Cross spider ?️ - description of the internal and external structure

General characteristics. External structure

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.

Is it dangerous to humans?

The cross is absolutely harmless to people. There are stories that the spider is poisonous and that after being bitten a person can die. This is wrong. Yes, he can bite and the bite will be painful. There are rules that will help you get rid of pain. You need to know that the crossman never attacks first. It can bite if a person gets caught in its net with their hand. Not on purpose, but for the spider this is a signal of a threat to its life. He defends himself as best he can.

Rice. 5. Spider Araneus diadematus When bitten, after 5 minutes the following sensations occur:

• your head starts to hurt;
• weakness appears in the body;
• there is aching in the joints;
• the bite site is very itchy;
• Subcutaneous hemorrhages may appear on the body.

It is recommended to wash the bite area with soap and water. Then apply something cold. Ideally, ice. For headaches and fever, it is best to take paracetamol. If you have allergies, you need to take antihistamines.

Important! If a child is bitten by a spider, urgent medical attention is needed!

It is known that the bites of some species of crosses are more painful than the bites of scorpions.

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.

Population and species status

The cross spider lives over vast territories, inhabiting almost the entire territory of Eurasia, as well as the territory of North America. Cross spiders are grouped into a large number of subspecies that live either in large spaces or in limited areas. If you take the Hawaiian wolf spider, it is found in a limited area of ​​Cautan Island.

The spider, called the striped hunter, is found throughout the vastness of modern Europe. To date, there are no programs or efforts related to the conservation and increase in the total number of such arthropods.

Cross spiders, along with many inhabitants of our Planet, are part of the global ecosystem of wildlife. Many people argue that if a living creature is poisonous, then it has no place near a person. This opinion appears in people as a result of lack of education or as a result of various phobias. They are frightened even by the simple word “spider,” not to mention the sight of a live spider.

In fact, you need to understand that the destruction (disappearance) of one of the chains of our ecosystem can lead to unpredictable consequences.

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.

What's the use?

• Scientists used spider webs to create an air analyzer. The net catches all the microparticles of the air and, by examining it, you can see what we breathe.
• The threads have antibacterial properties. Used in optical instruments.
• The spider catches up to 500 insects per day. Millions of crosses live in nature. It is possible to calculate how many insects are destroyed, including those that pose a threat to humans and agriculture. Scientists are considering crosses as a biological weapon for pest control.

Rice. 6. Spider Araneus albotriangulus

general information

You can meet the common cross spider in almost every country. They live on all continents except northern and southern latitudes. In total, there are more than 40 thousand different species of arachnids in the world, 2 thousand of which are crosses. The territory of Russia can boast of only 10 species of these arthropods. They belong to the family of orb-weavers, a genus of araneomorphic spiders. They are most common in the areas:

• Rostov;
• Smolenskaya;
• Astrakhan.

Arthropods are very often found in the Mordovian region.

The size of cross spiders is quite small. But it is worth noting that the female of this species is larger in size. The length of the male is only up to 1.1 cm. His partner can reach 4 cm. The female and male sexes can be distinguished from each other by their abdomen. In males it is small and narrow, in females it is round and large. The external structure of the cross spider does not differ significantly from its relatives in its genus. At first glance, this is a completely ordinary spider, except for the peculiarities of its external color.

What are the benefits of the crusader spider?

Firstly, we dispelled the myth that the cross spider is poisonous to humans. Secondly, it must be proven that it brings considerable benefits in nature. An adult crosswort, of any type, destroys a large number of insect pests that are carriers of dangerous diseases.

1. Strong threads of spider web have been used since ancient times for weaving fishing gear: nets and nets.
2. The web is the basis of many fabrics and decorations. For example, the French wove stockings and gloves from threads of spider webs.
3. Even scientific research uses spider webs. It is used in microbiology to determine the composition of atmospheric air.
4. Some scientists have long been using spider webs in optical measuring instruments.
5. It is believed that the spider's web has disinfecting and antiseptic properties, as it is capable of destroying bacteria and viruses.

Therefore, if you meet a spider with a cross on the outside of its abdomen on your way, you should not run away “like fire”; remember that it is not dangerous, but very useful.

Sources

• https://faunistics.com/pauk-krestovik/
• https://dezplan.ru/vopros/pauk-krestonosec
• https://premier-agro.ru/pauk-krestovik-opisanie-stroenie-gde-obitaet-pitanie/
• https://wildfauna.ru/pauk-krestovik
• https://givnost.ru/krestovik-pauk-opisanie-osobennosti-vidy-obraz-zhizni-i-sreda-obitaniya-krestovika/
• https://obnaruzhil.ru/pauk/pauk-krestovik.html
• https://fishki.net/2171165-pro-pauka-krestovika.html
• https://TaraKlop.ru/pauki/pauk-krestovik/
• https://domvred.ru/pauk-krestovik/
• https://dezbox.ru/dezinsekciya/opasen-li-pauk-krestovik-dlya-cheloveka/

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Lifestyle, behavior

Predators live alone, gathering in pairs for a very short time - during the mating season

The males crawl up to the female’s web and carefully move the threads. A hungry spider can easily eat a gentleman before he even begins to court

If the chosen one remains in the center of the web, sits motionless, you can approach her.

Crossbills feed on insects. Their trapping nets catch butterflies, flies, grasshoppers, crickets, wasps, bees, fruit flies, and mosquitoes. The spider pierces the chitinous cover, injects poison and saliva. The toxic substance causes muscle paralysis and immobilizes the victim. The mica turns the insides into a liquid mass, which the predator then drinks.

Toxicity

Its venom is toxic to us and about five minutes after the bite you can feel the following unpleasant symptoms.

Symptoms

If your health deteriorates seriously, it is recommended to consult a specialist, as there is a risk of complications. Most often, more unpleasant symptoms appear in children and people with weakened immune systems. The child is at high risk of an allergic reaction. Symptoms include:

1. Itching. It almost always occurs, but the degree of discomfort can vary greatly.
2. Sharp and chaotic headaches. Possible dizziness and short-term disorientation.
3. Joint pain. This especially applies to older people suffering from joint diseases (for example, arthrosis or arthritis).
4. Change in body temperature. In the absence of a severe allergic reaction, in most cases there is a slight increase.
5. Slight weakness. Less commonly, minor apathy and increased drowsiness may occur.

It is worth noting that some pets are practically not sensitive to the bites of this arachnid. This applies to dogs, guinea pigs, horses and sheep. It is also necessary to pay attention to the fact that the pain of the bite can vary. This depends on the size and variety of the crusader. It is believed that bites from large individuals can be extremely painful, on par with much more dangerous arthropods.

How long do they live?

The lifespan of a cross spider can vary greatly. Most individuals die young due to other predators or adverse weather conditions. However, if we talk about death from old age, this arachnid can live 10-12 months. There are individuals whose lifespan is as much as 2 years.

It should also be taken into account that most males are eaten after mating. Thus, their lifespan is only about 3 months. Females most often die immediately or some time after creating a cocoon, i.e. they live for about 6 months.

Features of the poison

In crosses, the poison looks like cloudy lymph, has a dense consistency, and has hemolytic qualities. What makes it toxic is heat-labile hemolysin, which can disrupt the integrity of human red blood cells, but horses, dogs and sheep have absolute immunity, so bites are absolutely safe for them.

Neurotoxins block the transmission of nerve impulses. In addition, the poison excites special receptors sensitive to glutamate and aspartate, which leads to desensitization. For vertebrates, toxic substances lose their negative effects over time, which does not happen in invertebrates.

The jaws of the cross are weak for humans, but they can bite through thin skin, and the sensation will be similar to a wasp sting. In other cases, the victim only feels a prick, similar to a needle puncture, or experiences absolutely no sensation at all.

In females during the breeding season, the amount of toxins increases. Euperotoxin is eliminated from the body naturally and does not remain in the body on the second day. The swelling subsides after a few days.

Where does it live?

The species is distributed throughout Europe, with some species found in North America. Favorable living conditions are high humidity, high temperature, and the absence of direct sunlight. Ideal habitats are coniferous forests, swamps, edges, hedges. Less often they settle in meadows, fields, gardens, vegetable gardens, outbuildings, and residential buildings. There are about 30 species of crosses living in Russia and the CIS countries.

On a note!

Once in a person’s house, the spider chooses places away from noise and light. Occupies corners at the top of the room, below behind the furniture. Weaves a web. It feeds on “domestic” insects – flies, cockroaches. To get rid of a spider with a cross on its back, you need to remove its web, throw it outside, and poison the “living creatures.”

Pavuk khrestovik

The spider spider is classified as an arthropod, a representative of the spider-like class. Pavuk-khrestovik his zdobich to catch for additional pavutini. The spinning apparatus of spiders is made up of external structures - spider warts - and internal organs - spider veins. Three pairs of spider web warts grow on the back end of the petiole. This skin wart is pierced at the end with a hundred different openings. From the skin opening a speck of sticky thread is woven, like a spider weaving into the thinnest thread in Russia. These threads become angry and thicken in the wind. The result is a thin, scarlet thread. This kind of glue can be seen in numerous cobwebs growing in the back of the stalk. Ducts open on their spider warts.

What to do if bitten by a cross

A spider attack is practically no different from a wasp, bee, or hornet bite. Initially, you need to wash the wound, remove any remaining poison, and disinfect it to prevent infection.

First aid after a spider bite:

1. Rinse the wound under running water.
2. Lather with laundry soap, leave for 5 minutes, rinse.
3. 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.

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.

Precautionary measures

Although in general the crusader spider is not dangerous to humans, its bite can cause some discomfort. When going for a walk, you need to take care not to become a victim. Rules to follow:

• If you plan to spend the night in a tent, shortly before going to bed you should check whether spiders have climbed inside. Before getting dressed and putting on your shoes, it is very advisable to look around all your clothes, turn them inside out and make sure that there is no cross anywhere.
• Bedding needs to be very carefully and carefully straightened, as females can hide in the folds. If you see a web, you should not touch it, as the female may attack. Males are more peaceful, and they do not weave nets.
• If you encounter an arthropod, it is better not to react to it in any way. You should not run away; you should try to carefully move away so as not to disturb the forest dweller.

Thus, the cross spider is poisonous, but it does not pose a danger to humans. You still need to take precautions, because those who are prone to allergies may develop unpleasant symptoms, although without serious consequences.