The cross spider is the most common species, which is found in almost all regions except the northern and southern latitudes. It prefers places with high humidity and is most often found in gardens, in fields, among shrubs growing near water bodies, as well as in groves and woodlands. It can also inhabit eaves and facades of buildings.
Description and features
Spiders are very interesting representatives of the biological kingdom, and some of them are far from harmless. They also have an amazing structure. Some species of these creatures have special appendages in the mouth, the so-called jaw claws.
These include araneomorphic spiders - members of a large group from the arachnid class. These natural adaptations are called chelicerae. They allow these creatures to successfully attack prey that are large in relation to their size, which gives them the opportunity to win the evolutionary race.
It is to such creatures that spider cross - a bright specimen from the orb weaving family.
This creature earned its name not by chance, but due to 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 the body that resembles a cross.
This feature of appearance is very useful for these biological organisms. This gift of nature is a sign that can scare away many hostile living beings from them. The rest of the characteristic features are clearly visible on spider spider photo.
As you can see, he has a rounded torso. It turns out to be practically one whole 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 not larger than 26 mm, but there are specimens of such spiders that are only one centimeter long and much shorter.
Moreover, crosspiece endowed with eight sensitive flexible legs. He also has four, and paired, eyes. These organs are located versatile, which allows this animal to have a circular view in all directions. However, these biological organisms cannot boast of particularly sharp colorful vision.
They distinguish only outlines of objects and objects in the form of shadows. But they have very good sense of taste and smell. And the hairs covering their body and legs perfectly capture a variety of vibrations and vibrations.
Chitin, a special natural binding compound, serves as the cover of the body and at the same time as a kind of skeleton for such creatures. From time to time, it is dumped by these arachnids, being replaced by another natural shell, and during such periods the growth of the organism is carried out, freed for a while from the elements that fetter it.
The cross is considered a poisonous spider, but its poison is not dangerous for people
This representative of the biological kingdom of arachnids is able to secrete a substance that is toxic to all types of organisms. So spider spider is poisonous or not? Without a doubt, this little creature is dangerous to many living things, especially invertebrates.
And the poison secreted by them has an extremely detrimental effect on their neuromuscular organization.
Characteristic
The cross spider, or crusader, got its name from the fact that, as you can see in the photo, it is formed from white spots. The abdomen of an arthropod is colored brown and has a teardrop shape. The cross has 8 legs, on which the supersensitive organs of smell are located. There are 8 eyes on the head, they are directed in different directions, which makes the view as wide as possible.
The male cross spider looks the same as the female. The only difference is the size. So, females are somewhat larger than males and their size can be from 16 to 25 mm, the size of the male's body is about 10-11 mm. Throughout their life, these arthropods molt several times, and this happens at regular intervals.
Food
Krestoviki are hunters who are most active at twilight and at night. During the day, they prefer to sit out in secluded places. Their diet contains:
- flies;
- butterflies;
- mosquitoes;
- vile, etc.
During the hunt, the crusader spider is located in the center of its web and freezes. From the outside it may seem that he is dead. But as soon as the victim gets into the net, the hunter reacts with lightning speed. It quickly runs up to the entangled insect, plunges its sharp claws into its body, which are located on the front pair of legs, and injects paralytic poison. After a while, the caught victim freezes. Moreover, in different situations, spiders either immediately eat their prey, or leave it in reserve.
The cross spider eats quite a lot - the total amount of food consumed per day is approximately equal to its body weight. And at one time he is able to eat about a dozen insects. For this reason, he spends almost all his time hunting, constantly being in the web and waiting for the next victim. A small part of the day is allotted to rest, but even during this period the signal thread is necessarily tied to one of the hunter's legs.
Reproduction
During the spring and summer, young males are mainly engaged in weaving and hunting, trying to provide themselves with normal food. Closer to the mating period, they leave their shelters and move from place to place in search of a female. At this time, they feed extremely poorly, which explains the significant difference in mass between them and the spiders.
After the male finds the female's web, he makes several attempts to inform her of his appearance - he carefully steps on the edge, causing vibrations. The female immediately takes off and tries to catch up with the male, thinking that this is another victim
And the male, in turn, flees along his own thread, which he prudently lowers down in advance. This continues until the spider understands who exactly came to visit her.
Immediately after mating, the spider tries to hide faster. However, only a few - the most efficient ones - manage to do this. Most die from the female's venom. This period falls around the end of summer or early fall.
The fertilized female makes a clutch. Eggs, of which there can be about 300-800 pieces, she places in a cocoon tightly woven of cobwebs and carries it on herself for some time. Then the spider finds a suitable shelter, where she leaves the clutch. Often, such a place is the bark of a tree lagging behind the trunk, cracks in the wood, fallen leaves, etc. Eggs are stored there until spring. At the same time, the future offspring in the cocoon is absolutely safe - it is warm in it and does not get wet.
With the onset of heat, small spiders appear from the eggs.
After the birth of young crosses, they need a sufficient amount of food, but the territory where they first saw the world is not always able to feed them
Therefore, it is important for spiders to leave this densely populated area as soon as possible, otherwise many of them risk being eaten by their fellows or simply starving to death. However, these arthropods are not able to independently make a long distance movement, since their legs are very poorly developed.
Often they are carried by a favorable wind - the spider waits for windy weather, clings to its web and flies, thus, from place to place.
Considering the above, it is easy to calculate how long the spider spider lives. In the spring, the young come out of the eggs, and in the fall they already mate. Males in most cases die immediately after fertilizing the female, and the spiders a little later - they spend several weeks near the hidden cocoon and, having fulfilled their parental duty, die before winter arrives. It turns out that the nature allotted to the cross is not so much - only 6-8 months.
Types of spider spider
The number of species of such spiders is impressive, but of the arachnids known to science, about 620 species are described in the genus of crosses. Their representatives live all over the world, but nevertheless they prefer to settle more in temperate and tropical zones, because they cannot stand too cold climate.
Let us present some of the varieties in more detail.
1. Ordinary cross. This type is considered the most common. Similar living creatures live among bushy shoots, in meadows, fields and coniferous forests of the European, as well as the northern part of the American continents.
They prefer wet areas, they take root well in swampy areas, not far from rivers and other bodies of water. Their body is reliably protected by a durable thick shell, and moisture retains a special waxy coating on it.
Decorated with such spider spider white on a general brown background with a pattern. Such an intricate pattern, upon close examination, can seem very interesting.
Common spider
2. The angular cross is a rare variety, and in the Baltic regions it is generally considered to be disappearing. It is interesting that such arthropods, although they belong to the genus of crosses, do not have a characteristic mark on their bodies.
And instead of this feature, on the abdomen of creatures, covered with light hairs, two humps, insignificant in size, stand out.
Angular cross
3. The Owen Spider is an inhabitant of North America. The trapping nets of these creatures, which are sometimes significant in size, can be found in abandoned mines, grottoes and rocks, as well as not far from human habitation.
These creatures are dark brown in color. By means of such coloring, they are masked against the background of their surroundings. The legs of such spiders are striped and covered with white hairs.
In America, there is a kind of cross - barn
4. Cat-faced spider is another inhabitant of regions of America similar to the previously described species. Its body is also covered with nap, and the hairs can be either light or dark. These are very insignificant creatures. Some specimens may be less than 6 mm.
But if it big spider cross of this type, then for sure it is a female, because their size 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 the cross usually flaunts among relatives.
The cat-faced spider has a shape similar to a cat's face on its body.
5. Spider Pringles - small-sized resident of Asia, also common in Australia. A very interesting color has such crosspiece: black its abdomen is marked with a funny white pattern, while the cephalothorax and legs of such spiders are green to match the rich vegetation of the edges where such creatures live. The size of males in some cases is so small that it does not exceed 3 mm.
Spider pringles
Is it dangerous to a person?
The cross is absolutely harmless for people. There are stories that a spider is poisonous and after a bite a person can die. This is not true. Yes, it can bite and the bite will be painful. There are rules to help you get rid of the pain. You need to know that the cross is never the first to attack. He can bite if a person gets into his net with his hand. Not on purpose, but for a spider it is a signal of a threat to his life. Defends himself as best he can.
Fig. 5. Spider Araneus diadematus When bitten after 5 minutes, the following sensations arise:
- the head starts to hurt;
- weakness appears in the body;
- there is an ache in the joints;
- the bite site itches a lot;
- subcutaneous hemorrhages may appear on the body.
It is recommended to wash the bite site with soap and water. Then apply something cold. Ideally ice. For headaches and fever, it is best to take paracetamol. For allergies, you need to take antihistamines.
Important! If the spider bit a child, urgent medical attention is needed!
It is known that the bites of some types of crosspieces are more painful than the bites of scorpions.
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 themselves a shelter nearby, among the foliage of small bushes or tall trees.
Therefore, spiders take root well in forests, in quiet, untouched areas of gardens and parks. Their cobwebs can also be found in various corners of neglected buildings: in attics, between doorways, window frames and other similar places.
On the abdomen of such creatures there are special glands, which in excess produce a special substance that makes it possible to weave trapping nets. As you know, they are called cobwebs. From the point of view of chemistry, the natural building element for them is a compound, which should be considered very close in composition to soft silk, which indicates its relative strength.
Patterned weaving, formed from the specified, at first liquid and viscous, material when it further solidifies, spiders weave usually with endless persistent tenacity. And after one or two days they destroy the old, worn-out net and weave a new one.
The specified structure can be called a true work of weaving art, formed from threads, the total length of which is 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 net to another.
And this cannot but lead to admiration, for it causes 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 specified time of day, most of the enemies of spiders indulge in rest, and no one bothers them to do their favorite business.
In such an occupation, they do not need helpers, and therefore spiders are individualists in life. And they do not spend a lot of time communicating with their relatives. Thus, having created a trapping net, they ambush and begin to wait for their prey, as always, all alone.
Sometimes they do not particularly hide, but are located in the very center of the web woven by them. Or they watch, sitting, on the so-called signal thread, which allows them to feel all the connections of this weaving.
Sooner or later, some kind of victim falls into the spider's trap. Most often these are mosquitoes, flies or other flying small insects. They easily get entangled in the net, especially since its threads are sticky. And the owner of the fishing line instantly feels their flutter, as he is able to pick up even the smallest vibrations well.
Further, the prey is killed. Spider bite for such small creatures it is certainly fatal, and the victim has no chance of salvation when he uses his poisonous chelicera.
Interestingly, the small insects themselves can also pose a danger to spiders. After all, individual species of flies and, taking advantage of their usual immobility, are quite capable in the twinkling of an eye to settle on the back of eight-legged predators and lay 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 entangled in their trapping net, because they move only strictly along certain, radial, non-sticky areas.
Beneficial features
Few people know that arthropods benefit the environment. For example, a spider eats a large number of harmful insects - carriers of infectious diseases.
There are other benefits to spiders.:
- The web is very strong, and various fishing tackles are woven from its threads.
- The spider web is used to make many jewelry and clothing, French women really like fishnet stockings and gloves woven from such threads, which look very delicate and elegant.
Thanks to the habitat of the cross in your home, you can get rid of some of the small insects, of course, if the presence of a spider does not bother you - In the scientific world, it is used in some measuring instruments.
- In folk medicine, the spider web is used as a means that has a disinfecting and antiseptic effect.
There are more than 2000 varieties of crosses, only 30 subspecies can be found in the vastness of Russia. They differ only externally, and the features of their vital activity are almost identical.
It is interesting: apartment spiders.
Food
The described living things are carnivores. In addition to the already mentioned flies and mosquitoes, aphids, various gnats and other small representatives of the insect world can become their prey. If such a victim has fallen into the network of this predator, then he has the opportunity to feast on it immediately.
But, if he is full, he is able to leave food for later, entangling him with a thin sticky thread. By the way, the composition of such a "rope" is somewhat different than the thread of a web. Further, the spider hides its food supply in any secluded place, for example, in foliage. And he eats it when he feels hunger again.
The appetite of such spiders is very excellent. And their bodies need a lot of food. The daily norm is so high that it is approximately equal to their own weight. Such needs make the described representatives of the animal world and work accordingly.
Krestoviki, trapping prey, sit in ambush practically without rest, but even if they are distracted from business, then for a very short time.
These creatures digest their food in an extremely interesting way. This does not happen inside the body, but outside. Just a portion of digestive juice is released by the spider into the body of the victim, wrapped in a cocoon. In this way, it is processed, turning into a substance suitable for consumption. This nutrient solution is then simply drunk by the spider.
It happens that in the networks placed by these eight-legged creatures, prey comes across too large, with which such a kid is simply not able to cope. The spider strives to get rid of such problems by deliberately breaking off the threads of the network connecting with itself.
But if the threat does not stop there, for the purpose of self-defense, he is quite capable of successfully using his chelicera against huge, from his point of view, creatures. For example, a frog in a quarter of an hour after its bite may be completely immobilized.
But spiders are dangerous for humans or not? Actually, the venom of these creatures does not produce irreversible changes on the organism of all vertebrates. On people, due to the small amount of toxic substances released by these arachnids in comparison with human sizes, they are not able to act in a serious way. The bitten subject will only feel mild pain, which will go away rather quickly.
Reproduction
In the fall, the males of the cross begin to look for a girlfriend for procreation. Interesting that the spider finds the female's web and weaves a thread there,
which will signal the lady that the potential father of her future children has come to her. In addition, the thread serves as a retreat path along which the male escapes from the female in a critical situation. The spider does not immediately accept the newly-minted groom.
Important! After the act of love, the male dies. The female eats it: she needs strength, and it is best to eat those who are nearby. It does not always work out that way, some cross-fittings safely avoid a sad fate.
After fertilization, the female lays eggs in a special cocoon. For several days she keeps the future offspring next to her and hides in a quiet and peaceful place. This could be a crack in the wall or a crevice under the bark of a tree. The spiders winter calmly and are born in the spring. In the summer, young crosses can already reproduce.
The spider lays about 800 eggs. They resemble amber in color. Cocoon reliably protects offspring from hypothermia in winter and spring. Not all spiders will survive. Someone will be eaten, someone will die without food. Therefore, young crosses are in a hurry to find their place in the sun. They move around the territory using the web.
In case of gusts of wind, the thread can carry the spider up to 400 km.
When the web falls to the ground, the spider immediately begins to act, settling in a new place.
Internal structure
Digestive system
The spider's digestive system consists of the mouth, pharynx, esophagus, stomach, intestine (anterior, middle and posterior). In the midgut, long blind outgrowths increase its volume and absorption surface.
Undigested residues are excreted through the anus. The spider cannot eat solid food. Having caught a prey (some insect), with the help of a cobweb, he kills it with poison and lets digestive juices into his body. Under their influence, the contents of the caught insect liquefy, and the spider sucks it in. From the victim, only an empty chitinous shell remains. This method of digestion is called extraintestinal.
Circulatory system
The circulatory system of the spider is open. The heart looks like a long tube located on the dorsal side of the abdomen.
Blood vessels depart from the heart.
In a spider, the body cavity is of a mixed nature - in the course of development, it arises when the primary and secondary body cavities are connected. 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 evolved from the gills of the distant ancestors of spiders that lived in the water.
The spider-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 ganglion and numerous nerves extending from it.
Excretory system
The excretory system is represented by two long tubes - malpighian vessels. At one end, the Malpighian vessels blindly end in the body of the spider, with the other they open into the posterior part of the intestine.Through the walls of the malpighian vessels, harmful waste products come out, which are then removed to the outside. Water is absorbed in the intestines. Thus, spiders save water, so they can live in dry places.
Lifestyle
The natural habitats of crusader spiders are natural habitats, but they can often be found in human dwellings. They show their main activity at night, and in the daytime they prefer to hide in their shelters. Therefore, the spider weaves its web at night. Being in the natural environment, a spider builds a house out of leaves, and weaves a web in the intervals between trees.
The spider's web is a rather complex engineering structure, consisting of 39 radii of various sizes, of 35 spiral turns, as well as 1245 points of contact of the threads. As mentioned above, some species can weave a web up to 2 meters in diameter.
Interesting fact! The spider weaves a web at night, and during the day it works, that is, the victim falls into it. In case of damage to the web, the spider repairs it or weaves a new one. Spiders also enter the diet of birds, but at night the birds rest, so the spiders go hunting.
Behavior in the wild
Arachnids of the orb-web family are carnivorous. They settle on the tops of trees, in the branches, where they put trapping nets into which small insects come across. The leaves are used as a refuge.
In natural conditions, the predator's web is smaller than in captivity. Every day or two, the crosses destroy the woven net and make a new one. They are engaged in "construction" of a new trap at night, so that in the morning it would be possible to catch prey. This daily activity is due to the fact that in the dark there are fewer enemies, insectivorous birds are asleep, and you can “work” calmly.
