Light molluscs. Is squid animal
Indeed, unlike squids or octopuses, squids do not seek to charm a female, trying on bright colors and protecting a convenient bottom area from competitors, and not proudly showing outstanding parts of their bodies, hinting at their readiness for a long-lasting act.
The main characteristic of the process is how squid breed, speed and practicality, no sentiment, only a short meeting to transfer the necessary mating detail - the spermatophor. Reproduction of squid occurs with a special tube containing sperm, the length of which can vary from centimeter to meter. Spermatophore is a rather complex biological device, equipped with a powerful ejecting apparatus, sensitive hair, a complex shell and a kind of “tube” that produces glue.
Initially, the spermatophore is in the male's nidhem bag and is transferred to the female when it encounters with the help of a penis or a modified hand, equipped with special clips, which provide a firm grip. On the body of the female there is a place intended for placement of the spermatophore, depending on the type of squid, it can be the oral membrane, the fossa in the area under the beak or on the back of the head, the inside of the mantle or the area of the gills. Having got rid of the “cargo”, the male leaves his girlfriend or more and does not participate in the breeding process, sometimes a long period passes from the moment of handing the tube with spermatozoa to fertilization. It is not excluded that the fathers of little squid are no longer alive when they are born, since the male is rather unceremonious and can safely transfer the spermatophore to the female before reaching puberty and not capable of spawning.
As soon as the spermatophore is removed from the male and attached to the body of the female, its shell comes in contact with sea water, as a result of which the sensitive hair breaks the thin membrane, causing a so-called spermatophoric reaction.
Water penetrates into the spermatophore and exerts pressure on the spring, due to which the inner shell of the cunning natural device also breaks. The spring literally flies out and pulls the inside of the organ behind it, but at the same time the “tube” works, releasing the glue, which securely holds the bag with the sperm on the female's skin.
It turns out that sperm is ready for spawning and it remains to wait until the female decides to reproduce the offspring, which, by the way, happens only once in the life of squid. If the female is a mature specimen, it soon begins to throw eggs, which pass near the spermatophorus attached in the gill area. When placing the device on the back of the head, sweeping occurs through the holes located on the sides of the neck, but in any case fertilization is guaranteed.
Thus, several dozens of eggs are laid, which the female can hide in a secluded place, for example, among dense thickets of algae. However, spawning often occurs right on the bottom, where squid accumulates, and the multitude of clutches of whitish and oblong eggs looks like a huge carpet.
In most species, the larvae remind their parents little after birth, but within 2 months the small squids change in appearance and become sexually mature participants in the endless chain of spermatotophore transmission.
By the way, some breeds of cephalopods still have a secret, for example, males are not found in the hook-like squid species, however, fertilization with the help of a spermatophorus occurs, and the apparatus is placed in a long section on the abdomen, which the female cannot perform with the beak.
Deep-sea inhabitants of the sea depths are in no hurry to reveal to a person their own secrets, you can know how squid breeds, but do not know what causes this type of cephalopods to literally produce offspring without showing the slightest sympathy for each other.
In the depths of the sea a lot of interesting things. The most unusual are the phosphorescent inhabitants of the deep sea. Squid, an animal one of the few, endowed with such an ability.
The underwater world is a mysterious environment, which has not been fully explored so far. Among the inhabitants of the depths there are creatures that are not only striking in their beauty, but also terrifying in their size and strength. One of these amazing creatures is an ordinary squid - a representative of the order of ten-armed mollusks, belonging to the class of cephalopods.
How externally recognize squid?
The average body length of this mollusk is 50 centimeters. One individual can weigh about one and a half kilograms, while female individuals are smaller than male ones. Body color has gray and red tones. On the sides of the body there are fins - there are two of them in squid. Therefore, when the fins are in the straightened state, the body takes the form of a rhombus.
Near the mouth opening, in a circle, there are 10 tentacles equipped with suction cups. And in the mantle of the animal there is a special bag with ink that squid uses in case of danger. When the mollusk needs to quickly escape from the enemy, it simply releases the ink fluid and floats away from the pursuer, leaving it in a black cloud.
Squid habitat
The eastern part of the northern regions of the Atlantic Ocean (from the western coast of the African continent to the North Sea) is densely populated by squid; moreover, this animal is found in the Adriatic and the Mediterranean.
The depth of the habitat of this animal is up to 100 meters, however, observations of the mollusk showed that it can live at a depth of 400 to 500 meters! Soil prefers oozy or sandy.
Animal lifestyle
Squids are migratory mollusks, they travel long distances in search of food. Squid can not be called either solitary or gregarious animals, because there are both individuals living alone, and large groups. If the squids have gathered in a group and live together, then they will hunt together.
Dwarf squid pig (Helicocranchia pfefferi) got its name from the barrel-shaped body and the tiny "nose-piglet", which in reality is a photoformat Typically, the depth of the habitat under water at an ordinary squid ranges from 20 to 50 meters, however, for the most part, the depth of residence depends on the time of year: in the summer months, the mollusk swims closer to the surface of the water, and in winter it goes to depth.
Squid often swims leisurely, making graceful sweeps with its fins, but, if necessary, it can also develop greater speed: to do this, it begins to rhythmically contract muscles, thereby absorbing a large amount of water under the mantle, then through a sharp ejection of water, it quickly pushes your body forward.
Squid Diet
Squid is a predator. The basis of its “dinner table” is fish. But squid does not shun crayfish, polychaete worms, as well as other representatives of the cephalopod mollusk class. Scientists have even documented cases of cannibalism.
The process of catching food is as follows: with two tentacles, a squid seizes a victim, killing it with its poison. After the “food” is immobilized, the animal begins systematically, without hurrying to tear off the pieces from the victim and eat them.
Reproduction of mollusks
Immediately after the end of the winter months, breeding season begins for squid. The breeding of offspring is the formation of egg laying, which looks like a sausage. Squids attach their clutches to fixed rocks and sometimes to shells of marine mollusks. Often, the laying of eggs occurs at a depth of 30 meters.
Breeding squids
LOVE Squid? I, too, tenderness ... This is not to you cuttlefish, in which the male chooses the best bottom area ahead of time, protects it from other males, lures the female and, dressed in the most catchy colors, beautifully cares for her. And not octopuses, in which the male specifically demonstrates to the female different parts of his body so that she learns that he is quite ready for an important service and cannot be eaten immediately, except after mating, but it can last (for example, in the giant North Pacific octopus from Far East) for more than an hour ... The mating of squid, of course, of those that were studied, is closer in duration to a fleeting air battle: if it flew together — grappled — scattered ... And no ceremonies! So when my colleague, the famous polar explorer Igor Melnikov, in the summer of 1992 returned from the drifting ice floe from the Antarctic (from the US-Russian drifting station "Weddell-I") and said that they were there on the ice floe, in the hole, they caught a net of two squids and they will be brought soon - I could not have imagined what cruel squid love would open to me. But in order!
Mating in all cephalopods consists in the fact that the male transmits one or several spermatofors to the female2. A spermatophore is a sperm-like bag that resembles a narrow tube. Spermatophores can be short or long (from a few millimeters to more than a meter, usually centimeter-sized). And this is not just a tube with sperm, but a tricky device with a complex shell and a very sophisticated device for throwing out sperm, equipped with a sensitive hair, a powerful spring and a tube of glue that attaches the live to the living, and even in the aquatic environment (just a surgeon's dream!) . Spermatophores are in the male in a special organ (nidhem bag), ending with a penis, which can also be a simple tube or a complex apparatus. And he gives them to the female in some species the penis, in others - with a specially modified hand; it is called "hectocotyl" and is equipped with special clamps or tweezers to firmly grab the spermatophore coming out of the funnel (the open conical tube on the underside of the head is the jet propulsion nozzle of the cephalopod mollusk) and place it in the right place.
It is a definite place and its own squid species: some have spermatofors for fossa under the mouth with a parrot-like beak typical of squid, others are located on the oral membrane, a ring around the mouth, in the third - near the gills, on the inner wall of the mantle (a muscular shell of the body, for which squid is valued because it is eaten), in the fourth - on the back of the head, in a special fossa. However, there are, it seems, such types of squids, for which the male doesn’t care where the spermatophores are stuck - even on his head, even on the tail, just to unload.
Whether the spermatophores are placed in a special hole, glued to the inner side of the mantle or distributed around the mouth - in any case, coming out of the body of the male, they come in contact with sea water, and then the process begins, called the spermatophoric reaction, or, more simply, the spermatophore explosion. The sensitive hair tears a thin membrane, and sea water osmotically enters the spermatophoric membrane. But the shell is strong, double-layered, the water presses on the spring, compresses it, and in the end the outer shell does not stand up and breaks off at the front end of the spring. The spring flies out, pulls out the inner shell containing the sperm, and a tube of glue attaches it to the skin of squid. There, sperm quietly awaits spawning, which squid only has once in its life. A squid may mate just before spawning, being fully mature, and maybe long before spawning, after two months, after three months, and still being completely immature. In this case, there are no males at all in the spawning area, by that time they may not even exist in the world.
Here the female is making eggs. If the spermatophores are glued near the gills - the eggs pass by them immediately after leaving the oviducts; if the spermatophores are placed on the nape of the female - the eggs are swept with two strings through two holes on the sides of the neck, to the right and left of the nape, but if they are swept through the funnel, then they pass by the ring of spermatofors around the mouth. Either way, the eggs must be at the place where the sperm is stored, and fertilized.
Rapid mating in squid is really like an air battle. And in fact, and in another case, success in advance is ensured technically: in aviation, with a locator, computer calculation of attack and the most complex device of a rocket or air cannon, and with squid, with a sophisticated spermatophoric structure and extremely sophisticated devices for attaching sperm in the right position and keeping it viable condition for 2 - 3 months - without any liquid nitrogen!
It seems to be all clear. But for some reason I managed that far from everything. I just came to work at the Institute of Oceanology of the Academy of Sciences and began to study oceanic squid and octopus, as I caught two females of squid - they took them out of the stomach of alepizavra fish caught in 1963 in the Indian Ocean, south of Sumatra, my boss N.V. .Parin. Both squid were completely gelatinous, as if not squid, but jellyfish, and without tentacles. But not because of the gelatinous, that they were overcooked, and not because of the tentacles, because their fish bit off: the squid were fresh, their color remained, and both were struck by one short strip on the belly. Strange stripes - as if cut with a sharp knife, start a little bit away from the front edge and go towards the tail parallel to the body axis. Spermatofors heads peep out of each incision, and what is interesting: the spermatofors themselves are neatly laid under the skin (completely intact!) In the mantle tissues, and only their heads (the place where the sensitive hair is attached) and the neck (where the spring lies) stick into the incision. Moreover, all spermatophores are empty, without sperm, only shells. Obviously, the sperm was used for its intended purpose: both females spawned, and they did not have mature eggs.
Such squids have long been described in the literature. This was believed to be a special genus and species of Chaunoteuthis mollis (mollis in Latin is mild), in which, oddly enough, only females were known, all mature, all gelatinous, all without tentacles and with cuts on the belly: who has one cut , to the right or to the left of the middle of the belly (a - in the figure), who has two (on both sides). And in the cuts - spermatophores. But this species and species belong to the family, in which all other genera and species are fleshy, with large tentacles with tentacles and tentacles. The family is called: hook squid, Onychoteuthidae. Think: fleshy hook-like squids, but without meat and hooks. And without males.
How do the cuts on the belly of the female appear and how are the eggs fertilized? Different authors expressed the assumption that, say, the male makes cuts with his beak, and the female, throwing out eggs, chases them away under her belly, and along the way they are fertilized. Strange: a squid's beak, like a parrot's beak, is not a claw; it is good for cutting through, and not for cutting food; it can break the soft mantle of a female, but not cut it. Eggs go out through the funnel towards the head, and it is difficult for the female to turn them to the belly, and if it succeeds, will there be many eggs fertilized during such a strange operation?
Those who live at a depth of more than 2 km, to multiply very difficult. That is why deep-water squids have developed fancy breeding methods.
Biologist Henk-Jan Hoving from the University of Groningen (University of Groningen) became interested in how Decapodiform sphalopods breeds. In addition to this cephalopod, Hoving investigated at least ten more squid and cuttlefish species - from 12-meter giant squid to mini-squid with a length of no more than 25 mm.
As Hoving says, it is still very difficult to study deep-water squids, because it is very difficult to reach them. To observe these cephalopods in their natural environment requires special equipment. Therefore, the biologist had to reconstruct the sexual habits of squid, content with already dead specimens and descriptions of other specialists. But still, some Dutch discoveries were made.
As the biologist himself says, "reproduction is not fun, especially if you are a squid."
In the Taningia danae mollusk variety, males injure the body of females with a five centimeter depth during mating. And all because this type of squid simply does not have suckers. But from such a “self-harm” partners derive considerable benefit. Males put sacks containing spermatozoa into the cuts - spermatophors.
Representatives of another variety of deep-sea "multi-armed" - Moroteuthis ingens use the same method. However, the process of such a kind of fertilization in these squids is more peaceful. Spermatophores penetrate the skin without traumatizing it. According to Hoving, males have some kind of substance, most likely an enzyme that allows you to "melt" the skin.
Hoving found confirmation that the spermatophores penetrate the skin on their own. The biologist was able to see this process in freshly caught squid. Moreover, Japanese physicians have registered a case of squid spermatophors growing into human tissue. Not so long ago, in the Land of the Rising Sun, an operation was carried out, during which “bags of sperm” of cephalopods were removed from the throat of a lover of sashimi.
But the mini-squid Heteroteuthis dispar decided to increase the birth rate. Females of this species fertilize their eggs independently, inside the body. According to Hoving, they have formed a special bag for storing sperm, which is directly connected with the internal body cavity and reproductive organs.
When mating males fill this tank with sperm. And it is so generous that its stock can be up to 3% of the body weight of the female. According to the biologist, this method has many advantages for both sexes. Females can grow eggs long enough and fertilize them gradually as they mature. And the "bombed" males still have a guarantee that their girlfriends will have very specific sperm.
Found Hoving among squids and "effeminate" males. Squids are not snails, they usually do not have hermaphroditism. But Ancistrocheirus lesueurii showed small glands that are involved in egg production in females. The length of the body of these nedosamtsov, too, was not quite standard - more than that of normal "men".
Hoving cannot explain this phenomenon and believes that it is hormone-like substances from human pills. Which at first with sewage fall into the coastal zones of the ocean, and then to the depth. But, the biologist adds, this may turn out to be the own “invention” of squids - a kind of way to get closer to women.
The scientist hopes that his study will not only help to learn more about deep-sea cephalopods, but also help to protect them from human greed. After all, not only research probes penetrate to depth, but also new fishing trawls.
The research results are published on the website of the University of Groningen.
Related articles
