Characteristic
This spider belongs to the orb weaver family. Cross spiders are considered the most common type of spider. Researchers have found that they live almost all over the world. True, they do not at all favor the climate of southern and northern latitudes. Arachnids live in places with high humidity. Therefore, the spider web is found in thickets near rivers or lakes. They happily live on garden and forest trees. They prefer to weave a network in their crowns.
Rice. 1. Spider Araneus cavaticus on a catching net After studying the life of the spider spider, scientists gave it the following classification:
- relates to the animal kingdom;
- is of the phylum arthropod;
- belongs to the class Arachnida and the order Spiders;
- suborder: araneomorphic spiders;
- family Araneidae and genus - crosses.
Latin name Araneus.
Description
The cross is small in size. But there is a significant difference between a male and a female. If the size of the first reaches 10-11 mm, then the spider is 2-4 times larger. Its size ranges from 17 mm to 40 mm. The body of arthropods has a chitinous shell. They shed it when they molt.
Structure
The cross has a structure typical of all arachnids. It has 10 limbs: 4 pairs of walking legs with claws, one pair of pedipalps and one pair of chelicerae:
- for pedipalps is
cenopods. With them, arthropods recognize and hold the future victim. - The jaws
of arthropods are called chelicerae. With these limbs the spider captures and kills prey. - at the last articulation of the pedipalps
. It's called cymbium.
The spider has 4 pairs of eyes. But this does not mean that he sees his surroundings perfectly. On the contrary, his world is blurred, there is only a play of light and shadows around.
Important! The crossbreed has a very developed sense of touch. In this he is helped by tactile hairs, which are located over the entire surface of his body. It is interesting that some of them allow the spider to recognize sounds, others allow it to sense air vibrations, and some of the hairs provide information on chemical stimuli.
Rice. 2. Spider Araneus diadematus
Web glands
In the lower part of the spider's abdomen there are three pairs of arachnoid warts. In total, they contain a thousand glands, thanks to which arthropods produce webs.
Important! It is worth noting that spider threads can have different purposes. So, cross spiders separately produce threads for hunting; for a cocoon, the quality of the web will be completely different.
Digestive system
The spider has external digestion. After the prey is completely entangled in the sticky web, the hunter injects juice into it, which will digest the insides and allow him to suck out the resulting solution.
Respiratory system
Arthropods breathe through pulmonary sacs and tracheae, which are located on the abdomen. Arthropods do not have blood; hemolymph circulates through the vessels. It contains water, organic compounds and inorganic salt. Thanks to it, nutrients and oxygen are distributed throughout the body. Arthropods have a heart that looks like a long tube. The organ is located in the dorsal part of its abdomen.
Excretory system
The excretory system consists of coxal glands and Malpighian vessels. From the decay products, everything is removed from the body except water, which is absorbed back by the intestine of the cross. For life on land, this circumstance is very important: it allows spiders to use water sparingly and wait out the dry, hot weather. The spider lives from 1 to 2 years.
Excretory organs
The system through which the body gets rid of various wastes is called excretory. In arachnids, the excretory organs are vessels called Malpighian . They are located at the junction of the middle and posterior sections. Their secretion, along with food debris, enters the rectal bladder, and is removed from it through the rectum and anal tubercle. In addition to the Malpighian vessels, coxal glands are formed in spiders at the embryonic stage. As they grow older, they gradually atrophy.
Kinds
Scientists know about the existence of two thousand species of crosses. About 30 of them live in Russia and neighboring countries.
Ordinary
The common cross is found in Europe and some states of America. Prefers coniferous forests and swamps. The female reaches a size of 2.5 cm, the male - 1.1 cm. A wax-like substance covers the body of arthropods. The shell covers the cephalothorax.
Rice. 3. The final stage of construction of a new network
Angular
This type of cross is rare. There is no cross pattern. There are two small humps on the abdomen, and the whole body is covered with light hairs. The size of the female is 1.8 cm, the male is 1.2 cm.
Araneus albotriangulus
The cross spider Araneus albotriangulus is a resident of Australia. It is not widespread. It can only be found in South Wales and Queensland. One of the small species among other crosses. Females grow up to 4 mm, males 2 mm. There is also no characteristic cross on the abdomen. There are yellowish spots, similar in shape to triangles with right angles.
Araneus cavaticus
The cross spider Araneus cavaticus also has another name - the barn spider. His place of residence is North America. Settles on cliffs and in mine openings. Sometimes located near people's homes. Females and males are almost identical in size. The female individual grows up to 2.2 cm, the male - up to 2 cm. You can distinguish the spider by the light yellow center of the abdomen.
cat-faced
The cat-faced spider is widespread in the American West and Canada. Spiders grow up to 2.5 cm, males - up to 7.9 mm. On the abdomen there is a pattern of a cat's face.
Araneus mitificus
Cross spider Araneus mitificus. It is often called Pringles. Habitat: India, Nepal, Bhutan, Australia. “Pringles” acquired its name due to the similarity of the pattern with the design of chips of the same name, where a cheerful mustachioed face is placed. Pringles hunts for prey from an ambush, into which he extends a signal thread. The size of females is 9 mm, males are 5 mm.
Araneus sturmi
The cross spider Araneus sturmi is very rare. Prefers to live in coniferous forests. Individuals are very small in size. Females up to 5.5 mm, males up to 4 mm. Most often you can find crosses of a modest brown color, but nature has also given them amazing bright colors of yellow-red-green shades. The spider can be distinguished by the so-called epaulets, dark spots located in the front of the abdomen.
Chilly
The chilly cross lives in deciduous forests. Color - orange and beige. The abdomen is decorated with small spots, which makes it look like a strawberry. By the way, the English name is translated as “strawberry spider”. Females grow up to 13 mm, males - up to 6 mm.
Rice. 4. Spider Araneus mitificus
Reproduction
In the fall, male crossworts begin to look for a mate for procreation. Interestingly, the spider finds the female’s web and weaves a thread there,
which will signal to the lady that the potential father of her future children has come to her. In addition, the thread serves as an escape route, along which the male runs away from the female in a critical situation. The spider does not immediately accept her new groom.
Important! After the act of love, the male dies. The female eats it: she needs strength, and it is best for those who are nearby to refresh herself. It doesn’t always work out this way; some cross members successfully avoid a sad fate.
After fertilization, the female lays eggs in a special cocoon. For several days she keeps the future offspring close to her and hides them in a quiet and peaceful place. This could be a crack in the wall or a crevice under the bark of a tree. The spiderlings spend the winter quietly and are born in the spring. In summer, young crosses can already reproduce.
The spider lays about 800 eggs.
They resemble amber in color. The cocoon reliably protects the offspring from hypothermia in winter and spring. Not all spiderlings will survive. Someone will be eaten, someone will die without food. Therefore, young crossers are in a hurry to find their place in the sun. They move around the territory using webs. With gusts of wind, the thread can carry the cross up to 400 km.
When the web falls to the ground, the cross immediately begins to act, settling in a new place.
Puberty and mating
Throughout the spring and summer, young males are mainly busy getting food for themselves and constantly weaving new webs. Such hunting guarantees them adequate nutrition. When the time comes for puberty, they leave their shelters and go in search of a female. While searching, they feed sparingly, which may explain the significant difference in weight category between males and females during the mating season.
Attracting a female is through mating games. To attract the attention of the female, the cross-tailed spider swings its web and dances at the same time. Mating involves the transfer of seminal fluid from the male's pedipalps to the female. After transferring the seed, the spider tries to hide as quickly as possible. But not many people succeed in this. Most of the crosses die from the poison of the female.
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.
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
Cobweb (catching net)
A distinctive feature of all spiders is their ability to secrete webs (Fig. 75B). The arachnoid glands are located at the end of the abdomen, from them there are ducts that open on the arachnoid warts. The released liquid secretion immediately hardens in air and turns into a spider thread. The spider twists individual thin threads into a common web thread using comb-like claws on its hind legs. There are many glands that form the web, and different glands secrete different webs: sticky and non-sticky, light and strong, depending on their purpose. Spiders not only use webs to build hunting nets, but also cover the walls of their shelters, make cocoons for eggs, and use them as “communication routes” or kites for flight.
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| Rice. 75B. Spider net |
