Tour to Neocene
This chapter is based on the idea of Timothy Donald Morris.
New Zealand, or Aotearoa, that means “The Land of Long White
Cloud” translated from Maori language, turned to isolated island in Mesozoic
era. It also remained an island in human epoch, and 25 million of years, separating
Neocene from the era of human domination, have changed nothing in this order
of things. This archipelago is still separated from other continents by vast
spaces of Pacific Ocean. New Zealand gradually moves to the north in common
with Meganesia, being shifted by Antarctica moving from the south. Pacific Ocean
determines the climate of these islands – it is very humid and rather warm.
Because of ocean influence the island summer is cooler a little bit compared
to the continents at the same latitude, but winter is rather mild – only at
the Southern Island a year there are morning frosts for some weeks. In Neocene
in New Zealand snow has remained only at mountain tops.
Humid climate, appeared under the influence of the ocean, favors to growth of forests. In eastern part of islands forests are more damp, and there huge gymnosperm kauri trees, or dammars (Agathis) dominate; and under their forest canopy low tree ferns develop. Drier forests on western slopes, differing in rather thin canopy, are plentifully grown with prickly bushes – low growing species of conifers and descendants of blackberry introduced to the islands by people a long time ago. For the western slopes of islands palm groves are characteristic. At movement to the north the vegetation of New Zealand gets more features, characteristic for tropical flora. Coniferous trees are gradually replaced by broadleaf kinds of angiosperms, and also numerous perennial lianas with thick trunks appear.
The humid climate promotes the prosperity of epiphytes. In New Zealand plants of this life form can be seen everywhere – from cool mountain forests of Southern Island up to warm coasts at the north of the archipelago. On trunks and roots of huge trees rich cushions of mosses and tiny ferns with lacy fronds develop. Above them, in forest canopy, they are replaced by rich “beards” of lichens and bright “flower baskets” of orchids, which are obviously related to the Australian species. Climatic conditions at the edge of Holocene and Neocene did not favor to the survival of the majority of exotic kinds of plants introduced by people, and the local vegetation appeared mostly steady against intrusion of strangers.
The destiny of fauna of islands is more tragic, rather than destiny of flora. The unique fauna included relicts of early geological epoch and distinguished by high level of endemism has strongly suffered from the introducing of various species of animals. Due to the people in New Zealand ground-dwelling mammals have appeared, and they were completely alien to unique local fauna. Ungulates rendered significant influence to the mountain ecosystems – their activity in destruction of plants promoted the erosion of hillsides. And predatory mammal even in human epoch managed to exterminate a plenty of species of unique local birds and reptiles. But in general on New Zealand much more descendants of local kinds of animals and plants are present in comparison with a nature of other islands (for example, of Mauritius island).
Before the human colonization of New Zealand numerous kinds of flightless birds were typical for fauna of islands. It was the consequence of absence of mammals at the islands: birds had no enemies and competitors, and they could replace the herbivorous beasts. In human epoch the great number of wingless birds had died out, but some kinds managed to survive even among predatory mammal introduced by people. And one of these kinds managed not to survive simply in their shadow, but to evolve to the creature perfectly adapted to changed habitat.
The large bird slowly walks in the forest. This creature is very big, resembling some kinds of New Zealand moas extinct in human epoch, but much smaller compared to these huge birds. The body of this bird is covered with thin feathers more similar to mammalian wool – such feature is characteristic for birds lost ability to flight a long time ago. It is a ruacapangi, one of few descendants of native New Zealand species in Neocene fauna of islands. Its similarity to moas is very remote – these extinct feathery giants were silly herbivores, and ruacapangi is a true threat of local fauna, the furious predatory bird able to attack actually any animal living at the islands. Usually it eats smaller animals, finding them in underbrush. The bird easily catches them up, kills with one beak impact and swallows entirely, having thrown up before. Sometimes ruacapangi can attack larger animals – in New Zealand sheep descendants live, remarkable in large size and force, and ruacapangi eats their calves.
Searching for prey, bird cautiously steps on a carpet of rotten foliage, looking through lacy fern fronds forming rich thickets in underbrush. Bird watches cautiously, hoping to notice casually stirred frond which will give out presence of any smaller animal. Usually after that fast rush and exact impact of beak follow. Having noticed the moving among fern fronds, the bird cautiously creeps, keeping head hunched in shoulders. Its attention is extremely concentrated, and neck muscles are tensed – bird is ready to attack at any moment. The animal wandering in fern thickets obviously does not care about the possibility of being noticed: herbivores do not behave so. Some more cautious steps, and ruacapangi sees the animal, which presence had interested it.
In ferns the clumsy thickset creature having wool of brown color wanders. Small spots make this animal poorly distinct against the background of wood litter. But camouflage coloring of body contrasts with well appreciable coloring of head, which is covered with white wool with longitudinal black strips stretching from eyes to nose. This animal belongs to descendants of the animals introduced to New Zealand, and is named New Zealand unbadger. It is the omnivorous predator resembling the European badger, but descending from ferret. The animal digs wood litter with nose and paws, searching for small vertebrates, insects and snails. Having sniffed fern thickets, it begins digging out rotten foliage near one plant, and soon takes large snail from the ground. Having sniffed it, the animal cracks shell of a mollusk with one bite and chews pulp, spitting out splinters of shell. Keen on search of food, the animal does not suspect at all, that it became a subject of attention of predator itself. At such a moment unbadger has heard the suspicious rustle, turned back and has seen ruacapangi cautiously coming closer to it. If it will run, ruacapangi will easily catch it up, and the impact of beak of pursuing bird can simply break beast’s backbone. Therefore unbadger preferred demonstration of force rather than a pursuit. The animal presses ears against head sides – it gives out a mix of fear and threat in a condition of the animal. Having risen on hind legs, unbadger displays threat to predatory bird: it fluffs “whiskers” of long wool on sides of heads to look larger. Black strips are perfectly visible on the background of almost white wool of head, and any predator decided to have fight with it will remember this coloring, having received a strong bite. Beast growls and makes lunges by paws directed to the bird, forcing ruacapangi to recede. But unbadger itself is afraid of combat and recedes slowly to roots of tree, where there is one of spare entrances to its hole. Ruacapangi is stronger than it, and the animal can not defend for too long time. Ruacapangi also does not wish to get unnecessary wounds from this animal, therefore attacks not as intensively as it could. At last, unbadger reaches an entrance to the hole, turns around instantly and hides inside it. The bird does not pursue it: it is useless business. Ruacapangi must search for another prey, but it will not remain hungry: another animals inhabit forests of islands – defenseless and tasty ones.
Ruacapangi continues walking in forest, searching for food. The attention of bird is not escaped with the attributes indicating presence of other smaller ground-dwelling animals. Movement in ferns and rustling of foliage cause bird to stop and to look attentively. Ruacapangi sees a small mammal with rounded ears eating plants and filling with food its well-advanced cheek pouches. It is one more descendant of the people-introduced species named castle rabbit. This animal is young, that is appreciable from pale strips on its cheeks, having only slightly lighter shade compared to another parts of the body. It seems the animal is too deeply occupied with gathering of plants: it bites off fern fronds and pushes them into cheek pouches with forepaws. Ruacapangi often preyed such animals – castle rabbits are numerous in forests of New Zealand. The bird steps on the ground cautiously, creeping to the rabbit, and then accelerates speed sharply and attacks.
The rabbit can be as much as strongly occupied with gathering of food, but for millions years of evolution it had developed one important feature: very wide field of vision. Just in time it has noticed the attacking ruacapangi and has instantly rushed away from it. The rabbit escapes in way characteristic to hares, sharply winding among trees and jumping among the roots rising above the ground. Its intention is simple: this way massive long-legged ruacapangi lags behind appreciably. But ruacapangi has a feature not present at the rabbit – it’s an endurance. The bird is able to pursue its prey for longer time, than rabbit is able to support such speed of run. And moreover, castle rabbit is rather short-legged creature. Therefore chances of the escape for the rabbit are insignificant even in this case.
The ruacapangi’s chase has frightened away some more rabbits of the same species and of about the same with the animal chased by bird. The pursuit goes on in bushes, but ruacapangi does not lag behind the rabbit: beast hears footfall of huge bird behind. This sound is closer and closer, and ruacapangi almost overtakes the rabbit, having not reaching up to it only some centimeters by beak. Castle rabbit already began to exhaust, but it precisely knew, what way it needs to run to be escaped. Suddenly the rabbit as if vanished: it has disappeared in one of the numerous holes dug out in forest. The massive bird has stopped after mad race not immediately: having made some more steps, it has returned to the hole in which the rabbit disappeared so unexpectedly. Ruacapangi has not refused yet the desire to eat the rabbit: it looks into the hole by one eye, and then tries to dig this hole out. The bird pecks edges of the hole and throws out falling off lumps of the ground by foot. But its efforts are vain: the hole is already empty for a long time, and the rabbit managed to move along the underground tunnel far from this dangerous place. Having pecked the ground and having dug out about half-meter of the rabbit tunnel, ruacapangi leaves to search for any other prey. Sooner or later this bird will manage to prey such rabbit for the meal – they may be met frequently in forest, and it is one of numerous species of Neocene mammals of New Zealand.
Under roots of trees the complex and diverse underground world is stretched, and in some places of the forest the ground is literally pored with holes. Inside them castle rabbits constantly scurry – these are the main builders and inhabitants of these holes. The rabbit escaped from ruacapangi is only one of inhabitants of the whole labyrinth of holes. Having recovered its breath after the escape from a predatory bird, it moves along the tunnel and soon is literally poured in the live stream of numerous rabbits moving in holes, and loses its individuality. It represents only a small part of the numerous colony of this species living at the given area of the forest.
Holes of castle rabbits stretch to tens meters in some directions, but they have the unite center. At one wood glade the construction similar to the termitary towers, reaching the height of about five meters. The stones and branches built in walls, and also wide holes penetrating this construction indicate that builders of such constructions are much larger than insects are. The whole construction is created by activity of castle rabbits and represents the center of their colony. In this forest such large colony is only one at the area of approximately four square kilometers. At the same area there are also two or three small colonies founded only two years ago. Sometime one of these small colonies will become as big, as this one is, and this colony will be devastated by illnesses and destroyed by time and elements.
While the colony is healthy and strong, construction represents true rabbit “castle”. In the center of the “core” of the colony the main high construction is located – it is an old rendered habitable colony, from which the growth of this settlement began. The colony is many years old now; each generation builds on and increases walls of the “castle”. In walls of this construction many entrances open, and from the top downward it is penetrated by ventilating shaft with a screw exit to the top of the building. Near the main construction some more “watchtowers” of approximately two-meter height rise. Constructions are strengthened thoroughly – from walls gnawed branches stick out, and here and there even stones weighting about half kilogram are walled. On the surface construction is covered with clay thrown out from underground holes and stamped densely by paws of numerous rabbits. Near the basis of a colony flat stones lay, which rabbits could not turn or drag aside. But they are also were useful: some entrances to the colony open right near them. Massive stones prevent a predator to dig out a hole to penetrate into dwelling of rabbits. Walls of construction are free of grass – they are stamped so densely, that the grass is simply not able to sprout through them.
Colony of castle rabbit has a complex social system and separating to castes. But, as against ants, the caste belonging of each animal is not predetermined to all further life –the social status of each individual changes according the age. In forest exclusively young individuals engaged in food gathering may be met – the foragers of the colony. They have low social status, and they pay “bloody tribute” to numerous forest predators. These individuals are busy in food gathering for a colony, and bring food to the extensive holes inside the colony – to the “pantries”. Sometimes in forest among foragers larger individuals may be seen. They are drifters, digging new underground tunnels to feeding areas. Drifters dominate above foragers, and on their cheeks the expressed white longitudinal strip is visible. More often males act as drifters. Some individuals do not dig holes in forest, but work in a colony, repairing tunnels and strengthening walls of the “castle”. Rabbits drag branches from forest and pull out stones from the ground. All this is put on the construction from above, and becomes covered by a layer of clay. And so walls of rabbit “castle” are gradually built on. Gradually in them the additional tunnels and living chambers appear.
When male grows up and gains strength, it looses the desire to dig holes and to take part in building. It becomes much stronger, than the individuals replaced it in holes and feeding areas, and then passes to the next caste – to “guards”. “Guards” differ in striped black-and-white cheeks – in their blood there is an increased level of testosterone, and it influences the color of wool on their cheeks. Large males of this caste keep near hole entrances, not passing out the borders of lived-in zone of a colony.
Smaller foraging individuals fill cheek pouches with food. This adaptation is typical for young individuals, and with aging, when the need for them will be gone, they will decrease. Having gathered the enough amount of food in forest, forager rabbits come back to the colony. When they come closer to any entrance, the sentinel male sniffs at each of them, defining their belonging to the colony. Having convinced, that there are no strangers among the foragers, it passes them inside the “castle”. Along the radial tunnel rabbits move down to one of the lower levels. Here in thickness of the ground spacious “pantry” is dug, where food stocks of the colony are stored temporarily. Earlier, when the colony was young, there was dam chamber here. But gradually “castle” had been built on, and adult females had moved to the top levels, and in the empty chamber “pantry” had been arranged. Foragers feel a strong smell of rotten vegetation – this colony gathers plenty of food, and it is not eaten entirely. The rests of plants in a far corner, which is not reached by “castle” inhabitants, have already started to rot. But these rests also do not vanish: the set of small animals eating the rests of the rabbit food has settled in rabbit “pantry”. When foragers reach “pantry”, from under their feet numerous cockroaches run away. These tiresome insects have come crawling here from the forest and breed quietly in heat. But in colony of rabbits not only they live: here there are small predators preventing the breeding of cockroaches. From the ceiling of “pantry” rustle and crackling is heard – on it upside-down crickets hold, having seized the arch of the cave by claws. They regularly catch smaller cockroaches creeping on walls.
Forager rabbits exempt cheek pouches from food. In their mucous membrane there is no salivary glands, therefore grass brought by them is almost dry. When they leave, in “pantry” another rabbit appear – it is a young female. It is older a little compared to foragers, and some weeks ago diligently supplied this colony with food. But now its specialty is changed: young female has passed to the category of “servants” and has ceased to move outside the borders of colony. It sniffs at the food brought by foragers, choosing the freshest one. It has a crucial task – from it the quality of food eaten by adult females of the colony depends, and these ones continuously produce posterity. Having filled cheek pouches with food to the full, it leaves “pantry” and moves up to the dam chamber located above. This one of the safest places in a colony – this chamber is protected by thick walls from predators and is not filled in by water during the rains.
In the “castle” existing for many years in succession there are some extensive and well aired dam chambers with thick layer of litter, where nursing females live. It is the centre of reproduction of the colony – young animals are born only here. All sexually mature females of the colony live in dam chambers and never budge from the place. Adult females of castle rabbit can never see the sunlight. Their only occupation is to rear young growth all the time – to make the future foragers and guards of the colony. While they are full, the colony will not have lack of workers and defenders. If the nursing female is not pregnant, it is busy with bringing up of young growth, and not only its own ones, but also another’s. Such life demands a plenty of food, therefore young females from the stock of “servants” are constantly busy with delivery of forage. But one day they will be impregnated and will stay in dam chamber forever.
Despite of “imprisoning”, females can live much longer, than rabbits of other specialties. Among members of the colony there is one very old female, which lives in dam chamber among the younger ones. Its age is about eight years, and it is a last representative of one of the first generations of castle rabbits founded this colony. The muzzle of this female is turned grey, and she has tearing up eyes with cataracts. On the surface this old female would hardly live longer than one hour, having fallen a victim to predators; it is unable not only to search for food independently, but also simply to move. Old rabbit female is hardly capable to creep on weak shivering paws. But in dam chamber it is looked after: when old female utters the special sound similar to silent sucking, the young female from the number of “servants” runs to it immediately and starts feeding it from the mouth, giving the old female food from cheek pouches. Old female is still useful to a colony: though it lost the ability to give birth two years ago, it has kept the ability to nurse with milk. In fact due to such amplified care almost all infants survive.
Higher than dam chamber there are extensive “imperial apartments”. This place is occupied by the dominant couple, the strongest male and the strongest female of the colony. “King of the castle”, large male with striped black-and-white cheeks, is larger than any of “guards”: it is the rabbit weighting about 3 kilograms (the average “guard” weighs no more than 2 kg). Because of surplus of testosterone this male has bright cheeks with wide white strip, which is shaded with black not only from below (as at “guards”), but also from above: the area around of eyes is also dark. Dark coloring on the bottom side of head is stretched even to the lower jaw. Any rabbit, having met contrastingly colored “king”, will find it out even in twilight of tunnels.
“Queen” of a colony is a female – as large, as the “king” is. The “royal couple” lives separately from other rabbits, and does not need the services of the forager rabbits serving to the females in dam chamber. The dominant couple moves freely in the colony and from time to time appears on the surface. However, male stays in “imperial apartments” a little bit less often, than female: it regularly visits dam chamber, where searches by smell females ready to fertilization. It copulates with them and marks females, sprinkling them with its own urine. This feature of behavior is its exclusive right. Females of dam chamber couple also with males of “guard” caste, and sometimes even with young “builders”. But “king” keeps up the hierarchy, and all the time confirms the right to copulate with females of the colony, expelling subdominates from dam chamber. But nevertheless, despite of efforts from the side of the “king”, about the half of total number of infants represents the posterity of other males. The posterity of different males is brought up by females in common, therefore descendants of “king” and “builder”, grown up in dam chamber, have approximately equal chances for survival. And all the same in colony there are young animals, that are the undoubted descendants of the “king”: these are the infants brought by “queen”. Its posterity is a litter of large rabbit cubs, which can be twice larger than their coevals in the common chamber. The difference in size between infants is connected to different conditions of life. At females from dam chamber the permanent density results in stress; hormonal factors have the influence to the physical features of posterity. Large infants are born as a result of pregnancy of female outside of stress. The destiny of “royal” posterity develops more successfully, than at other rabbits: young animals quickly establish domination above the others. As a rule, they become “guards” of a high rank, and can even organize their own colonies.
An “imperial apartments” represent the safest part of the building. A dome of the colony is well fortified, working individuals constantly heap on it new sets of branches and clay. Pointed tips of branches stick out of the ground, and these tips are directed downwards, preventing any predator to rise on top of a building. Besides some tunnels open near to the top of the dome. As a rule, in these places large “guards” keep, which take part in protection of colony against feathery predators. At the top of construction the wide spiral tunnel serving at once as a corridor and ventilating shaft opens. It is also constantly protected by some large “guards”, which look around the vicinities of the colony.
Life around of the colony is in full swing all the day. Castle rabbits from the caste of builders constantly renew constructions, throwing out lumps of clay to the surface of the ground and tamping it with paws. Occasionally on the surface young female from the number of “servants” appears and throws out pieces of dirty litter from dam chamber. Tiny birds at once gather to such dust and begin hasty pecking of insects creeping away in all sides. Forager rabbits scurry along the tracks laid among grass. For many years tracks have already turned to flutes, and animals are half hidden in them from the detached onlooker. Some rabbits move to distant fodder grounds using underground galleries. These galleries stretch under the ground at the small depth. Near to the colony they are very wide, but in the distance from the colony they can turn so narrow, that in them two rabbits can hardly move in opposite directions. They stretch under the ground for hundreds meters, and on the surface of the ground, in secluded places under roots of trees, there are spare entrances to these galleries, in which animals hide in case of danger. To not be overtaken unawares, animals gather food in groups. While some foragers gather food, one of them observes of enemies. But in dense underbrush of New Zealand forests many foragers turn prey of various predators. As against fodder grounds, the colony is very well protected: some “guards” constantly watch the surrounding trees from tops of “castle” and “watchtowers”. Rabbits are not too clever, and escape mostly because the surrounding district is watched to a greater or lesser extent by all “guards”, because of what the sudden attack of a predator is improbable. But in “guerrilla war” their number loses to sharpness and cunning of the opponent.
Branches of young kauri tree move not only because of wind – in them the enemy of castle rabbits is hidden. Kauri grows near to a colony of rabbits, and from its branches it is perfectly visible how between constructions foragers scurry and some “guards” look around vicinities lazily, sitting on the dome of main “castle”. Kauri tree belongs to gymnosperm plants, but its branches are covered not with needles, but with wide leaves, which hide from sights of sentinel rabbits one of the cleverest predators of New Zealand. The large bird with plumage of green and brown shades is poorly visible in branches of tree, while observing for rabbits. The bird is hidden near the trunk to not give out itself by the moving of thin branches. It is one more descendant of native New Zealand species of birds – eagle kea, the large carnivorous parrot. It is dangerous to rabbits: the adult skilled bird knows many ways of hunting for these animals. Young eagle keas live with parents for a long time before they become completely ready to independent life. Parents train their posterity in ways of getting of food, and the acquired experience is gathered in generations, promoting a survival of these parrots in various habitats – from forests up to hillsides and the Alpine meadows. These parrots can concede to rabbits in speed, but much more surpass them in cunning. Eagle kea, observing of rabbits, does not hurry up to attack from air – there is a probability of the meeting with aggressive “guards”, which can bite a bird strongly by sharp incisors. If they will manage to press a predatory parrot to the ground, they can easily kill it – the “guards” of castle rabbits do not correspond in the behavior to a stereotype of the rabbit as peaceful and defenseless creature. Besides noise of the bird flying off from the crone of tree, will deprive it of advantage of a sudden attack. Therefore eagle kea tries not to frighten off rabbits, and passes to another way of hunting. The parrot flits from one branch to another, and then moves downwards the trunk, clinging with the help of paws and beak. It seems, it is not noticed: rabbits led usual life, and alert signals are not audible. Young forager individuals gather grass and leaves of bushes – they can fall easy prey of predatory parrot. Eagle kea moves down from tree and hides among ferns. The bird perfectly knows the area, and clearly remembers all rabbit exits from underground galleries at the territory. Parrot simply finds an entrance to the hole, hides near it and begins waiting. Due to soft plumage it is enough to this bird simply to stand in ferns to become absolutely invisible to the rabbit. The patience of eagle kea is renumerated in some minutes. From the hole rabbit appears cautiously. It looks around, smells air, and leaves a hole. It is followed by some more animal. Pale strips on cheeks indicate that these ones are foragers – individuals of low rank.
Eagle kea attacks the rabbit silently: by one jump the bird overtakes the animal, seizes its neck by beak from behind and bites off its backbone. The weak crunch is heard, and the body of the forager rabbit softens in the beak of carnivorous parrot. When last spasms of prey went down, eagle kea has dragged rabbit body far away from the colony to have a meal quietly.
Having left from the colony of rabbits, eagle kea has thrown the body of rabbit on the ground. Pointed beak of bird has easily cut skin of prey, and the parrot began tearing off pieces of meat and swallowing them hasty. Eagle keas eat any prey they can find – from small vertebrates up to bodies of large herbivores living in New Zealand. Millions years ago birds were the only predators of islands but when people introduced mammals to New Zealand, conditions for evolution of birds have changed. In Neocene predatory birds of islands are compelled to compete to local species of predatory mammals.
Sense of smell at the majority of bird species is poorly advanced, but this one of the main senses at mammals. The smell of blood of eagle kea’s prey draws attention of New Zealand unbadger. This massive mammal willingly eats carrion and at an opportunity attacks on other predators, winning over their prey. Relatively to its size New Zealand unbadger is surprisingly strong: its thickset body is very muscular. Having sniffed to the appetizing smell extending in underbrush, this animal hastens to receive the share of another’s prey.
Eagle kea has heard rustle of foliage and noise of steps sounding nearer. Having raised its head from prey, it has seen, that among bush a certain rather sizable animal walks in its direction. Eagle kea faces with attempts to take hold of its prey not for the first time. By experience the bird clearly understands, in what case the robber can be banished, and in what case it is better to recede, saving its own life. Therefore the bird begins watching the beast coming nearer, estimating its force. Just in case the bird is ready to fly up, but does not hasten to do it, trying to understand the real line-up of forces. At last, eagle kea sees the beast coming nearer and recollects the characteristic dark marks on light grey muzzle. Some times the bird managed to defend its prey, when the animals of the same kind laid claim on it, and therefore readiness to depart is replaced by intention to protect prey. The parrot stretches wings to look larger, and clicks its beak threateningly. Feathers on its head are fluffed up, and the bird looks even more impressively.
Until the last seconds unbadger imagined badly, what kind of creature it should clash for prey; therefore it was ready to attack every creature it will notice near the food. Some more jumps – and it have faced literally face to face with furious eagle kea. Any time ago the beast managed to drive away these birds from their prey; therefore readiness of parrot to protect its prey has not stopped the unbadger. It expected to frighten this bird by menacing grin and several warlike jumps in its side, but such dodges work only at a sudden attack when the bird hardly had time to understand what kind of enemy attacked it. However this time everything is different: the large predatory parrot even does not try to fly off, but only hissed shrilly, when the predator has appeared from bushes. The smell of torn-apart rabbit body has stimulated the unbadger’s appetite, and the beast has decided to catch eagle kea’s prey. Unbadger instinctively sprinkles smelly liquid from anal glands on the ground, and in air the pungent smell is spread. In case of trying to reave prey at any animal with well advanced sense of smell, this dodge would work very successfully. But at parrot sense of smell is very poorly advanced, and the predator’s “secret weapon” obviously has no effect to it. Having fluffed wool on nape and having grinned, unbadger walked around eagle kea, and the bird, having covered its prey by wings, continuously kept it up, having slightly opened its beak. In reply to unbadger’s growl eagle kea uttered unpleasant gnashing cry, extending its neck every time when unbadger approached too close to its prey. Both animals do not want to recede, and their conflict could be delayed. But one unbadger’s fatal mistake determines the outcome of struggle: the beast has tried to take away bird’s prey, has rushed to rabbit body and has pulled it to itself. But in reply to it the parrot has put to it only one impact by beak. Eagle kea’s pointed upper mandible is perfectly adapted to tear meat, therefore the resulted wound has turned out rather deep and painful. Unbadger is compelled to recede: on its nose a deep scar bleeds, and the bird had not wounded its eye only casually. Such traumas are inadmissible for a predator – it would make the beast unable to hunt. Therefore unbadger turns around and hides in bushes. Having convinced, that nobody else is going to interrupt its dinner, eagle kea continues its feeding.
Small animals have lots of enemies. Castle rabbits are partly protected from them due to their building activity – strong walls of the “castle” stop a part of predators and give animals a shelter in a case of acts of nature. But even under protection of strong walls of their shelter castle rabbits can not feel like in the perfect safety. In their dwelling there is a special environment – air is warm and humid because of breath of numerous animals, and tunnels are rather dark and quiet in comparison with forest. Therefore a plenty of species of small invertebrates and vertebrates had found a shelter within walls of rabbit “castles”. Among them there are certain species using the rabbit constructions only as temporary habitation, and also those ones which does not live in other habitats at all. Some species find in the rabbit dwelling not only shelter, but also food. And the presence of some animals does not stay unnoticed for castle rabbits.
Castle rabbit from the number of “guards” is scratching against the wall of hole. In its wool flat brown insects covered with thin hair creep – these are the rabbit bugs. These descendants of the bed bug appeared at the islands in human epoch have lost a habitual inhabitancy when people disappeared, but had found the new home in mammalian holes. And in constructions of castle rabbits they evolved to the new species, the specific parasite of rabbits. These insects feed on rabbit blood at any stage of development. During the sting in wound put by insect’s proboscis the saliva gets, rendering expressed irritating action. Stings itch for a long time, and the skin begins itching strongly. The rabbit tormented by parasites loses appetite and wariness. Trying to get rid of insects and to appease a pain somehow, the animal constantly scratches against floor and walls of the chamber. When rabbits touch each other, insects easily pass from one animal to another. Populations of parasitic insects exist in each colony of castle rabbit – they get there on founder animals moving from colonies growing old. The specific structure of parasitocenosis may vary – in one colony bugs may dominate, and in another one various ticks settle. Each day in wool of forager rabbits parasitic ticks from the forest get to the colony.
So numerous and diverse parasites could exhaust rabbits in their own holes. But in a nature such situation can not develop simply, because parasites themselves turn to the food to other kinds of insects. The litter of rabbit shelters in the bottom part of the colony, where working individuals and adult rabbits of the lowest rank live, is literally infested with insects. Air in such chambers is poorly ventilated and is constantly warm – it favors to breeding of insects. But abundance of small live prey attracts predatory insects, and some of them are characteristic only for colonies of castle rabbit.
As if live ink jet, in litter the shiny black insect with long flexible body creeps. Raising its head, it moves in air with short antennae, defining the presence of prey by smell, and then continues its searches. Despite of long worm-like body this creature is a beetle named cleaning rove beetle. This beetle is comfortable in damp close air of the bottom levels of the rabbit colony. It feeds on bugs which hide in litter and on walls of living chamber. Worm-like beetle is capable to penetrate into the narrowest cracks, where bugs hide especially often, when filled with blood. Larva of this beetle lives in rabbit wool, exterminating smaller parasites, especially ticks and bug nymphs. Its thin body slides between hair of rabbit skin, and it is very difficult for parasites to escape from it.
The places of the rabbit body most vulnerable for parasites are its ears. The skin on inner side of ears is hairless, and outer side is covered with thin short wool. Blood vessels are located close to the body surface and are easily accessible to parasites. Bugs and ticks stick to rabbit ears more often. These animals put proboscis in blood vessel, and are strongly fixed with its help on skin of animal. Parasites suck lots of blood, their abdomens inflate, and through the stretched covers the exhausted blood appears visible. It is rather difficult to clean off the stuck parasite, and the torn off head or proboscis remained in the wound can cause a suppuration. Larvae of cleaning rove beetles help rabbits to get rid from bloodsuckers. Using sharp mandibles, which tips are bent downwards, they accurately pull out from skin of the rabbit bugs and ticks with their proboscises, and immediately kill them.
Under vaults of holes, and more often on ceilings of living chambers, the blind crickets of a separate species keep – they do live anywhere, except for settlements of castle rabbit. These ones are upside-down crickets, creatures having strong legs, long antennae and rather furious behavior. They catch the insects gathering in rabbit holes – both constant inhabitants of the colony and casual “visitors”. These crickets spend the whole life, having turned back down, hence their name.
Usually on ceilings of holes large moths spend the daytime – crickets often hunt them. With the help of long antennae cricket feels a smell of the insect, and begins creeping to it. When the distance to the moth is rather short, the cricket seizes ceiling with back pair of legs and sharply straightens them, pressing the moth to the ceiling from below by two forward pairs of walking legs. When the insect is caught, the cricket hangs from the ceiling, keeping on it with rear legs, kills its prey with several bites and starts eating it, holding with front legs. After its hunting only dry inedible wings of torn off insect fall down. For breeding crickets prefer to move to the bottom levels of holes, where air is more humid and warm. Here females lay eggs, placing them in cracks on a ceiling with the help of long ovipositor. In thickness of the shelter small crickets are in safety, and their prey comes crawling to them itself – in cracks bugs and ticks hide, and they eat them.
Dam chambers of rabbit “castle” represent one more place where rabbit parasites and symbionts gather. In these rooms numerous females continuously brings up posterity, not leaving for a long time from this chamber. In litter of dam chamber various small insects swarm. Some ones eat the rests of plants making the litter, others eat wool which rabbit females pull out from themselves to make the litter for infants, and the third ones eat blood of rabbits. Small fleas lop on animals, and their larvae also develop here, in litter layer. Females scratch frequently – they are attacked by fleas and rabbit bugs. Young females from the number of “servants” diligently support cleanliness in dam chamber – they pull out pieces of dirty litter to the surface, and replace it with fresh one. But not their work, but larvae of cleaning rove beetle do not give fleas to eat rabbits in dam chamber alive. Rove beetles and their larvae catch parasites all day and night.
In a hole the mosquitoes involved with a smell of animals and their heat fly frequently. They feed on rabbits, and have a rest right on a ceiling above them. But it is unsafe for them: in the neighborhood with them on ceiling upside-down crickets keep. Despite of visible awkwardness, they catch mosquitoes and devour them. Easier young crickets succeed in it especially.
Adult life of castle rabbit females passes in dam chamber, where they raise posterity. They support cleanliness of the litter, leaving their droppings in one corner, where the deep “lavatory” hole is specially dug. For rabbits the phenomenon of coprophagy – eating of their own dung – is typical. But they eat not every piece of dung. In their caecum the special dung is formed – a product of processing of grass by the numerous bacteria living in this gut. It is rich in nutrients and vitamins, therefore rabbits at once eat it. And other droppings, not suitable for “secondary processing”, they leave in “lavatory”. Wishing to empty its intestines, female turns its back to the edge of a lavatory, and its dung is dumped downwards. It would seem, at an abundance of rabbit females in dam chamber “lavatory” should be filled soon up to its edges, but it does not happen. Rabbits do not clean their droppings – in colony there are other animals engaged in it.
On walls of “lavatory” shiny small beetles of rounded shape creep. They gather actively when feeling the smell of fresh droppings, and some of them even land right on the body of the rabbit visiting “lavatory”, trying to pick up the ball of its droppings. These ones are natural cleaners of animal droppings, sanitary dung beetles. Females of these beetles, distinguished from males in larger size and olive coloring of elytra, are interested in rabbit dung especially actively. Males with golden elytra keep above the females, almost on the ceiling of chamber. They only occasionally fly downwards to have a meal and copulate with female.
When in “lavatory” traces of the presence of the next rabbit appear, beetle females react to this event very actively. They gather near the rabbit droppings and take it away quickly. The nature has helped them a little bit: rabbits leave their feces already as balls, and beetles should not mould and roll dung balls, as, for example, scarab beetles of Holocene epoch did. Every female takes a dung ball with rear legs and carries it away, having lifted it above itself. One such female, managed to get such “treasure”, is followed by some more beetles attracted by smell of fresh dung. Among applicants for dung ball there is even one male, but it does not interest this female: it is already impregnated and prepares to lay an egg. It creeps away upwards on a wall, seizing dung ball in rear pair of legs. When one of beetles almost catches it up, on its back one more female lands, and between beetles fight is fastened. Pushing away each other from the dung not belonging to them yet, two beetles fall from the wall right into the “lavatory”. Having established their relations, they get out of a dung layer one by one, and begin cleaning themselves. Having freshened themselves up hastily, insects fly up on the wall above “lavatory” and wait for new portions of droppings.
At this time female with a ball of droppings in legs has crawled away from the general congestion of beetles to one of the corridors next to “lavatory”. It has climbed on wall and has started the important occupation – the laying of the new egg. Female of sanitary dung beetle “pins” the dung ball on tip of its abdomen and lays egg into it. Rabbit dung will be the first food for beetle larva. But it will need to develop in a quiet place, and female is ready to provide its larva with habitation. On its head there are the strong thorns sticking out forward and in sides. Holding the dung ball with the laid egg in rear legs, the insect keeps against the wall of rabbit hole by two pairs of walking legs, and digs small mine in wall using its own head. When the mine is of necessary depth, female turns back to it, pushes into it accurately dung ball with egg inside and slightly fills up a surface of wall near to its mine, masking its location. Many sanitary dung beetles breed in holes of the castle rabbit, and in some places, where rabbits arrange their “lavatories”, walls are pitted with beetle mines. Near to the mine made by sanitary dung beetle female there is one similar mine. About two weeks ago another female has buried in it a dung ball with its egg, and now the grub leaves a mine. It had hatched safely from egg and had eaten a stock of dung left by its mother. Sanitary dung beetles do not provide their posterity with a full stock of forage, but have higher fertility compared to other dung beetle species. From the certain moment of development grub of this beetle should care of itself. It gets out of a hole, falls downwards and creeps in hole to the rabbit “lavatory”, being guided by smell sense. When grown up, it will leave “lavatory” to pupate somewhere in a hole which rabbits use seldom. At the bottom of “lavatory” grubs of various ages creep all the time, eating rabbit droppings, therefore rabbits can not care of cleanliness of the dwelling.
Some grubs creep in litter of dam chambers, eating the dung left by rabbit infants. In this case a competition between them is not so great, but they are trapped with other dangers. “Tramp” grubs may be crushed at casual movement of rabbits in dam chamber. In addition they risk to be eaten – near to them thin larvae of rove beetles creep. Rove beetle larva is smaller than dung beetle grub, but is stronger. Also it is a furious predator, like the adult beetle, and sanitary dung beetle grubs often enter its menu.
Dung beetle grub creeps slowly – it has rather short legs. On the tip of the body of this grub there is a firm chitinous plate with denticles on the bottom edge: with its help grub pushes from the ground. But it can not compete in speed and armament with rove beetle larva, which moves with the help of strong legs, and has pointed and hooked mandibles. Like a wolf, it prowls about in chamber litter, searching for grubs and flea larvae. Having overtaken dung beetle grub, rove beetle larva attacks it, twisting its body around prey. Two larvae, white and black, roll in chamber litter and wriggle, but outcome of struggle is predetermined beforehand. Larva of cleaning rove beetle bites dung beetle grub in throat, thus breaking off its nerve cord by mandibles. Dung beetle grub at once softens lifelessly, and the predator drags off its prey to quieter place, and there eats it.
Numerous insects and other invertebrates settle in constructions of castle rabbit, but they represent only a part of its “lodgers”. Larger inhabitants of rabbit “castles” are lizards and birds of various species. Birds nest in upper levels, occupying seldom used holes and even reconstructing them to the taste. As a rule, in rabbit construction parakeets and small passerine birds settle. But these ones are only temporary inhabitants of a colony – when fledglings leave nests, they leave “castle” and fly out to the forest. And among reptiles there is one constant inhabitant of colonies – small cat-eyed gecko. This lizard can pass the whole life cycle in the same colony of rabbits. Here it finds excellent shelter from various small predators, and set of edible insects, constantly breeding in dwelling of rabbits.
Similarly to the majority of geckos, cat-eyed gecko is a nocturnal reptile. In day time these lizards are cautious: they try to avoid meetings with castle rabbits and hide in rarely visited parts of holes. Sometimes these geckos use characteristic for them ability to climb on ceiling, and move in “castle”, not facing with rabbits. These lizards have kept love to fresh air, therefore they do not move down to the bottom levels of holes, where the ventilation is bad. But these lizards are often guests on walls of dam chamber and in “imperial apartments”. Some individuals constantly keep in ventilating holes of the colony.
When there comes evening, forager rabbits gradually begin gathering within the walls of the common dwelling. The colony prepares for dream, and animals have a rest after the intense day. Guardian rabbits with expressed strips on cheeks also leave holes, that had been under their protection. Occasionally among them it is possible to see even the “king”, which moves to the surface for a short time. “King” cares of strengthening of its position in the colony; therefore it constantly forces the subordinated individuals to render to it the signs of submission – “king” bites them or displays its incisors.
Castle rabbits heat in beams of setting sun making the way through branches of trees. “King” of the colony occupies the best position – on the western slope of the colony, where sun beams heat for longer time. It is surrounded by massive “guards”, and there is always a hole near it, where it is possible to hide from a sudden attack. “King” allows itself to relax: it dozes in sunlight, scratching when insects creep in its wool.
Near to rabbits cat-eyed geckos crawl. In the evening these black lizards with white marks creep out to hole entrances. They are heated in beams of setting sun, and catch the insects gathering near to rabbits. All of this proceeds no longer than half an hour. When sky darkens, rabbits one by one leave walls of “castle” and hide in holes. Lizards stay outside a little bit longer: they crawl for some time between the stones heated up by sun, and lay on them, having stretched paws in sides.
The New Zealand evenings resound by calls of various nocturnal animals: crickets spin out their endless monotonous songs, and cicadas utter prolonged rattle. Males of cat-eyed geckos join their voices to night concert: they rise on stones, and begin “croaking”: their voice represents a series of abrupt short sounds. With the help of this call male declares to contenders its presence, and also invites female to pairing. The courtship season at these lizards proceeds actually till the whole summer, and also includes the most part of spring and an autumn.
At night life in the “castle” does not stop, though rabbits gather in living chambers and sleep. The empty holes fill with life again, but now not rabbits, but other animals live there. On walls of holes cat-eyed geckos creep and on ceilings upside-down crickets move quickly. Insects and lizards prefer not to face with each other: geckos eat small crickets, and crickets can attack on newborn geckos. Cat-eyed gecko belongs to the number of viviparous reptiles. Females of this species rise to posterity right in holes. Young individuals are independent since the first minutes of life: they at once abandon mother and search for good shelter where they will live until they will grow up a little. Young geckos frequently travel in thickness of construction of castle rabbit, where branches lay loose and form cavities. The young geckos are more cautious than adults, and leave shelter only when there are no adult individuals beside.
When on the surface the evening dawn dies away and air becomes cooler, blind upside down crickets begin chirring. Their murmuring sounds are gentler, than loud singing of wood crickets in vicinities of the “castle”. Geckos continue the unmelodious courtship calls, and therefore noise in “castle” will die away for a short time only in the early morning.
Surprisingly, but night noise in holes does not prevent rabbits to sleep. Having gathered in living chambers, rabbits sleep, having nestled to each other. They slightly turn and move with paws while dreaming, and whiskers and ears of animals pull. For thousand years of symbiosis with various loud-voiced animals multiple generations of rabbits have got used to night noise in holes. Nocturnal animals bring the great benefit to rabbits: they serve as natural sentinels. When they stop chirring and calling, alarm sets in rabbit holes: it means, the predator tries to penetrate into the settlement.
Night life of castle rabbit symbionts suddenly appears disturbed: suspicious noise from outside has silenced some crickets. One cat-eyed gecko uttered some “croaks” in the come silence and also subsided. Gradually the wave of alarm filled the whole dwelling of rabbits, and there the absolute silence has come, interrupted only by calls of nocturnal birds far in the forest. At this time every one, that did not sleep, have heard the sounds broken the rest of “castle” inhabitants: in bushes near to one “watchtower” snorting and puffing is heard. Then the thickset beast has left bushes, raised head and has sniffed. Not having heard sounds of alarm, it has continued movement and has stolen up to one of the nearest holes. New Zealand unbadger goes for hunting – this carnivore frequently visits rabbit “castles” at night. This animal is an expert in hunting in holes, and it would not be stopped even by well strengthened walls of rabbit “castle”. This strong animal can pull out branches from “castle” wall and roll away the stones, preventing this beast to penetrate into the hole.
In the silence set in the sound of a stone breaking out from
wall is heard. The beast undermines it, snuffling silently, and then hooks by
claws and pulls. The stone rolls down the slope of the rabbit settlement, and
the predator begins digging out a hole with its claws. Some strong movements
are enough – and the entrance to rabbit “castle” is dug out enough to make possible
to penetrate inside. The predator silently steals in tunnel, trying to not make
superfluous noise. It looks in the lateral holes opening to the gallery, searching
for suitable prey. In some places it finds only the holes leading to the lower
levels, or the “pantries” full of grass and roots. At last, the smell emitting
from one chamber indicates that the predator has found what it thirsted to find
most of all. In silence the shrill squeak is heard, and then it is broken sharply
– unbadger has found a hole where the scared half asleep rabbits have bunched,
and has seized young male, belonged yet to forager caste. Sharp teeth have bitten
through its skull, and the animal perished in few seconds. Nobody has come to
help it – in darkness courage of “guard” rabbits is replaced by fear, and they
do not leave their holes. In day time the colony of rabbits can easily drive
such predator away, but night separates animals and transforms an amicable colony
into a congestion of cowardly singles.
The night horror recedes: unbadger moves away using the same tunnel, via which it has come. It moves back, dragging killed rabbit seized in teeth. The instinct gradually gathers waking up “guard” rabbits to protection of the colony, and from one side tunnel the large “guard” with striped cheeks appears. It bites unbadger’s side and pulls its skin strongly with sharp incisors. In answer unbadger emits from anal glands a cloud of smelly secretions, and continues pulling the carcass of killed rabbit. It has no desire to combat and to get wounds, and a pungent smell represents good means to drive away “guard” rabbits, while they are half asleep.
The predator leaves with prey, but its smell remains in holes for a long time, reminding about the night incident. Rabbits from living chamber visited by unbadger move to another places – they can’t sleep, when in hole the suffocating smell of predator’s anal gland secretions is felt.
Gradually the colony calms down, and castle rabbits fall asleep again. And other animals continue their fussy life interrupted by predator’s visit. In the set in silence cat-eyed gecko gives shy voice. It “croaks”, but does it uncertainly, as if trying its voice. Then the reptile utters some calls in succession, and another male living in one of “watchtowers” joins it. And in some minutes all gecko males inhabiting the rabbit colony begin shrill muster. Upside-down crickets wave their antennae anxiously, creeping on ceiling of corridor, in which New Zealand unbadger had sprayed its liquid. But this smell does not mean danger for them, and soon males of this insect spin out an endless trill.
At first light nocturnal inhabitants of the rabbit colony hide in shelters. Rabbits wake up and sniff cautiously – they feel a smell of unbadger’s secretions and make their way aside the gallery visited by this beast at night. “Guard” males appear braver, rather than foragers – they gather in small group and check a tunnel, cautiously taking a view and sniffing at walls. The pungent smell of unbadger’s secretions may disguise the presence of other predators, which could penetrate into dwelling of rabbits imperceptibly and hide inside. But it is obvious, that the predator has left, and there is no danger. After “guard” males the group of working rabbits follows. These are males of low rank, which have grown from forager age, but are not enough strong and aggressive to become “guards”. These animals begin digging in tunnel the ground on which the smelly liquid of unbadger has got and throwing it out from the tunnel. Gradually the ground exhaling a smell frightening rabbits, appears on the surface of the colony, and other rabbits scatter it far away from the “castle”. But the entrance to the colony is destroyed by unbadger in great degree – the beast had turned out from the wall of a colony one large stone which had been pushed out on a surface at a deepening of a tunnel a very long time ago. That stone blocked an entrance to the “castle” to large predators, but now it has fallen down. Castle rabbits are insufficiently clever to lift it and to place back. They begin repairing an entrance with simple hereditarily programmed actions. Animals drag many branches on the damaged place and fill the ground atop of them. Within several hours above the dugout entrance the small heap of ground grows, under which the new entrance to the gallery is dug. The surrounding ground will be gradually trampled down by other rabbits, and this entrance will becomes almost same strong, as earlier. Working rabbits labor fast – the colony must be protected from predators at any time. While they restore and strengthen an entrance, there are some “guards” near them, ready to repulse any opponent, decided to attack colony at this moment.
Castle rabbit has lots of enemies, and one of the most dangerous of them is flightless bird ruacapangi. The single rabbit, even the strongest “guard”, is defenseless against this predator, and, most likely, will try to escape in flight. But if the bird has attacked a whole colony, many rabbits at once come to protect it, and their behavior changes. Being surrounded by congeners, each castle rabbit behaves much braver, and can attack resolutely any animal which it will consider as an enemy.
The family of ruacapangis wanders in forest – two adult birds and their chick search for food. Young ruacapangi had abandoned nest right after drying of it’s down, and during some weeks learns at parents how to search for food. Adult birds kill various insects and small reptiles with exact impacts of beaks, and offer them to their chick, holding prey in beaks. Usually the male is engaged in it, female hunts at this time. The chick eats prey killed by parents, and gradually tries to repeat their actions itself. Sometimes it takes dead animal from parent’s beak, throws it on the ground and simulates movements of adult birds during the hunting – it jumps on prey by legs, tries to peck it, throws up, jumps aside and turns around sharply. Young bird only plays yet, but some more months will pass, and these movements will acquire accuracy and become killing for various inhabitants of islands.
The family of predatory birds moves to dwelling of rabbits. Adult ruacapangis successfully attacked colonies of castle rabbits many times and are ready to repeat an attack this time. But earlier they met rather small colonies, which population did not render the essential repulse to birds. And the colony numbering some hundreds of adult and young individuals, represents the force which any predator should take into account. While even adult ruacapangis do not know about it – they have mastered this territory recently, and did not attack yet the large colony of castle rabbits.
Ruacapangi female slinks to the colony, hiding in bushes: it expects to prey a rabbit, having attacked suddenly from shelter. The bird cautiously steps on wood litter, having bent down to the ground not to be found out casually too soon. It has planned a suitable prey – the rabbit of “guard” caste, having the rest near to “watchtower”. The bird does not hurry up to attack: near the chosen rabbit there is one more beast looking around and able to notice ruacapangi casually. But “guard” behaves very carelessly: it is sure in its own safety and has a rest on the basis of construction heated up by sun, having extended paws and having closed eyes. The beast does not notice the moment, when its neighbor leaves, and stays to bask in sun. It does not see a predatory bird hidden in bushes nearby. Distance to it makes three jumps of an adult bird, and ruacapangi female decides to attack. It rushes out from bush, as if a whirlwind, breaking branches. But it literally had not a split second to overtake the rabbit – it jumped up in air with one strong bound, had pushed by hind legs from a wall of “watchtower” and jumped over the bird attacking it. Having fallen in grass, the rabbit has rushed to the nearest hole and has disappeared in it.
Presence of predators has ceased to be a secret for a colony. Sentinel from the top of one “watchtower” uttered an alarm signal when ruacapangi female rushed out from bushes, and the rabbits scurrying around of “castle” have rushed to the nearest holes. In few seconds vicinities of a colony have become deserted. Ruacapangi male and chick approached to the “castle”, and the family of birds began wandering around of dwelling of rabbits.
They examine attentively entrances to the colony and sometimes try to get hidden animals from holes. Birds cautiously push heads into holes to see, whether the rabbit or other inhabitant of their colony has hidden near to an entrance. However the colony is large enough and animals can hide far away from entrances, outside of reach of ruacapangi. Birds do not stop attempts to get anybody from construction: female tries to peck wider an entrance to the hole and to pick off the stone. It pecks strongly hole edges, and chick scurries near to her, imitating its movements. But the dwelling of rabbits is strong enough, and efforts of birds bring no result – they only break away small pieces of walls of rabbit “castle” by beaks. To reach rabbits with such speed they need to work some days in succession.
Of course, ruacapangis can’t give so much time to excavation of the rabbit dwelling. They will not manage to “besiege” the construction of castle rabbits even for some hours – birds will be prevented to do it. The lonely castle rabbit is defenseless against enemies, but the colony representing the “superorganism” is able to banish even larger animals. The first wave of fright has gone, and the besieged animals leave outside. But these daredevils are not small and young gatherers, but true defenders of the colony, “guards”, adult males with bright black-and-white cheeks. One by one they get out on the surface of “castle” and watch the birds destroying one of entrances. While there is a little number of them, they do it cautiously. But, noticing their congeners, “guards” behave more and more defiantly. They gradually leave holes and gather in small groups. Ruacapangi male wandered aside, while female tried to break an entrance to rabbit “castle”, and it had noticed the several rabbits looking at them. It has uttered a short alarm signal, and female has stopped useless occupation. When birds came out from the construction of rabbits and have looked around, they have seen numerous beasts around of themselves. “Guard” rabbits are obviously not going to escape, and ruacapangis vacillate in indecision: they do not attack animals not escaping from them. When one of birds comes too close to the group of rabbits, these beasts do not run away. They rise on hind legs, simultaneously display to it their incisors and growl threateningly. They even make some short steps towards the bird. Gradually around of birds numerous animals gather, and their boldness grows proportionally to their number. Ruacapangis do a mistake: instead of leaving vicinities of rabbits settlement immediately, they try to hunt. Male tries to peck one of the rabbits, sitting right in front of it. But this time the reaction of rabbits to ruacapangi’s attack is unexpected: animals begin counterattacking these birds. Having jumped aside from ruacapangi male, the rabbit unexpectedly rushes to its legs and bites the bird. It becomes a signal to attack – castle rabbits snatch on birds simultaneously. Jumping on ruacapangis, they try to bite their legs or featherless skin on throats. One rabbit has especially succeeded in defense – in one long jump it has overtaken ruacapangi chick and has seized plumage of young bird. Scared by such attack, ruacapangi chick has cried uneasily and has run, dragging on its body the “guard” rabbit, which has seized in its plumage by death grip. Female attacked by rabbits obeyed a parental instinct and has rushed to it to the help. It has put neat peck in skull of attacking rabbit, and has killed it on the spot.
Forces of predators and colony defenders are obviously unequal – the number of “guard” rabbits is more compared to ruacapangis, and they constantly run into birds, forcing them to recede. Step by step “guards” push ruacapangis from the colony to the side of forest. Birds understand that this hunt is failed, and defend from colony guardians not too intensively. At last, they turn around and leave in thickets with fast steps. Probably, sometime they will return to this colony and will take here their share. But it will be another time, and for now the victory has remained for defenders of the colony.
When predatory birds leave, rabbits hide in holes and have a rest after battle. Only few signs remind of the fight played here: ruacapangi feathers scattered near the “castle”, flocks the rabbit wool, drops of blood and huge three-toed footprints of feathery predators. And in grass the body of one “guard” killed by ruacapangi’s beak lays. Impact of bird’s beak has pierced its head through, and the animal has died instantly. Its place in hierarchy of the colony will not remain empty: one more rabbit from the number of grown up “builders” will pass to “guard” caste, and a colony will be well protected again.
Dead rabbit with the broken skull lays in grass. Its body involves not only the numerous flies hovering above it. Bushes at the edge of castle rabbits settlement move, and from them unbadger appears. This individual has no its own territory, and differs in leaner body compared to its “thrifty” relatives. “Tramp”, however, does not suffer from famine: it constantly accompanies with ruacapangi family and eats the rests of their prey. It frequently gnawed bones of large animals which feathery predators managed to slaughter. Having sniffed air, unbadger directed by slow gait right to the dead rabbit laying in grass. It has picked up the corpse of an animal and has dragged it in bushes. When unbadger will feel in safety, it will eat rabbit body almost entirely, having left only inedible pieces of skin. Due to mighty jaws this animal will easily chew even bones of prey.
Inhabitants of the “castle” return to habitual rhythm of life. The alarm passes, and rabbits gradually appear from holes. They are cautiously put out from shelters, look around and smell air cautiously. Having convinced, that predators have left their colony, rabbits move to the ground surface. In bushes the first gatherers appear, moving on search of forage. They are not afraid of repeated attack: now the forest is as safe as never, because predators seldom come back at once to the place where hunted.
Appearing of predators and collective defense represent strongest stress. Castle rabbits do not differ in great mind, but can die because of strong nervous overloads. Therefore “guard” males, leaving on the ground surface, begin behaving very strange. The whole “garrison” of the rabbit settlement has a rest – to relieve the stress guardian males play like infants. Some dominant individuals bound on the ground, having pulled up tails, as if competing in high jumps. Other “guards” roll on the ground and have dust baths, somersaulting in shallow holes near the basis of “watchtowers”. Some “guards” competed with each other in peace time for the best berths and forage, but now they diligently lick each other’s wool on heads. These actions are absolutely necessary for them – at overstrain “guards” can die from stress, and actions like this help them to relieve an exertion. Having had a rest, “guards” will be ready again to defense the colony against any animal which they will consider as dangerous for them.
Life of any herbivore terminates in teeth of predators more often, and only separate individuals may die from old age. Even for such fortified settlements, as “castle” of castle rabbit, this rule is true. But tactics of joint action shows excellent results, and helps animals to survive in the dangerous world.
rabbit (Sociolagus fortificator)
Order: Lagomorphs (Lagomorpha)
Family: Hares (Leporidae)
Habitat: New Zealand, woodlands on plains and in foothills.
The New Zealand fauna of pre-human epoch had been remarkable in antiquity and high degree of endemism. Many groups of animals usual for other places of the Earth were absent in it. But in human epoch the situation has appreciably changed: people have introduced to the islands the set of animal species alien to native flora and fauna. As a result the significant number of species of animals and plants of New Zealand appeared at the edge of extinction in human epoch. And after human disappearance descendants of the introduced animals began to evolve, not constrained by hunting and extermination from the side of people. Among the animals introduced to the islands there were rabbits (Oryctolagus cuninculus), whose descendants have developed unusual, but very effective strategy of survival.
The descendant of feral rabbits of New Zealand is a small species of rabbits living in numerous colonies. This kind of mammals builds extremely complex and extensive underground holes, in which living chambers, pantries and emergency exits exist. Entrances in holes open in barrows of mix of ground and excrements (hardening up to cement solidity), serving as fortifications and observation posts. Smaller barrows are only about half meter high, but the biggest ones, true “castles” penetrated with numerous holes for observation and ventilation, reach the height of up to four meters. The mix of dried dirt, excrements and urine with stones and branches hardens and forms the strong, cemented fortification. For the building activity the animal is named the castle rabbit.
This species is herbivorous animal. The largest representatives of this kind do not exceed the length of 30 cm. Castle rabbit has large big eyes located on sides of head, and also wide and rather short mobile ears. This species has many enemies, and the most effective way to protect against them is to notice and to hide from them in proper time under the ground. This animal has rather short paws, and concedes in speed to the common rabbit known in human epoch.
Wool of this animal is grey with brownish shade, lighter on stomach. On animal’s head there are “recognition marks” – white spots on cheeks. At the most aggressive animals they are larger and shaded with black strip along the edge. The size and contrast of such spots depend on amount of testosterone in animal’s blood.
Castle rabbit lives in numerous colonies, in which the certain social system is formed, including “diggers-foragers” (this is a role of young animals/subordinate individuals of both genders), “sires-guards” (mature/dominant males) and “dams-feeders-nurses” (mature/dominant females). The structure of caste system at castle rabbit is more similar to the structure existing at termites: the belonging to a certain caste is fixed not rigidly, and changes with aging.
About 2/3 of the number of colony is made of young individuals of both genders – diggers and foragers. They move to fodder sites and gather grass and roots, then pulling them to “pantries”. The majority of them lives in stress because of the expressed relations of domination from the part of adult individuals and settles at the edges of the colony.
Young males not reached yet sexual maturity are the animals engaged in digging of new tunnels and repair of constructions. They study to battle to enemies, spending a lot of time in physical play. Such animals live closer to the main colony.
The majority of adult males is made of aggressive “warriors”. They are able to feed themselves and spend a long time on the ground surface, but do not supply the colony with food. The part of them keeps skills of builders and repairs fortifications. “Builders” drag from the forest branches and strengthen entrances to the colony with stones dug out by younger “diggers”. Adult males can copulate with females and be the fathers of infants. The high level of testosterone in blood (and the higher aggression and bright black-and-white marks on cheeks as a consequence of it) results in behavior of these individuals: aggression of males is directed to the strangers appeared near the colony. They do not tolerate the presence of alien males in colony, and also drive predatory mammals and birds away from holes. Protecting the colony, “guard” males attack predators, gathering in groups. They jump up fiercely, trying to drop on back of predator and to seize it with sharp incisors. On the ground they interfere with penetration of a predator into holes and destruction of constructions. It happens, “guards” drive away from constructions even large animals like taurovis, which can destroy rabbit “castle” casually.
When young females become mature, they automatically pass to the caste of the “nurses” engaged exclusively in breeding and care of posterity. Having matured, they never leave on surface and young forager females feed them, bringing them forage from “pantries”. White marks on cheeks of adult females are very pale. The majority of females of “nurse” caste almost permanently are either pregnant or feed posterity. Even old females, being sterile for a long time, keep ability to produce milk and feed posterity of other females. They also lick young cubs of other’s litters and change litter in chambers, throwing it out to the common galleries. Main female of the colony permanently displays its domination to them by biting and pushing other females. Because of stress posterity of the majority of low rank females is small, but numerous (up to 7-9 infants) – these are future warriors and foragers.
Among breeding individuals the main “royal” pair is noticeable – the pair engaged almost exclusively in breeding. Main male is remarkable in large size and contrast black-and-white cheeks. It is almost not engaged in building or defense of the colony, but is an actual father of about the half of all infants born by females of “nurse” caste. It lives in depth of a hole, in well-fortified and ventilated “imperial chamber”, but regularly leaves it and pairs with the majority of females. Also it whenever possible prevents another males to copulate with females, banishing them from holes where “nurses” live.
Main female gives rise to lesser number of infants – it has only 3-5 ones in litter. But they are larger and stronger: these are the future founders of colonies and dominants. But all the same at such distinction of posterity expressed from the childhood, the caste belonging at castle rabbit is determined not only by status of parents, but also by conditions of life. Therefore one of strong “nurse” females can easily become main one and “depose” the former main female down to the status of simple “nurse”.
Various animals connected to this species by relations of symbiosis and parasitism live in the colony of castle rabbit. Parasites of castle rabbit include fleas of several species and ticks. Flea larvae live in dust at the bottom of chambers. Parasites are eaten by other inhabitants of colony – by blind crickets and beetle larvae. In some holes small songbirds and parakeets nest. One of permanent inhabitants of castle rabbit colonies is a small gecko. These animals do not represent any danger to the colony, therefore “guards” relate to them indifferently.
The idea about existence of this animal was proposed by Timothy Donald Morris, Adelaide, Australia.
Zealand unbadger (Enanthiomephitis nonmeles)
Order: Carnivores (Carnivora)
Family: Mustelids (Mustelidae)
Habitat: New Zealand, flatland forests and woodlands, mountain forests.
Picture by Alexander Smyslov
New Zealand is an archipelago of very ancient origin. These
islands were separated from Gondwana supercontinent at the end of Mesozoic,
therefore many representatives of terrestrial fauna not able to swim or to fly
simply could not reach this isolated world. Earlier at the islands ground-dwelling
mammals were absent: only pinnipeds and bats were native inhabitants of islands.
And the most part of ecological niches at the islands had been occupied by huge
flightless moa birds of various species. After the introducing of mammals to
the islands and after the extinction of people the new page of evolution of
fauna of these islands had been written. The fauna of island has lost the unique
features caused by isolation, and became more similar to fauna of continents.
Among the animals introduced to the islands there were some species of carnivores
of mustelid family. Presence and evolution of these predators have strongly
affected the ways of evolution of fauna of islands – in Neocene in fauna of
New Zealand there is very little number of ground-dwelling and flightless birds.
Mustelids have formed some species occupying various ecological niches.
One species of Neocene New Zealand predators, feeding on small ground-dwelling animals is New Zealand unbadger, which is very large descendant of the ferret (Mustela putoris) introduced to the islands. This is a massive mammal, little bit similar to badger, about one meter long. Coloring of animal’s head is striped, that gives to it the remote similarity to badgers: eyes are surrounded with dark strip, which prolongs forward as a dark strip along the nose bridge. Sides of head and forehead of animal are colored light grey, almost white, and nape is rusty-red. The lower jaw and chin of animal are dark. The wool on lateral parts of head is lengthened and forms “sidewhiskers” hiding short ears of animal. Body of New Zealand unbadger is thick and heavy, with short legs and short fluffy tail. Wool on the top part of animal’s body is brown with small spots on sides, stomach is colored lighter. But this animal differs from badger externally: its muzzle is short, with massive jaws, strong chewing muscles and wide crushing teeth.
The tail of unbadger is covered with very long white hair forming a rich tuft. Warning the enemy about intention to protect itself, this animal jerks it up and shakes. If the enemy continues attempts to attack this animal, unbadger protects itself with the help of smelly liquid secreting by anal glands. Beast sprinkles it in air, creating a smelly cloud, which smell is intolerable for sense of smell of mammalian predators. If this way of protection does not help, animal attacks the enemy and puts to it strong bites and wounds by forepaws.
In its habit of life New Zealand unbadger is remotely similar to its prototype from Eurasia and North America. It is ground-dwelling plantigrade animal, which is not able to climb trees, but digs the ground very well and builds deep holes. Claws of this mammal are very long; on forepaws they are thicker, rather than on rear legs.
New Zealand unbadger is omnivorous and unfastidious in choice of food. It eats with equal pleasure vegetable food (up to 40% of its diet) and various animals – from small reptiles and nestlings of ground birds up to carrion. With the help of strong paws New Zealand unbadger digs out of the ground roots and insect larvae. In ecosystems of New Zealand where limited island resources can’t support many species of the specialized predators, it fills a favourable ecological niche of “universal” omnivore. New Zealand unbadger frequently feeds on carrion or the rests of prey of other predators.
This mammal leads a solitary way of life. Every unbadger occupies territory of total space of about one square kilometer, where some holes are made, used by animal alternately. This animal digs holes by itself among roots of trees, in bushes or under stones. Depth of hole may reach 5-6 meters, and in it there may be some emergency exits. At the bottom of the hole there is a living chamber with litter of plant matter. When in hole parasites become too numerous, animal leaves it, moving to the next one. Borders of territory are necessarily marked with odorous secretions. Separately standing trees or large stones usually serve as boundary marks: on them some different animals leave labels simultaneously.
Seasonal prevalence in breeding of New Zealand unbadger is expressed only at the southern borders of an area, where female brings posterity only once a year. In tropical conditions on Northern Island of New Zealand female gives rise to posterity twice per one year. In litter at this species there are 2-3 well advanced cubs. They open eyes for the second day of life, and at week age begin leaving hole for games. At young animals front part of head is light, and dark marks appear to the time of sexual maturity at the beginning of the second year of life. Young animals remain with female up to 3-4-monthly age.
Life expectancy of New Zealand unbadger is about 25-30 years.
The idea about existence of this animal was proposed by Timothy Donald Morris, Adelaide, Australia.
gecko (Geogekko medialis)
Order: Squamates (Squamata), suborder Lizards (Lacertilia)
Family: Geckos (Gekkonidae)
Habitat: New Zealand, settlements of castle rabbit, tree-trunk hollows and other shelters.
Picture by Sauron from FurNation
With the occurrence in New Zealand of various predatory mammals
the herpetofauna of islands has suffered the big damage. Some kinds of reptiles
had become extinct forever, and others were compelled to change way of life
for the sake of survival. As the evolution proceeded, at the islands the new
kinds of reptiles have appeared, adapted to the neighborhood of various mammals,
and even taking from it the benefit for their own survival. One local mammal,
castle rabbit, lives in colonies in huge and well protected constructions –
“castles”. One species of New Zealand geckos has adapted to life in these constructions:
there it finds safe and warm habitation, and also plentiful nourishing meal
of insects settling in the neighborhood of rabbits.
This gecko is an insectivorous reptile about 20 cm long including long tail. Its very remarkable feature is large yellow eyes, shining in darkness like cat’s ones. This is an adaptation to life in conditions of insufficient illumination: geckos of this kind seldom leave holes of rabbits. Similarity to cat eyes is strengthened by vertical pupil; because of this feature the lizard is named cat-eyed gecko.
The shape of cat-eyed gecko is typical for these lizards. It has flattened body and rather wide head. The tail of this reptile makes about half of total length. In an autumn in its basis the fat necessary for successful wintering is gathered.
The majority of free-living geckos has bright and gaudy coloring, or on the contrary, is painted like color of an environment. Cat-eyed gecko is colored strict black with white spots on muzzle near eyes. Its throat is snow-white, due to what it is appreciable even in twilight of the rabbit hole. Displaying throat to each other, gecko males declare their rights to territory and females.
Cat-eyed gecko leads nocturnal way of life. These reptiles become more active in the evening, when castle rabbits gather to spend night. Lizards are heated in beams of setting sun, and then crawl away to holes. At night they are very active: at this time lizards hunt insects. This gecko has tenacious claws and cross corneous ridges of microscopic fibers on paws. Due to such adaptations lizard is able to run on vaults of holes and living chambers of the rabbit dwelling.
Despite of living in rabbits holes having rather constant microclimate, life of the lizard is subject to seasonal rhythms. Creeping out to the surface of rabbit dwelling, lizard feels seasonal changes in nature, and behaves in appropriate way. Winter in habitat of this gecko is not frosty, but cool, and within approximately two months in the mornings weak frosts happen. At this time gecko hides in depth of rabbit “castle” and winters on the ceiling of the deepest hole. Usually the lizard gets into suitable cracks of construction, but sometimes expands close shelter. In winter this gecko stays motionlessly in shelter and moves only being disturbed casually by other inhabitants of rabbit settlement.
In spring lizard gradually becomes more active and begins more active feeding, preparing to courtship season. It begins, when warm weather is finally established. In courtship season males utter loud sounds similar to frog croaking. They become aggressive, and between them fights are frequently fastened. Pairing occurs since late spring up to an early autumn. This species is viviparous; after the pregnancy continuing for about 3 months female rise to two rather large juveniles. Length of newborn gecko is about 6 cm. After late autumn pairing pregnancy is delayed for the period of wintering, and female brings posterity approximately in the middle of spring of the next year. Juveniles are more mobile, than adults: they do not have limited territory, and they settle more easily. Adult lizards display aggression in relation to juveniles; therefore young geckos usually leave colonies and settle using the tunnels built by rabbits. They can live in forest for certain time, outside of the rabbit colony (more often it happens at the north of an area), but to winter they should necessarily find a place suitable for life.
This kind of animals was discovered by Timothy Donald Morris, Adelaide, Australia.
rove beetle (Micragilisoma syncuninculus)
Order: Beetles (Coleoptera)
Family: Rove beetles (Staphylinidae)
Habitat: New Zealand, holes of predatory mammals and settlements of castle rabbit.
Symbiosis is a favorable strategy of survival which is used frequently by live organisms of various systematic groups. In this case two species, coexisted and connected in their life cycles, receive mutual benefit. Various cases of symbiosis arose repeatedly in various places of the Earth in due course of evolution, and in Neocene such strategy of survival has received the further spreading.
Castle rabbit settling in colonies lives in New Zealand and erects the strong constructions penetrated with set of tunnels. In the colony of castle rabbit there is a community of species of live organisms which can’t be met anywhere else. The important role in it is played by the predatory beetle about 2 cm long with thin long body – cleaning rove beetle. It settles in litter of living chambers in holes of this mammal. This beetle has found a favorable place for life: all rove beetles are hygrophilous and settle in places of increased air humidity, including holes of mammals. Cleaning rove beetle has passed from temporary use of holes as shelters to permanent life there. One more advantage from symbiosis of this beetle with rabbits is a constant presence of food sources: in holes of castle rabbit always live numerous small insects and their larvae. Some of them are parasites of rabbits (bugs, for example), others damage forage stocked by rabbits or simply live in holes.
Body of cleaner rove beetle is very thin and flexible, and head is narrow, with large mandibles directed forward. Such feature of anatomy permits this insect to creep freely in litter of rabbit holes, searching for parasites. This beetle almost constantly lives in darkness, therefore its eyes are small, and it searches for prey with the help of sense of smell. Wings at cleaning rove beetle are not present, only short elythra have remained. Insect has black color with metal shine, female is a little bit larger compared to male.
This insect lives in litter of rabbit nests and in the cracks penetrating the colony, eating various insects settling in the neighborhood with rabbits: crickets and cockroaches, flea and beetle larvae.
For egg laying female gets on body of the rabbit. It is easy for making: female ready to lay eggs creeps on the arch of hole, and waits while under it any rabbit will pass; it simply jumps off on its back. Female lays eggs on wool of animal, closer to the basis of hair. It chooses places where the rabbit scratches wool seldom – near root of tail or near the bases of ears. Freshly laid egg has sticky shell and attaches to hair easily; its incubation lasts 2-3 days. In total female lays about ten eggs on each animal; general fertility is up to 150-200 eggs.
Larva of early age lives on body of animal and eats ectoparasitic insects. Such feature was characteristic for some staphylinids of Holocene epoch. It brings special benefit by exterminating bugs and ticks deeply penetrating in top layer of skin (especially on ears of rabbits). Tips of larva mandibles are slightly bent downwards, and it easily pulls out the attached parasite. Its legs are well advanced, larva is able to creep and keeps for wool of rabbit at its movement on holes. Life of the larva in rabbit’s wool proceeds till about 2 weeks, and larva passes two moults on body of animal.
In advanced age cleaner rove beetle larva passes from animal to the hole and lives in litter and eats parasitic insects and casual inhabitants of holes of castle rabbit.
As this kind of beetles is not able to fly, it is settled only with the help of rabbits. Moving occurs at the stages of egg and larva, and the animals, leaving a colony, transfer them to other habitats.
Cleaner rove beetle is not unique Neocene beetle entered symbiotic relations with mammals. In South America narrow-sided fur beetle of leather-winged beetle family (Cantharidae) lives and settles directly in mammalian wool. It settles on large animals, and can pass the whole cycle of development on them.
dung beetle (Hygeiocopros sanitaris)
Order: Beetles (Coleoptera)
Family: Dung beetles (Geotrupidae)
Habitat: New Zealand, forests and woodlands, settlements of castle rabbit.
In the complex of species formed in holes of various animals, commensals and parasites are very numerous. In most cases the animals living in holes, leave their dung outside of the dwelling, therefore various coprophags do not enter so close relations with the host species. But in colonies of castle rabbit the situation is a little bit different: females engaged in reproduction are almost not shown on ground surface, and cleanliness in dam chambers is supported due to presence of special toilet chambers where they leave their dung. The special kind of dung beetles eating exclusively rabbit dung settles there. This insect is sanitary dung beetle, the descendant of certain species of beetles introduced to islands by people.
This insect is a small beetle (about 15 mm long) of robust constitution. Its body is of rounded shape, prothorax and elythra are strongly convex. Shins of legs are expanded, like at all species of dung beetles, and supplied with denticles on external edge. At females the rear pair of legs has the expanded distal ends of shins and is armed with claws and spur-like outgrowths. At danger this beetle draws legs in and closes with them the bottom part of body, turning to the armored ball. Its armor is firm to prevent predatory insects living near this one to bite through it. The body of sanitary dung beetle is covered with small amount of bristles and is colored brightly: elythra at females are olive, and at males golden with expressed metal shine. Head and prothorax at beetles of both genders are reddish-brown.
This beetle has small flat head on mobile strong neck; on front edge of a head five large denticles grow, being especially well advanced at females. With their help female digs mines in which it raises posterity. Antennae are short and fanlike; males have larger ones compared to females. When female digs mine, it folds antennae under head.
In spite of the fact that samitary dung beetle spends the most part of life in holes of castle rabbit, sight at this species is well advanced. From time to time insects abandon rabbit colony and search for new places for life. This way an exchange of genes between different populations takes place, and beetles can survive, if the rabbit colony perishes.
For copulation females involve males with smell. Attracted by smell of adult female, some males gather, and they may combat against each other for the opportunity of pairing. Beetles breed almost the year round with a break in some coldest winter days, when the temperature drops even inside the rabbit settlement.
Usually dung beetles gather a plenty of animal dung, enough for the grub to finish development completely. But this species represents the exception from the rule. Female lays eggs in rabbit droppings. It grasps a ball of fresh droppings in rear pair of legs (using for this purpose spurs on shins and tarsi) and carries it away from rabbit “lavatory”, preserving it from competitors. Then it lays one egg inside it, and, keeping dung ball with an egg, creeps on wall of the hole farther from the congestion of adult beetles. On wall it finds a deepening or digs small mine by head, and pushes in it egg with a ball of dung. In total for its whole life it lays in such a way up to three hundreds eggs.
In warm chambers made by rabbits the development of egg lasts for about one week. Grub quickly eats ball of droppings, creeps out of mine and then leads free life. As a rule, it falls directly in “lavatory” of rabbits and continues feeding on droppings. It looks like grubs of cockchafer, but its legs are rather longer, and it is more mobile. On the back end of sanitary dung beetle grub body there is well-developed corneous shield with denticles on the bottom edge. It helps grub to push from the ground at crawling. Grub can live in litter of nest, moving freely among animals. In case of anxiety grub quickly buries itself in the ground, using wide head as a shovel. For pupating it creeps away to the holes less visited by animals, and buries itself in wall of the hole. The pupa lays in ground in horizontal position, and its head is directed to the space of hole. Metamorphosis lasts for about three weeks.
bug (Paracimex cuniculivorus)
Order: Bugs (Hemiptera)
Family: Parasitic bugs (Cimicidae)
Habitat: New Zealand, colonies of castle rabbit.
Some kinds of insects have received colossal advantages from human activity. Some of them could increase their number sharply, becoming parasites and pests, others managed to settle in the most remote parts of the Earth, using transport, and the third ones had been settled by people on the Earth purposefully. When people disappeared, some synanthrope species had died out. But some species remarkable in wide specialization managed to go through ecological crisis of the boundary of epochs, and evolved then, becoming a part of new ecosystems.
In Neocene epoch in New Zealand many species of mammals live – these are descendants of the species introduced by people. Among them the small herbivore species – castle rabbit (Sociolagus fortificator) – is very interesting. This animal settles in numerous colonies and erects high and strong constructions penetrated with set of holes. In colonies the complete community including various symbiotes, commensals and parasites of this species of beasts is formed.
In parasitocenosis of rabbit settlements there is a species of bugs descended from bed bug (Cimex lectularius), a widespread species settled due to people in the whole world. It is named the rabbit bug as it is specialized to life in settlements of this rabbit.
Rabbit bug is small wingless insect about 3 mm long. Its body is flat, brown and covered with thin hair from above and bordered with hook-like bristles from the bottom side of abdomen. This adaptation helps to cling to rabbit wool when the insect is feeding. Rabbit bug not constantly lives on the host animal. It gets on it only for feeding, and the rest of the time keeps in cracks penetrating the whole construction of rabbits. This species is able to creep quickly and so escapes this way from other insects living in rabbit settlement. Rabbit bug develops in heat faster, and adheres to warm, constantly inhabited chambers.
This insect completely blind, but absence of sight is compensated by very keen sense of smell. Mouth parts of this kind represent pointed proboscis like at all bugs, which at not feeding insect is folded under body. Its length is approximately equal to length of insect body. Rabbit bug feeds exclusively on blood of warm-blooded animals, attacking castle rabbits and also birds settling in their constructions. For one feeding the average bug can exhaust as much blood, as it weighs. Its saliva causes irritation to rabbits; the bitten animal scratches a place of a sting, and the smell of blood involves new parasites.
In stable microclimate of the rabbit settlement this insect breeds almost the year round, except for several weeks in winter. Female lays 3-5 eggs daily in secluded places of nest. From them nymphs burst and actually at once attack rabbits. Before the molt nymph should suck the certain amount of blood. Development of this bug lasts for about one month; for this time nymph passes through 5 molts. Fertility of one female can make over 300 eggs per life, but a plenty of nymphs perishes from predatory insects.
Number of rabbits is subject to great fluctuations – sometimes it is reduced in tens times for 2-3 years because of illnesses or stress. When rabbits abandon their settlement or perish, the population of this insect degrades, but does not disappear completely. Adult insects and nymphs of early age usually perish. But grown-up nymphs survive and can wait for new prey for about one year and more. They run into a kind of catalepsy and leave this condition when feel a smell of warm-blooded animal.
At the islands close species of bugs live also:
Gecko bug (Paracimex gekkophilus) – a blood-sucking insect living in forest. This species leads more mobile life and feeds on blood of reptiles. Its length is about 4 mm; abdomen and thorax are expanded, body outlines are disc-like. The top part of body of this bug is smooth; on bottom there is a small amount of hair in the bases of legs. The insect lives in cracks of tree bark and waits for reptiles hiding under bark. This bug frequently attacks geckos and sometimes even clings to them and keeps directly on the lizard, moving on its body when the reptile tries to dump or catch this insect. As against the rabbit bug, this kind has advanced sight sense.
Cave bug (Paracimex cavernicolus) has returned to place where its ancestors lived – to caves. It eats blood of birds nesting there, and also attacks bats. This cautious insect up to 4 mm long hides in cracks and among dust at the bottom of cave. Cave bug is richly covered with hair and in addition puts on itself various dust for masking.
cricket (Invertogryllus caecus)
Order: Orthopters (Orthoptera)
Family: Crickets (Gryllidae)
Habitat: New Zealand, caves, holes of mammals, constructions of castle rabbit.
New Zealand fauna differs in originality – it is a result of long-term evolution in isolation from continental ecosystems. But people had broken the isolation continued for millions years, when they introduced to the islands a plenty of continental species. Due to rather soft climate the majority of the introduced species had successfully gone through extinction of mankind.
One of descendants of introduced species – castle rabbit – constructs complex dwellings with set of holes. Many species of small animals live in constructions of this mammal – reptiles, insects and other invertebrates are found there. Among permanent residents of its colonies there is one species of cricket – blind insect about 2 cm long with very long antennae (their length is up to 3 cm). It is a descendant of house cricket (Gryllus domesticus) introduced by people. This insect spends the most part of time on ceilings of holes, hence its name upside-down cricket. This is an insect of reddish-brown color with darker head and prothorax, massive constitution and strong legs. It is not able to jump, but its rear legs have all the same remained long and strong. This insect lives in darkness and completely lacks of sight sense: from eyes only two protuberances with rudimentary facets remain on each side of head. Absence of sight is compensated by keen hearing and sense of smell.
Upside-down cricket is a commensal of castle rabbits. It just lives in their holes, not contacting directly with rabbits. Occasionally this species settles in holes of other mammals, and can settle in warm caves (especially at the north of archipelago or in areas of volcanic activity).
Many species of crickets are vegetarians or omnivores. Upside-down cricket does not leave constructions of castle rabbit and does not require vegetative food: it is an active predator eating the insects living in constructions of castle кастеляна. Upside-down cricket attacks prey with exact throw, keeping itself on ceiling with the help of rear legs. Having seized them against the arch of hole, it straightens them and makes “throw”, seizing prey by two front pairs of legs. Cricket eats it also originally, hanging down on rear pair of legs and keeping prey by front legs.
Wings at this insect are reduced, but elythra have remained: males chirr with their help. Song of this species is similar to chirr of house cricket. For amplification of sound males choose a ceiling of large chambers. These insects are very sensitive to extraneous sounds: at anxiety they stop chirring.
Males are aggressive to each other. They find the opponent being guided by sound and smell; push it away from the chosen place, trying to push off the ceiling of hole. Sometimes larger male can even eat the contender.
Female is larger than male and differs from it in presence of long ovipositor. When laying eggs, it sticks ovipositor deeply in ceiling. The egg develops in safety in thickness of rabbit construction during 9-10 days. Young insects live in thickness of building, eating fungi and microscopic invertebrates. Having matured, nymph settles in holes and begins hunting like adult insects. At any stage of development for these insects cannibalism is characteristic. This insect turns to imago at the age of 5-6 months.
This cricket settles independently, moving in tunnels of rabbits made in the ground. Occasionally nymphs of younger age cling to wool of rabbits and are transferred by them to new colonies.