Is a spider bite dangerous? Description. Cross spider - structure and behavior Black spider with a white cross

The cross-spider can be found in the forest, park, on the window frames of village houses and cottages. Most of the time, the spider sits in the center of its trapping web of sticky thread - cobwebs.

The body of the spider consists of two sections: a small elongated cephalothorax and a larger spherical abdomen. The abdomen is separated from the cephalothorax by a narrow constriction. Four pairs of walking legs are located on the sides of the cephalothorax. The body is covered with a light, strong and rather elastic chitinous cover.

The spider periodically molts, shedding its chitinous cover. During this time it grows. At the front end of the cephalothorax there are four pairs of eyes, and below a pair of hook-shaped hard jaws - chelicerae. With them, the spider grabs its prey.

There is a canal inside the chelicerae. Through the channel, the poison from the poisonous glands located at their base enters the body of the victim. Next to the chelicerae are short, covered with sensitive hairs, the organs of touch - the leg tentacles.

At the lower end of the abdomen there are three pairs of arachnoid warts that produce cobwebs - these are modified abdominal legs.

The liquid released from the spider webs instantly hardens in the air and turns into a strong cobweb thread. Various parts of arachnoid warts secrete cobwebs different types. Spider threads vary in thickness, strength, stickiness. Various types The spider uses cobwebs to build a trapping net: at its base, more durable and non-sticky threads, and concentric threads are thinner and stickier. The spider uses the web to strengthen the walls of its shelters and to make cocoons for its eggs.

Internal structure

Digestive system

The digestive system of a spider consists of a mouth, pharynx, esophagus, stomach, intestines (anterior, middle and posterior). In the midgut, long blind outgrowths increase its volume and absorption surface.

Undigested residues are brought out through the anus. The spider cannot eat solid food. Having caught prey (any insect), with the help of a web, he kills it with poison and lets digestive juices into his body. Under their influence, the contents of the caught insect liquefies, and the spider sucks it up. Only an empty chitinous shell remains from the victim. This type of digestion is called extraintestinal.

Circulatory system

The spider's circulatory system is not closed. The heart looks like a long tube located on the dorsal side of the abdomen.

Blood vessels branch off from the heart.

In a spider, the body cavity has a mixed nature - in the course of development it arises when the primary and secondary body cavities are connected. Hemolymph circulates in the body.

Respiratory system

The respiratory organs of the spider are the lungs and trachea. Lungs, or lung sacs, are located below, in front of the abdomen. These lungs evolved from the gills of the distant ancestors of aquatic spiders.

The spider-cross has two pairs of non-branching tracheas - long tubes that deliver oxygen to organs and tissues. They are located in the back of the abdomen.

Nervous system

The nervous system of a spider consists of the cephalothoracic ganglion and numerous nerves extending from it.

excretory system

The excretory system is represented by two long tubules - Malpighian vessels. With one end, the Malpighian vessels blindly end in the body of the spider, with the other they open into the posterior intestine. Through the walls of the Malpighian vessels, harmful waste products come out, which are then brought out. Water is absorbed in the intestines. Thus, spiders conserve water, so they can live in dry places.

Reproduction. Development

Fertilization in spiders is internal. The female cross spider is larger than the male. The male carries the spermatozoa into the female genital opening with the help of special outgrowths located on the front legs.

She lays her eggs in a cocoon woven from a thin silky cobweb. The cocoon weaves in various secluded places: under the bark of stumps, under stones. By winter, the female cross spider dies, and the eggs hibernate in a warm cocoon. In the spring, young spiders come out of them. In autumn, they release cobwebs, and on them, like on parachutes, they are carried by the wind over long distances - spiders are resettled.

Spiders are very interesting representatives of the biological kingdom, and some of them are far from harmless. They also have an amazing structure. Some species of these creatures have special appendages in their mouths, the so-called jaw claws.

These include araneomorphic spiders - members of a large group from the class of arachnids. These natural adaptations are called chelicerae. They allow these creatures to successfully attack prey that is quite large in comparison to their size, which gives them the opportunity to win in the evolutionary race.

It is to such creatures that spider spider- a bright specimen from the family of orbweavers.

This creature deserved its name not by chance, but because of a very noticeable feature - a mark on the upper side of the body in the shape of a cross, made up of white, in some cases light brown spots.

The spider got its name for the color on the body resembling a cross.

This feature of appearance is very useful for these biological organisms. This gift of nature is a sign that can scare away many hostile living creatures from them. Other characteristic features are clearly visible on photo of a cross spider.

As you can see, it has a rounded body. It turns out to be practically one with the head, dividing into two regions, which are commonly called the cephalothorax and abdomen.

The size of such living creatures cannot be considered too large. For example, females, which are more impressive in size than males, are usually not larger than 26 mm, but there are specimens of such spiders that are only a centimeter and much shorter.

Besides, cross endowed with eight sensitive flexible legs. He also has four, and paired, eyes. These organs are located versatile, which allows this animal to have a circular view in all directions. However, these biological organisms cannot boast of particularly sharp colorful vision.

They distinguish only the outlines of objects and objects in the form of shadows. But the sense of taste and smell are very good. And the hairs covering their body and legs perfectly capture a variety of vibrations and vibrations.

Chitin, a special natural binding compound, serves as a body cover and at the same time a kind of skeleton for such creatures. From time to time, it is shed by these arachnids, being replaced by another natural shell, and during such periods, the growth of the organism is carried out, freed for a while from the elements that bind it.

The cross is considered poisonous spider, but its poison is not dangerous for people

This representative of the biological kingdom of arachnids is able to release a substance that is toxic to any type of organism. So Spider spider poisonous or not? Without a doubt, this little creature is dangerous to many living creatures, especially invertebrates.

And the poison they secrete is extremely detrimental to their neuromuscular organization.

Types of spider cross

The number of species of such spiders is impressive, but of the arachnids known to science, about 620 varieties have been described in the genus of crosses. Their representatives live all over the world, but still prefer to settle more in temperate and tropical zones, because they can not stand too cold climate.

Let's take a closer look at some of the varieties.

1. Ordinary cross. This type considered the most common. Similar living creatures live among shrubs, meadows, fields and coniferous forests of the European, as well as the northern part of the American continents.

They prefer wet areas, take root well in swampy areas, near rivers and other bodies of water. Their body is reliably protected by a strong thick shell, and moisture retains a special waxy coating on it.

Decorated like this spider white on a common brown background with a pattern. Such a complex pattern, upon closer examination, may seem very interesting.

Common cross spider

2. An angular cross is a rare variety, and in the Baltic regions it is generally considered to be endangered. It is interesting that such arthropods, although they belong to the genus of crosses, characteristic mark do not have on the body.

And instead of this feature, on the abdomen of the creatures, covered with light hairs, two small humps stand out.

Angled cross

3. The barn spider is an inhabitant of the North. The trapping nets of these creatures, which are sometimes of considerable size, can be found in abandoned mines, grottoes and rocks, as well as near human habitation.

These creatures are dark brown in color. By means of a similar coloring, they are masked against the background of their surroundings. The legs of such spiders are striped and covered with white hairs.

In America, there is a type of cross - sheep

4. The cat-faced spider is another inhabitant of areas of America similar to the previously described species. Its body is also covered with pile, and the hairs can be either light or dark. This is a very small creature. Some specimens may be less than 6 mm.

But if this big spider cross of this type, then it is probably a female, because their sizes can reach up to 2.5 cm. These arachnids got their name for a very interesting pattern on the abdomen, vaguely resembling a cat's face.

This decoration for these creatures is located in the place where the relatives usually flaunt the cross.

The cat-faced spider has a shape similar to the muzzle of a cat on the body

5. The Pringles spider is a small-sized resident of Asia, also common in. It has a very interesting color cross: black its abdomen is marked with a funny white pattern, while the cephalothorax and legs of such spiders are green to match the rich vegetation of the regions where such creatures live. The sizes of males in some cases are so small that they do not exceed 3 mm.

spider pringles

Lifestyle and habitat

For settlement, these representatives of the animal world prefer to choose areas where there is no lack of moisture. These creatures are able to catch the eye wherever there is an opportunity to weave a web.

It is especially convenient for such creatures to arrange such a skillful trapping net between branches, and at the same time, having found shelter nearby, among the foliage of small shrubs or tall trees.

Therefore, spiders take root well in forests, in quiet, untrodden areas of gardens and parks. Their webs can also be found in various corners of neglected buildings: in attics, between doorways, window frames and other similar places.

On the abdomen of such creatures there are special glands that produce a special substance in excess, which makes it possible to weave trapping nets. They are known to be called cobwebs. From the point of view of chemistry, the natural building block for them is a compound, which should be considered very close in composition to soft silk, which indicates its relative strength.

Patterned weaving, formed from the specified, at first liquid and viscous, material with its further solidification, spiders usually weave with endless persistent persistence. And after one or two days they destroy the old, worn-out network and weave a new one.

This structure can be called a true work of weaving art, formed from threads, the length of which is 20 m in total. It has a regular geometric structure, being endowed with a strictly defined number of spiral turns with specific radii and distances from one network circle to another.

And this cannot but lead to admiration, because it causes aesthetic pleasure. But it is not vision that helps spiders to create perfect lines, they are guided by sensitive organs of touch.

These curious representatives of the biological kingdom weave such structures, usually at night. And all this is extremely expedient and correct, because at the indicated time of day, most of the enemies of spiders indulge in rest, and no one bothers them to do their favorite thing.

In such an occupation, they do not need helpers, and therefore spiders are individualists in life. And they do not spend much time communicating with relatives. Thus, having created a trapping net, they crawl into an ambush and begin to wait for their prey, as always, all alone.

Sometimes they do not particularly hide, but are located in the very center of the web they have woven. Or they watch, sitting on the so-called signal thread, which allows them to feel all the connections of this weave.

Sooner or later, some prey will fall into the spider's trap. Most often these are flies or other flying small insects. They are easily tangled in the net, especially since its threads are sticky. And the owner of the Putin instantly feels their fluttering, as he is able to capture well even the most insignificant vibrations.

Interestingly, small insects themselves can also be dangerous for spiders. After all, individual species of flies and, taking advantage of their usual immobility, are quite capable in the blink of an eye to settle down on the back of eight-legged predators and lay their eggs in their body.

In this case, the spiders are helpless, they are omnipotent only when their prey gets stuck in the web. The spiders themselves cannot get tangled in their trapping web, because they move only strictly along certain, radial, non-sticky areas.

Nutrition

The described living creatures are carnivores. In addition to the already mentioned flies and mosquitoes, aphids, various gnats and other small representatives of the insect world can become their prey. If such a prey fell into the network of this predator, then he has the opportunity to feast on it immediately.

But, if he is full, he is able to leave food for later, entangling it with a thin sticky thread. By the way, the composition of such a "rope" is somewhat different than the thread of the web. Further, the spider hides its food supply in any secluded place, for example, in foliage. He eats it when he feels hungry again.

The appetite of such spiders is very excellent. And their bodies require a lot of food. Daily rate so large that it is approximately equal to their own weight. Such needs force the described representatives of the animal world to work accordingly.

Crosses, lying in wait for prey, sit in ambush with little or no rest, but even if they are distracted from business, then for a very short time.

Extremely in an interesting way these creatures digest their food. This does not happen inside the body, but outside. It's just that a portion of the digestive juice is released by the spider into the body of the victim, wrapped in a cocoon. In this way, it is processed, turning into a substance suitable for consumption. Further, this nutrient solution is simply drunk by the spider.

It happens that in the nets set up by these eight-legged creatures, prey comes across that is too large, with which such a baby is simply not able to cope. The spider seeks to get rid of such problems by deliberately cutting off the threads of the network that connect with it.

But if the threat does not stop there, for the purpose of self-defense, he is quite capable of successfully using his chelicera against huge, from his point of view, creatures. For example, a frog, a quarter of an hour after its bite, may be completely immobilized.

But for humans, cross spiders are dangerous or not? Actually, the poison of these creatures does not produce irreversible changes on the body of all vertebrates. On people, due to the small amount of toxic substances released by these arachnids in comparison with human sizes, they are not able to act in a serious way. The bitten subject feels only mild pain, which resolves fairly quickly.

Reproduction and lifespan

The life of these creatures takes place on the web. Here, for them, the process of reproduction of their own kind begins. And the time for it is usually the end of autumn. At first spider male finds a suitable partner.

Next, he attaches his thread somewhere on the lower edge of her web. This is a signal that the female immediately feels. She feels the special fluctuations of weaving and perfectly understands from them that it was not someone, but it was the applicant for mating who violated her loneliness.

Then she goes down to her stalls, which responds to his signs of attention. After intercourse, male individuals no longer remain alive. But the female continues the work begun. She creates a special web cocoon and lays her eggs there.

Spider spider nest

At first, she carries this house for posterity on herself, but having found a suitable place for it, she hangs it on a makeshift thread. Soon cubs appear there, but they do not leave their house, but remain in it for the whole winter. They emerge from the cocoon only in spring. But their mother does not survive until warm times.

Young spiders grow up, live the entire warm period, and then the entire reproduction cycle is repeated again. From here it is easy to understand: how long do cross spiders live. The entire period of their existence, even if counted together with wintering, turns out to be less than a year.

Cross spider (Araneus) - arthropod belonging to genus of araneomorphic spiders And family of orbs(Araneidae). They live in almost every country, except for the southern and northern latitudes. This type is the most common. There are 2000 species of this spider in the world, about 10 species live in Russia. Most often, this insect can be found in the Republic of Mordovia, Astrakhan, Smolensk and Rostov regions.

Appearance

The external structure of the cross is represented by the abdomen and arachnoid warts, the cephalothorax and walking legs, consisting of the thigh, knee joint, lower leg, pretarsus, paw and claw, as well as the chelicera and pedipalp, acetabular ring and coxa.

Crosses are spiders quite small in size, however, the female of this arthropod is much larger than the male. The body length of the female is 1.7-4.0 cm, and the size of an adult male cross, as a rule, does not exceed 1.0-1.1 cm. time for another molt.

The cross has 10 limbs:

One pair of chelicerae, which serve to seize and kill the victim. These limbs point downward, hooked inward.
Four pairs of walking legs with claws at the ends.
1 pair of pedipalps that recognize and help hold prey. characteristic feature of these limbs is the location on the last segment of the copulatory apparatus. This apparatus receives seminal fluid, which is subsequently introduced into the female's seminal receptacle.

The spider-spider has very poor eyesight, despite the fact that it has 4 pairs of eyes. This spider distinguishes only light, shadow and blurry silhouettes. But this does not prevent him from being perfectly oriented in space, because he has a well-developed sense of touch. It is carried out thanks to the tactile hairs covering the body. Every kind of hair has its own function: some perceive the sound, others catch the change in air movement, and still others react to various kinds of stimuli.

Adult males on the last segment of the pedipalps have a copulatory organ, which is filled immediately before mating with seminal fluid, which enters the seminal receptacle located on the female, due to which offspring appears.

This is interesting! The visual abilities of the cross are very poorly developed, so the arthropod sees poorly and is able to distinguish only blurry silhouettes, as well as the presence of light and shadows.

Cross spiders have four pairs of eyes, but are almost completely blind. An excellent compensation for such a visual deficiency is a well-developed sense of touch, for which special tactile hairs located on the entire surface of the body are responsible. Some hairs on the body of an arthropod are able to respond to the presence of stimuli. chemical type, air vibrations are perceived by other hairs, and all kinds of ambient sounds are captured by the third.

The abdomen of cross-spiders is rounded and completely devoid of segments. In the upper part there is a drawing in the form of a cross, and on the lower part there are three pairs of special spider warts, which contain almost a thousand glands that produce spider webs. Such strong threads have various purposes: building reliable trapping nets, arranging protective shelters or weaving a cocoon for posterity.

The respiratory system is located in the abdomen and is represented by two lung sacs, in which there is a significant number of leaf-shaped folds with air. Inside the folds, liquid hemolymph circulates, enriched with oxygen. Also included in respiratory system includes tracheal tubes. In the dorsal region of the abdomen there is a heart, which in its appearance resembles a rather long tube with outgoing, relatively large blood vessels.

Nutrition

Crosses are hunters who are most active at twilight and at night. During the day, they prefer to sit in secluded places. Their diet contains:

vile, etc.

During the hunt, the crusader spider is located in the center of its web and freezes. From the outside, it looks like he's dead. But as soon as the victim gets into the net, the hunter reacts with lightning speed. He quickly runs up to the entangled insect, pierces his body with his sharp claws, which are located on the front pair of legs, and injects paralytic poison. After a while, the caught victim freezes. At the same time, in different situations spiders either immediately eat their prey, or leave it in reserve.

The cross-spider eats quite a lot - the total amount of food absorbed per day is approximately equal to mass his body. And at one time he is able to eat about a dozen insects. For this reason, he spends almost all his time hunting, constantly being in the web and waiting for the next victim. A small part of the day is allotted for rest, but even during this period, the signal thread is necessarily tied to one of the hunter's legs.

On a note! Not all insects are included in the diet of the spider-cross. If a victim with an unpleasant odor, someone poisonous or too large gets into the web, then the hunter prefers in this case to let the unwanted guest go. He bites through the restraining threads and lets go!

Spiders, along with most other spiders, have an external type of digestion.. In anticipation of their prey, spiders are usually located near the network, located in a hidden nest, which is made of a strong web. A special signal thread is stretched from the central part of the web to the spider nest.

The arthropod is unable to digest the caught prey on its own, therefore, as soon as the victim gets into the network, the cross spider quickly injects its very aggressive, caustic digestive juice into it, after which it wraps the prey in a cocoon from the web and waits for some time, during which the food is digested and turns into a so-called nutrient solution.

The process of digestion of food in a cocoon usually takes no more than one hour, and then the nutrient fluid is absorbed, and only a chitinous cover remains inside the cocoon.

How long does a cross live

cross spiders different types, compared to many of their counterparts, live quite a short time. Males die immediately after mating, and females die immediately after weaving a cocoon for offspring.

Thus, the life expectancy of male crosses does not exceed three months, and females of this species can live for about six months.

Spider venom

The venom of the cross is toxic to vertebrates and invertebrates, as it contains thermolabile hemolysin. This substance can adversely affect the red blood cells of animals such as rabbit, rat and mouse, as well as human blood cells. As practice shows, sufficiently high resistance to the toxin is possessed by guinea pig, horse, sheep and dog.

Among other things, the toxin has an irreversible effect on the synaptic apparatus of any invertebrate animal. For human life and health, crosses are in most cases absolutely harmless, but if there is a history of allergies, the toxin can cause a strong burning sensation or local tissue necrosis. Small cross-spiders are capable of biting through human skin, but total injected poison, is most often harmless, so its presence under the skin is accompanied by mild or quickly passing pain symptoms.

Important! According to some reports, the bites of the largest crosses of some species are no less painful than the sensations after a scorpion sting.

Cross web

As a rule, crosses settle in the crown of a tree, between branches, where large trapping nets are arranged by a spider. The foliage of the plant is used to make shelter. Quite often, a spider web is found in shrubbery and among window frames in abandoned buildings.

The cross spider destroys its web every other day and starts making a new one, as the trapping nets become unusable because not only small, but also too large insects get into them. Usually, new network trudges at night, which allows the spider to catch prey for itself in the morning. The webs built by an adult female cross spider are distinguished by the presence of a certain number of spirals and radii woven from sticky threads. The distance between adjacent coils is also precise and constant.

The building instinct of the spider-cross is brought to automatism and programmed in nervous system on genetic level, therefore, even young individuals are able to very easily build high-quality cobwebs and quickly catch the prey necessary for food. The spiders themselves use exclusively radial, dry threads for movement, so the cross is not able to stick to trapping nets.

Range and habitats

The most common representative common cross(Araneus diadematus), is found throughout the European part and in some North American states, where spiders of this species inhabit coniferous forests, marshy and shrub plantations. Angled cross(Araneus angulatus) - disappearing and very rare view living in our country, as well as on the territory of the Palearctic region. The Australian cross spider Araneus albotriangulus also inhabits the territory of New South Wales and Queensland.

In our country, the most common oak cross spiders(Araneus seroregius or Aculeireira seroregia), which settle in tall grass on forest edges, in groves and gardens, as well as in fairly dense shrub thickets.

Cross Araneus savaticus or barn spider, for arranging a hunting net, it uses grottoes and rocky cliffs, as well as inlets into mines and barns. Quite often, this species settles in close proximity to human dwellings. Cat-faced cross spider(Araneus gemmoides) lives in the western part of America and Canada, and the natural range of a typical representative Asian fauna spider-cross Araneus mitificus or "Spider Pringles" became India, Nepal, the territory of Bhutan and part of Australia.

Reproduction and offspring

Young males during the spring and summer are mainly engaged in weaving webs and hunting, trying to provide themselves with normal food. Closer to the mating season, they leave their shelters and move from place to place in search of a female. At this time, they eat extremely poorly, which explains the significant difference in mass between them and spiders.

Spiders are dioecious arthropods. The courtship process usually takes place at night. Males climb onto the net of females, after which they arrange simple dances, consisting in raising their legs and shaking the web. Such manipulations serve as a kind of identification signals. After the male touches the cephalothorax of the female with his pedipalps, mating occurs, which consists in the transfer of the sexual fluid.

This period falls approximately at the end of summer or the beginning of autumn. As a rule, the cocoon woven by the female turns out to be quite dense, and for some time the female cross carries it on herself, after which she hides it in a safe place. The cocoon contains from three to eight hundred eggs, which are amber in color.

Inside such a “house”, eggs with spiders are not afraid of cold and water, since the spider cocoon is quite light and absolutely waterproof. In the spring, small spiders emerge from the eggs, which for some time continue to sit inside a warm and cozy shelter. Then the spiders begin to gradually spread in different directions, and become completely independent.

Due to the very large natural competition, small spiders that were born risk starving to death and can be eaten by relatives, so young individuals try to disperse very quickly, which greatly increases the chances of the cross to survive in adverse environmental conditions.

This is interesting! Possessing small and weak legs, small spiders use a web to move around, on which the crosses plan from place to place. In the presence of a fair wind, spiders on the web are able to cover a distance of up to 300-400 km.

Cross spiders are often kept as pets. To grow such home spiders, you need to use a terrarium of sufficient size, which is due to the scope of the web. The bite of the cross is not dangerous, but when caring for indoor exotics, all precautions must be observed.

Due to its high strength and elasticity, the spider web threads of crosses have been used for the manufacture of fabrics and jewelry for a long time, and the inhabitants of the tropics still weave nets and fishing nets from it.
Immediately after mating, the spider tries to hide faster. However, it is possible for units - the most agile. Most die from the poison of the female.
The spider's web is used in microbiology to determine the composition of atmospheric air and as the thinnest optical fiber.
The spiders themselves inside the web move along radial, dry threads, therefore they do not stick to their own trapping network.

Description of popular species

Common cross

It is the most common type of spider with a cross on its back. Such a spider can be found in Europe, North America. This species prefers to settle in swamps, bushes, and also in coniferous forests. The female has a size of 20–25 mm, while the male reaches 11 mm in length and has a narrower body. In both sexes, the body has a waxy coating that retains water. The cephalothorax is under the reliable protection of a strong shell.

Angled cross

It is one of the rarest species. This species of arthropod is on the verge of extinction and is even listed in the Red Book of the city of St. Petersburg. The range of the angular cross is Europe, Asia, Russia and northern Africa. A characteristic difference of this species is the absence of a cross of white spots. Instead of spots on the spider, there are 2 angular humps on the abdomen. The body of this species is covered with numerous light-colored hairs. Females reach 15–18 mm, while males grow up to 10–12 mm.

barn spider

This species can be found in the northeastern United States, North America and also in Canada. Prefers to settle in places of rocky cliffs, near the entrance to the mines. The size of females differs slightly from males. The female representative has a size of 13-22 mm, and the male grows up to 10-20 mm. The body of the female is lighter or yellow, and the center of the belly is represented by brown jagged edges. In the lower part of the spider there is a strip of dark color, and on top of the black background you can see two dazzling white spots.

Spider Pringles

He is a resident of India, Austria, Nepal. They named it after an interesting pattern in the upper part of the abdomen, reminiscent of a mustachioed uncle, from a package of well-known chips. During the hunt, spiders sit in a shelter with a signal thread that is triggered when the victim enters the trap. These spiders have small size. The female grows up to 6–9 mm, and the male up to 3–5 mm.

Meadow cross

This spider can be found in damp areas with densely planted grass. In shape and size, it can be compared with an ordinary cross. Characteristic spots in the form of a cross on the belly have a dark or light shade, depending on the color of the surface of the abdomen. At the bottom, you can see a blurry drawing in the form of a sheet. The body is light green or dark brown. On the paws you can see stripes of light color. The female grows up to 17 mm, while the male is only 8 mm in length. Adult females have the properties of a chameleon, in other words, they can merge with the environment.

The cross is chilly

This species is a lover of temperate climates. Lives in forests deciduous trees. In appearance, it resembles a meadow cross. The difference is the color of the spider. This species is dominated by beige and orange. On the abdomen there are numerous specks of light color, due to which it resembles a strawberry. The female reaches a length of 13 mm, and the male is only 6 mm.

oak cross

The favorite habitat of this spider is thickets of bushes, as well as tall grass. Spider prefers temperate climate. hallmark of this species is the abdomen of females pointed at both ends. It also has numerous hairs covering the cephalothorax. Against the background of a brown abdomen, you can see a pattern in the form of a white Christmas tree. In the lower part of the belly there is an elongated yellow spot. The female reaches 14 mm in size, and the male grows up to 7–8 mm.

cat face spider

Lives in the western part of the USA, as well as in Canada. The body, covered with villi, can have a dark and light color. In the place where the cross should be, there is a drawing that resembles a cat's face. The size of the female of such an arthropod is 13–25 mm, and the male reaches up to 8 mm in length.

Video

Sources

http://simple-fauna.ru/spiders/pauk-krestovik/ http://beetlestop.ru/pauk-krestovik/

Spiders are a genus of araneomorphic spiders that is part of the orb weaver family. In the world fauna, there are more than one and a half thousand species of cross-spiders. They can be found in all corners of Europe. 15-31 species inhabit the territory of the CIS countries.

The spider-cross prefers to settle in forests, shrubs, gardens, neglected groves, especially near water bodies, as well as in buildings. His favorite habitat is the crowns of trees, between the branches of which he weaves his trapping nets. Their leaves serve as a refuge for him. It happens that the web of a cross-spider can also be seen under the eaves or in the window frames of abandoned buildings.

The cross is recognizable by the white spots on the abdomen, which in combination form a pattern similar to a cross with four ends. The common cross-spider has a yellowish-brown color, sometimes with blackish tints. On his legs, brown rings stand out in contrast. Depending on the environment The spider's coloration can change, allowing the spider to camouflage itself while waiting for prey.

Spider-cross is a predator. Nature gave him all the tools necessary to kill the victims. In the role of victims, different types of flies most often act. All spider jaws end in a segment that looks like a sharp and movable claw. At the base of the jaws are special glands that produce poison. As soon as the jaws pierce the body of the victim, a deadly poison is injected into it through the holes of the claws.

How to Avoid a Spider Bite

If a person tries to touch the cross-spider, he immediately runs away and hides. In most cases, the cross bites a person only when the latter still manages to pick it up. Therefore, in order to protect yourself from a spider bite, it is enough to follow a few simple recommendations.

First, when staying overnight in nature, carefully close the entrance to the tent.

Secondly, carefully check the bed before going to bed, as well as clothes and shoes in the morning.

Thirdly, be careful around symmetrical and openwork spider webs. Near them is usually a female waiting for her prey.

Fourth, be vigilant in old abandoned premises

Fifth, be careful during summer garden and garden work.

Sixth, when you find a cross, do not try to touch it or pick it up. Do not let children play with it.

Consequences of a spider bite

It is worth noting that a spider of any kind is a priori poisonous. All arachnids are natural predators and use their venom for food and protection. Spider venom is a slightly cloudy, colorless, viscous liquid with hemolytic properties.

The poison of the cross has a toxic effect. The thermolabile hemolysin in its composition destroys the erythrocytes of rabbits, rats, mice, and also humans. It has no effect on the erythrocytes of a guinea pig, horse, sheep, dog. The thermostable neurotoxic element of the poison has Mr~1000.

The venom neurotoxin is involved in blocking synaptic transmission through acetylcholine and glutamate synapses in vertebrates and invertebrates. Plus, the poison contributes to the initial excitation of receptors, which are characterized by sensitivity to glutamate and aspartate, and provides subsequent desensitization. And if the effect of the poison on the synapses of vertebrates is reversible, then it acts irreversibly on the synaptic apparatus of invertebrates.

Spider chelicerae can damage human skin only in those areas where it is very thin. Its sting can be compared to the sting of a bee. At first there is a feeling of a prick with a thin needle. It often happens that a person does not notice the bite at all.

After a bite, only local toxic effects are observed. A small white spot immediately appears on the affected area, which does not exceed the size of a five-kopeck coin. The patch usually has pink or red edges. After 5-20 minutes, the following symptoms begin to develop:

headache
weakness in the body
pain, joint pain
colic and burning sensation in the bitten place
subcutaneous hemorrhages.

So far, not a single fatal outcome has been registered with the bite of the cross. However, after recovery, in some cases, soft tissue necrosis is noted at the site where the poison was injected into the skin. The body of the spider contains eiperotoxin, a special concentration of which is observed during egg laying. This poisonous product dissolves and is excreted from the human body in a day. At the site of the bite, swelling persists for several days.

What not to do when bitten by a cross spider

Do not burn the affected area. The bite of the cross has no serious consequences, and thus you only further injure yourself.

You should not dissect the bite site for the same reasons as described above.

Do not rub or scratch the wound, as this can lead to infection.

What measures can be taken when bitten by a spider-cross

Although contact with the cross does not threaten the victim fatal, to provide him with timely first aid is still worth it. The detailed algorithm of actions outlined below will help you with this.

1. Wash the injury site under running water and soap to avoid potential infection of the wound.

2. Apply to the puncture site cold compress ideally ice.

3. With a headache and a slight increase in body temperature, take the same paracetamol or some other drug of a similar effect.

4. If you develop a mild allergic reaction, take any over-the-counter antihistamine.

If a cross spider has bitten a child, or if there is a rapid development of symptoms and a sharp deterioration in the condition, consult a doctor immediately.

Interesting facts about cross spiders and their bites

If spider venom has a local toxic effect on the human body, then its web, on the contrary, contributes to the destruction of pathogenic bacteria. It has long been used in traditional medicine for the purpose of disinfecting open wounds.
The poisonous substance eiperotoxin is found even in the eggs laid by the female cross.

The cross spider (Araneus) is an arthropod belonging to the genus of araneomorphic spiders and the family of orb-weavers (Araneidae). To date, there are more than one thousand species of crosses in the world, which live almost everywhere.

Description of the cross

Appearance

four pairs of walking legs with relatively sharp claws at the ends;
one pair of pedipalps, which perform a recognizing function and are necessary to hold the caught prey;
one pair of chelicerae used in the capture and killing of the caught victim. The chelicerae of the crosses are directed downwards, and the hooks of the chelicerae are directed inward.

This is interesting! The visual abilities of the cross are very poorly developed, so the arthropod sees poorly and is able to distinguish only blurry silhouettes, as well as the presence of light and shadows.

Cross spiders have four pairs of eyes, but are almost completely blind. An excellent compensation for such a visual deficiency is a well-developed sense of touch, for which special tactile hairs located on the entire surface of the body are responsible. Some hairs on the body of an arthropod are able to respond to the presence of chemical stimuli, other hairs perceive air vibrations, and still others capture all kinds of ambient sounds.

The respiratory system is located in the abdomen and is represented by two lung sacs, in which there is a significant number of leaf-shaped folds with air. Inside the folds, liquid hemolymph circulates, enriched with oxygen. The respiratory system also includes tracheal tubes. In the dorsal region of the abdomen there is a heart, which in its appearance resembles a rather long tube with outgoing, relatively large blood vessels.

Types of crosses

Despite the fact that there are a lot of varieties of cross-spiders, only thirty species are found on the territory of our country and in neighboring states, which are characterized by the presence of a pronounced “cross” located on the upper part of the abdomen. Common species include the four-spotted or meadow cross spider (Araneus quadratus), which settles in wet and open, grassy areas.

This is interesting! Of particular interest is the rather rare spider Araneus sturmi, which lives mainly in conifers on the territory of the Palearctic region, whose modest size is compensated by a rich variety of colors.

The common cross (Araneus diadematus), whose body is covered with a waxy substance that retains moisture, as well as a rare species listed in the Red Book called the angular cross (Araneus angulatus), which is characterized by the fetal absence of a cruciform pattern and a pair of small the size of the humps in the abdomen.

How long does a cross live

Cross-spiders of different species, in comparison with many of their counterparts, live quite a short time. Males die immediately after mating, and females die immediately after weaving a cocoon for offspring.

Thus, the life expectancy of male crosses does not exceed three months, and females of this species can live for about six months.

Spider venom

The venom of the cross is toxic to vertebrates and invertebrates, as it contains thermolabile hemolysin. This substance can adversely affect the red blood cells of animals such as rabbit, rat and mouse, as well as human blood cells. As practice shows, a guinea pig, a horse, a sheep and a dog have a fairly high resistance to the toxin.

Among other things, the toxin has an irreversible effect on the synaptic apparatus of any invertebrate animal. For human life and health, crosses are in most cases absolutely harmless, but if there is a history of allergies, the toxin can cause a strong burning sensation or local tissue necrosis. Small cross-spiders are capable of biting through human skin, but the total amount of venom injected is most often harmless, so its presence under the skin is accompanied by mild or quickly passing pain symptoms.

Important! According to some reports, the bites of the largest crosses of some species are no less painful than the sensations after a scorpion sting.

Cross web

The cross spider destroys its web every other day and starts making a new one, as the trapping nets become unusable because not only small, but also too large insects get into them. As a rule, a new web is woven at night, which allows the spider to catch prey for itself in the morning. The webs built by an adult female cross spider are distinguished by the presence of a certain number of spirals and radii woven from sticky threads. The distance between adjacent coils is also precise and constant.

This is interesting! Due to their very high strength and high elasticity, crosses have long been widely used in the manufacture of fabrics and various decorations, and among the inhabitants of the tropics they still serve as a material for weaving nets and fishing nets.

The building instinct of the cross-spider is brought to automatism and programmed in the nervous system at the genetic level, so even young individuals are able to very easily build high-quality cobwebs and quickly catch the prey necessary for food. The spiders themselves use exclusively radial, dry threads for movement, so the cross is not able to stick to trapping nets.

Range and habitats

The most common representative is the common cross (Araneus diadematus), found throughout the European part and in some North American states, where spiders of this species inhabit coniferous forests, swampy and shrub plantations. The angular cross (Araneus angulatus) is an endangered and very rare species that lives in our country, as well as in the territory of the Palearctic region. The Australian cross spider Araneus albotriangulus also inhabits the territory of New South Wales and Queensland.

On the territory of our country, oak cross-spiders (Araneus seroregius or Aculeireira seroregia) are most often found, which settle in tall grass on forest edges, in groves and gardens, as well as in fairly dense shrub thickets.

The Araneus savaticus cross, or ram spider, uses grottoes and rocky cliffs, as well as entrances to mines and barns, to equip the trapping network. Quite often, this species settles in close proximity to human dwellings. The cat-faced cross-spider (Araneus gemmoides) lives in the western part of America and Canada, and India, Nepal, the territory of Bhutan and part of Australia became the natural habitat of a typical representative of the Asian fauna of the spider-spider Araneus mitificus or "Spider Pringles".

Food, mining of the cross

The main diet of the cross is represented by a variety of flies, mosquitoes and other small insects, which an adult spider can eat about a dozen at a time. After a fly, a small butterfly or any other small insect enters the net and begins to beat inside it, a noticeable oscillation of the signal thread immediately occurs, and the spider leaves its hiding place.

This is interesting! If a poisonous or very large insect is caught inside the web trap, the cross spider quickly breaks the web to get rid of it. Also, crosses strenuously avoid contact with insects that can lay eggs in other arthropods.

The process of digestion of food in a cocoon usually takes no more than one hour, and then the nutrient fluid is absorbed, and only a chitinous cover remains inside the cocoon.