home

Cross spider black and white. Common cross (spider): description, habitat. Description and characteristics

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

The spider's body 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, durable and quite elastic chitinous cover.

The spider periodically moults, shedding its chitinous cover. At this time it is growing. At the anterior end of the cephalothorax there are four pairs of eyes, and below there is 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, poison from the poisonous glands located at their base enters the victim’s body. Next to the chelicerae there are short organs of touch, covered with sensitive hairs - the 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 arachnoid warts instantly hardens in air and turns into a strong web thread. Different parts of arachnoid warts produce different types of webs. Spider threads vary in thickness, strength, and adhesiveness. The spider uses different types of web to build a trapping network: at its base there are stronger and non-sticky threads, and concentric threads are thinner and stickier. The spider uses webs to strengthen the walls of its shelters and to make cocoons for eggs.

Internal structure

Digestive system

The spider's digestive system consists of the mouth, pharynx, esophagus, stomach, and intestines (front, middle and back). In the midgut, long blind processes increase its volume and absorption surface.

Undigested residues are expelled through the anus. The spider cannot eat solid food. Having caught prey (some 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 captured insect liquefy, and the spider sucks it up. All that remains of the victim is an empty chitinous shell. This method 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 extend from the heart.

In a spider, the body cavity is of a mixed nature - during development it arises from the connection of the primary and secondary body cavities. Hemolymph circulates in the body.

Respiratory system

The spider's respiratory organs are the lungs and trachea. The lungs, or pulmonary sacs, are located below, in the front of the abdomen. These lungs developed from the gills of the distant ancestors of spiders that lived in water.

The cross spider 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 spider's nervous system consists of the cephalothoracic nerve ganglion and numerous nerves extending from it.

Excretory system

The excretory system is represented by two long tubes - Malpighian vessels. One end of the Malpighian vessels ends blindly in the body of the spider, the other opens into the hind intestine. Harmful waste products come out through the walls of the Malpighian vessels, which are then excreted. Water is absorbed in the intestines. In this way, 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 transfers sperm to the female's genital opening using special outgrowths located on the front legs.

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

In our area, one of the most striking representatives of arachnids is the cross. About 30 species live in Russia. They differ in color and slightly in size. A characteristic feature is the presence of a cross-shaped pattern on the abdomen. Whether the cross or crusader spider is dangerous for humans remains to be seen.

Description of appearance

Rinse the wound under running water.
Lather with laundry soap, leave for 5 minutes, rinse.
Wipe the bite area with alcohol or a tincture based on it.

If you have to act in the wild, use improvised means:

vodka;
lemon, orange juice;
juice of celandine, plantain, dandelion;
saliva.

On a note!
To relieve swelling, apply ice cubes and a cold compress. You can eliminate itching, burning, and also disinfect the damaged area with baking soda paste, vinegar solution, shaving foam, and toothpaste.

In the future, to accelerate the therapeutic effect, a cream or ointment with an antihistamine effect based on medicinal herbs and special substances is used. The wound is treated 2-4 times a day until the condition of the skin improves. The condition returns to normal within 3 days.

Use:

balm Zvezdochka;
Psilo-balm;
Fenistil gel;
calendula ointment;
Menovazin;
Advantan.

If the wound gets infected, ulcers appear, treat with local antibiotics - Levomekol, Tetracycline ointment, Elokom S.

To eliminate general allergy symptoms, take an antihistamine orally - Fenistil drops, Claritin, Diazolin tablets, El-Cet, Eden, Suprastin. Treatment continues for 3 days without consulting a specialist. If the condition does not return to normal, you should consult a doctor.

The cross spider rarely bites, but every nature lover should be aware of the possible consequences. Prompt first aid will help avoid serious consequences.

Araneus mitificus or "Spider Pringles"«

a typical representative of the Asian fauna, distributed from India, Nepal and Bhutan to Australia. A notable feature of the cross spider is an exact copy of the mustachioed face from Pringles chips packages, located in the place of the traditional cross. These spiders hunt only from ambush, and their networks are always missing one section, but there is a signal thread stretched into the shelter. The size of adult females is 6-9 mm, males - 3-5 mm, but their modest sizes do not prevent spiders from proudly wearing the “face” of popular chips.

Araneus ceropegius, Aculepeira ceropegia)

lives in thickets of bushes and tall grass of forest edges, groves and gardens of the temperate climate zone. Oak crosses live in Europe, Russia, northern Africa, as well as in Asian countries north of the Himalayas, excluding the Arabian Peninsula. Females and males are characterized by an abdomen pointed at both poles and a well-pubescent cephalothorax. The length of the female cross is 1.2-1.4 cm, the male - 0.7-0.8 cm. The upper side of the brown abdomen is decorated with a light herringbone, and below there is an elongated yellow spot.

or meadow cross(Araneus quadratus)

Found in damp, open grassy areas. Lives in Europe, Central Asia, Russia, Japan. The shape, size and color are very similar to the common cross. On the upper part of the abdomen, the cross spider has 4 round light spots or 4 dark dots, depending on the main color of the body. Below is a blurry leaf-like pattern. The main body color varies from light green and carmine to black-brown. There may be light stripes on the paws. The length of females is 1.7 cm, males are half as long. Adult female cross spiders can change color and blend in color with their surroundings.

Araneus sturmi

A rare orb-weaving spider, it lives primarily in coniferous forests in the Palearctic region (Europe, Russia, Asia north of the Himalayas, northern Africa). The maximum body length of these spiders is 5.5 mm, females are usually longer than males: the length of females is 5-5.5 mm, the length of males is 4 mm. The modest size of the cross is compensated by the variety of colors. The usual color of individuals of both sexes is reddish-brown, but very beautiful, red-yellow-green specimens are found. A distinctive feature of this species of cross spider is the “epaulets,” dark areas in the front of the abdomen.

(Araneus alsine)

a typical inhabitant of moist deciduous forests of the temperate zone. Externally, this spider resembles a meadow cross and has 4 similar large spots on the abdomen, but differs in color, which is dominated by orange and beige tones. The spider's abdomen is dotted with small light spots, so the spider looks like a strawberry (hence its English name “strawberry spider”). Females of the chilly cross grow from 7 to 13 mm, the length of males is 5-6 mm.

Reproduction and development of the cross spider

The mating season of crosses occurs in autumn, when sexually mature males wander through the forests in search of a female sitting in her web. Having found a suitable option, the male cross weaves a thread from the edge of the web, which serves as an escape route and at the same time an invitation to mate. The female recognizes such vibration as a signal for reproduction and leaves her network, and immediately after mating is completed the male dies.

The fertilized female cross spider builds a cocoon of soft silky threads, where she very soon lays eggs. She keeps the cocoon with herself for several days, and then hides it in a secluded place, hanging it in the cracks of the walls of residential buildings or under the bark of trees, where the cocoon will safely overwinter. After this, the female dies.

The offspring are born in the spring, and by summer the young spiders are already able to reproduce.

Photo taken from travelswithmusti.net

Due to their high strength and elasticity, spider web threads have been used for making fabrics and jewelry since ancient times, and tropical residents still weave nets and fishing nets from it.
The web of the cross spider is used in microbiology to determine the composition of atmospheric air and as the finest optical fiber.
The cross spiders themselves move inside the web along radial, dry threads, so they do not stick to their own trapping network.

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 chelicerae hooks 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 seminal receptacle 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 chemical irritants, other hairs perceive air vibrations, and still others 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. The respiratory system also includes tracheal tubes. In the dorsal region of the abdomen there is a heart, which in 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 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, guinea pigs, horses, sheep and dogs are quite resistant to the toxin.

Among other things, the toxin has an irreversible effect on the synaptic apparatus of any invertebrate animal. In most cases, crosses are absolutely harmless for 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 the total amount of 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 the point of automatism and is programmed in the nervous system at the genetic level, so even young individuals are able to very easily build high-quality webs and quickly catch 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 spider (Araneus diadematus), found throughout the European part and in some North American states, where spiders of this species inhabit coniferous forests, swampy and shrubby plantations. The angular cross (Araneus angulatus) is an endangered and very rare species that lives 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 bush thickets.

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 the natural habitat of a typical representative of the Asian fauna, 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 an external type of digestion. While waiting for their prey, spiders are usually located near the net, located in a hidden nest, which is made of durable 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 spider 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 gets into the net and begins to fight 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.

Cross spider (Araneus) is an arthropod belonging to genus of araneomorph spiders And family of orb weavers(Araneidae). They live in almost every country, except for southern and northern latitudes. This type is the most common. There are 2,000 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