The silver spider is a unique aquatic inhabitant. Inhabits stagnant fresh water bodies, rarely appears on the surface of the water, does not creep out onto land. Widely distributed in European countries. In terms of toxicity, the poison is second only to karakurt, tarantulas. An unusual creature differs from other types of bunches in its habitat, behavior, appearance, reproduction.
PORTRAIT OF THE HERO
In appearance, the silverfish is not easy to distinguish from its land relatives. Dark brown, with black lines and spots, the cephalothorax of the spider is almost naked. She has eight eyes. On the dorsal side of the brown abdomen, covered with velvety hairs, two rows of depressed punctures are noticeable. Young spiders are yellowish-gray, old ones are much darker, sometimes almost black in color. The male is larger than the female - a rare occurrence among spiders. Perhaps that is why he remains alive after mating and lives peacefully side by side with his wife. In addition to the smaller size, the female is distinguished by a light gray coloration of the back of the body, and the abdomen of the male is more elongated.
Structural features
Any sea spider, both deep-sea and coastal species, has a typical structure. The body is divided into two tagmas (divisions). Their name is segmented prosoma and non-segmented descisoma. The prosoma is characterized by a cylindrical or disc-shaped shape.
The body of sea spiders is smaller than the limbs and is covered with a chitinous cuticle. There is a division into the cephalothorax and abdomen (which is rudimentary). The cephalothorax has 7 to 9 segments, 4 of which are fused together. The fused part of the cephalothorax is called the head segment. The remaining segments can be either fused or dissected. In front of the head segment, there is a cylindrical or ovoid trunk. On the lateral parts of the trunk, 2 pairs of limbs are fixed: cheliphores and palps. On the ventral side of the head section, the third pair of limbs (ten-segmented oviparous legs) is fixed. One of the structural features of sea spiders is that the 3 front pairs of legs do not reach the ground and do not participate in walking.
The walking legs of the sea spider are fixed on the lateral processes of the head segment of the body. Most often there are 4 pairs of them, but some representatives have 5-6 pairs.
SCUBA DIVERS
Serebryanka lives in stagnant and slowly flowing reservoirs rich in vegetation, therefore 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 the body with a water-repellent substance - a modified secretion of the spider's glands. When immersed, they trap air bubbles, and the spider appears silvery. This stock of silver is enough not to 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 the 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, raking with all their legs, like oars.
Reproduction
Different-sex individuals of the water spider form pairs and are able to live side by side for a long time. The breeding process takes place mainly in the female's summer bell.
Before starting to reproduce, the male spider pulls out separate threads from the spider's warts, which do not stick together. He secretes sperm on them, then collects it with tentacles and goes to the female's nest.
Having met, the arthropods occupy a characteristic position, after which the male inserts sperm into the female genital slit with a palp process.
The fertilized female covers the upper part of the nest with cobwebs, after which she lays up to 160 eggs on it. The eggs are strengthened and covered with cobwebs, resulting in a partition between the egg compartment and the living part of the nest. The female spider is located on this partition upside down and protects the clutch until the hatched offspring leaves the cocoon. All this time, the female does not eat anything and leaves the nest only to rise for a new portion of air.
HOUSE OF BUBBLES
The silverfish not only hunts under water, but also lives in the full sense of the word. The dwelling of this spider is an air dome, shaped like a bell, the size of a hazelnut, or even a pigeon's egg. It is held in place by a spider web stretched between aquatic plants. Building materials - air bubbles - the spider delivers on its body from the surface. To do this, he pokes the end of the abdomen out of the water and pushes the spider warts apart, after which he quickly dives, taking 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 reserves. Scientists have found that the air bell itself carries out gas exchange. Oxygen enters it from water when its concentration becomes lower than in the environment, and carbon dioxide, on the contrary, goes into the water. But it is still necessary to replenish the air reserves: over time, nitrogen begins to leak out of the spider house, the pressure drops, and it shrinks like a punctured ball.
Varieties
There are several types of water spiders.
Hydrachna cruenta Mull
This species is sometimes called the water mite, the red spider.
The arthropod lives in swampy bodies of water with warm stagnant water. The spider looks like a small red ball, it moves quite quickly on the surface of the water. It feeds on larvae and small crustaceans, but quite often it itself becomes prey for predatory insects or fish.
Red spiders make clutches on the inner parts of the leaves of aquatic plants, connecting the eggs to each other with a sticky solution.
Juveniles are born with six legs. At first, young individuals parasitize on beetles and bedbugs, clinging to them with their proboscis, but soon they leave for water holes, where they pupate and turn into full-fledged spiders.
Limnochares holosericea Latv
A kind of red spider. It has a square body, for the most part it is kept at the bottom of the reservoir.
Dolomedes fimbriatus L
Spider-hunter. This species does not live in water, but next to it or on its surface.
The arthropod is gray-brown in color with white or yellow passing along the sides of the body.
strip. In the middle of the body, you can see two rows of light gray dots, the thoracic part is mainly colored yellow, the abdomen is gray. The female hunter spider reaches 2.5 cm in size, the male is several times smaller.
The hunter spider is great for building rafts. Due to the lack of the ability to move on the water surface, the arthropod collects leaves and sticks floating in the water and connects them with a web. Having found prey, the spider quickly gets to it on its floating island, drags the victim onto the raft and eats it there.
Females lays eggs on plants growing along the shores of the reservoir, sticks around them with a cocoon of cobwebs and guards until offspring appear.
Clubionafallax
The silver spider (or dropsy) is the most common type of aquatic
spiders. This population has adapted to living underwater, where spiders build several types of oxygen-filled domes for different purposes:
- summer (for shelter, eating food and mating);
- sperm (for collecting semen);
- egg (for laying eggs and the appearance of offspring);
- for molting;
- wintering.
To fill the nest with air, the spider has to rise to the surface for it at least 80 times.
Males are gray-green or black in color and reach 15 mm in size. Females are lighter in color and 2-3 mm smaller than their partners.
Meal lying on the back
The silverfish feed on various small crustaceans and other invertebrates that fall into their trapping net or directly into their tenacious legs. Spiders do not see well, but the hairs on their legs allow you to feel the smallest shaking 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 tissues, after which the spider sucks out the resulting nutritious 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 a clean silverfish takes the undigested remains outside.
Notes (edit)
- Annotated List of Rare and Endangered Species of Invertebrates Specially Protected within Russia // 2003 * Russia * Red List of Specially Protected Rare and Threatened Animals and Plants. (2nd edition). Part 2. Invertebrates (Bulletin of the Red Book, 2/2004 (2008)) / otv. ed. V. E. Prisyazhnyuk. - M .: Laboratory of the Red Book of the All-Russian Scientific Research Institute for Nature Conservation, 2004 (2008). - S. 118 .-- 512 p. - ISBN 978-5-9243-0158-7 Full text
- Lange A.B. Subtype Chelicerata // Animal Life. Volume 3. Arthropods: trilobites, chelicerae, tracheal breathing. Onychophores / edited by M. S. Gilyarov, F. N. Pravdin, ch. ed. V.E.Sokolov. - 2nd ed., Rev. - M .: Education, 1984 .-- P. 68 .-- 463 p. - 300,000 copies
- I. I. Akimushkin.
Diving bell patent // Insects. Spiders. Pets. - 4th ed. - M .: Mysl, 1995. - T. 3. - S. 219-220. - (Animal world). - 15,000 copies. - ISBN 5-244-00806-4. - Microcosm (film, 1996), 40th minute
UNDERGROUND BATISCAFFE
Silverfish hibernate in a special especially durable air dome. Sometimes they even use pond shells for this. Having dragged a supply of air there and attaching a shell to a duckweed floating on the surface of the water, the spider seals the entrance and falls into a state of deep rest. In the winter, the duckweed drowns, dragging the shell along 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 winters most of all, females are fewer. Sometimes late egg cocoons hibernate together with females.
Is a water spider bite dangerous?
Water spiders rarely attack first: they are not too aggressive. However, when a threat arises, the spider can bite.
The bite of an arthropod is not life-threatening, but it causes severe pain.
The wound left by the poisonous jaws aches at first, then the pain spreads around it. Numbness may occur. As a rule, after a few days, the painful sensations disappear.
Some species of water spiders, such as the silverfish, are considered endangered and are listed in the Red Book, so even if such a spider has bitten you, do not harm it.
Danger to humans
It bites very rarely. A person can get hurt by accident by pulling him out of the water along with the fish. The bite is for the purpose of self-defense. Redness, pain, burning, swelling, swelling appear on the body. In people prone to allergies, with weak immunity, small children of a spider bite, there may be a deterioration in well-being. Weakness, nausea, dizziness, headache appear, the temperature rises. The condition returns to normal after a few days. To accelerate the therapeutic effect, antihistamines are taken.
Breeding
The silverfish spider destroys fry, reducing the number of useful fish.It tolerates captivity well and is an interesting object to observe. A container of water with a volume of 5 liters or more is suitable for keeping a spider. To weave the bell, the spider will need a frame made of twigs or aquatic plants, so you can control exactly where the spider builds the bell. Some of the branches should come out of the water so that the spider has the opportunity to go to land in order to gain fresh air. You can feed the silverfish with small fish, gammarus, water donkeys and bloodworms. Male and female can live in the same volume without showing aggression, but if spiders are underfeeding, cannibalism can take place.
