment to the female. Their pincers
also are not similar to pincers of adult crab: they are thin and serve for
grab of food particles from water. The larvae of this species feed on rests
of female’s catch. The female bearing posterity eats catch not the same mode,
as the male or the female without posterity does it: it does not tear off pieces,
but chews the caught prey and does not swallow it. Particles of food get in
water, and the posterity catches them. Till the bearing of young growth the
female eats a little and prefers to swim slowly to keep offsprings on its back.
After the second molt swimming legs of young crabs of this species get the
shape characteristic for them, and they abandon mother ready to independent
life. At the age of four months they reach the size of adult crab and start
to breed. Life expectancy of crystal swimming crab does not exceed two years.
Bloodsucker crab (Infantoportunus sanguisugus)
Order Decapods (Decapoda)
Family Infantoportunids (Infantoportunidae)
Habitat: Indian and Pacific oceans, from moderate up to tropical latitudes
of both hemispheres, the parasite of pelagic animals.
In the process of evolution it happens, that the new group of live organisms
occurs from representatives of one of already existing groups by the evolution
of larval stage. The larva as if “replaces” an adult stage, getting ability
to breeding. This process occured independently at different live organisms
not related to each other. In Neocene by such way the separate family of crabs
– Infantoportunidae family – evolved from swimming crabs (Portunidae). Larval
stage began prevailing at them, and even adult crabs keep some larval features.
The most appreciable attribute of these animals is flattened body with transparent
shell through which internal organs are visible.
Swimming crabs during the history were active predators. Small fishes and various
invertebrates were their catch. Specialization to predating at infantoportunids
was developed even deeper – some of their species passed to parasitic habit
of life at all. Jaws of these crustaceans had changed: they became narrow and
long. During the feeding of the animal they form a kind of pointed proboscis
which length at some species can exceed width of carapace of the animal. Predatory
infantoportunids catch small animals by pincers and suck them out.
The bloodsucker crab is the least specialized to pelagic way of life species
of family. It lives in sea shallow waters and sucks blood of various fishes.
This is rather small translucent crustacean with the advanced swimming legs
and disc-shaped body. The own colouring of crab is greenish, dark liver and
intestines with food appear through the shell. Width of carapace of the bloodsucker
crab is about 6 – 7 cm. Walking legs at this species are very small and weak,
turned to similarity of hooks. Pincers of this crab are also thin and lengthened.
Swimming legs (last pair of walking legs) are very well advanced – with their
help the bloodsucker crab is able to swim quickly, chasing fishes.
At the bloodsucker crab sense organs are well advanced. At it there are large
eyes and good sight, and also there is the keen sense of smell by which it
is guided in search of animals on which it eats. This crustacean eats exclusively
blood of fishes. Having noticed the school of fishes, hungry bloodsucker crab
hides, and attacks when they appear near to it. This animal is able to swim
quickly, sharply changing the direction of movement; therefore not any fish
can catch it. But the crab easily reaches the chosen fish, especially when
on its body there are small wounds – the smell of blood strongly attracts this
animal.
Bloodsucker crab attaches to wounded areas of fish body, and when the fish
is not wounded, it prefers to perch behind a head, near gills. Having chosen
by smell the suitable place, crab finds blood vessel and sticks proboscis in
skin of fish. When the animal is hungry, it is almost not visible on skin of
fish because of translucent body. But when the crab starts to be sated, the
exhausted blood of fish appears visible through its intestines. Due to elasticity
of shell the crab can suck blood in quantity up to 50 % of its body weight.
The full animal unhooks from fish, and tries to hide itself at sea-bottom.
Hiding from enemies, crab can be dug in sand, raking it on itself by back legs.
Bloodsucker crabs breed the year round. The male at this species is much smaller
than female, and also leads more active habit of life. Females of bloodsucker
crabs live at the certain territory and come back to it after the attack on
fish. Males have no constant territory: they wander in shallow waters, searching
for females ready to fertilisation.
Fertility of the female of bloodsucker crab is about 500 large eggs. Egg-laying
repeats each 2 months. Eggs are left with floating pelagic larvae which will
spend in plankton over three months. In plankton they are active predators
also attacking mainly young growth of fishes. The young bloodsucker crab settles
on bottom, being about 2 cm long, and gradually passes to parasitic way of
life.
The species close to the bloodsucker crab, jellyfish pilferer (Infantoportunus
medusivorus), has lodged in open ocean. It is small species of crustaceans
- width of its shell is usually no more than 4 cm, and the length is even less.
Walking legs at this animal are reduced up to thin hooks, and on the bottom
side of swimming legs suckers develop. This crustacean lives and eats on jellyfishes.
The crab sits on the cupola of the jellyfish from above, avoiding touches of
poisonous tentacles. On one jellyfish one female of this species lives always,
and all noted characteristics of species concern to it. Males of jellyfish
pilferer sharply differ from females: they are animals not exceeding 1 cm length.
The male actually represents the larva with developed sexual glands. Covers
of body at it are transparent, and the body is short and also very much extended
in width. It lives on the female in her branchial cavity, and eats blood of
female, piercing its covers. Actually, the male parasitizes on the female.
Its contribution to breeding is limited to that it regularly lays spermatophores
to sexual apertures of female. In the rest time male is completely motionless.
His walking legs are reduced, only former swimming legs (back pair of walking
legs) modified in suckers are advanced. In connection with parasitic habit
of life the sight of jellyfish pilferer is very weak – in each eye there is
at all about one hundred facettes. But at it the sense of smell permitting
this crab to search the host animal is perfectly advanced.
At jellyfish pilferer there is the sharp proboscis reaching 10 cm length. It
is almost constantly dipped in body of jellyfish on which this animal lives.
The proboscis of jellyfish pilferer pierces covers of the jellyfish and reaches
its digestive cavity. The crustacean eats only animals semidigested by jellyfish.
The female of jellyfish pilferer lays hundreds of eggs per one week. From them
small pelagic larvae having no sex hatch. First days of life they are predators,
and attack pelagic crustaceans. Further larvae search for young jellyfishes
and settle on their bodies. On the jellyfish larva transforms to young crab,
and the pointed proboscis develops at it. Such larvae turn to females. Having
settled on the female, larva turns to the male.
If the jellyfish perishes, the female of jellyfish pilferer moves to other
jellyfishes – it is able to swim and can spend any time in thickness of water,
expecting for new host jellyfish.
Gill-sucking crab (Branchioportunus parasiticus)
Order: Decapods (Decapoda)
Family: Infantoportunids (Infantoportunidae)
Habitat: Pacific Ocean, from equator up to Subantarctic.
In Neocene crabs of swimming crabs family (Portunidae) distinguished by active
predating way of life had made the attempt to develop the pelagic habit of
life among many groups of coastal sea animals. They had successfully realized
the opportunity received during the global changes in biosphere and had formed
the separate family of crabs Infantoportunidae distinguished by preservation
of some juvenile features in adult condition. Representatives of Infantoportunidae
are adapted to inhabiting in thickness of water where their whole life cycle
passes.
Representatives of new family had actively started to evolve, developing various
ways of food getting. They became numerous predators of plankton, and some
species passed to parasitic habit of life. One
species of infantoportunids
is feeding, exhausting contents of gastral cavity of jellyfishes. And its relative,
the gill-sucking crab, had passed to parasitism at vertebrate animals. It lives
on gills of sailerfish – very large pelagic fish of southern part of Pacific
Ocean.
Similarly to the majority of specialized parasitic species of animals this
crab had undergone the deep degeneration in comparison with ancestors. The
adult individual of the branchial crab female is about 2 cm long, and the male
is even smaller. Body of this animal it very thin and translucent; its bottom
side is flat and top is slightly convex. Walking legs at the female of branchial
crab are strongly reduced and modified to hooks with which the animal keeps
for branchial arch of fish. For additional fixing suckers serve to branchial
crab: they are modified terminal blades of back legs used for swimming earlier.
The adult female of branchial crab almost constantly keeps motionlessly on
gills of fish, and is unhooked from it only for the period of molt. Sometimes
the animal can slowly creep from one site of gills to another, moving suckers
alternately. Males of this species are much more active, rather than females
– they are able to creep on branchial arches of fish, fertilizing females.
At them walking legs are more advanced. Among males living on gills of the
same fish, battles may happen, resulting in death of one of them – strongest
male kills all weaker ones and privately-owned fertilizes females living on
gills. Sometimes in population there are hermaphrodites able to fertilize each
other (self-fertilisation does not take place).
Mouth organs of branchial crab are modified to pointed proboscis with which
help animal is feeding. In adult condition branchial crab is able to eat only
liquid food – blood of fishes.
In connection with almost motionless habit of life the adult crab has degeneration
of all sense organs. Only the chemical feeling and touch appear more or less
advanced at adult individual. Till the process of growth at branchial crab
eye reduce.
The female of branchial crab lays weekly about some hundreds eggs. After 2
– 3 days from them tiny plankton larvae burst leading the predating habit of
life. They attack mainly spineless invertebrates. After 5 – 6 molts (at the
age of approximately 2 months) young animal should get on host fish, otherwise
death threatens to it. The young branchial crab does not search for the host
fish: it finds the crab itself. The animal gets in mouth of fish during its
feeding: when sailerfish is swimming in congestion of plankton with widely
opened mouth, young crabs sediment on its gills and attach to them. First time
they keep features of diet of young animal – eat plankton sedimenting on gills
of sailerfish. But after each new molt the developing branchial crab loses
more and more attributes of freely living animal – at it legs shorten, suckers
develop and eyes reduce. When pincers of animal reduce so that crab could not
gather plankton animals sedimented on gills of fish, it passes to feeding exclusively
on blood of fish.
Mollusks
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Hawaiian bird-eating snail (Horrohelix ovisuga)
Order Stylommatophors (Stylommatophora)
Family Spiraxids (Spiraxidae)
Habitat: Hawaiian islands, rainforests of hillsides and valleys.
In human epoch at Hawaiian Islands the set of ground snails had lived. They
formed tens of various species distinguished by shell coloring. But their prosperity
had ended when people had introduced from Africa the huge snail achatina (Achatina
fulica). This mollusk multiplied, and became the agriculture pest. And as biological
measures of struggle from Florida predatory snail Euglandina rosea (Rosy Wolfsnail)
had been introduced. In common with collectors shells it had exterminated a
plenty of endemic local species of snails, but not introduced achatina. Due
to continental “training” and rather soft climate of Hawaii till the epoch
of biosphere crisis it had successfully gone through climatic cataclysms of
the boundary of Holocene and Neocene. The Hawaiian bird-eating snail is its
lineal descendant.
It is rather large mollusk – shell length is about 15 cm, weight of adult snail
is approximately 400 grams. Shell of animal is egg-shaped with the blunt tip
and wide fauces; last curl of it is the biggest. The shell is colored very
floridly and brightly: red - brown with pattern of black strips of different
width stretched along curls.
Body of bird-eating snail is long; its forward part is flexible and head is
rather small. Covers of bird-eating snail have mesh pattern: dark red gauze
on pinkish background. On head there are two pairs of feelers; on long feelers
(“hornet”) eyes are placed, and another pair grows near the mouth.
This mollusk lives in forests and is rather mobile: the snail easily gets on
trees and creeps on branches in searches of food.
The Hawaiian bird-eating snail has completely kept, and even has strengthened
the injurious bents inherent in its ancestor. It eats various ground mollusks,
and attacks small vertebrate animals: it sucks bird eggs and even eats nestlings.
Sight sense of this mollusk is bad; therefore it is not able to track down
catch, as a cat. But sharp sense of smell helps this animal to find nest with
eggs or nestlings. Having found out a clutch of any bird, this snail bites
through eggshell by radula, and licks contents of egg. Then it bites edges
of the bore, expanding it, and thrusts head inside of shell. It takes about
twenty minutes to eat one egg by size like pigeon’s one at this snail. Feeding
by eggs is especially important during growth of mollusk: this way the snail
fills up stocks of calcium necessary for shell forming.
Bird-eating snails are hermaphrodites, and also breed the year round. Before
egg laying the animal feels need for protein food, and much more willingly
eats various invertebrates and nestlings of small birds. The saliva of this
snail has paralyzing properties, therefore the animal bitten by it any more
cannot escape by flight.
When snail has received enough protein food, in its organism development of
eggs begins. In oviduct the cocoon containing about hundred of rather large
eggs is formed. The snail hides it in wood ground between roots of trees. For
one year it can make up to ten such clutches. In two weeks from cocoon young
snails hatch. They eat small insects, and at the age of about one year their
shell reaches size about 10 cm. Further growth of snail is slowed down, but
it starts to breed.
Despite of successful existence in ecosystem of Hawaiian Islands, this mollusk
has many enemies. Ground crabs easily break open with pincers shells of these
snails, and some birds have adapted to eat various ground snails including
this species.
Ant snail (Myrmiachatina melanoleuca)
Order: Stylommatophors (Stylommatophora)
Family: Achatinids (Achatinidae)
Habitat: tropical woods of Hawaiian islands, ant hills.
Social insects are representatives of two absolutely not related orders: hymenopters
(ants) and termites. Both those insects differ in various degrees of development
of building art, but always live in colonies with complex system of hierarchy
and castes. Any aggressor solved to attack settlements of these insects, takes
the risk to receive serious repulse from insects of soldier caste, and can
perish easily.
But despite of real danger which is represented by these insects for other
live creatures solved to penetrate into their dwelling, constructions of both
groups of insects became a habitat for set of species of other animals - from
smallest insects up to lizards. To escape in society of these well armed insects,
other invertebrates develop smart methods of interaction with owners of dwelling.
Some of them are very cautious, and whenever possible try to slip away from
owners of dwelling, others camouflage to look like lawful owners of dwelling
by smell and appearance. But the most widespread way of interaction is to become
“friends” of armed insects and to provide to itself safety by that at life
side by side with them. The simplest way of this interaction is to produce
substances which ants or termites like. In nests of these insects it is possible
to find, for example, beetles and strange wingless flies secreting substances
liking to ants. For the sake of sweet secretions ants carefully preserve, and
even “breed” plant lice, protecting them and sometimes constructing shelters
above them. For the same purpose ants take care to caterpillars of hairstreak
butterflies (Lycaenidae family) which inconsiderately devour their own posterity.
In historical epoch ants represented an alien component of fauna on Hawaiian
islands, but to Neocene descendants of first introduced species became a part
of the ecosystem formed on islands, and some other animals began to “search
for friendship” at these well protected insects. Among them there was even
one species of local ground snails had lodged near to ant hills.
Hawaiian ant snail is rather small species of gastropods: diameter of its shell
does not exceed 5 cm. Certainly, it looks large in comparison with the majority
of snails known to humans, but much larger giant African snail (Achatina fulica)
introduced to Hawaii had been its ancestor - the shell length of this giant
reached 15 cm. For millions years of natural selection smaller individuals
of ancestral forms of this snail survived, and gradually it had turned to the
dwarf.
At ant snail there is not bright, but contrast black-and-white shell colouring
forming striped pattern - at various individuals the ratio of black and white
colors varies, and striped pattern is individual. The body of snail is covered
with an epithelium of yellowish color.
The ant snail uses protection of ants because it secrets slime which involves
ants with taste and smell. Special glands specially intended for this purpose
are advanced on edges of mollusk’s creeping sole and marked by black points.
Insects thirsting for secretions, gather around the snail, and tickle it by
antennae. Replying to their action, the ant snail emits a portion of slime,
continuing feeding. These mollusks keep near settlements of some local species
of ants, expecting upon their “protection”.
This snail uses not only protection of ants, but also feed near to ant hills.
It eats not only plants, but also insects brought by ants in colony. It eats
even dead ants from colony which protects it.
The only time when it must leave a colony is the time of breeding. These snails
are hermaphrodites, and two any individuals can mutually fertilize each other.
When in organism of snail eggs ripen, it finds a secluded place away from tracks
of ants, and hides in wood litter about hundred of small transparent eggs.
In 2 weeks from them the posterity hatches.
Young ant snails have no glands developing a liquid which involves ants. Therefore
they keep in thickets of grasses and on the bottom side of leaves. Later, when
shell diameter of snail reaches about 15 mm, these glands develop, and snails
find a colony of ants. It happens that some ants search for these snails, and
specially drag them to their dwelling.
Garlic snail (Scorodonodora foetidissima)
Order: Stylommatophora (Stylommatophora)
Family: Ground snails (Helicidae)
Habitat: New Zealand, forests and bush of Northern Island.
The appearing of mammals in New Zealand is the new factor for endemic flora
and fauna existed without them within millions years. Animals introduced by
people had changed the direction of evolution of ecosystems of archipelago.
Occurrence of various small mammals had caused the reduction of number of large
invertebrates endemic for these islands. Many species kept by people in captivity,
in reserves and nurseries, had quickly vanished after human extinction, superseded
by descendants of introduced species. But some species of large invertebrates
managed to survive – at them new protective adaptations had appeared, permitting
to resist to new neighbours.
Snails in most cases survived due to high breeding rate and passive protection
– strong twisted shell. Some species of snails became poisonous, and it also
raised probability of their survival. In human epoch small insectivorous mammals
had appeared in New Zealand, and as the answer, at the lot of species of ground
snails effective chemical protection against them had formed.
The large snail with very appreciable white shell lives in forests of New Zealand.
Coils of shell are covered with longitudinal black dabs, and such colouring
is well appreciable from apart on the background of grass or forest litter.
But bright appearance is a part of protection of snail. If any animal disturbs
this mollusk, snail emits the unpleasant garlic smell which is frightening
off the aggressor. For this feature it has received the name “garlic snail”.
But protection of snail is not limited by smell: if the predator does not stop
the attack, snail secrets the caustic and sticky liquid sharply smelling as
garlic. In air this liquid thickens and it is very difficult to deliver from
it. Therefore garlic snail is not afraid of attacks of small and medium-sized
predators at all.
Garlic snail almost does not differ in appearance from other ground snails
from other parts of the world. At it there are shorter tentacles on head and
wide oral blades plentifully covered with receptors, allowing to find out even
such catch, which is hidden in ground at the depth of about 10 cm. Garlic snail
is the omnivorous mollusk with a bias in predating. It willingly eats delicate
greenery of ferns and other plants, and also mushrooms. This snail also eats
any food of animal origin, which it manages to find. But its special food predilection
includes various ground invertebrates and carrion. Hunting for ground animals
demands the special receptions which this snail owns. Similarly to police dog,
it finds with the help of keen sense of smell worm or grub digging not deep
in ground. Having defined the location of prey, snail plunges head in ground,
and starts to dig a tunnel of prey. Thus the head of snail works similarly
to body of earthworm – with the help of contraction of muscles it is extended
and forces the way forward; when the snail contracts muscles of back part of
body, head expands the hole.
Having reached the body of prey, snail uses the deadly weapon. In its mouth
there in fleshy tongue – it is the radula armed with several pointed teeth.
Teeth of garlic snail are similar to knifes: they lack of poison, but easily
cut the body of prey. Snail devours catch, not pulling it out from ground.
Similarly to the majority of ground snails, garlic snail is the hermaphrodite.
It lays large eggs in small portions, digging them in friable ground between
roots of trees where probability of egg founding or damage is less. For this
purpose snail digs by head small holes in ground the same way, as at hunting,
and digs them out after egg laying. Egg laying repeats every 7 – 8 days; the
incubating of clutch lasts about 2 weeks. Young snails at once lead predatory
habit of life and can emit caustic odorous substance. At first they eat very
small invertebrates – soft insects and small worms. They reach the size of
adult snail at the age of one year, and can live up to 5 years.
Hissing slug (Virolimax stridor)
Order: Stylommatophors (Stylommatophora)
Family: Slugs (Limacidae)
Habitat: humid forests of temperate and subtropical zones of Pacific coast
of North America.
At the narrow strip between Rocky Mountains and Pacific coast of North America
in Neocene there were conditions favorable for growth of deciduous forests
of special type, so-called “moss forests”. In such forests there are favorable
conditions for growth of moistureloving plants and life of moistureloving animals
– amphibians and terrestrial mollusks. In warm Neocene climate some invertebrates
evolved to original and remarkable species. Large and brightly colored species
of slugs named hissing slug is very characteristic for moss forests.
It is herbivorous species of shell-less gastropods. The length of its spindle-shaped
body reaches 10 cm. Such large invertebrates frequently appear very vulnerable
for various predators – birds, reptiles and amphibians. But hissing slug protects
against them with the help of strong poison which is accumulating in slime
covering its body. At this mollusk bright warning colouring was developed –
it is black with longitudinal rusty-red strip on each side of the body. Disturbed
hissing slug additionally displays its self-protecting with the help of some
features of behaviour. At danger it starts to swallow air and inflates body.
At this moment bright colouring of its covers becomes especially appreciable
- at puffed up slug the forward part of the body becomes similar to small bubble.
On body covers at this moment large drops of poisonous slime are secreted.
Puffed slug moves head, displaying warning colouring to aggressor. When the
enemy recedes, mollusk starts to blow off, letting air out from the mouth.
Thus it hisses and even whistles loudly enough. Such sounds in addition frighten
off from it small predators from among vertebrates.
Hissing slug is peaceful vegetarian; this one eats moss and mushrooms. And
it eats poisonous mushrooms without harm for itself, and uses their poison
for self-defense – poisons of mushrooms (muscarine and even more poisonous
amanitine) secret plentifully in slime of disturbed mollusk. This slug keeps
mainly on the ground, among windfallen trees and large grassy plants.
Hissing slug is hermaphrodite (it is typical of the present group of mollusks).
Sexual partners find each other by smell. Courtship ritual at this mollusk
resembles a little ritual competition of snakes – two mollusks raise forward
part of body and inflate it. They push each other by inflated bodies while
one of partners will start to blow off, displaying its defeat. After that winner
slug couples to it and creeps away on searches of new partner. But in case
of loss in competition it also may be fertilized by other slug.
After fertilization slug lays transparent eggs similar to fish eggs in moss.
In each clutch it is totaled up to 50 – 100 eggs which incubation lasts about
ten days. Young slugs have no warning colouring and emit very small amount
of poison. They lead secretive way of life and hide in moss. As they grow,
they pass to feeding on mycelium of poisonous species of mushrooms and gradually
start to eat their fruit bodies. Till the process of poison accumulation colouring
of growing mollusks becomes brighter and they start to lead undisguised life.
Enemies of hissing slug are grubs of lighting bugs and other predatory insects
eating young ones. Grubs of lighting bugs of advanced age can attack adult
slugs. During sudden attack slug has not time to produce enough of poisonous
substances, and insect can quietly eat it, having torn open body covers of
mollusk.
Goblet-like
false rudistes (Rudistoconcha ostreoides)
Order: Rudistokonchs (Rudistoconchomorpha)
Family: False rudists (Pseudorudistidae)
Habitat: reeves of tropical and subtropical zones of Pacific Ocean.
After extinction of reef-building corals their place in ecosystem of ocean
was occupied by other animals. In tropical, and even in moderate waters of
Neocene seas and oceans reeves, rich in life, have appeared again. But they
are formed not by coelenterates. In tropical seas separate relic species of
soft corals were kept, but at reeves of Neocene they play a supporting role.
Perhaps, most important builders of Neocene reeves are bivalve mollusks. Having
entered symbiotic relations with algae representatives, they have turned to
amazing sedentary animals: their role at reeves of Neocene is comparable only
to role of corals in earlier geological epoch.
Reeves of a Neocene are made by these mollusks, covered by goblet-like shell.
In the top part such shell is closed by flat operculum. On surface of shell
there are traces of annual increase as relief ring-formed belts are visible.
According them, highest, meter tall shells reach, probably, age of centenary.
But more often such big and old shells are almost completely overgrown by various
sea inhabitants - sponges, worms and limy algae. Only uppermost, recently grown
edge of shell is still rather clean. Its natural color is black, but numerous
algae and sedentary animals will quickly hide it.
When the mollusk is disturbed with nothing, the operculum is slightly opened,
and from under it two tubes of siphons and the whole fan of flat pinkish tentacles
jut out. They spread under sun beams, as if leaves of plant. In crack between
operculum and shell light pink body of animal is appreciable. From time to
time, when small animals touch tentacles, they contract for shares of second,
and then spread again. But when larger animal shows interest to them, all tentacles
are instantly involved, and operculum densely slams.
This builder of reeves is goblet-like false rudistes, very big bivalve mollusk
with shell valves of unequal size. In Mesozoic era rudists, large sedentary
mollusks lived in sea, having had similar habit of life. But false rudistes
is not their lineal descendant: it is the close relative of oysters (Ostrea),
sedentary bivalve mollusks of Cenozoic era.
False rudists form very original reeves. Mollusks of various age form either
“walls”, or dense congestions, in which animals are distributed at regular
intervals in the big area. Mollusks frequently form dense joints on shells
of older individuals.
In connection with motionless habit of life shell, and after it the body of
false rudistes have strongly changed, having lost symmetry. The left valve
of this mollusk adheres to substratum when soaring larva settles on bottom
and finds favorable place for life. This valve is strongly curved - in it all
body of mollusk settles down. It grows up along all edge, gradually extending
and increasing in height. Right valve became flat – it serves as an operculum.
The ligament between valves is reduced, due to what shell forms the characteristic
goblet-like structure. When the larva of mollusk settles on inclined surface,
shell gradually bends and directs up – at adult mollusk it grows strictly vertically.
The body of false rudistes is approximately in the top third of shell. Gills
of animal from the right side of body (inverted upwards) are reduced, but gills
from the left side have grown up, forming the accomplished filtration system
occupying a significant part of pallial cavity. The filtering system of this
mollusk works not only due to ciliar epithelium, but also is supplied with
valves actively pumping over water through the left gill. These valves are
formed by the edge of pallium turned to tube. When the mollusk is not disturbed,
this tube juts out from shell and makes slow pulsing movements.
To be only filtrating organism is not so favorable, especially in congestions
formed by false rudists. But mollusks have developed more progressive way of
feeding due to which during evolution process they have occupied prevailing
position on reef. At these animals at the edge of pallium there is set of tentacles
(on right (top) valve they are short, on left (bottom) one much longer). In
tentacles there is a main ally of these mollusks in struggle for existence
– symbiotic red algae. Because of them feelers of false rudists have pinkish
color. Red algae favorably differ from green and brown ones in their ability
to lead photosynthesis at the greater depth because they are content basically
with beams of blue and green part of spectrum, penetrating in water especially
deeply. Therefore false rudists easily grow at the depth up to 15 meters, and
separate individuals survive even at depth of 25 meters. Algae get into the
body of young mollusk at the stage of spores (probably, some larvae may grasp
them, soaring in plankton).
False rudists are hermaphrodites. In time of maximum high inflow they simultaneously
spawn in water clouds of tiny eggs (up to 10 – 13 million ones from one adult
mollusk) and sperm liquid. Larvae spend first 10 days of life in plankton,
then settle to the surface of firm objects and turn to young mollusks. At the
first year of life up to 60 % of all larvae perish, and to the end 5 - 6-th
year of life only separate young mollusks from the generation remain. To this
moment they reach height 4 - 5 cm at diameter up to 10 cm. Further at them
active growth in height begins, and the 10-years old mollusk may reach height
up to 20 cm at same diameter.
Longevity of these mollusks is too sizeable: the majority of adult mollusks
easily live up to 100 years, and in lagoons of some islands there are even
170-years old “patriarchs”.
Limestone drill (Petroteredopsis calcareoterebra)
Order: Venerids (Venerida)
Family: Pholadids (Pholadidae)
Habitat: reeves of Indian and Pacific Ocean.
Reeves of Neocene epoch differ from Holocene ones. The basic reef-builders
of Holocene reeves were corals. But at the boundary of Holocene and Neocene
number of these coelenterates had appreciably decreased, and many species of
corals had died out. In Neocene the role of reef-building organisms was partly
undertaken with mollusks, worms and sponges. They form prolong solids of limestone,
as against porous and lacy structures of Holocene coral reef. Such feature
of Neocene reef favours to evolution of drilling forms of animals. On reeves
even sedentary octopuses drilling holes in reef body had evolved. Activity
of rock-boring organisms raises productivity of reef: many species of animals
settle in their holes.
Bivalve mollusks inclined to formation of various sedentary and inactive lifeforms
had succeeded in drilling of reef limestone. One of their species, living on
reef, is named limestone drill. It forms numerous congestions at the reef,
and area of limestone, drilled by these mollusks, turns similar to bee honeycombs.
This large bivalve mollusk has convergent similarity with so-called shipworms,
mollusks of close family Teredinidae drilled burrows in wood.
The shell of limestone drill is reduced up to two strong ridge limy plates
on the forward end of body. It does not serve any more to this animal as protection,
and is intended for limestone drilling. The body of this mollusk more than
one meter long at thickness about 2 cm is covered with thin delicate skin of
pinkish-white color. The pallium of limestone drill has grown together almost
at all extent to original “case”, and opens only on the back end of worm-like
body of mollusk. Right behind rudimentary shell on pallium there are some ring
lines of corneous knobs, with which help mollusk moves in tunnel back and ahead.
Pallium is “threaded” with longitudinal and ring muscular fiber, and also has
mobility.
Limestone drill bores tunnels, using shell. Mollusk supports by corneous outgrowths
against walls of hole, and starts to rotate shell from side to side. At the
forward end of its body there are glands secreting weak solution of hydrochloric
and acetic acids. Limestone is the carbonate easily dissolving even by weak
acids. At influence of mollusk secretions it turns to products soluble in water,
therefore limestone drill does not have problems with removal of dust. Secreting
some surplus of acids, mollusk expands tunnel, dissolving a part of limestone
on its walls. From time to time mollusk sharply contracts body some times,
throwing out from tunnel water with products of reaction and small insoluble
dust. The tunnel of limestone drill has the special form: in the top third
(bored by mollusk at young age) it has S-shaped bent, forming ell protecting
this animal against fishes with tweezers-like jaws, and against crustaceans.
Living in tunnels, this mollusk has kept a way of feeding characteristic for
the relatives. Limestone drill feeds, continuously passing water through gills.
Gills located at the forward end of body had practically lost respiration function.
They are covered with set of corneous bristles and represent the effective
filtration device. Mollusk gathers from them edible particles by mobile tentacle
– the modified rudiment of foot. It passes through itself water at speed up
to five liters at one hour. Water sucking proceeds through siphon formed by
pallium plica, and water is thrown out by sharp contraction of ring muscles
of pallium.
To compensate the inconveniences caused by transformation of gills into filtrating
device, this mollusk has false pallial “gills” representing several outgrowths
similar to tentacles growing on the internal side of pallium near to edge on
the back end of its body. In rest the mollusk juts out back end of body from
tunnel, and stretches pallial “gills” like a flower. As mollusks of this species
settle in colonies, they form a certain similarity of colony of hydroids or
original underwater “flower bed”. Limestone drill is very sensitive to movements
of water – on pallial “gills” the set of cells feeling change of pressure,
touch, and even change of light exposure is located. At the slightest attribute
of alarm mollusk retracts pallial “gills” inside of pallium and sharply contracts
body, supporting by corneous knobs against walls of hole.
Pallial “gills” also have one more function – they are covered with very thin
epithelium, through which this mollusk can acquire the organic substances dissolved
of water. It is the additional feeding source of limestone drill.
The form of hole, in which it is difficult to push straight jaws and claws
deep, protects this mollusk from large and nonflexible predators. But it does
not help to protect against flexible small predators – annelids. Against them
limestone drill uses the chemical weapon – it emits in water strongly smelling
liquid which frightens worms off. The same means helps limestone drill to compete
to sedentary worms: having settled near to them, mollusk oppresses worms with
its secretions. At the same time larvae of limestone drill willingly settle
near to adult individuals, forming colonies.
Limestone drill is hermaphrodite. At this sedentary mollusk there is external
fertilization – breeding individuals, settling beside, synchronize the development
with the help of hormones secreting in water, and simultaneously throw out
in water eggs and sperm liquid. At these mollusks self-sterility had developed,
therefore the risk of self-fertilization and the subsequent degeneration does
not exist. Each individual lays up to 30 thousand tiny eggs at once; breeding
at limestone drill repeats each lunar month.
The larva of this mollusk spends in reef plankton about one week, and then
settles down at the reef and turns to young sedentary mollusk. Having attached
to surface of reef, it starts to produce an acid and to bore a vertical tunnel.
Within one year the young mollusk grows up to 20 cm, and larger specimens are
10 years old ones.
“Palm worm” (Foliosiphon palmatus)
Order: Venerids (Venerida)
Family: Pholadids (Pholadidae)
Habitat: reeves of Indian and Pacific Ocean.
At the reeves of oceans tropical zone in Neocene epoch drilling bivalve mollusks
live. They play an important role in life of reef: boring massive of reef
limestone by firm shells, these animals promote settling of thickness of
reef and increasing
of biomass of reef inhabitants. In burrows made by them crustaceans, worms
and fishes settle. Drilling mollusks also have various vital strategies.
Limestone drill (Petroteredopsis
calcareoterebra) belongs to widely spread
species of drilling bivalves. Its long worm-like body is hided in tunnel
bored in thickness of reef, and only the back end of body is seen from outside
–
a tube of pallium with pallial “gills” jut out from it. This evolutionary
idea has received original continuation. At reeves of tropical Indo-Pacific
some
species of leaf-siphon mollusks (genus Pholiosiphon) related to limestone
drill live; they are adapted to different way of feeding.
Pallial “gills” of limestone drill have a permeable epithelium, through which
this mollusk absorbs the organic substances contained in water. Leaf-siphon
mollusks also absorb organic and besides of it also mineral substances through
epithelium of pallial “gills”. But these substances intend not to mollusk,
but to numerous “lodgers” in its tissues – to unicellular algae. In coexistence
with them there is the secret of well-being of this group of mollusks. Mollusk
receives oxygen and feeding from microalgae, giving them carbonic gas, mineral
substances and protection against enemies.
The typical representative of leaf-siphon mollusks is “palm worm”. Its name
indicates two features of shape of this animal.
The body of “palm worm” is lengthened and flexible, covered by tube-like
pallium. This species is very large representative of bivalve mollusks: its
length reaches
200 cm at thickness of about 4 cm. This mollusk drills burrows in thickness
of limestone, using the rudimentary bi-valved shell similar to shell of limestone
drill. Its tunnels differ in spiral form – only young mollusk bores vertical
shaft, and further it is bent, making the animal inaccessible to many predators.
The second feature of this mollusk distinguishing it from limestone drill
is the shape of its pallial “gills”. They are very big (up to 15 cm long
being
straightened) and have a plumose structure. Mollusk has 4 – 6 pallial “gills”
and consequently the back end of its body jut out from hole resembles small
palm tree, and the colony of these mollusks is similar to palm grove. In
tissues of pallial “gills” there is a plenty of symbiotic green microalgae,
which give
to them green colouring. In case of danger mollusk quickly retracts pallial
“gills” inside of pallium, and hides in hole. Each leaf of pallial “gills”
has a longitudinal muscular fiber contracting in case of danger and shorting
“gill”.
On the forward end of body of “palm worm” there are some ring lines of peaked
knobs, with which animal supports against walls of hole. Shell of “palm worm”
is reduced, thick and ridge. It is transformed into drilling tool like at
limestone drill. This mollusk produces smaller amount of acid at tunnel drilling,
using
mainly the movements of shell.
On reeves one more species of leaf-siphon mollusks, “sea rose” (Foliosiphon
rosa-marina), lives. Its pallial “gills” are wider and have rounded
shape with longitudinal plicas. Because of it the back part of body of “sea
rose”
looks
like a flower – it has determined the name of this species. This species
has much smaller size, than “palm worm”: body of “sea rose” is about 60 cm
long
at thickness of no more than 2 cm.
Both species of these mollusks settle at well lighted shallow sites of reeves.
But “sea rose” lives at sites which may dry at outflow, and “palm worm” prefers
deeper places. During outflow “sea rose” is hidden in hole and sticks an
entrance by mucous fuse.
The breeding biology at these species is similar to those at limestone drill.
Perseus's octopus (Perseoctopus medusophorus)
Order: Octopuses (Octopoda)
Family: True octopuses (Octopodidae)
Habitat: Pacific Ocean, top water layers.
The open ocean is very specific environment. Top layers of water are inhabited
by huge amount of plankton organisms soaring in thickness of water and are
constantly carrying by current being not able to resist to it. Here constantly
severe struggle for existence proceeds, in which various live organisms use
the most refined ways of survival. After mass extinction of plankton organisms
at the boundary of Holocene and Neocene the new plankton community was generated
by descendants of coastal and ground animals survived in ecosystems poorly
affected by extinction. Among new plankton organisms there are various worms,
crustaceans and swimming gastropods. Characteristic representatives of Neocene
plankton are cephalopods of various species. Descendants of coastal species
had passed to existence in thickness of water even in Holocene, and mass extinction
of plankton animals had increased their chances of success.
Very favourable form of mutual relation in various communities is the union
of two species of organisms – mutualism (mutually advantageous), commensalism
(with unilateral benefit) or parasitism (causing any damage to one participant
of the community). One species of cephalopods had solved set of problems having
concluded the favourable union with jellyfishes – one of the most dangerous
plankton inhabitants. This transparent creature about 10 cm long with thin
one meter long tentacles lives in congestions of jellyfishes and is named Perseus's
octopus to commemorate the mythical hero being victorious over monstrous gorgone
Medusa.
The Perseus's octopus is a pelagic cephalopod. It spends all life in thickness
of water, and is not connected to the oceanic bottom in any period of life.
This animal almost nothing differs externally from other octopuses. The body
of Perseus’s octopus is transparent like bodies of the majority of cephalopods
living in plankton. When the octopus is quiet, only its big eyes partly disguised
by brilliant film on external surface of eyeball are visible only. On skin
of the octopus on closer examination a plenty of tiny black points is visible:
it is special iridocyte cells containing light-reflecting substances. Opening
them, animal becomes shining: it is a protective reaction (alternation of shine
and transparency distracts predator, preventing it to concentrate at the octopus
searching). The disturbed octopus represents very interesting show – it opens
iridocytes till one second, brightly flashing in sunlight, and then instantly
retracts them, becoming translucent and poorly appreciable among jellyfishes
swimming around.
The Perseus's octopus protects itself and obtains food, constantly holding
in tentacles two jellyfishes. Besides it has immunity to poison of jellyfishes
and other coelenterates, therefore it can freely swim among jellyfishes, impudently
robbing their tentacles. Besides slime of Perseus’s octopus has inhibiting
properties – it interrupts the reaction of stinging cells of jellyfish tentacles.
At Perseus’s octopus immunity to poison of jellyfish of certain species using
at present is developed. But being compelled to coexist the jellyfish of other
species, the mollusk receives from it slight stings first time. But it just
is necessary, because at this moment the mollusk develops the immunity and
accumulates the inhibitor to new “pet”. Tentacles of Perseus’s octopus have
some sensitive suckers in the middle part which are not damaging delicate body
of the jellyfish kept by the octopus. If the octopus is attacked by predatory
fish, it tries to stick to it into the head tentacles of jellyfish kept by
it. It happens, that mollusk even kills an attacking animal this way. In this
case it uses an opportunity and simply eats it, and jellyfishes get shreds
of meat floating in water.
The male of Perseus’s octopus is smaller by size, rather than the female. It
prefers to court to it “keeping the distance”, being afraid of tentacles of
jellyfishes kept by it. The male arranges “light show” for the female, during
which on its tentacles and body shining waves glance. For this purpose animal
emerges holding jellyfishes to the surface of water where it is shined better
with sunlight. If the female reacts positively to courts of the male, one of
his tentacles, filled with sperm liquid (it is called “hectocotylus”) is torn
off and searches the entrance to pallial cavity of the female itself. Swimming
hectocotylus continues courtship “show”: on it iridocytes open by waves, that’s
why it seems flickering. After the courtship ritual male can grow the lost
feeler, and during life it repeats courtship ritual up to five times with different
females.
The female of Perseus’s octopus lays some hundreds of small eggs. She bears
them on turned inside abdominal pair of tentacles within three months. Till
this time the female eats of nothing. It sits on the bell of large jellyfish
from above, having clasped it by all free tentacles, and having hidden the
clutch under the body. If there is lack of suitable jellyfish, the female of
Perseus’s octopus covers eggs with the top pair of tentacles and holds two
smaller jellyfishes by lateral tentacles, choosing for self-defense the most
poisonous species.
From eggs young octopuses hatch; they are similar to adult individual, but
have short tentacles and are lack of iridocytes. They begin the life, searching
for jellyfishes of less poisonous species and gradually developing immunity.
Their immune system is rather weak; therefore a sting of strongly poisonous
jellyfish may kill them. But till the process of growth young animals get immunity
and develop life even on the most poisonous jellyfishes of the ocean.
Similarly to all octopuses, Perseus's octopus grows quickly, and reaches the
limiting size at the second year of life.
Balloon octopus (Sphaeroctopus inflatus)
Order: Octopuses (Octopoda)
Family: True octopuses (Octopodidae)
Habitat: reeves of Caribbean Sea.
The rich fauna of shallow waters of Caribbean Sea had strongly suffered during
the global ecological crisis at the boundary of Holocene and Neocene. Reef-building
corals had especially big damage – they had practically completely become extinct.
The plenty of species of sea animals connected in daily life with corals had
died out in common with them. Subsequently in early Neocene on sea shallows
new ecosystems had started to develop – heat and abundance of sunlight favored
to their prosperity. These communities are as rich in life, as coral reeves
of Holocene were; here also there is strict competition and there is a set
of predators of various trophic levels.
In similar conditions at various animals various ways of protection develop.
But also it often happens in nature, that the same “technical decision” is
embodied in different groups of live creatures. The most popular tactics of
protection is to exaggerate the own size. Various plicas of skin and outgrowths
unwrapped aside the contender, and also extremities stretched in sides are
different ways of the decision of such problem. One more popular way to exaggerate
is to be inflated. Such tactics is used by different vertebrates: amphibians,
reptiles and fishes. In Neocene among such deceivers the octopus had appeared.
The balloon octopus living on Caribbean reeves is small species of cephalopods.
Length of its body is about 10 cm, and tentacles reach the length of half meter.
This species is colored rather brightly: the basic background of skin is light
yellow; on it brick-red spots with silvery border are scattered. Behind eyes
there are two larger spots. The annoyed octopus can turn almost black for a
split of second. But colouring is not main feature of this mollusk.
When the predator comes nearer, balloon octopus does not hide. It is able to
repulse predators: in the mouth of this mollusk there are poisonous glands
secreting deadly poison. One bite of balloon octopus can kill fish larger than
one meter long for some seconds. But poison is not fighting, but the hunting
weapon, therefore octopus tries to avoid near fight with predator, and uses
poison only in case of extreme danger, when there is no another way to escape.
Warning the enemy about the protection, octopus puffs body, exaggerating the
own size, and colors skin brightly, becoming appreciable from apart. Being
disturbed, it emits in water poisonous ink which paralyze olfactory nerves
of fish attacking it for some time. After such protection of octopus fish remembers
its colouring, and does not attack these mollusks any more.
It is simple to the octopus to use such way of demonstration – its anatomy
favors to ability to change the body shape any way. Octopuses do not have internal
skeleton; and soft tissues are easily extendable. Pallial cavity of balloon
octopus has strong ring muscle on the edge, “tightening” it when the animal
is inflated; and edges of pallium are covered with spongy tissue skintight
to body. Swimming funnel can work as the delivery pompe – it pumps up water
in pallial cavity by pulsing movements. The disturbed animal quickly gathers
water in pallial cavity, and its visible size increases some times: the body
is inflated up to half meter diameter sphere. Colouring of animal fades, and
on skin behind eyes the special pattern appears: two big black oculate spots,
frightening off predator. Inflated animal keeps tentacles pressed to each other
like the “beak” of huge bird's head.
Such demonstration very effectively affects to medium-sized predators: fishes
are frightened of suddenly appeared in front of them “live head”, and swim
out. But balloon octopus can stay not for long in such position: when pallial
cavity is closed, water in it is not freshened, and animal simply begins to
choke. mollusk compensates this circumstance partly by skin respiring, but
if the demonstration is delayed, octopus prefers to seek safety in flight:
it sharply “exhales” water from pallial cavity, and uses the ensued strong
jet push to hide in the nearest shelter. At this moment it sharply changes
well appreciable colouring to pale grey one and as if “is dissolved” on the
background of water. It also gives to it precious seconds to escape from predator.
Similarly to all cephalopods, balloon octopus is a predator. It eats small
fishes and crustaceans, getting them from cracks and holes by long tentacles,
or catching by throws from ambush.
Balloon octopus breeds once a life – it is the characteristic feature of octopuses.
Pairing of these mollusks is preceded with original courtship displays. During
courtship ritual the male is inflated and shows to the female various spotty
patterns on the body, simultaneously touching her by tips of tentacles. If
near the female two males meet, their courtship becomes much more active and
more colorful. They are inflated, and, holding by tips of tentacles for reef,
try to push away each other from the female by body. Competing males try to
inflate as much, as possible, and to keep in such condition longer, than the
contender. The male “blew off” before the competitor, loses. It leaves the
place of courtship display, having replaced bright courtship dress to cryptic
coloration. And the winner starts to make court. It cautiously moves nearer
to the female, and enters in her pallial cavity the tentacle carrying spermatophors.
At the culmination moment muscles in the basis of tentacle tear from sharp
contraction, and it stays in pallial cavity of the female. If the female was
already courted by other male, new partner tries to pull out the tentacle left
by the previous male. After pairing the lost feeler quickly grows. The male
is able to repeat courtship ritual two – three times per life, and then perishes.
When the female starts to lay eggs, tentacle of the male in her pallial cavity
bursts from contractions of the special muscles, and eggs are fertilized. The
female lays up to 200 thousands of small eggs. She places them in shelter –
deep crack or large bivalve shell. The incubating lasts about two months. From
eggs small larvae differing from adult mollusk by short tentacles and pointed
translucent body hatch. After their hatching the organism of the female quickly
degrades, and she dies.
Young animals grow very quickly, and already at one-year-old age reach the
size of adult mollusk. Males become able to breeding at the age of 16 – 18
months, and females up to 20 months.
Hermit
octopus (Diogenopus vermisomus)
Order: Octopuses (Octopodida)
Family: Porter octopuses (Phoroctopidae)
Habitat: mollusk-spongial reeves of Pacific Ocean.
Octopuses are cephalopods completely have lost shell: at them even a rudiment
of this organ did not remain. Therefore they can not expect for passive protection
as it was made by their relatives – ammonites and nautiloids. Feature of behavior
of octopuses is their disposition to hide into different kinds of shelters.
And absence of firm parts of body gives them big advantages in this sense:
octopus can hide in very narrow shelter, where predator having a firm skeleton,
will not squeeze through. But shelter is not always “near at hand”: the mollusk
should leave it to hunt. In Neocene some octopuses have solved this problem
by very simple way: they simply began carry shelter on themselves. The most
simple and accessible among small and enough strong shelters on Neocene reeves
are mollusk shells. During evolution process the special family of octopuses,
which have mastered using these shells for daily life similarly to hermit crabs,
has appeared.
The characteristic representative of this family is the hermit octopus. It
is medium-sized mollusk: its tentacles are up to half meter long (measurements
of the female are described here, male is much smaller). At usual octopuses
leading free life there is short and thick body, but at this mollusk body is
long and flexible. Hermit octopus practically constantly drags on itself found
mollusk shells in which it hides in case of danger, therefore such body shape
permits it to use volume of portable shelter most rationally. In connection
with such unusual habit of life its tentacles have a little changed: from eight
tentacles two ones (last pair) became short, flat and wide, and their bases
have moved back and upwards. These tentacles are intended for keeping of shell
on the body of mollusk, therefore getting it out from the shelter is rather
uneasy: for keeping at smooth internal surface of shell on these tentacles
suckers are well advanced. Other tentacles have a structure typical for octopuses,
and are used the same way as usually. The hermit octopus has kept ability to
change colouring of body, but its body nevertheless makes it less successfully,
than head and tentacles. In rest colouring of tentacles is grey with pinkish
and white “marble” pattern of cross strips and spots, but it also can change
from white up to rubiginous and black color. Eyes are large, greenish with
white rings around, exaggerating visually their size.
At all species of hermit octopuses both males and females search and carry
shells.
This kind of octopuses is named after the philosopher of human epoch Diogenes,
lived, as the legend says, in barrel. Such name rather precisely indicates
features of behavior of this octopus: characteristic for these cephalopods
aspiration to occupy various shelter has resulted to that hermit octopuses
have originally returned to feature which their far ancestors have refused
millions years ago. However, as against fossil cephalopods, carrying shell
till all their life, the hermit octopus can leave it at the will not for a
long time. It makes it very seldom, and only when there is no other way to
reach any significant purpose. However it does not leave from the house far:
by one tentacle the hermit octopus constantly keeps for shell, being ready
at any moment to involve itself in shelter by sharp contraction of this tentacle.
Because of heavy shell and thin long body the hermit octopus has lost the ability
to swim. Usually it creeps on the bottom, extending forward the forward pair
of tentacles and tighten on them. It does not have need to swim quickly: its
food in case of danger does not aspire to rescue by flight. Similarly to all
cephalopod, this octopus is a predator. It eats crustaceans and fishes dug
at danger in sand, or hiding in holes. Usually such octopuses one by one wander
on reef, tracing for smells dissolving in water. Having felt smell of possible
catch, octopus slowly moves to its source. It does not try to disappear: it
has no need to creep as closer, as it is possible, and then to rush and to
chase prey; it hunts by other way.
Having noticed a predator, any fishes and shrimps swim out, and any ones hide
themselves in sand. This mollusk also hunts for them. It immerses tentacles
in sand, and sensitive chemoreceptors on their surface permit this mollusk
to define, where there is a catch. Though the mollusk does not see prey, it
chases it in thickness of sand by tentacle by smell. If the catch dug in sand
will try to slip away, electroreceptors catching activity of nervous system
of hidden catch include to hunting.
Strong suckers at tips of tentacles help to keep seized catch. When the chased
animal has got, octopus jerky contracts tentacle and pulls catch out from sand.
Even if at this moment it will escape, it will not be possible to rescue to
it: octopus covers a place of hunting by shell in which it is sitting, and
catch slipped away all the same appears in trap.
Octopus kills caught prey by sting which is very poisonous and instantly kills
even animals with slow metabolism. With the help of stings octopus protects
itself from enemies – predatory fishes and other species of octopuses. For
protection another traditional for cephalopod kind of weapon, poisonous ink,
is also used. But it is the extreme case: ink is poisonous for the octopus,
and it can not leave quickly the poisoned zone. Therefore it splashes ink through
swimming funnel extending like tube, and at once presses shell to bottom. If
the bottom is sandy, octopus even “anchors”, deeply immersing free tentacles
in sand and being dug in it by edges of shell.
For breeding male finds female by smell emitting by it. Having found shell
of the female, male cautiously gets on it, and waits, while the female will
find out his presence herself. If he will be careless, the female may easily
have eaten him. When the male will be convinced, that the female knows about
his presence, he cautiously starts closer acquaintance: he warns her about
his intentions by easy touches to tentacles of the female. The female unready
to pairing simply banishes the unlucky “groom” by impact of tentacle. If the
female is ready to pairing, she lets tentacles out and touches by them the
male, answering him. An accustoming of animals to each other proceeds so. For
pairing the male pushes tentacle filled with sperm liquid (it is larger than
others) in pallial cavity of the female, and then by sharp contraction of muscles
in the basis of this tentacle tears it off. His mission in breeding is executed,
and the male leaves out. The torn off tentacle will regenerate, and he one
– two times again can repeat courtship. His tentacle some time lives in pallial
cavity of the female. When she starts to lay eggs, this tentacle bursts and
fertilizes them.
The female of this species carries eggs pasted in vault of shell like grapes.
As all octopuses, during protection of posterity she becomes inactive and eats
of nothing. Development of eggs lasts about one month, and then from them tiny
translucent youngs hatch. First some days of life they spend in shell near
to mother. They hang on wall of shell almost motionlessly. At this time at
them large yolk sac resolves, and body gradually starts to get colouring. After
the young growth abandons shell, female lives not for long: about one week.
In her organism irreversible physiological changes take place, and she perishes.
Leaving from parental shell, young hermit octopuses first two months live usual
life, characteristic for the majority of octopuses. Later their body starts
to extend, and they look for a shell to themselves.
Hermit octopuses are short-lived: duration of their life does not exceed three
years.
Close species:
Flat-bodied
hermit octopus (Diogenopus platysomus). It is small species: the length
of tentacles does not exceed 10 cm. At this mollusk body is strongly flattened:
it lives in shells of mollusks with narrow chink-like fauces. All body of flat-bodied
hermit octopus is translucent; covers have pattern coloration of grey spots,
and eyes are silvery. This species eats mainly small crustaceans and sedentary
worms. Due to strong beak-looking jaws it can break open sideways limy tubes
of sedentary worms and shells of small snails.
Garbaging
octopus (D. ostracophylus) is the
most low-specialized species of genus: the
mollusk uses valves of shells of bivalve
mollusks as shelters. In case of danger this
octopus presses shelter to firm substratum
and sticks by all tentacles; therefore it
avoids sites with soft sandy bottom and keeps
basically on rocky and calcareous sites of
reeves. This species differs in small sizes
(length of tentacles is about 8 cm) and short
body. Covers are colored rather brightly:
they are yellow-colored with small black
spots, and the body is colored as brightly,
as tentacles are. It eats different small
animals, and also willingly eats rests of
catch of large predators.
Polyp
octopus (Polypoctopus sessilis)
Order: Octopuses (Octopodida)
Family Sedentary octopuses (Sessiloctopidae)
Habitat: coastal waters of Indian and Pacific oceans, oyster reeves.
When coral reeves have disappeared, new productive natural community, reeves
constructed by bivalve mollusks, basically by stone oysters and various species
of tridacnas, has appeared to replace them. Entering commonwealth with algae
they have constructed an ecosystem populated almost as is rich and various,
as coral reeves. Cephalopods in any epoch were characteristic inhabitants of
such coastal communities. Mastering different ecological niches, they sometimes
have fantastical and unexpected shape.
In Neocene among cephalopods living at algal-mollusk reeves completely unexpected
creatures have appeared: octopuses replaced active life of free hunters to
life of passive homebodies. And they became so adhered to the house, that seldom
leave it at own will, spending at times the most part of life sitting at same
place.
The polyp octopus, one of such “homebodies”, is medium-sized species of octopuses
with sharp sexual dimorphism. The female is about 10 cm long, with very long
tentacles which can extend up to 1 meter length. She constantly sits in once
chosen shelter: empty shell or crack in rocks. In connection with such life
she had strong changes in appearance. The body of such female grows, filling
by itself the chosen shelter and accepting at times the most fantastical and
wrong form. Sense organs also have undergone changes: sight at the female of
polyp octopus is very weak, eyes are substantially reduced. But instead of
sight at her the sharp chemical feeling sense was developed, permitting to
receive the exact information about world around.
The body of female of polyp octopus is colored light pink, skin on it is translucent,
and interiors of animal appear through it. Tentacles are colored brown with
greenish and white irregular-shaped spots. However, their colouring can easily
vary.
On the back side of body skin sucker, assisting to keep in shelter, develops.
Similarly to all representatives of cephalopod classus, the polyp octopus is
a predator. The female of this species arranges ambushes, having stretched
on surface of reef tentacles with well advanced suckers. Having felt presence
of catch, mollusk by sharp movement of tentacles seizes it and draws to mouth.
For catch killing the polyp octopus uses poisonous sting. Jaws can be pushed
forward, putting sting to the seized animal. The basic catch of females of
polyp octopus is small and medium-sized fish.
The male of this species is radically differing from the female by appearance
and habit of life. It is very small (length is about 6 - 7 cm with tentacles),
leads active and mobile life. On his body there are muscled fins with which
help the mollusk can swim very quickly. At him eyes and organs of chemical
feeling are well advanced: all sense of his life is finding of females for
the sake of breeding. The skin of the male is colored red - brown, but it can
change shade from grayish-white up to spotty and black. After approach of sexual
maturity (at the age of half-year) the male actively searches and fertilizes
females. But the male lives not for long time: about nine or ten months.
For fertilization of the female the male falls on bottom outside of her tentacles
reach zone. One of tentacles of the male tears off the body by the sharp muscular
contraction, and independently creeps to the female. To come nearer to her
for fulfillment of courtship ritual is unsafe for the tiny male: she easily
can take him for catch and to have eaten. But independently creeping tentacle
does not cause in her reaction of attack, and easily reaches oviducts of the
female, attaching there to wall and at the moment of egg laying emitting liquid
sperm. At the male new tentacle grows soon, and he searches for the next female
which may be fertilized. Sometimes in oviduct of one female some tentacles
of different males can wait for “hour of triumph”.
The female pastes clutch of large translucent eggs (about 200 ones) looking
like cluster of grapes in shelter, and then diligently protects the future
posterity within one month, eating of nothing. After larvae hatching (actively
swimming transparent larvae are externally similar to the male) she lives not
for long and soon perishes. Life expectancy at females of this species does
not exceed two years.
The young growth first two months leads active life; later females look for
themselves any shelter and turn to inactive sedentary creatures. Males continue
swimming and hunting, but their growth is sharply slowed down, and they remain
dwarfs to all stayed life.
Worm-like
octopus (Vermoctopus serpuloides)
Order: Octopuses (Octopodida)
Family: Sedentary octopuses (Sessiloctopidae)
Habitat: coastal waters of Pacific Ocean, spongial and mollusk reeves.
This species belong besides to family, as previous one, but its specialization
to inactive habit of life has gone any other way: this mollusk arranges holes
in calcareous basis of reef. As the adaptation to such way of life the large
gland producing acid secret was developed at the back end of body. Because
limestone is easily dissolved even by the weakest acids, its drilling does
not cause any difficulties.
At this species the sexual dimorphism is less expressed, than at previous one:
male is only a little smaller, than female. Body of mollusks of both sexes
is worm-like: its length at the female is about 30 cm (male is about 20 cm
long) at thickness of body only 3 - 4 cm. Tentacles are strongly extendible
(in quiet condition their length is about 15 cm, extended ones can reach length
of 60 - 70 cm), suckers are only on their tips. Skin of worm-like octopuses
is grey with small black speckles on tentacles. On the back end of body, near
the acid gland, there is a large sucker assisting to animal to keep in hole.
Eyes of these mollusks are rather well advanced: animals can see colors and
small moving objects, but they are too near-sighted: at the distance of two
meters the large fish turns for their sight to blurred shadow. But well advanced
chemical feeling permits them to perceive presence of the enemy and to hide
in hole before it will get in their field of vision.
For simplification of breath the respiratory siphon of these mollusks became
long and extensible. Its end is covered with set of receptors detecting movement
of water and presence of chemical substances in it. Even when whole mollusk
sits in hole, the siphon serves to it as though as “window in the world”, and
permits to keep under the control conditions around of hole.
The worm-like octopus lives, as the sedentary tube worm (Serpula): it juts
tentacles out from hole and waits, while any small animal will come nearer
to the distance from which it may be seized easily. In case of danger this
mollusk instantly disappears in hole and closes an entrance by “fuse” (stone
or massive shell) which it constantly holds in one of tentacles. If the enemy
appears excessively curious or persevering, the mollusk can frighten him off
by jet of ink containing unpleasantly smelling and poisonous substances. But
in this case the octopus should hold its breath itself for some minutes, expecting
while poisonous liquid will be carried by current aside.
As against to majority of octopuses, worm-like octopus is not gloomy single.
The male lives in hole of the female, having drilled for itself separate lateral
burrow. Both animals in common gather food and share it with each other.
Ritual of acquaintance of male and female proceeds very interestingly: the
young male, still living independently, finds a hole, bored by female, by smell.
He cautiously comes nearer to her hole, ready to slip away any minute at first
sign of displeasure from the female. Gradually the female gets used to smell
of the extraneous octopus, and the second stage of acquaintance begins. The
male settles near to the female in temporary shelter. He starts feeding up
the female, throwing to her hole killed fishes and shrimps. Gradually he passes
to the third stage of acquaintance, to tactile contact. He any more not at
once releases catch intended to the female, but any time keeps it. At this
time female can feel his body by tentacles, and chemoreceptors located on them
supplement with the new information an image of the male applying for pair
forming. If all stages of acquaintance are passed successfully, the male may
fearlessly get into her hole and start to bore his own “apartments”. The female
helps him, by strong “exhalations” of water throwing out from hole “building
dust” – sand and products of limestone dissolution.
However, sometimes mollusks of this species use temporary shelters: they dig
holes in sand, strengthening their walls by slime. Not sexual matured males
and very young females were not found suitable place for arranging of constant
hole make it.
The generated pair of mollusks hunts more successfully, than the single. Such
mollusks quickly grow and expand hole, dissolving by secret of acid gland layers
of limestone on walls. And once the female starts to build the big chamber
in lateral wall of hole. It means, that the male had fertilized her, and she
had stand on the way of materinity. The nest chamber is bell-shaped one. On
vault of the chamber female lays a cluster of small eggs (about 500 ones),
and starts to protect them both with the male. The male keeps closer to entrance
of hole. Under action of the substances secreted by the female, at him large
poisonous glands start to develop, and he turns to fatally dangerous creature.
After one month from eggs translucent larvae hatch. They swim out from native
hole, and lead secretive life in crevices of a reef the first month of life.
Later females start to bore holes fit to live in, using natural cavities as
a basis of construction. Males live at the sandy bottom of shallow waters,
but later they move to holes of females.
As at all cephalopods, this animal breeds once a life. Its life expectancy
does not exceed 1 year, and after larvae hatching the parental pair perishes.
Vineglass cuttlerfish (Utriculosepia pustulosa)
Order: Cuttlerfishes (Sepiida)
Family: Cuttlerfishes (Sepiidae)
Habitat: Pacific Ocean, top layers of water.
In human epoch one of tendencies in evolution of cephalopods was the pelagization
– the transition to life in thickness of water. Such way of development was
selected mainly by squids, though among other groups of cephalopods also pelagic
species evolved. People know species of pelagic octopuses and cuttlerfishes.
In Neocene mass extinction of plankton animals stimulated the new wave of settling
of open ocean by cephalopods. Among them many species at which the complete
life cycle passes far from coast had appeared. Some of them became strong and
muscled necton animals, fast swimmers overcoming longest distances. Others
had turned to fragile plankton organisms passively soaring in thickness of
water and freely transferring by currents. Life in plankton has made some cephalopods
fantastical creatures with strange, but effective strategies of life. The part
of plankton cephalopods has almost lost the art of swimming. These creatures
soar in water, moving only when someone will disturb them, or when they are
threatened. The rest of time they lead passive, perhaps, even “vegetative”
life. And sometimes in anatomy of animals practically direct parallels with
features of structure of some plants are shown.
Among the plankton organisms inhabiting waters of southern part of Pacific
Ocean there is one species of pelagic cuttlerfishes. This is small creature
(length of its body is only 12 – 15 cm) with big eyes and almost completely
transparent. Covers of body of this mollusk have bluish color; therefore it
seems that the cuttlerfish is made of blue glass. In thickness of water this
mollusk is completely invisible, and its presence is given out only by big
eyes, shining when the ray of sunlight from the surface of water gets in them.
Many similar mollusks live in thickness of water, and simply the pelagic cuttlerfish
of one more species may get lost among their variety. But it differs in very
specific receptions of hunting which do not meet at other cephalopods. At this
species of cuttlerfishes there are very long tentacles (extending to one meter
and even more), on which strongly changed suckers are located. Each sucker
represents formation like the transparent bladder placed on thin stem, or simply
small vineglass. For this feature the mollusk has received the name vineglass
cuttlerfish. Edges of suckers are strongly narrowed and supplied with the valve,
which is closed by tiny cover. The corneous hook on sucker is reduced and represents
thin sensitive bristle. When any small creature (fry or crustacean) touches
it, bladder opens and engulfs prey. The similar adaptation was developed on
leaves of floating plant bladderwort (Utricularia) – this feature represents
a surprising example of convergence of animal and plant.
Such adaptation was developed for feeding on the most accessible plankton catch
– small crustaceans. Vineglass cuttlerfish simply passively soars in thickness
of water, having stretched tentacles. Its fins are reduced up to two small
“patches”. With their help mollusk supports the necessary position in water,
but can not swim quickly. Soaring in thickness of water, cuttlerfish waits,
when plankton crustaceans will touch its tentacles. Having filled suckers with
caught crustaceans, cuttlerfish stretches feelers near the mouth one by one,
squeezing out prey by contractions of bladder right in mouth. Dwarf males of
this species differ from females not only externally, but also by preferred
diet: they eat small shrimps.
For self-defense the vineglass cuttlerfish uses two tentacles with pointed
corneous hooks - the disturbed animal extends them aside the aggressor. Thus
the body and trapping tentacles blacken. After attack the animal sharply turns
transparent and contracts tentacles. It can swim, pushing water from pallial
cavity. If the enemy is small and represents the same fragile plankton creature,
vineglass cuttlerfish can attack it, but against the large and well-protected
animals it is defenceless. In case of attack of fishes it tries to leave from
chasing, using the ability to autotomy: with the help of the special muscle
one or two tentacles tore off from its body and start to contract and to wriggle
actively, distracting attention of predator from the mollusk.
Vineglass cuttlerfish lives within about two years. It breeds once a life,
bearing the clutch of several hundreds of small eggs on tentacles during three
– four months. This time the female eats of nothing and leads the extremely
passive way of life – it moves only when it is necessary for protection of
posterity.
At this mollusk the male is very small – its length does not exceed 5 cm. At
it there are reduced tentacles, except for one, about 10 cm long. With the
help of this tentacle the male fertilizes females. In fact the male is the
larva finished growth early and having reached sexual maturity. It lives less
than half-year, but for this time it can fertilize several females. During
the courtship ritual the male blackens, showing itself to the female. It accurately
“perches” on the body of the female from above, trying to not touch her tentacles
– the female can easily catch and eat the own groom. If the female is ready
to fertilization, male enters spermatophors in her pallial cavity with the
help of long tentacle, and then leaves the female.
Syphonophora squid (Natarospectrum mollissimus)
Order: Squids (Theutida)
Family: Onychotheutids, or Clawed squids (Onychotheutidae)
Habitat – deep-water zone of Pacific Ocean,.
From the moment of occurrence on Earth cephalopods were mainly active swimmers
and strong contenders of pelagic fishes. But some species of these mollusks
in different geological eras passed from life in top layers of water to life
in oceanic depths, and some ones even on oceanic bottom. Here, in conditions
of low temperatures, darkness and enormous pressure, they varied up to unrecognizability,
getting the most fantastical shapes. In depths at lack of catch it is energetically
unprofitable to be active swimmer, but the passive predator, patiently expecting
suitable prey achieves much more success in survival. Therefore squids lodged
in abyss, have almost lost ability to swim.
Syphonophora squid is one of such deep-water pelagic squids. It spends all
life in thickness of water at the depth from one and half up to three kilometers.
This mollusk passively floats in water, having stretched tentacles in sides.
To facilitate floating this squid in water, its large liver with stock of easy
fat serves as a float. Body of this mollusk is very soft, jelly-like and translucent.
Syphonophora squid is a creature, not much more dense, than the jellyfish.
Eyes of this creature are large, telescopic, sit on flexible “stems” and can
turn in various sides.
Principal organs of movement at squids are muscled fins and the jet device
of swimming funnel and pallial cavity. Syphonophora squid had lost ability
to jet swimming because its muscles are strongly reduced. Fins at this species
are short and wide, a little bit similar to fly wings by shape. Squid usually
passively soars in thickness of water and swims only when it is disturbed.
In this case it flaps by fins, as by wings. However it can not swim for a long
time, and quickly becomes exhausted.
For all cephalopods presence of different amount of tentacles is typical: it
is a former forward part of creeping sole (the back part had turned to swimming
funnel). Tentacles of the syphonophora squid are long, and also have very characteristic
shape for what the animal has received the name. They very much resemble a
colony of any coelenterates. Tentacle bases have relatively advanced muscles,
and due to this tentacles can move. But in the significant part of muscles
they are reduced, and cannot be bent any more. Distal part of tentacles is
thin; suckers are partly reduced and strongly modified. The part of suckers
has turned to glue glands, secreting on the surface of tentacles sticky secret.
Here and there among them there are luminous glands - the modified large suckers
looking like bulbs. They are almost closed, forming bladder in which secretions
of the special gland containing luciferin and luciferase enzyme mix up. When
the squid simultaneously emits two reagents in cavity of bladder, it brightly
flashes for any time.
Tentacles are the main hunting adaptation of this squid. Being a passive animal,
this squid has not ceased to be a predator. Simply prey itself comes to a predator
now. Lighting squid involves to itself small fishes and invertebrates. These
creatures are simply pasted to feelers, and while they have failed to free,
the squid grips and eats them.
Except for usual tentacles, for squids two trapping tentacles are characteristic.
At this species they are very well advanced, and muscles easily permit them
to bend in any direction. Trapping tentacles are thin, easily extensible, and
on their ends suckers and horn hooks are advanced. Having felt that to tentacles
small catch is pasted, the syphonophora squid lets out one trapping tentacle
(usually it keeps them involved), and seizes prey before it will free.
Syphonophora squid is rather large creature: though length of its body is only
about 25 – 30 cm, tentacles of this cephalopod are very long – up to 2 meters.
The male is much smaller than the female – its length is about one and half
meters including tentacles. At it organs of smell sense are strongly advanced,
and it swims much more actively than the female, searching for her by odorous
trace.
Similarly to all squids, this species breeds only once a life. The female bears
clutch of 400 – 500 large eggs about half-year, then young squids remain on
the body of female till one month. They feed with prey caught by parental tentacles
(after their hatching the female does not eat any more, and her body degrades).
The posterity cautiously creeps on parent tentacles, eating the catch pasted
to them. They do not paste to tentacles of the female because covers of body
at them secret the substances interfering action of glue of this species. Usually
young squids abandon the female when it perishes and also its tentacles cease
to emit sticky secret. They become able to breed at the age of approximately
five years.
Unequal-handed angler squid (Lophiotheutis anisomanus)
Order: Squids (Theutida)
Family: Angler squids (Lophiotheutidae)
Habitat: Atlantic Ocean, depth from 200 up to 2000 meters.
“Planktonic accident” at the border of Holocene and Neocene rendered enormous
influence to fauna of deepwater organisms. Inhabitants of depths, where the
sunlight does not reach, entirely depend on efficiency of top layers of water.
Therefore in epoch of mass extinction of pelagic animals deepwater fauna had
suffered serious damage.
In Neocene depths of oceans are populated as richly, as in Holocene, but their
inhabitants belong to descendants of shallow-water and coastal forms. In depths,
as well as at the surface of water, fishes and cephalopods compete to each
other.
Among deepwater cephalopods the group of passive predators evolved – these
ones are angler squids, or unequal-handed squids. They live in all oceans and
populate the thickness of water. Some species keep near to continental slope
and at underwater mountains. These ones are passive and slowly moving forms
with rounded fins and short body. They swim slowly, and mostly passively hang
in thickness of water, having stretched tentacles, which serve only for supporting
of body in water thickness.
Unequal-handed squid is the typical representative of this group of animals.
It is widely settled in Atlantic from temperate latitudes of both hemispheres
up to equator. Length of body of this mollusc is about 20 cm. It has short
sac-like body with rounded fins. In rest the squid supports the necessary position
in thickness of water, slightly waving by fins. Maintenance of buoyancy is
promoted also by fatty liver shifted to the forward part of its body.
Tentacles of unequal-handed squid are wide and flat. They had lost almost all
suckers (only a few pairs of suckers directly near the mouth are kept), and
had turned to organs promoting soaring in water thickness. The length of tentacles
does not exceed length of body of squid. In rest this squid soars in thickness
of water, having turned tentacles upwards and having stretched them in sides,
as petals of flower.
Angler squids are predators; they catch prey with the help of the trapping
hands modified in special way. Trapping hands of these molluscs have different
length and different purposes. Right hand is very long and extensible – usually
it may be extended to the length of up to three body lengths of the animal,
but at some species it extends even more. Along this trapping hand a bunch
of muscular fibres stretches, due to which this hand may be contracted very
quickly. The tip of right hand frequently may be translucent and leaf-shaped.
On it organs of luminescence are located; their size and amount vary at various
species. These are the modified suckers becoming a refuge of colonies of luminous
bacteria. The left hand of angler squids, on the contrary, is short and muscled,
with well advanced suckers and hooks. This animal allures prey by right hand,
imitating movements of small animals, and seizes and drags prey to the mouth
by left hand. In salivary glands of these molluscs the strong poison, killing
fishes and other animals with slow metabolism for some seconds, is producing.
At unequal-handed angler squid right trapping hand is extended to the length
of about one meter. On its tip some bubbles (modified suckers), containing
colony of luminous bacteria, are advanced. They are located in one line and
resemble a colony of doliolids or siphonophoras, when they are visible in darkness
of depths as a chain of fires. The hunting squid weakens muscles, extending
bait hand, and the luminous bait does not give out its presence. Some muscles
force bait to coil, strengthening similarity to colony of small live organisms.
Bait hand imitates movement of small animal so skilfully, that it seems, as
if other live being is adhered to squid – the difference between inactive animal
and mobile bait is expressed so. When the prey involved with bait swims up
closer, unequal-handed squid gradually contracts muscles of tentacle, forcing
prey to come nearer to trapping hand.
Trapping hand of this squid is really similar to trap. It is short, but its
tip is wide and is divided into two lobes with elastic cartilaginous “skeleton”.
Cartilages are connected by adductor muscles, which “slam” trapping hand, when
prey touches it. The inner surface of trapping hand is supplied with plenty
of suckers, and on its edge sharp corneous hooks grow.
At angler fishes of several families males attached to the female to all further
life and led parasitic way of life, but at other species males were simply
tinier, rather than females. At angler squids males always lead an active way
of life and are smaller, than females. They keep an anatomy and symmetry of
body typical for squids, and trapping hands at them are not modified. Males
of angler squids swim quickly and actively search for females ready to fertilization.
Sexually mature male can fertilize several females before it will die from
old age.
Ritual of “acquaintance” at these squids passes in some stages. Coming nearer
to the female, male keeps in the distance from its tentacles – the female can
seize him and eat. In order to allow the female to identify him, male emits
in water the special chemical substance, signalling to the female about his
presence. After that, being careful, male begins direct “acquaintance”. He
gradually comes nearer to the female, keeping directed to her by tentacles
and slowly waving by fins. Such pose enables him to feel movements of the female
with the help of receptor cells on tentacles, and to escape from the female
with the help of one sharp jet pulse in case of danger. If the female does
not show aggression and is ready to pairing, male goes to closer contact. He
cautiously creeps on head to the female and starts to touch her body. Having
found out an entrance to pallial cavity, he enters in it spermatophore of lengthened
form in dense cover, and abandons the female.
After fertilization the female actively eats till some time, and in her body
the clutch ripens – some hundreds thousands tiny eggs. In same time her internal
organs gradually start to degrade – inevitable process of ageing begins. The
female lays eggs covered by common slimy jelly-like mass, which strongly swells
in water. She keeps clutch by tentacles and trapping hand. In same time the
luminous bait on her hand degrades. But the part of luminous bacteria has time
to penetrate into clutch, and infects developing embryoes; therefore young
angler squids are already able to luminescence. After young growth hatching
the female perishes.
The complete cycle of development of this squid takes about three years, from
which last eight months of life fall to incubation of clutch.
Dwarf unequal-handed squid (Anisomanella subtilis)
Order: Squids (Theutida)
Family: Angler squids (Lophiotheutidae)
Habitat: Atlantic, depth from 200 up to 2000 meters.
Representatives of angler squid family appeared rather successful inhabitants
of depths. After the type of the passive predator squid alluring prey with
the help of tentacle had formed, this group of molluscs had evolved a plenty
of species adapted to various prey. The majority of these squids hunts fishes,
but some species prefer small prey like shrimps. Dwarf unequal-handed squid,
the smallest species of angler squids, belongs to the number of these species.
Dwarf unequal-handed squid is very small squid. The body length of adult individual
of this species does not exceed 5 cm. This squid is not adapted to swimming
and has the inflated body with small head. Fins are very wide; with their help
animal can move to small distances and supports position of body convenient
for hunting. Short flat tentacles with rudimentary suckers and advanced horn
hooks in rest are stretched in sides. They form the floating “anchor”, assisting
to stop at prey catching.
This tiny mollusc has very long bait hand – it can be extended to the distance
up to half meter. The bait on the tip of this hand is lengthened and consists
of the line of closely put luminous organs. It precisely imitates pelagic luminous
worms which deep-water shrimps, the basic food of this squid, eat. Besides
them, dwarf unequal-handed squid eats worms also involved with light of bait.
The modified suckers turned to organs of luminescence, are placed on each side
of the bait on long stalks, imitating articulated body of worm with outgrowths
on each side of segments. On tip of bait two corneous hooks with jagged internal
edge are advanced. They assist to drag prey closer to trapping hand. The animal
grapples the deceived shrimps by hooks, and sharply contracts bait hand. It
simultaneously tightens prey to itself, and moves nearer to it. Squid sticks
to armour of shrimp by trapping hand, not giving it an opportunity to escape,
and kills, putting to the crustacean a poisonous bite.
After fertilization by dwarf male the female lays eggs on internal surface
of trapping hand and keeps them to the development of young ones till about
3 months. At this time it eats of nothing and is quickly exhausted; its body
deeply degenerates. The significant part of muscles resolves, volume of liver
decreases, and the digestive path disappears almost completely: only a tissue
cord without lumen remains from it only. The female perishes soon after hatching
of young ones from eggs. The complete life cycle of this species lasts about
16 months.
Worms
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Spat
leech (Serpentobdella jaculata)
Order: Proboscisless leeches (Arhynchobdellea)
Family: Jaw leeches (Gnathobdellidae)
Habitat: tropical forests of Southern Asia.
The damp climate of Neocene epoch substantially favors to development of most
various groups of moisture-loving animals. In tropical rainforests where each
day it is rainy and it is always possible to find pools of fresh water, there
is especially favorable inhabitancy for various invertebrates: mollusks and
worms. But if snails are sluggish vegetarians, worms have turned to original
predators of forest canopy. Certainly, not all worms have achieved success
in development of wood habitats, and only their one group – leeches had become
such group. Ground leeches were known in Holocene, but they were basically
medium-sized animals. In Neocene they have grown to monsters of frightening
size, becoming among appreciable predators in wood ecosystems. Huge slobber
leech Titanobdella glutinosa places sticky traps on branches, from which
even the cat-sized animal may not escape. Having excellent masking and prompt
reaction adderleech Viperobdella
arborea catches small vertebrate animals, killing them by poisonous sting.
One more relative of these deadly creatures is the spat leech, developing an
original way of hunting.
Spat leech is large predatory worm living only on trees. Life of spat leech
is closely connected to water: its covers are soft, mucous, and very quickly
lose water. But this worm regularly humidifies skin, using water gathering
in crowns of epiphytic plants. The body length of this worm is up to 50 cm
at width about 8 - 9 cm, but it is rather changeable size: the leech can contract,
compressing almost to sphere or to stretch up more than twice. Colouring of
the top side of its body is cryptic: grey with longitudinal brown strips and
black strokes. The bottom side at this leech is colored brighter: it is yellow
with round black spots.
Spat leech eats insects and small vertebrates – frogs, lizards, and even tiny
birds. It is sluggish creature, but catches these mobile animals, spitting
out in them jet of saliva which in air becomes sticky and viscous (by the same
way Peripatus similar to hybrid of centipede and caterpillar, the representative
of ancient by origin phylum Onychophora, catches forage to itself). In salivary
glands of this leech two components are formed, each of which separately is
a liquid. But it splashes them simultaneously, and under action of oxygen of
air there is a chemical reaction between them.
Saliva splashing occurs due to strong ring muscles surrounding every gland.
Nerves approach to them from one pair of nerve ganglions, and under influence
of one impulse substances from two pairs of glands splash synchronously. The
distance of this “shot” may account about 1 meter. In searches of catch this
worm is guided first of all by sight: the spat leech has six well advanced
eyes. Sight at this worm is rather keen: this leech notices small beetle at
the distance of two meters, and especially sharply reacts to moving objects.
This worm spends all life on trees. More often leech passively waits, while
possible catch will come nearer to critical distance itself. After that well-aimed
“spittle” follows, and saliva of leech, having stiffened to rubber-like viscous
substance, pastes bird or insect to leaves. If the bird brought down by the
leech will fall on branches outside of reach of the leech, it has chance to
escape: the saliva of the leech thickens very quickly, and in some minutes
loses the property of sticking. Then it is easy to clean it off from feathers.
But more often at the pasted prey anywhere it is not time to leave – leech
snatches it, killing by sting of three cutting jaws, and then swallows prey
entirely.
This leech, similarly to all neighbours, is hermaphrodite. Adult animal leaves
mucous cocoons with eggs in tree-trunk hollows filled with water, or in crowns
of epiphytic plants and in leaf axils filled with water. In each cocoon it
is totaled up to 200 - 300 small eggs stuck together by slime in sticky paste.
In 2 months of incubating from eggs thin translucent young leeches hatch. They
crawl out on tree, search for damp places and more often settle in moss. Here
they are not threatened with danger to dry, and it is possible to find a plenty
of prey – small snails and insects with delicate covers. They grow and mature
slowly: only at the fifth year of life at length about 30 cm the leech becomes
adult. But these worms differ in longevity enviable for their size: the age
limit at spat leeches can reach 50 years.
Hanging wood leech (Dendrobdella pendula)
Order: Proboscisless leeches (Arhynchobdellea)
Family: Jaw leeches (Gnathobdellidae)
Habitat: rainforests of South-Eastern Asia, forest canopy.
In Neocene epoch when the ancient tropical fauna had strongly suffered as a
result of mass extinction, in new rainforests representatives of various groups
of animals, occupied before this time the subordinated position, had appeared.
In conditions of hot and damp climate in woods of South-Eastern Asia ground
leeches had reached the big prosperity. Some especially large representatives
of this group can successfully compete even to snakes, hunting small animals,
birds and insects. They have developed various tactics of hunting that has
permitted them to avoid a competition with each other – some of them put sticky
substance on branch, others catch small animals, masking in the environment.
Due to different tactics of food getting these worms do not compete with each
other.
Next large land leech lives in woods of South-Eastern Asia is the hanging wood
leech. It is rather sizable worm though some giants of rainforest from among
its distant relatives surpass this species in size much more. The length of
body of hanging wood leech in rest reaches 15 – 17 cm at width about 4 cm,
but it can stretch almost up to 30 cm, moving or attacking catch. Similarly
to the majority of leeches, this is rather passive predatory animal. Justifying
the name, hanging wood leech waits for catch, hanging for a long time on bottom
side of leaves and branches headfirst, keeping by strong back sucker and having
compressed. It arranges an ambush above the branch or leaves where small animals
appear oftenly. Sometimes it hides above flowers the where probability to meet
potential catch is higher. To be less visible for catch, and also to not fall
prey to large predators of different kind, this leech till the process of evolution
has got excellent masking. By colouring and shape of body it simulates plant
leaves: on the top part of body on green background light longitudinal strip
crossed from sides by short strokes stretches, and on edge light points bordering
a body like faltering strip are placed. The bottom side of body is grayish-white
– it simulates the bottom side of leaf.
Having hung under branch, this worm waits for catch. Quickly stretching, this
leech seizes by three sharp jaws small animal (usually insects, less often
small vertebrates – frogs, lizards, mammals) moving on branch in the bottom.
Smell organs and eyes are well advanced at this species – the animal determines
the presence of catch with the help of sight and sense of smell. Eyes of this
leech are rather large, located on edge of forward part of head. The animal
badly distinguishes colors, but determines contours of objects well and reacts
to movements. Especial interest at this leech is caused with subjects which
movements are well visible on general background. In connection with presence
of such predator some insects are adapted to mask from the hanging wood leech,
rocking in a step to movements of leaves.
Having caught prey, leech kills it by bite and swallows entirely. Having swallowed
catch, predatory worm becomes sluggish. The full leech hides on bottom side
of branch, having attached to it simultaneously by mouth and back sucker (thus
its body is bent U-shapedly), and digests food in relative rest.
Similarly to all leeches, this worm is the hermaphrodite. For breeding the
leech does not leave crones of trees: it lays slimy cocoons containing about
two hundred large eggs in top part of trunk hollow of large tree in which rain
water gathers. Frequently for this purpose some leeches use the same tree-trunk
hollow, and in one tree-trunk hollow it may be totally up to fifty cocoons.
The incubating of eggs lasts about two months. Young leech gets out of cocoon
and falls in pool of water accumulated in tree-trunk hollow. First some days
of life young leeches swim in this water, eating insects fallen in water, and
even their own smaller congeners. Later they abandon the hollow, and lead terrestrial
life in foliage of forest canopy.
Stomach lightworm (Gasteronereis luciferus)
Order: Phyllodocids (Phyllodocida)
Family: Nereids (Nereididae)
Habitat: Pacific Ocean, depths from 500 up to 1000 meters, symbiote of bathycrystallichthys
fish.
At the process of evolution the strategy directed to formation of symbiotic
connections between species, frequently led both species to success in struggle
for existence. Algae and fungi form lichens – unpretentious and hardy organisms.
Corals and other coelenterates, and also bivalve mollusks tridacna and goblet-like
false rudistes had formed strong symbiosis with unicellular microorganisms.
Glowing bacteria and fishes (or crustaceans) are the successful combination
for development of gloomy depths of ocean. There are many examples of success
of symbiotic species in struggle for existence.
In Neocene in depths of Pacific Ocean completely improbable symbiosis has appeared.
It is formed by two species, which at other trend of developments could play
roles of prey and predator. One species of bristle-bearing worms had exchanged
the ability to glow brightly to safety and full life, becoming a symbiote of
predatory deep-water fish. The strange habit of life of this worm has caused
its name – stomach lightworm.
This worm balances on thin side between symbiosis and parasitism. Its way of
life is rather interesting to that the animal lives simultaneously in two environments
considerably differing by conditions of existence. The back part of body of
stomach lightworm is attached in branchiate cavity, and front one – in stomach
of fish non-glowing bathycrystallichthys
(Bathycrystallichthys unlucens). Length
of this worm is about 20 cm, and thickness of body is only about 5 mm.
In connection with unusual way life forward and back halves of worm body strongly
differ in shape. The forward half of worm constantly located in stomach of
fish is protected from action of digestive juice by dense covers. On segments
of forward half there are no gills, and parapodiums are shifted to the bottom
side of body and modified to suckers permitting to attach strongly to stomach
wall of fish. The head of stomach lightworm has no eyes and tentacles, but
is supplied with strong jaws by which worm bites off food swallowed by fish.
Strong smooth rings of armour protect body of worm against traumas when fish
swallows large prey. The forward half of worm can move inside fish stomach.
On forward segments there are also large organs of luminescence. They are located
on lateral parts of segments in pairs and emit bright blue light which penetrates
through walls of stomach of fish and is seen from outside.
The back part of body of this worm strongly differs from front one. Distinctions
begin from segments which are at the level of entrance to gullet of fish. On
such segments there are gills – on first segments they are small, and closer
to the end of body turn larger, similar to bunches of thin red strings (blood
of stomach lightworm contains hemoglobin). Therefore worm does not choke, existing
more, than half inside the body of fish. On two back pairs of segments there
are corneous hooks serving for attachment. With their help stomach lightworm
is attached to branchial arch of fish. Also on back segments of worm paired
genital organs grow.
Stomach lightworm is a dioecious species. Males and females at this species
sharply differ in appearance; the present description concerns to the female.
Dwarf male no more 10 mm long adheres to back part of female body near one
of sexual apertures and feeds on her body as a parasite. It is actually necessary
for her only for egg fertilization. The gender at these worms is not determined
genetically and depends on destiny of the larva. If the larva succeeded to
attach to gills of fish, it develops as a female. When young worm starts to
develop in organism of bathycrystallichthys by “female” variant, young bathycrystallichthys
still swims in top layers of water, where the meeting with other larva is probable.
In this case it can attach to back part of body of young worm female and turn
to male. If the meeting of female and male had not taken place, the female
of stomach lightworm can breed parthenogenetically. Male has very simplified
anatomy; its body keeps only reasts of segmentation and is supplied with several
suckers on the forward end. After attachment to the female sense organs reduce
at him. The gullet of larva developing to male pierces covers of the female
and is turned out inside her body, supplying male with food.
Stomach lightworm breeds, regularly laying some hundreds tiny eggs made in
slime cocoon. The back part of male body keeps mobility, and it fertilizes
the female, entering sperm liquid in her ovoducts. Ovisacs are thrown out from
branchial cavity of fish by current of water, and emerge on ocean surface.
At this time from eggs planktonic trochophore larvae hatch. They gradually
develop to pelagic worm-like individuals which settle on gills of young bathycrystallichthyses.
The idea about existence of this species is proposed by Simon, the forum member.
Sprouting
tube worm (Phytoserpulopsis proliferus)
Order: Sabellids (Sabellida)
Family: Symbiotic tube worms (Symbioserpulidae)
Habitat: reeves of Indian and Pacific oceans, well illuminated areas of sea
bottom.
Corals took the separate place in ecosystems of Earth due to the symbiosis
with algae: they were original “autotrophic animals”, received a part of necessary
for growth organic substances as result of processes of photosynthesis. After
their extinction a plenty of various live organisms began “sharing” of their
original ecological niche – some species form body of reef from their firm
armors and shells, others catch tiny plankton, and third
ones increased organic substance due to energy of sunlight. So at Earth
of Neocene epoch the new generation of reef builders has appeared.
When water filtering and increasing of firm shell is not a problem for animals,
the function of photosynthesis at the reef was undertaken basically by green
and red limy algae forming at the bottom and underwater objects multi-colored
limy crusts and outgrowths. However among animals species, challenging at plants
their role at the reef due to symbiosis with microscopic algae, also have appeared.
Basically they are various species of mollusks, which had lodged algae in edges
of the pallium. But there are also other organisms which have offered cooperation
to algae.
On the firm bottom of reef somewhere at the depth about two meters it is possible
to see true “thickets” of limy tubes about 30 – 40 cm height, sticking up vertically.
Keeping immobility, it is possible to wait, while from tubes their builders
and inhabitants will appear. Really, some minutes after above separate tubes
clouds of dregs appear, and then tips feather-like tentacles of their inhabitants
are put outside. Gradually, having convinced of safety of world around, tube
inhabitants put out from tubes rich plumes of tentacles, unwrapped, as if exotic
flowers. Tips of tentacles are white, but their other part is colored emerald-green.
Gradually it appears more and more of them, while the congestion of tubes turns
to similarity of flower bed. However, it is enough to too curious fish or the
shrimp to swim up, and magnificent plumes disappear in a flash, having involved
in tubes.
Secretive inhabitants of limy tubes are sprouting tube worms, the special species
of sedentary worms. Their very delicate segmented bodies are constantly latent
in limy tubes. Only the head surrounded approximately with ten pinnate feather-like
tentacles up to 10 cm long, with which help the worm eats, is put outside.
The tube built by the worm, consists of layers of rather soft organic substance
inlaid with sand particles. But on it limy algae settle, giving to tubes durability,
sedimenting on them from outside thin layer of limestone.
On the caudal end of body of the worm some segments have formed sucker on which
edges there are bristles transformed to tenacious hooks permitting to be kept
strongly in tube.
At this species of worms in connection with sedentary way of life eyes have
completely disappeared. But absence of sight is repeatedly compensated by sharply
advanced organs of touch and chemical feeling. The cautious worm is difficult
for deceiving: it is enough too sharp or strong movement of water, and worms
instantly disappear in tubes.
Except for eyes, sprouting tube worm does not have also another, much more
important for life system of organs – digestive tract. The mouth at these worms
is completely disappeared, and only tissue band has remained from intestines.
But worms at all do not suffer difficulties with feeding because for some millions
years before Neocene their ancestors have entered symbiosis with photosynthesizing
protozoans. Due to this adaptation worms became rather independent organisms
living due to the symbionts.
In tentacles of worms, in friable connective tissue, colonies of photosynthesizing
protozoans, giving to tentacles of worm bright green colouring, live and breed.
Tentacles are repeatedly ramified, and this feature increases surface of their
contact with water. They are covered with permeable epithelium permitting to
symbionts of these worms to receive from water all mineral and organic substances
necessary for life. Symbiotic unicellular organisms penetrate into feelers
of each separate individual of the worm from outside. The immune system of
sprouting tube worm is arranged to allow the “own” species of protozoans to
penetrate into feelers and to occupy them, and against “strangers” the immune
system of animal works, tearing away them.
Just under wreath of tentacles some segments, producing building material of
tube, are placed. They increase tube by layers which are clearly visible on
its surface.
Body segments of the worm differ a little in structure. So, segments from middle
of an animal on which hooks are advanced, in themselves are thick and rather
not elastic. In them fat is gathering, serving as a stock of nutrients if the
forward end of worm will be nevertheless bitten off by fish or crab. And segments
from forward part of animal can stretch strongly and contract sharply: they
are responsible for impellent reactions of animal.
Most back segments of this species have completely surprising ability for animals:
they can form germs sprouting in new worms. Branches of all systems of organs
of the worm come into each such germ, and it starts to sprout through a wall
of tube. At first at the basis of tube the aperture appears, through which
it is appreciable as additional “head” moves and expands hole. Gradually this
“head” starts building of short horizontal tunnel sharply bent upwards. When
it reaches about two thirds of height of initial tube, at an affiliated individual
tentacles start to grow, and later they’ll be occupied by symbiotic protozoans
from an environment. In one colony it can be up to four generations of worms
connected together by channels of blood system. Growth of these “additional”
individuals occurs especially actively, when individuals of previous generations
are injured. Then, if damages are too strong, the founder individual may be
simply resolved by formed affiliated individuals, and the central tube becomes
empty.
At the time of highest inflow colonies of sprouting tube worms (and also of
other related species) as if blow up by eggs and sperm liquid. Eggs are carrying
away by waves to open ocean. In some hours from them larvae covered with ciliums
hatch. They will spend about one month in plankton, and then few larvae have
survived for this time will come to reef with next high inflow. They settle
on bottom and give rise to new colonies. Young worms have no symbionts, but
settle on sunny sites of reef. They still have intestines, and they differ
by nothing from other sedentary organisms. But gradually symbionts of the necessary
species find their tentacles and breed in them. Then intestines gradually degenerate,
and worm starts to live exclusively due to “lodgers”, providing them house
and safety.
Reeves of Indian and Pacific oceans are inhabited also by other species of
tube worms entered symbiosis with photosynthesizing organisms:
Poisonous
tube worm (Phytoserpulopsis toxicus).
This species, perhaps, is protected
from enemies better than others:
it enters symbiotic relations with
poisonous protozoan Gymnodinium.
Some species of these protozoans
cause deadly for many other animals
“red inflow”, but worms easily coexist
with such dangerous creatures due
to especial enzyme, neutralizing
poisonous substances getting in blood.
But fish or shrimp, having tried
reddish-orange tentacles of this
worm, will not want to make it second
time any more. As if understanding
its own safety, this worm is not
so cautious, as other species: it
hides only at rather strong movement
of water or direct touch to tentacles.
Despite of fine protection, this
worm is rather rare: the symbiotic
protozoan species occupying its tentacles,
meets too seldom, and most part of
larvae of the worm perishes, not
having met such symbiont. Tubes of
this species are narrow, but grow
in dense groups and reach about half
meter height.
Grey
tube worm (Phytoserpulopsis glaucus) has
given a shelter to cyanobacteriae,
and it also has made it inedible
for many fishes. Tentacles of this
species have bluish-green colouring,
and their edges form the expanded
blades which the worm keeps perpendicularly
to sun beams. For recognition of
sunlight in tissues of tentacles
special cells reacting to light were
developed. Due to wide prevalence
of symbiotic algae this species may
occupy extensive areas of reeves.
It differs in rather small size:
height of tubes is only 10 – 13 cm.
Golden
tube worm (Phytoserpulopsis chrysus) lives
in symbiosis with yellow-green algae
giving yellowish shade to translucent
feelers. It is the smallest species
of genus – length of body of the
adult worm is about 5 cm. Its tubes
grow basically in horizontal direction,
only their tips rise upwards. At
times limy algae completely cover
them, but it does good to worms:
they live in most restless part of
reef – on the top of valves of shells
of bivalve mollusks, on stones near
to a surface of water. Here the probability
to be eaten by fishes is minimal
for this worm.
Giant snail planaria (Titanoplana helicivora)
Order: Tricladids (Tricladida)
Family: Toothed planarians (Odontoplanariidae)
Habitat: Central and Eastern Europe, rivers and lakes.
At the boundary of Holocene and Neocene the Earth had gone through severe congelation,
even more severe, than all ones had taken place before it. This event rendered
colossal influence to the nature of the Earth. The climate became drier and
colder, and the amount of rains was strongly reduced. The congelation rendered
serious influence on freshwater reservoirs of Eurasia and North America. Glaciers
had changed character of river current, and because of drier climate in ice
age the part of reservoirs had simply vanished.
Freshwater flora and fauna had suffered in lesser degree, rather than sea ones.
The majority of kinds of invertebrates managed to keep the species variability.
The broken off areas and difference in conditions of inhabiting promoted the
evolution and active speciation. In places where favorable conditions and abundance
of food resources had kept, specialized species evolved. One of the main centers
of speciation in Europe is the Balkan region. In ice age this area appeared
in conditions of favorable enough temperature mode and moderate humidifying.
Mountain areas served as stores of moisture, and from glaciers rivers constantly
flew, filling reservoirs in valleys. A plenty of isolated habitats and remoteness
from the glacier promoted preservation of variability of species of freshwater
fauna.
In Neocene the climate of Balkan became damp due to influence of Fourseas stretched
in northeast. Forests favor to preservation of reservoirs, and surprising species
of live creatures prosper in them. One of new Neocene species is large freshwater
planaria up to 3 – 4 cm long. It lives in coastal thickets of water plants
and shows itself seldom.
By appearance this worm is the typical representative of its kind. The flat
body of giant snail planaria is covered with caustic poisonous slime. Its color
is grey with light cross strips forming “marble” pattern. On front edge of
the body there are two short blunt tentacles, sticking in sides, and small
eyes – 8 ones smaller, than poppy seed by size. Planaria sees badly and vaguely
distinguishes only contours of objects.
This worm is an active predator. Giant snail planaria eats snails, eating them
away from shells. For feeding on such specific protected prey at it the hunting
adaptation had developed. The characteristic feature of planarias is the gullet
supplied with muscles, able to extend and even to live independent life. At
giant snail planaria the gullet is considerably improved in comparison with
its tiny relatives. Due to ring muscular fibers it is able to extend strongly
(up to 10 cm long). On the tip of gullet some pointed corneous denticles grow.
This worm hunts snails very effectively. Having found out suitable snail, the
worm simply pushes the gullet in fauces of its shell and eats snail away alive
entirely – down to the last coil of shell. Certainly, mollusks with operculum
on the shell are more protected from this worm, but at young mollusks of such
species giant snail planaria gnaws through the operculum and also eats them
away.
Such large worm is well protected from attacks of fishes and water beetles
due to the cover of poisonous slime. But nevertheless these worms meet in European
reservoirs not so often – they also have enemies. Larvae of water beetles and
water bugs can attack this planaria. They do not bite it, inevitably receiving
a portion of slime, but simply exhaust the body of worm by proboscis or through
mandibles, not touching its slime. Sometimes water bugs attack on planaria
devouring snail and exhaust semidigested food right from its intestinal cavity,
having pierced the wall of body by proboscis.
Giant snail planaria has interesting feature of sexless breeding: having had
eaten large enough catch, the worm is able to divide spontaneously. The body
of planaria divides across with the help of contractions of longitudinal muscles.
After that each half completes missing organs till some days, using nutrients
of semidigested prey which had preserved in intestines. Thus gullet of planaria
also is separated and lives by its own life – it can creep, contracting muscles,
and reacts to approach of catch. Gullet of planaria attacks small snails and
other invertebrates, obviously preferring soft-bodied ones. It eats them, and
using received nutrients completes on the back end temporarily absent body.
If hunting was unsuccessful, gullet all the same restores the body, using the
nutrients which are accumulated in its tissues. Thus it “dries out” and strongly
decreases in size, but survives and even lives much longer the normal worm
of this species.
Giant snail planaria lives in conditions of seasonal climate. In autumn, when
water becomes colder, at this worm sexual breeding begins. Similarly to all
planarias, this species is hermaphrodite, and two any individuals can fertilize
each other. Eggs of this species develop in slimy cocoons which the animal
pastes to roots of trees or driftwood. Cocoons hibernate, and in spring young
individuals left them. In autumn young worms lay the first clutch, but do not
reach the maximal size. At the second year of life they reach the sizes of
adult individual, and start breeding by division. Life expectancy at giant
snail planaria may reach 5 years.
Burning flatworm (Nipponoplana tigrina)
Order: Tricladids (Tricladida)
Family: Bipaliids (Bipaliidae)
Habitat: Japan Islands, humid forests of southeast.
Tropical rainforests form the community supporting its own existence. Moss,
wood litter and roots of trees keep water as if a sponge, and the leaves falling
from trees, at once are decomposed and go to circulation of substances again.
The rich forest canopy supports a specific microclimate – equal and moist.
In such conditions life is especially rich, and some water inhabitants willingly
occupy land. Various species of large ground leeches settle in forests of South-East
Asia, and one species of fishes lives in South America in wood litter – it
is almost blind worm-like
catfish. One more species from the number of recent
immigrants from water lives in tropical forests of Japan – it is a large ground
planaria named burning flatworm because of bright colouring and burning taste
of the slime covering its body.
Burning flatworm is the true giant among planarias – it reaches the length
of 30 – 35 cm at width of about 2 cm. It is smaller, than at record by size
ground planarias of Holocene epoch, but all the same it surpasses the length
of the majority of species of ground planarias. Colouring of body at this worm
is very much remembered: it is cross-striped, on red background with orange
shade on edges and in forward part of body the set of cross strips of black
color passes. This large worm imitates the appearance of local tiger
millipede (Bradyjulius rubro-nigrum). Appearance of burning flatworm warns that the animal
is very well protected from an attack. Any animal which will snap this worm,
will feel the burning taste of its slime. Slime will irritate mucous membranes
of predator within several hours, and the memoirs on unpleasant meeting will
be remembered to the aggressor for a long time. Burning flatworm “maintains
the reputation”, having the security common for the species included to the
“ring” with such type of colouring. Besides this worm, tiger millipede is imitated
by one local snake. But burning flatworm has one more unique way of protection
which any of species from the “ring” does not own. If the body of animal is
injured, or any predator had seized it by paw, burning flatworm can break off
its body by voluntary retraction of muscles to some parts, slipping out from
predator’s grip. It does not bring any serious harm to it – each piece easily
regenerates, restoring the lost organs, and turns to small normal worm.
This planaria lives in leaf litter and hunts earthworms and insects. Gullet
located in the middle of the body, as if lives by independent life, searching
for food irrespectively of direction of movement of the worm. It can extend
to any side to the distance about equal to the body length of a worm. At edges
of the gullet sensitive cells and chemoreceptors assisting in search of prey
are located. Gullet can even dig in friable ground in searches of worms, catching
and swallowing them right in their own hole.
Head of this worm is flat, crescent and two-lobed. Very tiny eyes (this worm
has 10 eyes) are located in line on its front edge. They can distinguish light
from darkness and distinguish contours of large objects – it is quite enough
of it for worm, which gullet searches for prey by smell itself.
Slimy and thin covers of burning flatworm easily lose moisture, therefore burning
flatworm lives only in moist places. This planaria though is ground worm, can
behave as an amphibian: it can dive into cool water of forest streams, rich
in oxygen, and receive oxygen from water through external covers till any time.
It avoids pools with warmed up water, but can catch water animals, using mobile
gullet, which stretches under water. The favourite forage of this worm includes
aquatic snails. At the drought burning flatworm is dug in the ground and contracts
almost to ball, forming around of itself a slimy cover. Sand particles stick
to slime, and, drying up, the cocoon becomes covered with dense crust. After
rains it becomes soggy, worm absorbs moisture from ground, restoring its amount
in organism, and continues to lead usual life.
This animal is a hermaphrodite. After pairing the worm lays cocoons containing
up to 20 eggs in moist ground. After 3 – 4 weeks very small young worms having
as burning slime, as adult ones, leave them.
Enemies of this worm are predatory bugs, which can pierce by proboscis covers
of its body, passing a layer of slime, inject their poisonous saliva rendering
digestive action, and exhaust the dissolved tissues of worm. The adult worm
can escape from a bug, having divided to pieces, only one of which will be
exhausted by the insect, but young worms frequently have no time to make it
and perish after a sting of bug.
Anchor jellyfish (Anchorotentacula sessilis)
Order: Trachylids (Trachylida)
Family: Anchor jellyfishes (Anchorotentaculidae)
Habitat: Atlantic Ocean, algal fields near New Azora.
Relief of bottom of Atlantic Ocean in combination to currents has reasoned
the occurrence of extensive fields of floating seaweed near the New Azora Island.
Fields of seaweed, quickly expanding and equally quickly dying off, form the
favorable conditions for life of various sea inhabitants. Here they find not
only shelter and food, but also safe place for life: fields of seaweed soften
force of storm.
The majority of inhabitants of algal fields are represented by descendants
of coastal animals. Their ancestors settled at the stage of plankton pelagic
larva, and some larvae had to found the convenient place among floating seaweed,
having given rise to the population of algal fields of New Azora. Some inhabitants
of water thickness also had adapted to life in seaweed. One of these creatures
is the small jellyfish attaching to seaweed. In Holocene epoch jellyfish Lucernaria
led the attached way of life was known. It attached to substratum by dome,
upwards the mouth, and kept radial symmetry. But the Neocene jellyfish attaching
to seaweed differs from that species. At it the radial symmetry characteristic
for coelenterates is lost in some degree. From four tentacles of this jellyfish
one has the function of attaching – with its help the animal holds thalli of
seaweed. For this feature this coelenterate is named anchor jellyfish. Other
three tentacles have kept trapping ability. They are thin, ramified, and also
are able to extend strongly. On their tips urticators (lasso cells) are advanced.
Usually anchor jellyfish freely soars in water, having fixed by attaching tentacle
and having stretched in sides trapping tentacles. This is almost transparent
creature, practically invisible in water. Its body has spherical form with
thick mesogloea through which ramified gastral cavity is visible. The size
of adult anchor jellyfish may reach 10 cm, and the “anchor” tentacle is extended
to one and half meter. The anchor jellyfish belongs to number of most poisonous
inhabitants of ocean. Its food includes pelagic worms, crustaceans and small
fishes.
This creature is almost not able to swim. If the anchor jellyfish casually
tears off from substratum, it motionlessly soars in thickness of water, having
stretched tentacles in sides. When one of them touches seaweed or other substratum,
it is fixed on it and the jellyfish is dragging to substratum.
The attaching tentacle is thicker and longer, rather than trapping ones. On
it muscular fibrillas develop, able to contract in wide degree. When storm
comes, or beside large animal swims, muscular fibrillas contract, and the jellyfish
hides in seaweed thickets, having shrinked in mucous ball. Lasso cells of attaching
tentacle have changed: they had lost lasso and poison, and the sensitive hair
had turned to strong cornificate prickle. The attaching tentacle is ramified
on the end to some branches. The animal twists them around seaweed thallus
and keeps on the spot so. Sometimes casual movement of large animal or storm
wave breaks off attaching tentacle and tears off the jellyfish from substratum.
In this case the animal attaches to substratum by any of kept tentacles, and
it gradually turns to attaching one. And regenerating attaching tentacle becomes
trapping one.
Breeding of jellyfishes usually includes alternation of generations: polypoid
and medusoid stages. The anchor jellyfish belongs to species at which the stage
of polyp is lost a long time ago. Jellyfishes of this species lay eggs, from
which pelagic planula larva hatches. Growing up, it at first leads mobile life
under the carpet of seaweed, where there is a lot of food and few plankton
predatory animals. Having reached the diameter about 3 cm, young jellyfish
passes to sedentary habit of life. Life expectancy of this species does not
exceed three months.