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Spider cross

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Cross-spiders are distinguished by the fact that on the dorsal side of the abdomen they have light spots that form a cross-shaped pattern. More than 1000 species of spider-crosses are known, of which several dozen live in the USSR.

An ordinary spider-cross is from 1.7 cm to 2.5 mm (females) in length. The dorsal surface of the abdomen is reddish or black-brown with clear white spots located in front in the form of a cross. Widely distributed up to the Far North.

Usually settles in the crowns of trees, arranges hunting nets between branches, and makes a refuge for itself from leaves. Typical wheel-shaped tenets immediately attract attention when visiting a forest, garden or a grove. Sometimes a spider web can be found among the shrubbery or under the eaves and in the bindings of the window frames of abandoned buildings. If a male and a female spider-cross are found during the excursion, they must be compared and the presence of sexual dimorphism is established (the male is smaller than the female and differs from her in a strong bloating at the ends of the pedipalps).

Usually in September it lays eggs, building several cocoons, after which the females die. Spiders hatched in May become sexually mature the following year. Like many settled spiders, young spiders fly on cobwebs (a sign of Indian summer!), Populating ever new habitats.

Under natural conditions, the spider's hunting net takes up much more space than is necessary for it when kept in captivity. Every one to two days, spider-spiders destroy the cobweb and weave a new one, since the trap network becomes unusable from the ingress of not only small insects, but also large ones, from which the spider is released, breaking off cobwebs around unsuitable prey.

The construction of a new network usually occurs at night, and by morning it is already ready to catch insects. Such diurnal activity is an example of the spider’s advisable behavior, since it’s less enemies at night: insectivorous birds sleep, but for others it is not visible in the dark. Despite the lack of light, the construction of a new network at night is very successful, since the spider is guided in his work not by sight, but by a sense of touch.

The network of an adult female cross-spider has a strictly defined number of radii and spirals of adhesive threads and a constant distance between adjacent turns. For example, it was established that in its hunting net there are 39 radii, 35 turns of the spiral and 1245 points of attachment of the radii to the spiral. The observed automatism of the building instinct of the spider is the result of programming the entire complex of movements in the nervous system, which is fixed genetically in heredity, and therefore is characteristic of all individuals. This makes it clear why young spiders can build a spider web and catch prey like adults.

The spider does not respond to any vibrations of the network, but only to biologically adequate ones, of a certain strength and amplitude. If you call a spider from the shelter by vibrations of the tuning fork, then, having been deceived several times, he ceases to respond to it. However, in order for the spider to perceive the tuning fork sound as a prey signal, it is necessary to touch it to the network, otherwise the sound outside the web vibrations will take the spider to flight (negative vibrotaxis). This is due to the fact that the vibration of spider webs is perceived by the spider as a tactile sensation that it receives when it enters the prey network, and the sound outside the web scares him, since it can come from an approaching enemy.

The spider is afraid of wasps and flies flying up to it, laying eggs on living objects. So, for example, the fly’s melanophore swearing can be attributed to the enemies of the spider, which takes advantage of the immobility of the spider, waiting for prey in a state of hidden activity, sits on its back and instantly lays an egg in the body of its victim. If a fly were caught in a snare, it would die, but its behavior precludes such an outcome.

Vibration of the spider web can be obtained when not only the tuning fork, but also other musical instruments (harp, violin). In this case, the spider also leaves its shelter if the trembling of the web is similar to the signals of the prey that got into it. Hence the false notion of spiders' "love" for music. If a spider is pushed off the object on which it is sitting, it will begin to descend to the ground with the help of the web allocated to it.

It is not dangerous for a person, but a burning pain, hemorrhages in the subcutaneous tissue, headaches, weakness, sometimes colic and joint pains are felt at the site of the bite. Tissue necrosis may develop at the site of the bite. The treatment is symptomatic.

The venom of the spider is toxic to invertebrates and vertebrates. The poison contains thermolabile hemolysin, which acts on the erythrocytes of a rabbit, rat, mouse, and human, while the erythrocytes of a guinea pig, horse, sheep, and dog are resistant to it.

Literature:
1. Invertebrate animals. Studying them at school. V.P. Gerasimov. Moscow, 1978
2. Plants and animals. C. Nidon, Dr. I. Peterman, P. Scheffel, B. Shaiba Translated from German by N.V. Khmelevskaya, Moscow, Mir, 1991
3. B.N. Orlov, D. B. Gelashvili, A. K. Ibragimov. Poisonous animals and plants of the USSR. Moscow "Higher School", 1990

Origin of view and description

Photo: Spider Cross

The crosses are representatives of the spider detachment, the suborder of an araneomorphic spider, the Araneidae family, the genus of the crosses.

To date, scientists can only approximately indicate the period of the appearance of ancient arthropods. The chitinous carapace of these representatives of flora and fauna disintegrates rather quickly, leaving almost no traces. The few remains of ancient arthropods were found in pieces of frozen resin, or in amber. Today, zoologists call the approximate period of the appearance of arachnids - 200-230 million years ago. The first spiders had very small body sizes, which did not exceed half a centimeter.

Video: Spider Cross

Their body structure was also significantly different from the modern one. Spiders of that time had a tail, which was intended for the manufacture of durable spider webs. The so-called web was used to line their holes, or shelters, as well as to protect the masonry with eggs from damage and extinction. During evolution, the tail of the ancient arthropods fell away. However, the modern spinning machine that they have now appeared far from immediately.

The first spiders appeared supposedly on Gondwana. Then they spread very rapidly throughout almost the entire land area. Subsequent ice ages significantly narrowed their regions of residence. Arthropods are characterized by a fairly rapid evolution, during which spiders modified outwardly depending on the region of habitat, as well as on belonging to a particular species.

Appearance and features

Photo: Big Spider Cross

Like other representatives of arachnids, the body of the cross is divided into two segments: cephalothorax and abdomen. In addition, they have gossamer warts and the walking apparatus of the latter is represented by the thigh, knee joint, lower leg, pre-arms, paws and claw. Spiders also have chelicerae and pedipalps.

Crosses have a fairly small body size. Representatives of this species have pronounced sexual dimorphism - males are significantly inferior to females in body size. The average body length of a female is 2.0-4.5 cm, and that of a male is 1.0-1.2 cm.

The body of the arthropod is covered with a chitinous shell of sand color, which is typical for insects to dump during molting.

Spiders have 12 limbs:

  • one pair of chelicera, the main purpose of which is to fix and kill the captured prey. This pair of legs is pointing down
  • four pairs of walking limbs that have claws on their tips,
  • one pair of pedipalps that are designed to fix their prey. It is noteworthy that on the last segment of these extremities in males there is a reservoir into which seminal fluid enters, which is subsequently transferred to the female sperm.

The crosses have as many as four pairs of eyes, but they are poorly developed. The vision of these representatives of arthropods is poorly developed, they can only distinguish silhouettes and general outlines. The reference point in the surrounding space is touch. This function is performed by the hairs, which cover almost the entire body.

Interesting fact: On the body of spiders there are a huge number of hairs of various types. Each type is responsible for receiving certain types of information: light, sound, movement, etc.

The abdomen of the cross is round in shape. There are no segments on it. On the upper surface there is a distinct pattern in the form of a cross. In its lower part there are three pairs of special cobweb warts. It is in these warts that thousands of glands open, which produce strong, reliable spider web threads.

The respiratory system is located in the abdomen and is represented by two pulmonary bags and a tracheal tube. In the area of ​​the back is the heart. It has the shape of a tube and branching vessels from it.

Where does the spider dwell?

Photo: Spider Cross in Russia

Spiders of this species are ubiquitous. They live in almost every country in Eurasia. Also quite common in North America.

Crosses prefer a place with high humidity, a little sunlight and high air temperature. Spiders love to merge on the edges of forests, meadows, gardens, and fields. Not an exception and the home of man. Getting into living quarters, spiders climb into crevices or joints between walls, inaccessible places, spaces between furniture and a wall, etc. Often, crosses can be found on various types of vegetation located near a reservoir.

Geographic Habitats:

  • the territory of almost all of Europe,
  • Russia,
  • Africa,
  • Asian countries
  • North America.

Spiders prefer to settle where it is easy and convenient to weave their hunting nets, which are likely to get a sufficient number of insects. In Russia, the crosses are often found in city parks, squares.

Now you know where the spider lives the cross. Let’s see what he eats.

What does a spider cross feed on?

Photo: Cross Spider in nature

The cross is far from a harmless representative of arthropods. It belongs to the poisonous species of arachnids, and by its nature is considered a hunter. Going out to hunt most often at night.

What is the source of food:

Getting out to hunt, the cross is located in the central part of the web and freezes. If you observe him during this period of time, it seems that he is dead. However, if the prey gets into the network, the spider immediately thrusts into it the front pair of limbs, injecting poison at the same time. After a short period of time, potential food ceases resistance. The crosses can eat it right away, or leave it for later.

These representatives of arachnids are considered voracious. To get enough, a day they need an amount of food that exceeds the mass of their own body. For this reason, spiders spend most of the day hunting. Rest mainly in the afternoon. Even during the rest period, the signal thread is always tied to one of the limbs of the cross.

An interesting fact: the Spider cross is not eating everyone who falls into its hunting net. If a poisonous insect lands in them, or one that exudes an unpleasant odor, or a huge insect, the spider simply bites the fixing threads and releases it.

Arthropods have an external type of digestive tract. They cannot digest food on their own. They tend to partially digest it using the injected poison. Only after the insides of the captured insect under the action of the toxin turn into a liquid substance, spiders drink it. Also, spiders often, after paralyzing the victim, wrap it in the cocoon of their web. It also involves a partial digestion process.

Features of character and lifestyle

Photo: Common Spider Cross

Spiders are nocturnal arthropods, which tend to be most active at night. Most of their time is spent on hunting, they have little rest. As habitats, places where a large amount of moisture and little sunlight are necessarily selected.

Cobwebs often weave between branches of shrubs, trees, various types of vegetation, grass blades, etc. They themselves are located in a secluded place near their hunting network. The spider webs that are able to weave the crosses are very strong and able to hold even fairly large insects, whose dimensions are several times the size of the body of the spider itself.

The crosses are considered to be true hard workers, as they tirelessly weave their cobwebs. They tend to weave huge networks. After they become unsuitable for catching prey, they scatter it and weave new nets.

Interesting fact: The spider will never get confused in its own hunting networks, since it always moves strictly along a certain trajectory of non-sticky areas.

Spiders weave a web also mainly at night. This is due to the fact that the main enemies of the crosses lead a day lifestyle and prey on them in the daytime. Spiders in the process of forming a hunting web show accuracy, detail and scrupulousness. In the process of their life, they do not rely on sight, but on touch. The krestovik lead an exclusively solitary lifestyle.

Social structure and reproduction

Photo: Spider Cross

Throughout spring and summer, males are busy forming webs and providing enough food. During the breeding season, males leave their shelters and begin to actively search for a female for mating. During this period, they practically do not eat anything, which explains such a significant difference between males and females.

Crosses belong to dioecious arthropods. The period of mating and courtship of females more often falls at night. It consists in the performance by males of peculiar dances, which consist in tapping limbs. After the male manages to reach the head of the female with the limbs, the seminal fluid is transferred. After mating, most males die from the poisonous secret of the female.

The period of marriage is at the end of the summer season, the beginning of autumn. The female makes a cocoon from the web into which she places the eggs. In one cocoon can be located from 3 to 7 hundred eggs of honey color. At first, the female wears this cocoon on herself, then she finds a secluded place and hides it. Cocoon reliably hides future offspring from rain, wind and cold. In spring, spiders begin to appear from the eggs. For a short period of time, they are inside the cocoon, then emerge from it and creep in different directions. Small crosses immediately become independent and lead a separate lifestyle.

After the spiders leave the cocoon, they try to separate as quickly as possible. Due to the high competition and the ability to become food for older individuals, such a step will significantly increase the chance of survival.

Interesting fact: Due to the fact that the newly born young individuals have rather small and weak limbs, in order to separate from each other, they use a web on which they can fly up to several hundred kilometers, subject to the presence of wind.

Crosses are well adapted to new conditions. It is because of this that they are often brought in by lovers of exotic representatives of flora and fauna as pets. A sufficient amount of terrarium is used to maintain them to provide a place for a rather large web.

Natural enemies of the spiders of the crosses

Photo: Female cross spider

Despite the fact that the crusader is ranked among the dangerous, poisonous spiders, he also has enemies. It is in order to reduce the likelihood of being eaten that they are most active at night. The main enemies of this type of arthropod can be called feathered, as well as insects - parasites. Some species of wasps and flies wait when a spider freezes on its web in anticipation of another victim, fly up to it and instantly lay eggs on its body.

Subsequently, parasite larvae emerge from them, which, in fact, feed on the insides of the spider. When the number of parasites increases, they practically eat the spider alive. Crusaders are small, which often leads to the fact that they themselves become the prey of other, larger arachnids. The enemies of the crusaders are also mono attributed to some amphibians, such as lizards or toads.

The main enemies of the spider spider in vivo:

Man is not an enemy of a spider. Rather, the crusaders in some cases can harm human health. It is unusual for them to attack first. When meeting a man, these representatives of arthropods rush to hide. However, if they sense danger, they attack. As a result of a bite, an adult healthy person will not die, however, discomfort and a change in general well-being will definitely be felt.

The consequence of a cross sting is pain, dizziness, nausea, vomiting, swelling, suppuration of the bite site. Most often, all of the above symptoms disappear without medical treatment.

Population and species status

Photo: Spider Cross

To date, the spider cross is considered a very common representative of arachnids. It inhabits most of the territory of Eurasia and North America.

The crosspiece combines a large number of subspecies of spiders. Some of them are spread over a vast territory, others have a very limited habitat. For example, the Hawaiian wolf spider lives exclusively on the territory of the island of Kautai.

The spider, which scientists call the striped hunter, is widespread in almost the entire territory of Europe. There are no special programs and activities aimed at preserving and increasing the number of arthropods.

In many countries, in different parts of the world, people give birth to crusaders as an exotic animal in a terrarium. Spider crusader is an integral part of the ecosystem. Many people mistakenly believe that if an insect or arthropod is poisonous, it must certainly be destroyed. It's a delusion. A person must understand that if such an important link as spiders disappear, irreparable damage will be caused to the earth’s biosphere.

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