What the cross spider looks like, where it lives and what it eats. Common cross spider (spider): description, habitat Spider with a white cross on its back

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

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

It is to such creatures that cross spider- a striking specimen from the orb weaver family.

This creature earned 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 from the color on its body that resembles a cross.

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

As you can see, it has a rounded body. It turns out to be almost integral with the head, dividing into two areas, which are usually 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 no larger than 26 mm, but there are specimens of such spiders that are only a centimeter long and much shorter in length.

Besides, cross endowed with eight sensitive flexible legs. He also has four, paired, eyes. These organs are located diversified, which allows this animal to have a 360-degree view in all directions. However, with particularly acute colorful vision, these biological organisms They can’t boast.

They distinguish only the outlines of objects and objects in the form of shadows. But they have quite good senses of taste and smell. And the hairs covering their body and legs perfectly capture a wide variety of vibrations and vibrations.

Chitin, a special natural binding compound, serves as the covering of the body 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 occurs, temporarily freed from the elements that constrain it.

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

This representative of the biological kingdom of arachnids is capable of secreting a substance that is toxic to all types of organisms. So Is the cross spider poisonous or not?? Without a doubt, this small creature is dangerous to many living things, especially invertebrates.

And the poison they secrete has an extremely detrimental effect on their neuromuscular organization.

Types of cross spider

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

Let's present some varieties in more detail.

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

They prefer damp areas and take root well in swampy areas, near rivers and other bodies of water. Their body is reliably protected by a durable thick shell, and humidity preserves a special waxy coating on it.

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

Spider ordinary cross

2. The angular cross is a rare variety, and in the Baltic regions it is generally considered endangered. It is interesting that such arthropods, although they belong to the genus Crusader, do not have a characteristic sign on their body.

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

Angular cross

3. The barn spider is an inhabitant of the Northern. 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. Thanks to such colors, they are camouflaged against the background of their surroundings. The legs of such spiders are striped and covered with white hairs.

In America there is a species of cross - guinea

4. The cat-faced spider is another inhabitant of regions of America similar to the previously described species. Its body is also covered with fluff, and the hairs can be either light or dark. These are very small creatures. 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 reminiscent of a cat’s face.

This decoration for these creatures is located in the place where their relatives usually have a cross.

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

5. Pringles spider is a small-sized resident of Asia, also common in. This one 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 color of the rich vegetation of the regions where such creatures live. The size of males in some cases is 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 the branches, and at the same time finding shelter nearby, among the foliage of small bushes or tall trees.

Therefore, spiders take root well in forests and 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 in other similar places.

On the abdomen of such creatures there are special glands that produce in excess a substance that allows the creature to weave trapping nets. They are known to be called cobwebs. From a chemical point of view, their natural building block is a compound that should be considered very similar in composition to soft silk, which indicates its relative strength.

Spiders usually weave patterned weaves formed from the specified, initially liquid and viscous, material, which then hardens, 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 well be called a true work of weaving art, formed from threads, the length of which is a total of 20 m. It has a regular geometric structure, being endowed with a strictly defined number of spiral turns with specific radii and distances from one circle of the network to another.

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

These curious representatives of the biological kingdom usually weave such structures 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 activity.

In such an activity they do not need assistants, and therefore spiders are individualists in life. And they don’t spend much time communicating with their relatives. Having thus created a trapping net, they climb into an ambush and begin to wait for their prey, as always, completely alone.

Sometimes they don’t particularly hide, but are located in the very center of the web they weave. Or they keep watch, sitting on the so-called signal thread, which allows them to feel all the connections of this weaving.

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

Interestingly, small insects themselves can also pose a danger to spiders. After all, certain varieties of flies and, taking advantage of their usual immobility, are quite capable in the blink of an eye of perching on the back of eight-legged predators and laying their eggs in their body.

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

Nutrition

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

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

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

Cross hunters, lying in wait for prey, sit in ambush with virtually no rest, but even if they are distracted from business, it is for a very short period of time.

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

It happens that the nets placed by these eight-legged creatures catch prey that is too large for such a baby to handle. The spider tries to get rid of such problems by deliberately cutting off the threads of the network connecting itself.

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

But Are cross spiders dangerous for humans 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 quantities released by these arachnids, toxic substances Compared to human size, they are not able to act in a serious way. The bitten subject feels only mild pain, which subsides fairly quickly.

Reproduction and lifespan

The life of these creatures is spent on the web. Here the process of reproduction of their own kind begins for them. And the time for it is usually the end of autumn. At first male cross spider 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 senses. She feels the special vibrations of the weaving and understands perfectly well from them that it is not just anyone, but precisely the candidate for mating, who has violated her loneliness.

Then she goes down to her stall, which responds to his signs of attention. After intercourse, males no longer survive. But the female continues the work she started. She creates a special cobweb cocoon and lays her eggs there.

Cross spider nest

At first she carries this house for her offspring on herself, but having found a suitable place for it, she hangs it on a homemade thread. Soon the cubs appear there, but they do not leave their house, but remain in it throughout the winter. They emerge from the cocoon only in the spring. But their mother does not live to see warmer times.

Young spiders grow up, live throughout the warm period, and then the entire reproduction cycle repeats again. From here it is not difficult to understand: how long do cross spiders live. The entire period of their existence, even if we count wintering together, turns out to be less than a year.

Millions of different spiders live in nature, killing entire armies of insects that are dangerous both to humans and to their homes.

And if not for these arthropods, the number of mosquitoes, moths, aphids and other insects would be much greater, which would cause great discomfort to people and animals.

What it looks like: description, internal and external body structure

One of the most common representatives of the orb-web spider family is the cross spider, which has more than 1,000 species. Let's consider the most prominent representatives of this family, what are the main characteristics of the body structure.

Common crossweed (Araneus diadematus)

This type of cross spider is a small spider.

External characteristics he has the following:

the body of an adult male reaches a maximum of 1.1 cm, females are larger, specimens up to 4.0 cm can be found;
the body cover consists of a durable shell of a yellow-brown hue, which changes during the molting period;
when wondering how many legs an ordinary spider has, you need to know that the spider has 8 legs, each of which plays its own role in the life of the arthropod;
sense organs are well developed. The spider has a good sense of smell and taste, thanks to the hairs that cover its entire body, it can easily detect even the slightest vibration or vibration;
four pairs of eyes, each facing different sides, create a broad horizons.

Important! Despite large number eyes, arthropods of this species are myopic. They can only see shadows and the outlines of large objects.

Angular (Araneus angulatus)

Another species of cross spider, which is included in the Red Book in many countries.
External differences are represented by the following indicators:

females reach small sizes, a maximum of 1.8 cm, but they are still larger than the male, whose length is only 1.2 cm;
they do not have a cross, instead there are 2 small humps that are located in the abdominal area;
the whole body is dotted with light-colored hairs;
the oral apparatus is located on the cephalothorax;
eyes number 8;
There are 4 pairs of legs on the body.

In general, the body parts and respiratory organs are no different from other representatives.

Marbled (Araneus marmoreus)

This type of spider has its own external differences:

has significant sexual dimorphism. Females grow much larger than males. Their length is up to 18 mm, spiders grow up to 8 mm;
these arthropods are endowed with a wide range of colors and patterns. However, the most common one is the orange belly and black pattern. It is this variation that gives the species its name.

The remaining organs, as well as the digestive and respiratory systems, are the same as those of other spiders of this species.

Where does he live and how long does he live?

Habitat: damp and damp areas. The greatest likelihood of encountering it can occur in places where a large number of trees grow, where they stretch their web, as well as along the banks of reservoirs and even in the attics of various buildings.

Did you know? 2.5 billion years ago the first spiders appeared on Earth, which gave birth to more than 30 thousand species of spiders that live almost everywhere today.

More than 30 species of spiders live in Russia and the former CIS countries, including Ukraine. This species of arthropod is a hermit predator, and main feature his behavior is an extremely negative attitude towards others like himself. At night, these arthropods weave their hunting webs, and during daylight hours they hunt their victims.

What does it eat?

The main thing in the spider's diet are small insects. During the day, the female absorbs food in an amount equal to her weight. When an inedible insect gets into the web, the spider gets rid of it by breaking the threads.
He also tries to avoid flies and wasps, which can lay eggs on other animals. Hunting occurs in two ways: in the center of the web or from a nearby shelter.

The predator is not able to immediately consume food, so it quickly injects aggressive juice into the caught prey, places the prey in a cocoon and waits for the victim’s insides to turn into a nutrient solution. This process takes approximately 1 hour, after which the spider sucks out the prey, leaving the cocoon behind.

Web of the cross spider

All the webs that spiders weave are no different from one another, since the ability to weave webs is inherent in these predators at the genetic level. Only females weave such beautiful, intricate patterns.

Did you know? In microbiology, spider webs are used as the thinnest optical fiber to detect the composition of air in the atmosphere.

The web has strictly 39 radii and 1245 points of their attachment to the spiral, which, in turn, consists of 35 turns. The threads that make up the web are light, but at the same time they are very strong - they are used by tropical residents to weave nets and fishing gear. In addition, the threads are very elastic.
In the process of arranging her creation, the female uses two types of threads. The base and radii are woven from dry fibers of a durable structure without a sticky coating and stretched between the branches.

Then the spider begins to weave threads, which are located from the center to the edges, and a spiral thread, which will be the basis for the catching spiral. After the work has been done, the spider lays a web with an adhesive base from the center of her creation.

The spiders themselves move only along dry threads, so they do not get stuck on their fishing nets. It takes the spider approximately one hour to weave the entire web.

Poisonous or not

The venom of the brown cross contains heat-labile hemolysin, which has a negative effect on blood cells.

However, its dose is so small that it can only harm small animals. A spider bite is not dangerous for humans, but minor injuries may occur. discomfort if you are allergic to animal bites.
At the site of the bite, minor pain and itching occurs quickly. To quickly relieve these symptoms, you need to wash the affected area of skin with soap and apply something cold, ice if possible, then apply ointment to relieve inflammation.

Important! The spider never attacks first - a bite is possible upon accidental contact.

Reproduction and offspring

The mating season for spiders takes place in August. During courtship, the male, in order not to become a victim, carefully approaches the edge of the web, pulls the threads with his paws and waits until the female responds in kind. Then mating occurs, after which the male dies.

Belongs to the orb-weaver family, a genus of araneomorphic spiders. In total, there are more than 1000 species of representatives of this genus in the world, but in Russia and the CIS countries you can find from 15 to 30 species.

Habitats

Crosses live mainly in damp and damp places - in fields, meadows, forests, along the banks of reservoirs and rivers.

Cross spider

The structure of the cross spider

Dimensions, description
The size of the male is 10-11 mm, the larger female is 17-26 mm. The cross has 8 legs and a large rounded abdomen. On the upper side of the spider's abdomen, white or light brown spots form a kind of cross, hence the name of the spider. The cross spider has 4 pairs of eyes, like most spiders; they look in different directions, providing their owner with a fairly broad horizon. However, spiders see poorly, they are myopic and distinguish mainly shadows, movement, and the contours of everything that surrounds them.

Features of the cross spider

Spiders are dioecious animals. After mating, the male dies, and the female begins to weave a cocoon from the web for eggs, which she usually lays in the fall. The cocoon turns out to be quite dense; the female carries it on herself for some time, and then hides it in any safe place - in a crack in the bark of trees or behind a loose piece of bark. In spring, young (juvenile) spiders emerge from the cocoon. They become sexually mature by the end of summer, after which the female that gave birth to them dies.

In the first days of his life, the male cross spider also builds a web - he needs to eat something. But upon reaching maturity, he begins to wander in search of adventure and, of course, noticeably loses weight. During this period, he is driven by only one desire - to find the female’s web.

When the female's web is found, he makes every effort not to get to her for lunch. To do this, he weaves a thread for himself down from the edge of the web - for retreat. Then he carefully tugs the thread. The female immediately rushes in search of prey, and the male retreats down the rescue thread.

This is repeated several times until the female understands that it is not the prey who is pulling the web, but her long-awaited partner. Then she changes her anger to mercy, and the spiders mate. But the male must not let down his vigilance, because... after mating, the hunting instinct awakens in the female again. If he does not escape in time, he may well be eaten.

Reproduction of the cross spider
The cocoon, which the female weaves in autumn, contains from 300 to 800 amber-colored eggs. Under the protection of the cocoon, future spiderlings are not afraid of either cold or flood - it is very light and does not get wet. The eggs wait out the winter in the cocoon, and in the spring small spiders emerge from the eggs. For some time they sit inside the cocoon, afraid to leave such a cozy refuge. But gradually they spread out and begin to live on their own.

It is clear that it will be very difficult for such a huge offspring to get settled in life. Competition is very high, some will die of hunger, and others will be eaten by their relatives. Therefore, the young spiders face a serious task - to disperse as quickly as possible in order to increase their chances of survival.

Their legs are small and weak, so the spiders move, gliding with the help of their web, like real aeronauts. With a fair wind, the spider can fly a distance of 300-400 km. When the wind subsides, the web falls to the ground, the spider throws it away and begins to settle in a new place. If he is lucky with the site, he will be able to catch up to 500 insects per day with his nets. The hunt is ongoing.

According to naturalists, millions of spiders live in meadows, fields and forests, destroying entire legions of insects, including those dangerous to humans and their households. If it were not for spiders, the number of flies, mosquitoes, gnats, midges, moths and aphids would be several orders of magnitude greater and could seriously poison our lives. Experts do not even rule out the possibility of using spiders in biological control with pests.

The spider either eats the caught prey immediately on the spot, or, if it is not too hungry, drags it into a secluded corner or entangles it in a web. Around the web, under the leaves, you can find a whole food warehouse of flies entangled in the web, stored for a rainy day.

The behavior of the cross spider

How does a spider hunt? When a fly or any other insect gets caught in a web, the spider senses the vibration of the trapping web, it crawls into the victim and kills it with a bite of its poisonous mandibles, or chelicerae. The fly stops shaking the web, and the spider calmly swaddles it with a bundle of thin threads, pulling them out of the abdomen with a pair of its legs.

Having snacked on the surrounding threads, the spider takes its breakfast and goes to the center of the web to have a meal. He crushes his prey, injecting digestive juices into it. When the fly has digested inside its shell, the spider sucks up the semi-liquid contents into which the fly has turned and throws away the victim’s skin. During a successful hunt, a spider can eat about a dozen flies in one sitting. The venom of cross spiders is dangerous only for small insects; it cannot harm humans.

Habitat

Crossworts live mainly in the crowns of trees, make a secluded shelter from the leaves, and stretch the web between the branches. The wheel-shaped web can be found in a forest, grove or neglected garden. Sometimes it can be found in bushes or in window frames and under the eaves of abandoned houses.

The trapping web constantly requires repair, it is destroyed by both small and large insects, so every couple of days the cross spiders unravel the web and make a new one. They usually do this at night, and by morning the new web is ready for new prey. Thus, at night the spider is relatively safer, because it natural enemies, insectivorous birds, sleep at night. It does not need light to build a web; a well-developed sense of touch is sufficient.

The enemies of the cross spider are also flies and wasps, which lay eggs in the bodies of their victims. For example, the fly Melanophora rugalis - taking advantage of the spider’s immobility, it can fly up to it, sit on its back and in the blink of an eye lay an egg in its body.

Web of the cross
The web of the female cross has exactly 39 radii, 1245 points of attachment of the radii to the spiral and 35 turns of the spiral - no more, no less. The webs of all spiders are as similar to one another as two peas in a pod, because all the necessary data is genetically enshrined in their heredity. Therefore, even small spiders know how to build webs and catch prey.

Any web is not only beautiful in its symmetry and delicacy, it is very rationally arranged. All the threads that form it are very light and, nevertheless, very strong, and are connected in such a way that they only work to break.

How does a spider manage to build such an even, symmetrical web that is several dozen times its size? A spider (more precisely, a cobweb), having climbed onto a branch or tree trunk, releases a long web thread from its abdomen. It is picked up by a stream of air, and the spider waits patiently until the thread catches on something suitable.

If this does not happen and the thread hangs, the spider pulls it towards itself and eats it. Then he runs to another place and tries again. And so on until the thread is caught. Then the spider crawls to the hooked end of the thread and secures it well. Then it descends on its thread to some support. There he also firmly fastens this thread - now 2 threads are already fastened.

The spider returns along the second thread and drags along the third, which it secures at the starting point, i.e. where the first thread came from. The triangular frame - the basis of the future web - is ready. Inside this frame, the spider stretches several threads that intersect in the center. The spider marks the center of the web with a lump and begins to extend all its numerous radii from it, fastening them with a spiral thread, and then lays trapping threads. At the intersection points of the spiral and the radius, the spider binds them with its legs.

Note that the angles between all radii and the distance between the turns of the web are strictly constant values. How can such a little creature manage to maintain your web in strict accordance with geometry? For this you need at least the simplest meter. And, imagine, the spider has it! This is his first pair of legs that can act as a scale ruler.

While working on the web, the crossmaker regularly checks the distance between the spirals. His natural tool is so precise and reliable that it allows you to work in pitch darkness. The last step in creating a web will be a signal network, the end of which is laid to the spider’s shelter. To build the entire web, the spider requires several hours of painstaking work and approximately 20 meters of web.

From a chemical point of view, the web is a complex protein polymer - fibroin. The many glands of the spider's abdomen form this viscous liquid, which quickly solidifies in air in the form of thin filaments. The spider can produce several different types of web with different properties. For the frame of the web he makes a dry and thick thread, for the cocoon - silky and soft, for the catching spiral - thin and sticky. Why doesn't the spider itself stick to its web? Everything is very simple - he runs only on non-adhesive threads, and diligently avoids touching adhesive spirals.

The polymer liquid comes out from the glands on the spider's abdomen through thin tubes and hardens into very thin threads. If the spider needs special strength, it can weave several of these threads together. Scientists in recent years They are seriously studying the properties of spider “silk”. It turned out that it has many unique properties.

The technology for producing spider web threads is similar to the production of synthetic fibers. But in terms of strength, no synthetic fiber can compare with spider fiber - it can withstand loads of up to 260 kg per 1 sq. mm, which is stronger than steel. This is why residents of the tropics make nets from spider webs to catch birds, bats, insects, and even weave fishing gear.

The web is so elastic that it can stretch up to 30% of its length and shrink back to its original length. Its lightness and subtlety are involuntarily amazing, because 340 grams of web is enough to encircle the globe at the equator!

The use of cobwebs in agriculture and medicine
People have long tried to make fabric based on spider webs. In Germany, back in the 16th century, ribbons were woven from spider webs and various decorations. Then in France, artisans came up with the idea of making gloves and stockings from spider webs, which caused complete delight among fashionistas.

But it turned out to be impossible to launch this technology into large-scale production, and this was convincingly proven by the physicist and zoologist Reaumur. For such production to become profitable, it is necessary to contain and feed hundreds of thousands of spiders. But to feed them, it would be necessary to catch several million flies every day, which was completely impossible to implement in practice.

However, people still use the web, even today. For sights (crosshairs) in various optical instruments (microscopes, telescopes, sights, etc.), spider webs are simply ideal. Microbiologists have also found use for it, developing a unique air analyzer using it.

The cross spider is launched onto a special frame, fed, and the spider weaves its web based on this frame. Then air is pumped through a frame with a net, and the thinnest web perfectly captures the microbes that are in the air. This method of air analysis has been recognized as the most effective of all existing in the world.

IN folk medicine Since ancient times, spider webs have been used to disinfect open wounds. Research confirms that spider webs kill pathogenic bacteria, and with its help, drugs were developed that are harmless to animals, but deadly to all kinds of bacteria. As you can see, the cross spider is extremely useful for humans, in every sense.

The cross spider, or Araneus, belongs to the orb-weaver family, a genus of araneomorphic spiders. In total, there are more than 1000 species of representatives of this genus in the world, but in Russia and the CIS countries you can find from 15 to 30 species. Crosses live mainly in damp and damp places - in fields, meadows, forests, along the banks of reservoirs and rivers.

The structure of the cross spider

The size of the male is 10-11 mm, the larger female is 17-26 mm. The cross has 8 legs and a large rounded abdomen. On the upper side of the spider's abdomen, white or light brown spots form a kind of cross, hence the name of the spider. The cross spider has 4 pairs of eyes, like most spiders; they look in different directions, providing their owner with a fairly broad horizon. However, spiders see poorly, they are myopic and distinguish mainly shadows, movement, and the contours of everything that surrounds them.

Features of the cross spider

Reproduction of the cross spider

The cocoon, which the female weaves in autumn, contains from 300 to 800 amber-colored eggs. Under the protection of the cocoon, future spiderlings are not afraid of either cold or flood - it is very light and does not get wet. The eggs wait out the winter in the cocoon, and in the spring small spiders emerge from the eggs. For some time they sit inside the cocoon, afraid to leave such a cozy refuge. But gradually they spread out and begin to live on their own.

According to naturalists, millions of spiders live in meadows, fields and forests, destroying entire legions of insects, including those dangerous to humans and their households. If it were not for spiders, the number of flies, mosquitoes, gnats, midges, moths and aphids would be several orders of magnitude greater and could seriously poison our lives. Experts do not even exclude the possibility of using spiders in biological pest control.

Web of the cross spider

Cross spiders catch their prey using webs. More precisely, their females - male spiders do not weave webs. Female spiders guard their prey either in the center of the web or sitting next to it, on a signal thread. Mostly flies or mosquitoes get caught in the web. If it comes across prey that is too large and inedible, for example a wasp, the spider can free it by tearing off the web.

The behavior of the cross spider

Having snacked on the surrounding threads, the spider takes its breakfast and goes to the center of the web to have a meal. He crushes his prey, injecting digestive juices into it. When the fly has digested inside its shell, the spider sucks up the semi-liquid contents into which the fly has turned and throws away the victim's skin. During a successful hunt, a spider can eat about a dozen flies in one sitting. The venom of cross spiders is dangerous only for small insects; it cannot harm humans.

Habitat of the cross spider

The trapping web constantly requires repair, it is destroyed by both small and large insects, so every couple of days the cross spiders unravel the web and make a new one. They usually do this at night, and by morning the new web is ready for new prey. Thus, at night the spider is relatively safer, because its natural enemies, insectivorous birds, sleep at night. It does not need light to build a web; a well-developed sense of touch is sufficient.

Web of the cross

The web of the female cross has exactly 39 radii, 1245 points of attachment of the radii to the spiral and 35 turns of the spiral - no more, no less. The webs of all spiders are as similar to one another as two peas in a pod, because all the necessary data is genetically enshrined in their heredity. Therefore, even small spiders know how to build webs and catch prey.

The spider returns along the second thread and drags along the third, which it secures at the starting point, i.e. where the first thread came from. The triangular frame - the basis of the future web - is ready. Inside this frame, the spider extends several threads that intersect in the center. The spider marks the center of the web with a lump and begins to extend all its numerous radii from it, fastening them with a spiral thread, and then lays trapping threads. At the intersection points of the spiral and the radius, the spider binds them with its legs.

Note that the angles between all radii and the distance between the turns of the web are strictly constant values. How does such a small creature manage to maintain its web in strict accordance with geometry? For this you need at least the simplest measuring device. And, imagine, the spider has it! This is his first pair of legs that can act as a scale ruler.

The polymer liquid comes out from the glands on the spider's abdomen through thin tubes and hardens into very thin threads. If the spider needs special strength, it can weave several of these threads together. In recent years, scientists have been seriously studying the properties of spider “silk”. It turned out that it has many unique properties.

The use of cobwebs in agriculture and medicine

People have long tried to make fabric based on spider webs. In Germany, back in the 16th century, ribbons and various decorations were woven from cobwebs in villages. Then in France, artisans came up with the idea of making gloves and stockings from spider webs, which caused complete delight among fashionistas.

In folk medicine, spider webs have been used since ancient times to disinfect open wounds. Research has confirmed that spider webs kill pathogenic bacteria, and with its help, drugs have been developed that are harmless to animals, but deadly to all kinds of bacteria. As you can see, the cross spider is extremely useful for humans, in every sense.

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

Description of the cross

The external structure of the cross is represented by the abdomen and arachnoid warts, the cephalothorax and walking legs, consisting of the femur, knee joint, tibia, pretarsus, tarsus and claw, as well as the chelicera and pedipalp, acetabulum ring and coxa.

Appearance

Cross spiders are quite small spiders 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 spider, as a rule, does not exceed 1.0-1.1 cm. The entire body of the cross spider is covered with a very characteristic yellowish-brown chitinous durable shell, shed during time for another molt. Along with most arachnid species, cross spiders have ten limbs, represented by:

four pairs of walking legs, with relatively sharp claws located at the ends;
one pair of pedipalps, which perform a recognition function and are necessary for holding caught prey;
one pair of chelicerae used in capturing and killing the caught prey. The chelicerae of the crosses are directed downward, and the hooks of the chelicerae are directed inward.

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 spermatheca located on the female, due to which offspring appear.

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 capable of responding to the presence of stimuli. chemical type, other hairs perceive air vibrations, and third hairs pick up all kinds of surrounding sounds.

The abdomen of cross spiders is round in shape and completely devoid of segments. In the upper part there is a pattern in the form of a cross, and on the lower part there are three pairs of special arachnoid warts, which contain almost a thousand glands that produce arachnoid threads. Such strong threads have various purposes: building reliable fishing nets, arranging protective shelters, or weaving a cocoon for offspring.

The respiratory system is located in the abdomen and is represented by two pulmonary sacs, in which there is a significant number of leaf-shaped folds with air. Liquid hemolymph, enriched with oxygen, circulates inside the folds. Also included respiratory system tracheal tubes enter. In the dorsal region of the abdomen there is a heart, which with its appearance resembles a fairly long tube with branching, 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 in our country and in neighboring countries, which are characterized by the presence of a pronounced “cross” located on the upper part of the abdomen. Frequently encountered 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 cross spider Araneus sturmi, which lives mainly in coniferous forests in the Palearctic region, whose modest size is compensated by a rich variety of colors.

The most widespread are also the common cross (Araneus diadematus), the body of which 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 absence of a cruciform pattern and has a pair of small the size of the humps in the abdominal area.

How long does a cross live?

Cross spiders of various species, compared to many of their counterparts, live for a fairly 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 poison of the cross is toxic to vertebrate and invertebrate animals, since it contains heat-labile hemolysin. This substance can negatively affect the red blood cells of animals such as rabbits, rats and mice, as well as human blood cells. As practice shows, they have a fairly high resistance to the toxin guinea pig, horse, sheep and dog.

Among other things, the toxin has an irreversible effect on the synaptic apparatus of any invertebrate animal. In most cases, crosses are absolutely harmless to human life and health, 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 quantity the 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.

Web of the cross

As a rule, cross spiders settle in the crown of a tree, between the branches, where the spider sets up large trapping nets. The foliage of the plant is used to make shelter. Quite often, spider webs are found in bushes and among window frames in abandoned buildings.

The cross spider destroys its web every other day and starts making a new one, since the catching webs become unusable due to the fact that 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 adhesive threads. The distance between the turns located next to each other is also precise and constant.

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

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

Range and habitats

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

On the territory of our country, oak cross spiders (Araneus seropegius or Aculeira seropegia) are most often found, which settle in tall grass on forest edges, in groves and gardens, as well as in fairly dense bushes.

The Araneus cavaticus spider, or barn spider, uses grottoes and rocky cliffs, as well as entrance holes to mines and barns, to construct a trapping net. Quite often this species settles in close proximity to human habitation. The cat-faced cross spider (Araneus gemmoides) lives in the western part of America and Canada, and natural habitat typical representative The Asian fauna of the cross spider Araneus mitificus or “Pringles spider” has become India, Nepal, the territory of Bhutan and part of Australia.

Food, catch of the cross

Cross spiders, along with most other spiders, have external type digestion. While waiting for their prey, spiders are usually located near the net, located in a hidden nest, which is made from strong web. A special signal thread is stretched from the central part of the network to the spider's nest.

The main diet of the cross is represented by a variety of flies, mosquitoes and others. 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 falls into the net and begins to beat inside it, a noticeable vibration of the signal thread immediately occurs, and the spider comes out of its hiding place.

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

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

The process of digesting food in the cocoon most often takes no more than one hour, and then the nutrient liquid is absorbed, and only the chitinous cover remains inside the cocoon.