Photos of giant wood lice and description of the way of life of these huge creatures

News about the capture of more and larger specimens of wood lice in recent times constantly delight the scientific community. And when in messages it often began to slip information that the size of these creatures sometimes exceed half a meter, such giant woodlice began to attract the attention of ordinary citizens: is it a joke, because the huge woodlouse, whose length reaches 75 cm, is a real sensation.

However, an important nuance is that, in reality, giant wood lice are not at all usual for wood lice, living under the snags and fallen leaves in close proximity to the ground. These large creatures are deep-sea creatures: like ground lice, they belong to the order of decapod crayfish and have an appearance very similar to that of the wood lice itself.

The specificity of the "real" (small) woodlice lies precisely in their land, while the huge woodlice, which are caught at great depths by trawlers, evolved from sea crayfish, and none of their ancestors saw land.

On a note

However, certain types of "real" woodlice also successfully inhabit ponds. However, this happens only because these creatures, although living in water, have a land ancestor - they are secondary water.

Generally speaking, it is more correct to call huge deep-water wood lice as giant isopods. However, below we will call them simply giant woodlice, since it is this name that is more familiar to most readers.

So, giant woodlice - is a whole genus of crustaceans, in which today there are 9 species. The largest woodlouse in the world is the giant isopod Bathynomus giganteus, the largest of which was caught 76 cm long and weighed 1.7 kg. In general, woodlice that fall into deep-sea nets have a length of 15 to 40 cm.

Alphonse Edwards, a Frenchman who captured several young males in the Gulf of Mexico in 1979, became the discoverer of giant isopods.For a long time it was believed that giant woodlice live only in the Atlantic Ocean and its seas, but recent studies off the coast of Australia showed that these crustaceans also live in the Pacific and Indian oceans, differing little from each other in appearance and lifestyle.

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Huge woodlice were the first deep-sea creatures that zoologists could find. For science, it was a real revolution: until then it was believed that the great depths of the ocean were lifeless. The isopods gave impetus to the study of deep-water areas of the continental shelf and depressions in the oceans, and also expanded the understanding of scientists about the possibilities of adapting living things to extreme conditions of life.

 

What is the biggest woodlouse in the world?

Externally, the great wood louse strongly resembles its ordinary land relatives, sometimes called “watermelons” by the people.

However, its gigantic body has its own distinctive features:

1. The pronounced difference between isopods and small land relatives is the presence of a wide and long “tail” of several blades, which provides the ability to swim over short distances.Land lice do not have such a tail, but ordinary crayfish have one.
2. The paws of giant woodlice are armed with powerful claws, which, however, are not used for attack or defense. They are needed more for the convenience of moving on a clay or silty bottom.
3. Interestingly, giant woodlice have large eyes and good vision. It is not completely clear why it is for them in the depths at which they live, but the fact remains that they see giant isopods well.

In addition, in the event of danger, a large wood louse (as well as small land insects) may roll up into a ball, after which all areas of the abdomen that are soft and accessible to predators are protected by powerful exoskeleton plates.

 

Lifestyle and nutrition

The world's largest woodlice live at depths of 170 to 2000 meters. The greatest depth of their capture - 2140 meters.

These creatures prefer to settle on silty or clay soils, and avoid rocks and rock outcrops.

In their way of life, giant woodlice are loners, and only occasionally meet each other for mating. They do not show obvious hostility towards individuals of their own species, but they do not hold together either.

Giant isopods can rightly be called scavengers of the deep-sea seabed: their main food is the remnants of dead worms, fish, mollusks, crayfish, algae, and practically any other organic matter. If the woodlouse, in search of food, stumbles upon a colony of motionless underwater animals — sponges, radiolarians, sea cucumbers — she does not hesitate to eat them. Some experts believe that at large depths isopods can catch even small, slow-moving fish.

Given the extreme low population of the deep-sea bottom areas and the small amount of food available here, it becomes clear why isopods are accustomed to long-term hunger strikes. For example, in the experiment performed, these creatures placed in aquariums “fasted” for 8 weeks without harm to themselves.

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If the woodlouse nabdaet, for example, on a colony of sea cucumbers, it can overeat so that it almost loses the ability to move.

 

Reproduction Features of Giant Isopods

Breed giant woodlice in spring and winter. This is due to the fact that in the summer months the amount of food at great depths is significantly reduced.

After mating in the female isopod, a special brood bag appears on the abdomen, into which eggs enter from the oviduct, are fixed there and then develop. Young woodlice leave their mother's bag almost completely formed and differ only from adults in size.

Juveniles can live at the same depth as adults.

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The female does not show any concern for the young hatching from the eggs. For some time the larvae are just near the mother, and if they are born in a place with an abundance of food, they can linger on it for several days. But already from a very young age, the isopods are left to themselves and lead a completely independent lifestyle.

 

Why are they so big?

Scientists still can not unequivocally argue with what are the large sizes of deep-sea woodlice. One hypothesis states that because of the scarcity of fodder stocks at great depth, animals here reach puberty much later, and before this point they have time to grow to large sizes.

In accordance with another theory, the larger the body size of sea creatures, the easier it is for them to tolerate low ambient temperature and high pressure.This is very similar to the tendency of land animals to grow larger when settling to the north - it is near the poles that the largest predators, pinnipeds and some representatives of bird groups are found.

 

Other large woodlice

So to say, there are no “analogues” in size to the giant isopods among the land true wood lice. The largest species of land lice live in the tropics and only in exceptional cases grow to sizes of 4-5 cm in length, their usual dimensions are 1-2 cm.

This is partly due to the fact that, like all crustaceans, wood lice are in need of moisture, and their large size would lead to an increased risk of death from dehydration even in fairly wet places (the larger the body size, the larger the evaporation area from it) . In addition, all woodlice is a favorite food for a wide variety of animals, and if small representatives of this suborder can at least hide under stones, the large ones will simply be defenseless against enemies.

On a note

An untrained person can easily confuse woodlice and millipedes from the glomeris family. While the body of wood lice is divided into 11 segments, with the rear ones having a small size, glomerises have 12–13 segments, of which the back segment, similar to a flap, is especially large.

Here are a few photos of millopods from the glomeris family (not to be confused with wood lice!):

Interestingly, the largest of the true woodlice are again marine species. Ligia oceanica, for example, grows up to 3 cm in length, and lives in the shallow areas of the Mediterranean Sea and the north of the Atlantic. Unlike the giant isopods, Ligia oceanica is descended from terrestrial ancestors, and therefore can rightly be called a real wood louse.

It should be noted that no woodlice - even the largest in the world - do not represent commercial value. Extreme lovers all try to say that the ground woodlouse tastes like concentrated urine. On its background, giant isopods can be considered a delicacy: their meat to taste is similar to lobster meat.

However, given the extremely rare and accidental hits in the fishing nets, no one is seriously engaged in mining and preparing giant isopods.

 

Interesting video with a brief fragment of the life of the giant woodlouse

 

Giant isopod in the scientific laboratory: the details of its structure are clearly visible