A spider living under water. Water spider (Argyroneta aquatica)

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In this article we will look at one of the interesting and complex issues of today's game. A general article with all the questions and the correct answers to them will soon be published on the site. In it you can find out whether the players won something today, or left the studio with nothing.

What does the silverback spider fill its underwater nest with?

Water spider (Argyroneta aquatica) - large spider, living under the surface of the water. This is the only species of the Argyroneta family and at the same time the only spider that has fully adapted to life under water.

When silverback water spiders build a nest, they move air around their backside and leave small bubbles on the hairs. In addition, the air bubble receives constant replenishment due to the diffusion of water dissolved in the water and produced by aquatic plants into the bubble. Food intake occurs either in the bubble or in vegetation directly above the water level. Diffusion is sufficient to satisfy the spider's oxygen needs during rest, but otherwise requires active replenishment.

It has been experimentally shown that the spider recognizes the quality of air in the bubble and replenishes it as the carbon dioxide content increases. The female has a larger diving bell than the male, and the female replenishes it more often. Sometimes the silverback spider collects an air bubble in an empty hood.

• wings of flies
• algae
• air bubbles
• pearls

The correct answer to the game question is: air bubbles.

Underwater bell of silverfish or water spider ( Argyroneta aquatica) works like fish gills, effectively absorbing oxygen from water and removing carbon dioxide.

Serebryanka and his bell. Photo: Claude Nudisany & Marie Perennou

The water spider is the only one of the entire order that spends almost its entire life under the surface of the water surface, breeding and hunting in reservoirs with less or more stagnant water. The main thing is that the silverfish has no special respiratory organs allowing it to absorb oxygen in water.

This spider got out of the situation in a rather unusual way, glorifying it throughout the world: the silverfish creates a bell from the web on plants that grow under water and fills it with air, then it drags it with it under water. It holds this air bell with the help of hairs located on the abdomen, as well as between the arachnoid warts. And yours unusual name This spider got it because of the airy “silver” shell on its body.

The silverfish lives in this air bell and hunts small invertebrates. But scientists for a long time could not understand how this diving spider replenishes its air reserves in the air bell. They thought that he periodically surfaced to bring fresh air, but for this purpose such a procedure would have to be done every 20 - 40 minutes.

Entomologists from the University of Adelaide, Australia, as well as scientists from the Humboldt-Universität zu Berlin in Germany, have undertaken to find out this. In their laboratory, they managed to simulate a stagnant body of water into which they placed a spider. To carefully study the air bell, they used special sensors - optodes, which made it possible to determine the concentration of gases in it.

In a paper published in the Journal of Experimental Biology, Stefan Hetz and Roger Seymour report that silverfish may not leave the bell for 24 hours, even on a particularly hot day when oxygen consumption increases significantly. . After careful study, entomologists came to the conclusion that the bell for the spider is a kind of gills that ensure gas exchange. When the oxygen in the bell becomes less than in the water, it begins to enter the silverfish’s home directly from the water.

And CO2 dissolves very easily in water and is eliminated as it appears. And the spider emerges solely to maintain the pressure in the bell, since the relative concentration of nitrogen in it increases and it begins to gradually leave the bubble, which leads to the shrinking of the air bell. Actually, to maintain nitrogen, and therefore pressure, at the required level, it forces the spider to rise to the surface once a day.

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What does the silverback spider fill its underwater nest with?

The silver spider, or water spider (lat. Argyroneta aquatica) is a common species of spider in Europe from the family Cybaeidae. It is distinguished by long swimming setae on the hind legs and 3 claws on the legs of 3 hind pairs.

The correct answer is traditionally highlighted in blue and in bold font, but for now there is some information about the silverback spider from Wikipedia.

When a silverfish is immersed in water, the hairs of the abdomen, covered with a special fatty substance, are not wetted; air is retained between them (as it is not displaced due to the forces of surface tension of water) and therefore it appears silver under water. This layer of air allows the silverfish to remain under water for a long time; he occasionally rises to its surface to renew his supply of air. The water-repellent substance is a modified secretion of the arachnoid glands.

7. What does the silverback spider fill its underwater nest with?

• wings of flies
• algae
• air bubbles
• pearls

Is it really possible to build a castle in the air? You can if you are a silver spider. A small, most ordinary-looking spider is the only one who has perfectly mastered this complex art.

Silver grass is widespread in Europe. It can also be found in Asia Minor, the Caucasus, in Siberia, with its air, in Tibet, Sakhalin, the south Far East dome and in Korea.

PORTRAIT OF A HERO

In appearance, the silverfish is not easy to distinguish from its land-based relatives. The spider's cephalothorax is dark brown, with black lines and spots, and almost naked. It has eight eyes. On the dorsal side of the brown abdomen, covered with velvety hairs, two rows of depressed points are noticeable. Young spiders are yellowish-gray, old ones are much darker, sometimes almost black. The male is larger than the female - a rare occurrence among spiders. Perhaps this is why he remains alive after mating and lives peacefully side by side with his wife. In addition to its smaller size, the female is distinguished by a light gray coloration of the rear part of the body, and the male’s abdomen is more elongated.

SCUBA DIVERS

The silverfish lives in stagnant and slowly flowing bodies of water, rich in vegetation, which is why its second name is the water spider. At the same time she breathes | lungs and trachea, which open on the underside of the abdomen. The spider lubricates the hairs on its body with a water-repellent substance - a modified secretion of the arachnoid glands. When submerged, they trap air bubbles, and the spider appears silvery. This reserve is enough for the silverfish to not float to the surface for a long time.

The male can be distinguished from the female by the appearance of the bubble: the upper part of his abdomen is free of air. In the female, it surrounds the entire abdomen and part of the cephalothorax, so she always swims head down. Males can also swim horizontally, rowing with all their legs, like oars.

BUBBLE HOUSE

The silver fish not only hunts under water, but also lives in the full sense of the word. The home of this spider is an air dome, shaped like a bell, the size of a hazelnut, or even the size of a pigeon egg. It is held in place by a web stretched between aquatic plants. The spider delivers building materials - air bubbles - on its body from the surface. To do this, he sticks the end of his abdomen out of the water and pushes apart the arachnoid warts, after which he quickly dives, carrying away the bubble. Then he separates it with his hind legs and attaches it to the dome.

A spider can spend a whole day in its house without replenishing its oxygen supply. Scientists have found that the air bell itself carries out gas exchange. Oxygen enters it from water when its concentration becomes lower than in environment, and carbon dioxide, on the contrary, goes into the water. But it is still necessary to replenish air reserves: over time, nitrogen begins to leak out of the spider’s house, the pressure drops, and it shrinks like a pierced ball.

MEAL LYING ON YOUR BACK

Silverfish feed on various small crustaceans and other invertebrate animals that fall into their fishing net or directly into their tenacious paws. Spiders don't see well, but the hairs on their legs allow them to feel the smallest vibrations of the web, jump out and grab potential food. Digestion in silverfish is extraintestinal, like in all spiders. Enzymes injected into the victim's body digest soft tissue, after which the spider sucks out the resulting nutrient broth. To do this, he brings food to his bell and, lying on his back, rests his front legs against the wall of the dwelling. In this position, liquid food does not flow down, but falls directly into the spider’s mouth. Then the clean silverfish takes the undigested remains outside.

HURTING WITH HEAD DOWN

To reproduce, the female rebuilds the house: she lines the top of the bell with loose cobwebs, on which she lays from 15 to 160 eggs. The mother sits on them head down and guards them, without even taking food and only occasionally replenishing her air supply. This “incubation” takes about ten days. Young spiders emerge from the eggs bald and therefore can only breathe while inside the mother's bell. This is where their first two molts take place, after which they move on to independent life.

UNDER-ICE BATHYSCAPH

Silverfish overwinter in a special, especially durable air dome. Sometimes they even use pond snail shells for this. Having brought a supply of air there and attached the shell to duckweed floating on the surface of the water, the spider seals the entrance and falls into a state of deep rest. During the winter, the duckweed drowns, taking the shell with it, and in the spring, when the water warms up, it floats up again. Now the overwintered spider can leave its winter apartment.

Young spiders and males spend the winter most of the time; females are less numerous. Sometimes late egg cocoons overwinter together with the females.

For molting, young silverfish build a special bell. The spider gradually crawls out of the old skin, pulls out its legs and, exhausted and still soft, lies down to rest. After waiting for the new covers to harden, the silverfish leaves the moulting bell.

BRIEF CHARACTERISTICS

Class: arachnids.
Squad: spiders.
Family: cybeids.
Genus: Argyroneta.
Species: water spider, or silver spider.
Latin name: Argyroneta aquatica.
Size: female body length up to 12 mm, male up to 15 mm.
Color: from yellow-gray to almost black.
Life expectancy: up to 18 months.

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The class of arachnids is very diverse. The silver spider (or water spider) is one of the representatives of these eight-legged creatures known to us.

The silverback spider belongs to the order of spiders, the family of cybeid spiders. They are members of the genus Argyroneta. Often these animals can be seen swimming in a pond or lake. By the way, this is the only species of spider that has adapted to life in water element.

Despite harmless appearance, this spider is considered poisonous. The silver spider lives in the European part of Eurasia. You can see him standing fresh waters, where there is a lot of thick grass around.

How do you know if you are looking at a silver spider?

These spiders grow up to 1.5 centimeters in length. Females differ from males by having a more rounded abdomen.

The silverback spider is the only water spider in the world.

This eight-legged creature has 2 pairs of jaws. On the abdominal part there are waterproof hairs, thanks to which the animal breathes. But this feature of holding air between the hairs not only makes it possible to breathe, but also gives the spider a silvery color.

The spider carries the air collected under its abdomen into its burrow under water and creates something like an oxygen reserve. If there is enough air in the home, then the silverfish very rarely appears on the surface.

The body of the spider on the dorsal part has almost no hair. It is colored brownish-red.

How does the silver spider live and what does it eat?

The first thing worth noting is that these spiders swim well in water. In one second, the animal covers a distance of two centimeters. Considering the size of a spider’s body, this is quite a lot!

The silverfish builds its secluded home under water; it is a funnel-shaped nest woven from cobwebs. This “house” is attached to stones, plants or driftwood.

The silverback spider's lifestyle is strictly nocturnal. At night, this predator goes hunting. Its prey is small fish, crustaceans, as well as the larvae of various insects.

When winter comes, silverfish hide in empty mollusk shells or in cocoons specially woven for the winter cold. This is how the spider lives until the onset of spring, because with the revival of nature after winter sleep, the silverfish must begin to reproduce.

This spider is a poisonous creature.

How does the silverback spider produce offspring?

This phase life cycle again accompanied by the creation of a special cocoon. Its purpose: to be a refuge for spider eggs. In such a cocoon, woven from its own web, the female silverfish lays from 10 to 100 eggs.

The female very carefully and zealously protects her clutch from outside attacks. Babies that are born gain height and weight very quickly. When they are only two weeks old, they already leave their parents' home and begin to live independently.