In the world of spiders, it is the orb-webs that have earned a reputation. the best masters on weaving a web! Moreover, in 1973, two representatives of the orb-web family, the cross spiders Anita and Arabella, were sent into space aboard orbital station NASA Skylab so scientists can study the process of weaving webs in zero gravity.

It turned out that even in space, the structure of the web did not change; it still had the same characteristic circular shape. In the skill of weaving the nets, the circles left their relatives far behind: for other spiders, the web does not have such a clear shape, but is only sloppy "funnels" or sheets of tangled threads.

Orb-web spiders form a whole family Araneidae, which includes about 3000 species.

But uloborid spiders ( Uloboridae, several hundred species) - due to the similarity of the cobweb. Both the orb-webs and uloborids are widespread in the most different corners the globe and weave very similar trapping nets, but these hunters kill their victims in different ways.

Insect hunters

Spiral webs of orb-webs are one of the engineering wonders of nature. The diameter of the web can vary from a few centimeters to a whole meter, but all networks have a common basic structure: the “bridge” line stretched between the stems forms a triangle together with two “anchor” threads that “tie” the web to the ground. Inside the web is a series of "radii" threads, diverging from the center and forming a frame of a radial spiral, the very characteristic feature circular spider web.

It takes about an hour for a spider to create this miracle (more precisely, a spider, since males do not weave a web).

The circular web of the orb weaving is a real trap for insects, which, without suspecting anything, fall into it right on the fly. The orb-web is a passive predator. He sits in the center of a shiny silky spiral and waits for the "lunch" itself to fly to him.

The orb weaving has eight eyes, providing excellent visibility, although the spider does not need to look out for prey at all. He learns to replenish his grocery stores by vibrating the threads of the web. While waiting for prey, the orb weaving clings to the web with tenacious claws, which are located at the ends of the legs. He usually sits upside down, clinging to the non-sticky threads emanating from the center of the trapping Net.

Once in the cobweb, the unlucky insect sticks to the main spiral of filaments covered with a kind of "glue". Trying to break free from the networks, the victim becomes even more entangled in the sticky mass. The spider catches the trembling of the filaments and hurries along the dry filaments to the prey.

If the spider falls on the wrong thread, it will free itself, but the victim cannot get out of the sticky net.

The orb weaving is wary of insects caught in the web. If it's a dangerous catch, like a wasp, it usually breaks the threads around it. Some orb webs are armed with thorns to protect the spiders if the victim resists. When the insect is not dangerous, the spider kills it by biting with poisonous "fangs".

The poison not only kills, but also digests prey. The spider rarely starts eating immediately after catching the victim. First, he wraps a thread around the insect and waits. The spider eats liquid food and cannot chew, so it injects digestive juices into the body of a dead or dying prey. The enzymes eat away at the insect's tissues, turning them into a thick "soup", and the spider sucks it out.

Sly predator

Orb-web spiders hang their nets on insect routes - between plants, where they most often fly. Usually spiders leave their lair at night, although in the fall, when the females, as they say, work tirelessly to lay enough eggs, orb webs can be seen both at night and during the day. Construction begins with a single strand, a kind of "bridge", which the spider stretches out after climbing a branch.

If the orb-web is lucky, this thread, fluttering in the wind, will catch on the second support - the plant on opposite side... This process resembles launching kite... The spider tries to preserve the first thread as long as possible, and he removes the rest of the web almost every day.

After that, under the "bridge", the spider attaches a second, not so tightly stretched thread and runs to the center, in order to then go down on a new thread. It turns out a U-shaped frame - the basis of the web. Two "anchors" connect the base of Y to each stem, thus forming a triangle together with the "bridge" - the outer part of the web. Then the spider begins to weave dry radial threads, diverging from the center to the edges. There are about 20 such threads.

When the work comes to an end, the spider weaves a wide helper spiral from the center to the edge. It is dry silk that serves as a circular-weaving platform during the construction of a trapping spiral leading to the center. The trapping spiral has more turns than the auxiliary one, which the spider removes in the course of work.

Building the web takes about an hour, maybe two. After the spider has caught and eaten the prey, the hunter returns to his lair, hidden among the foliage. There the orb weaving sits all day until the next evening. Then the spider, or rather the spider, leaves the shelter to inspect the net. If the web cannot be repaired, the orb webs eat it, and the absorbed proteins are processed into silk, from which a new web is weaved.

Some types of orb-webs add thin threads to the design, forming a zigzag pattern. They are likely to divert the attention of potential prey, which, thanks to them, does not notice the trapping net until it is too late. Uloborid spiders do not weave sticky trapping spirals. Their webs are unusually thin threads that cling to their prey like one half of the Velcro fastener to the other. In addition, the uloborids strangle the victim with a tight cocoon.

Cautious courtship

The males of the orb weaving are much smaller, about 10 times, smaller than the females. Adult spiders, obsessed with the goal of finding a mate, stop worrying about food. But, having found the female's web, the spider must exercise maximum caution.

One wrong move - and the female will mistake it for prey! After mating, the male looks for new pair while the female is engaged in egg production. The spider lays them in a dense silk bag. The offspring of orb weaving, having overwintered in their "cocoon", will be born in the spring.

The web has incredible elasticity. Its thread can be stretched five times without breaking!

The circular spider web is practically invisible, unless the sun's rays fall on its shiny silk and illuminate an intricate spiral of threads, each of which is a fraction of a millimeter thick.

Spider silk is used for more than just weaving webs. The spider wraps its victim in a silk blanket and waits for the poison to take effect, so that it can then begin its meal.

It is said that the Carpathian peasants used pieces of cobweb as an antiseptic, treating wounds with them. Well, in the not too distant future, spider silk may well become a fairly common material.

In terms of tensile strength, a spider web thread can be compared to steel, and a cloth woven from a web of orb-webs is stronger than Kevlar ™ fiber. In addition, the wetted spider web shrinks, so it is likely that artificial muscles can be made from it.

Scientists are working to decipher the genetic code of proteins that make up the web of the orb weaving
Araneus ventricosus to learn how to make such strong threads industrially.

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Orb-web spiders (Latin Araneidae) have 3 thousand varieties, united in 170 genera. They differ from others in size, color. The largest representatives live in tropical countries, weave a web in a radius of up to 2 m. Locals use a "cloth" folded in several layers to catch fish. In our area, orb webs can be found everywhere. They love forests, gardens, a sunny meadow.

Photo and description of appearance

Color, sizes are different - from 5 mm to 28 cm.On the territory of Russia live small, average size copies. The structure of the body is typical - a convex abdomen, cephalothorax. The limbs are long, powerful, connected to the cephalothorax. Only 4 pairs. The color is gray, brown, black with various spots, patterns, stripes or without them. Photos of orb weaving spiders can be seen below.

On a note!

From the front of the cephalothorax there are pedipalps, which are similar to another pair of limbs. Movable tentacles help to hold the victim, grind, grind food. Chelicerae end with sharp canines, contain poisonous glands. With them, the predator pierces the chitinous cover of the victim, the skin.

On the head. The most important - 1 pair, are placed in the center. They catch visual images, silhouettes, shadows at a distance of 25 cm. Lateral - auxiliary eyes, provide horizons on all sides, warn of the approach of enemies, potential prey. Orb-webs respond well to movement, vibrations of the cobweb, and catch odors. The organs of smell and touch are the paws.

Lifestyle

Spiders are nocturnal, during the day they hide in a secluded place near their own web. For catching prey. They do this at night, it takes about 2 hours to form the canvas.

Outwardly, the web resembles a lace fabric. Initially, the predator stretches strong threads and forms a triangle. Many cells of different diameters depart from them. The ability to weave trapping nets is transmitted genetically. Little spider after birth, he is able to repeat everything that his mother does, but on a smaller scale.

Interesting!

The orb-web spends most of its life sitting on a web in the very center, or hangs down in anticipation of a hearty dinner. You can spot the predator during the day on a spider's web sparkling under the sun's rays in the pose of the letter "X". Weaves nets almost everywhere - on plants, grass, trees, snags, in abandoned buildings, outbuildings.

Nutrition

The main diet consists of insects, as well as small relatives:

  • midge;
  • snails;
  • worms;
  • butterflies;
  • bees;
  • beetles;
  • small spiders.

The orb weaving learns about the presence of a victim by the vibrations of the web. Approaches prey, bites, injects poison, saliva. Envelopes in cobwebs, crawls to the side, watches what is happening for several minutes. The toxic substance causes muscle paralysis, saliva turns the insides into a liquid mass. The spider tries to eat everything at once, leaving only a chitinous shell.

Interesting!

The spider can stay for about a year without food. Under normal conditions, a large number food is eaten 1 time in 7-10 days. The trapping nets are constantly renewing, crawling to another place. Throws damaged web after 12 casualties.

Reproduction

Orb-webs gather in pairs only in mating season... The male neatly approaches the female's web, fiddles with its paws, creating certain vibrations. If a lady is predisposed to acquaintance, she crawls out to the middle of the canvas, sits motionless. A hungry spider eats a gentleman even before he starts courting. The same fate awaits him if the chosen one suddenly gets hungry after fertilization.

The female forms a cocoon, lays several hundred eggs there. Attaches near its own hideout. Guards carefully. After 2-3 weeks, the younger generation appears. Almost immediately they spread out in different directions. They hibernate under foliage, in cracks, hollows, abandoned nests.

Is it poisonous or not

Orb-webs are no different aggressive disposition prefer to hide, rather than rush to attack. They can bite, defending their own life... Slight redness, swelling, pain appears on the spot. It passes in a few days. Orb-webs do not pose a serious danger to humans.

Orb-web spider family one of the most numerous families in the world, it has more than two and a half thousand species of spiders. This family includes the most different types spiders, they are all different from each other both in body shape, color, and lifestyle. The only similar nuance is the presence of special growths on the front pair of limbs in all species of spiders belonging to this family, thanks to which they are able to weave a special type of web. The most common and voluminous species of spiders of this family are Araneids, or as they are also called -.

The crosses live almost everywhere, but the largest number of them is observed on Far East, mainly they can be found in forests and fields. They weave just huge nets, which sometimes reach as much as two meters in diameter, they are very strong and solid, if an insect gets caught in such a web, there can be no hope of its salvation. In the tropics, nephilic orb-web spiders are widely known, they even weave traps up to eight meters in size, and only females do this, they are very large, they cannot be confused with anyone because of their bright, very original color. Males belonging to this species of spiders are inconspicuous and practically invisible against the background of their females, primarily due to their "compact" size. The web spun by such spiders is striking in its strength, it is very difficult to break it, and besides, it is amazingly elastic, it can stretch to a length three times its original size.

Spider cross found almost everywhere, it got its name due to the pattern on the abdomen, similar to the shape of a cross, the color of such a spider is usually black, but the pattern is made in lighter colors. Although spiders are not easy to find, their webs are found everywhere, mostly in open spaces, namely in fields and gardens. They are of average size, males are about one and a half centimeters, females - two and a half. Females lay eggs where, in her opinion, they are not in any danger, mainly for these needs they choose tree trunks. Quite quickly, young offspring appear from the eggs, which develops simply at a phenomenal rate and after only a few months it is already turning into fully mature independent spiders.

No less interesting for dating and Venezuelan cross, his hallmark is that unlike many other species of spiders, they live together. So, for example, females, laying eggs in cocoons, place them in a common nest, where they are until the moment when the spiders are born.

The Darwin spider (Caerostris darwini) is a very interesting spider from the orb-web family. Darwin's spider is named after naturalist Charles Darwin. His main feature is the spider web that represents special interest for scientists.

How Darwin's spider was discovered


Darwin's spider was discovered on the island of Madagascar in National park Andasibe-Mantadia. This discovery was made in 2001, but the spider was only described in 2009. Such a delay in the description of this species is due to the fact that its name is timed to coincide with the 150th anniversary of the publication of the work "The Origin of Species" by Charles Darwin. In 2009 Caerostris darwini was first described by Matjaz Kuntner and Inga Agnarsson, but the description was published in 2010.

Where dwells Caerostris darwini

As mentioned above Caerostris darwini was found on the island Madagascar. This island is considered the only habitat for this type of spider. Only 12 species of spiders of this family have been found on this island. In principle, it can be found everywhere, but Darwin's spider gives the greatest preference to places with water area... He weaves his webs mainly over the surface of rivers, but you can run into his webs on a regular path.

Description and behavior

For spiders of the species Caerostris darwini sexual dimorphism is characteristic. Females are usually much larger than males. Females have a body length of 18 to 22 millimeters, while males have a body length of about 6 millimeters. Females are usually black with white hairs on abdominal cavity and appendages. The limbs are about 35 millimeters long, while in males the limbs are about 15 millimeters long. Males are usually either red or light brown. The behavior of spiders also has an individual character, since the hunting of spiders for prey differs from its congeners. They hang a ball over a river or water surface of a lake and release a cobweb in the wind until it touches the other shore. Thus, they form a kind of bridges that are the basis of their trap.

Interest of scientists


The interest of scientists in this type of spider is that Darwin's spider, which in itself is not large sizes, weaves just a giant and very strong web. Gigantic, because the area of ​​the web is from 900 to 28,000 square centimeters. The length of the "cable" web is about 25 meters. But the main interest is the web itself. The tensile strength of this type of web is from 350 to 520 MJ / m³, while the ultimate strength of Kevlar is 36 MJ / m³. So that you understand, bulletproof vests are made from Kevlar for special units... Darwin's spider web is a highly complex mixture of elements that scientists around the world are studying.

  • Class: Arachnida Lamarck, 1801 = Arachnids
  • Order: Araneae = Spiders
  • Family Araneidae = Orb-web spiders

From the personal life of orb-web spiders

* Read more: Orb-web spiders; Spider spiders; Curious Spider Facts

Spiders evolved primarily through behavioral changes rather than morphology. Therefore, there are so many works on the biology of reproduction, network construction and other aspects of spider life. And all the time something new is being discovered.

Arachnologists T. Bukowski and T. Christensen, studying the biology of the North American orb weaving Mecrathena gracilis, which belongs to the group of spiny orb webs and has numerous spiny outgrowths on the abdomen, found out two features of their reproduction.

First, the male crawls into the net to the still immature female, shortly before her last molt. It molts fewer times than the female and becomes sexually mature earlier. This is beneficial: a female that has not yet molted or has just molted is less aggressive. Perhaps, over time, she "gets used" to the presence of a male. Analyzing the condition of males sitting in females' nets, American researchers found the absence of a part of the legs and other injuries in only a small proportion of males. At first, males behave passively and sit at the edge of the cobweb, apparently fearing an attack by females. After mating, the male quickly runs away, often even jumping out of the female's web. (Similar behavior of males is known in many snake spiders, including orb weaving.)

Secondly, double mating is characteristic of micrathenes: at first - short, and repeated - twice as long. In this case, the male tries to fertilize the female through both her paired copulatory holes. Most likely, this is necessary to guarantee the appearance of her own, and not someone else's, offspring - after all, the female is then able to mate with other males waiting in other corners of her network. Males try to remove competitors by cutting off their cobweb threads, etc.; By the way, they themselves can also mate with several females.

However, it remains unclear whether the sperm of the first male has an advantage in fertilizing the female, as has been noted in many other spider species. If so, then the second pairing becomes unnecessary. Maybe for the first time the male "out of excitement" injects an insufficient amount of sperm? It is also unclear how the male keeps track of the female's age. It was hypothesized that from time to time the male visits the growing female, and climbs into the net to her already "closer to the point" - before the last molt. But so far this hypothesis has not been proven.