Spiders - ruthless murderers. Having caught a victim in silk networks, they inject to it killing poison. Almost all spiders are poisonous, but only very much the few are rather dangerous to the person.
Spiders belong to a class arahnidov, or paukoobraznyh. The science knows about 32 000 kinds of spiders. Despite distinctions in sizes, appearance and behaviour, a structure of a body at all basically the identical.
The Body of each spider consists of two departments. Forward - golovogrud - represents accrete in a single whole a head and a breast. From it eight grow sustavchatyh feet. Other department - a paunch, or opistosoma. In it there are digestive organs and reproduction, and also web glands with which help the spider spins the networks.
the First pair of finitenesses of a spider is nogoshchupaltsa, or pedipalpy. They are often similar to short legs, but for walking are not used. With their help spiders probe road and bring food to a mouth. In nogoshchupaltsah males store sperm and use them in marriage rituals. Usually at spiders of 8 eyes, but some kinds have no any.
Before a mouth at a spider the pair helitser - powerful jaws is located. These are hollow tubes with sharp kogotkami on the end. Them the spider pierces a victim, is protected from enemies, and sometimes digs minks in the earth.
Being predators (carnivorous), spiders eat insects and other small living creatures. Some even large spiders - even eat small mice and small fishes, and birds and frogs. Differing kannibalskimi manners, the majority of spiders do not disdain also the colleagues.
Many spiders kill a victim, having injected it poison helitserami, others are capable to crush a victim to death. Having killed a victim, the spider enters to it inside a saliva droplet. The saliva contains special juice of spidery intestines which dilute fabrics of an insect then the spider exhausts substance similar to soup. It even has a special body - sosatelnyj a stomach which works as the pump and allows to extend literally from a victim all juice.
All spiders spin a web playing very important role in their life, and the most different applications find of it. It and web cocoons where in heat and safety from eggs tiny cubs develop; and saving cables like climbing which fasten to plants and do not allow to a spider to fall to the ground. From a web spiders svivajut nests for the winter and, at last, spin lovchie networks.
For the different purposes spiders are able to spin different threads. If the thread for lovchej is necessary to a network then the special glands close web, cover with its layer of sticky substance. To get over from place to place or to attach lovchuju a network, the dry thread is developed. Other glands allocate substances from which the thread for svivanija a cocoon is spun. The thread of a web is stronger than a steel wire of the same diameter and can, without having broken off, to be stretched on third of the length.
Not to get in own lovchuju a network, the spider constantly develops a little a dry thread. He well knows, where there are safe sites, and, having hidden on one of them, patiently waits, while the victim will not get to a snare. Besides, pads of a spider allocate oily substance thanks to which they are not pasted to a web.
Different kinds of spiders spin a different web. The most ordinary - and, perhaps, the most beautiful - a round web often catches sight somewhere in park or on a backyard. The special beauty to it is given by the dewdrops which have settled on thin threads on cool morning. Under the form it is close to a circle in which of the center spokes of the radial threads connected by the most thin sticky spirals extensively run up. Insects also get to this drag-net zazevavshiesja. Lovchie networks almost all spiders-krugloprjadov are usually insignificant, but in tropics they reach the huge sizes. So, huge wood spiders stretch between trees a strong snare in diameter to 2 metres, capable to keep even a small birdie. At the majority of spiders spinning a web a poor eyesight and extract livelihood they can only with the help lovchih networks. One spiders-krugloprjady suit an ambush in the network center, others hide somewhere in a corner, holding a pad on the alarm thread attached to one of "ёяшч" Webs. Having got to a sticky snare, the insect tries to be pulled out from them. From its movements all network starts to vibrate, and the spider receives a signal "хё=і ѕыют". It immediately runs out from an ambush, puts to a victim a deadly prick and entangles its web.
To Voronkovye spiders give the lovchej networks the cone form. Having weaved the big funnel in stalks of a high grass, between stones or logs, the spider hides at its bottom. It is necessary to a victim to appear too close as it runs out from a refuge, it suffices and wears out inside.
For what the web is still necessary
Other spiders weave huge shapeless panels. Threads-lipuchek in them are not present, but is эш=ш-"яюфэюцъш" forcing an insect to lose balance. Hardly careless small insect will stumble and will get confused in a web, its owner here as here with the killing prick. Such network is spun by house spiders.
It is possible to use a web and in another way. For example, the North American spider-bola lets out a thread in length about 5 see To its tip is attached businka glue which the spider strikes to a victim biting blow. This glue contains the special chemical substances involving males of moths. The spider swings lovchej a thread, involving extraction by a smell. Hardly the victim will come nearer, it strikes to it blow by this original kistenem, tightly pasting to a ball, and tightens to itself, as if the small fish on a fishing tackle.
The European and American spiders-bryzguny catch extraction, spitting out from helitser two thin streams of sticky substance then entangle its dense cocoon from sticky threads.
Australian ljudoedopodobnyj the spider weaves small lovchuju a network which holds before itself four forward finitenesses. When under a spider any insect crawls, he sharply throws out in the foot parties, trying to stretch a network as it is possible more widely, falls on the caught victim and wears out to itself in a nest. At these spiders excellent sight. They hunt at night and more sensitively react to light, than the majority of other animals.
Spiders-racers Hunting by day, slowly having crept to extraction, rush on it in a lightning jump. They usually jump not too far, but sometimes the length of a jump 20 times exceeds length of a body of the spider.
Almost all spiders have poisonous glands, but from all living in the world the few are rather dangerous to the person - no more than 3% from total number. Poisonous glands similar on two sack are located at the basis helitser. Large enough glands can grasp and a head part. With kogotkom helitsery they are connected by the special channel opening at the edge.
Poison of a spider differently influences different animals. The sting, disastrous for one, practically in any way does not operate on others, and it not always depends on the size of a victim. We will tell, to a spider "ёхЁэющ тфютх" it is required in 160 times more poison to kill a frog, than larger chicken. There are two kinds of spidery poison - nejrotoksichesky and gemolitichesky. nejrotoksiny are present at the majority of spidery poisons and influence nervous system of a victim.
Spiders "ёхЁэ№х тфют№" develop nejrotoksin, causing in the person a severe pain, muscular spasms and even a paralysis. Their stings are very dangerous, but though people, happens, perish from them till now, the antidotes allowing for some days to recover from poison for a long time already are created. But insects nejrotoksiny will paralyse so quickly that frequently the spider starts a meal when the victim though does not move, but is still live.
The Majority of kinds "ёхЁэющ тфют№" behave shy enough, preferring flight to an attack. The disturbed spider quite often pretends to be dead, having drawn in pads, and is started up in races, only if considers that danger passed. On the person "ёхЁэ№х тфют№" attack only if them to tease or frighten.
Haemolitichesky poison of the South American spider-violinist influences blood and a skin of the person, and on recover some months can be demanded. However, gemoliticheskie poisons bring also some advantage. Them apply in medicine to destruction of the vascular blood clots, capable to lead to a heart attack. Other versions of poisons are not less useful also. Some spiders, especially females, use poison for an attack on relatives. Spiders-males, being, much less females, come nearer to them cautiously - the risk of is too great that them will accept for a breakfast.
Males of some kinds offer a female as a wedding gift the insect entangled in a cocoon to distract it for the period of pairing. Almost all spiders develop feromony - special chemical signals, clear to representatives of the same kind. With their help they declare themselves and the intentions. Some males lay by the ground a thin thread of a web which serves for a female as a conductor.
The Spiders possessing good sight, for example, a spider-racer, use it and at pairing. The male is started up before a female in marriage dance, swinging brightly painted pads that that has identified it as the possible groom. This courting can last hours before the female will agree to marriage. After that the male places nogoshchupaltsami the sperm in genitalnoe an aperture of a female.
Some spiders spinning a web identify potential partners in the vibration lovchej networks.
Females of spiders depending on a kind postpone from one to several thousand eggs. The female postpones eggs in self-made kovshik, a bit similar for a ladle then entangles their cocoon from a web. In egg are based in a soft feather-bed, and are outside protected by more rigid external layer which preserves them against predators. At last, mummy attaches a bag with eggs to the body or hides in a secluded place.
Newborns pauchata are absolutely helpless. Without being able neither to be protected, nor to weave own web, they are compelled to keep at the beginning more close to mummy. Thanks to chemical signals which they thus exchange, mother does not eat own posterity. When comes it is time to leave the mother, each cub is attached pautinkoj to any plant and with the first whiff of a wind is started up in flight as if a balloon, departing at times on many kilometres. Having landed, they find a convenient place for own lovchej networks, and life cycle begins at first.