How does a spider weave a web, where does the spider silk come from?

Representatives of the arachnid squad can be found everywhere. These are predators that prey on insects. They catch their prey with the help of a web. This is a flexible and durable fiber, to which flies, bees, mosquitoes stick. As a spider weaves a web, this question is often asked at the sight of an amazing hunting web.

What is a web?

Spiders are one of the oldest inhabitants of the planet, due to their small size and specific appearance they are mistakenly considered insects. In fact, these are representatives of the arthropod order. The body of the spider has eight legs and two sections:

• cephalothorax;
• abdomen.

Unlike insects, they do not have antennae and a neck separating the head from the chest. Abdomen arachnid is a kind of web factory. It contains glands that produce secretions, consisting of a protein enriched with alanine, which gives strength, and glycine, which is responsible for elasticity. According to the chemical formula, the web is close to the silk of insects. Inside the glands, the secret is in a liquid state, and hardens in the air.

Information. Silk of silkworm caterpillars and cobwebs have a similar composition - 50% is fibroin protein. Scientists have found that the spider thread is much stronger than the secret of caterpillars. This is due to the peculiarity of fiber formation.

Where does the spider's web come from?

Outgrowths of the arthropod are located - spider web warts. In their upper part, the channels of the spider glands that form the threads open. There are 6 types of glands that produce silk for different purposes (moving, lowering, entangling prey, egg storage). In one species, all these organs do not occur simultaneously, usually in an individual 1-4 pairs of glands.

On the surface of the warts, there are up to 500 spinning tubes supplying protein secretion. The spider spins a web as follows:

• spider warts are pressed to the base (tree, grass, wall, etc.);
• a small amount of protein sticks to the selected place;
• the spider moves away, pulling the thread with its hind legs;
• for the main work, long and flexible forelegs are used, with their help a frame of dry threads is created;
• the final stage of manufacturing the network is the formation of sticky spirals.

Thanks to the observations of scientists, it became known where the spider’s web comes from. It is released by mobile paired warts on the abdomen.

Interesting fact. The web is very light, the weight of the thread that wrapped the Earth at the equator would be only 450 g.

How to build a fishing net

Wind is the best spider helper in construction. Having removed a thin thread from the warts, arachnid substitutes it under the air stream, which carries the frozen silk to a considerable distance. This is the secret way a spider weaves a web between trees. The cobweb easily clings to tree branches, using it as a rope, arachnid moves from place to place.

In the structure of the web, a certain pattern is traced. Its basis is a frame of strong and thick threads located in the form of rays diverging from one point.Starting from the outside, the spider creates circles, gradually moving toward the center. Surprisingly, without any adaptations, he maintains the same distance between each circle. This part of the fibers is sticky, and insects will get stuck in it.

Interesting fact. A spider eats its own web. Scientists offer two explanations for this fact - in this way protein loss is compensated for when repairing a hunting net, or a spider just drinks water hanging on silk threads.

The complexity of the web pattern depends on the type of arachnid. The lower arthropods build simple networks, and the higher - complex geometric patterns. It is estimated that female cross builds a trap of 39 radii and 39 spirals. In addition to smooth radial threads, auxiliary and hunting spirals, there are signal threads. These elements capture and transmit to the predator the vibration of the caught prey. If a foreign object (branch, leaf) comes across, the small owner separates it and throws it away, then restores the network.

Large tree arachnids pull traps with a diameter of up to 1 m. Not only insects, but also small birds fall into them.

How long does a spider weave a web?

The predator spends from creating an openwork trap for insects from half an hour to 2-3 hours. Its operating time depends on weather conditions and the planned network size. Some species weave silk threads daily, doing it in the morning or evening, depending on the lifestyle. One of the factors for how much a spider weaves a web, its appearance is flat or voluminous. Flat - this is the usual version of radial threads and spirals, and volumetric is a trap made of a bundle of fibers.

Web Appointment

Thin nets are not only traps for insects. The role of the web in the life of arachnids is much wider.

Catching prey

All spiders are predators killing their prey with poison. At the same time, some individuals have a fragile physique and can themselves become a victim of insects, for example, wasps. For hunting, they need shelter and trap. Sticky fibers perform this function. They entrap the prey that got into the network with a cocoon of threads and leave it until the injected enzyme brings it into a liquid state.

Arachnid silk fibers are thinner than a human hair, but their specific tensile strength is comparable to steel wire.

Breeding

During mating, males attach their own strands to the web of the female. By striking rhythmic hits on the silk fibers, they inform the potential partner about their intentions. The female receiving courtship descends into the territory of the male for mating. In some species, the female is the initiator of the search for a partner. She selects a thread with pheromones, thanks to which a spider finds her.

Home for posterity

Cocoons for eggs are woven from silk spider web secret. Their number, depending on the type of arthropod, is 2-1000 pieces. Spider web bags with eggs are suspended in a safe place. The cocoon shell is strong enough, it consists of several layers and is impregnated with liquid secretion.

In their mink, arachnids braid the walls with cobwebs. This helps to create a favorable microclimate, serves as protection from the weather and natural enemies.

Moving

One answer is why a spider weaves a web - it uses threads as a vehicle. To move between trees and bushes, quickly understand and fall, he needs strong fibers. For flights over long distances, spiders climb to elevations, release a quickly solidifying web, and then with a gust of wind are carried away for several kilometers. Most often, trips are made on the warm, clear days of Indian summer.

Why does a spider not stick to its web?

In order not to fall into its own trap, the spider makes several dry threads for movement. I am well versed in the intricacies of networks, it is safely selected for adhering prey. Usually in the center of the fishing net there remains a safe area where the predator is waiting for prey.

Scientists' interest in the interaction of arachnids with their hunting traps appeared more than 100 years ago. Initially, it was suggested that they had special grease on their paws to prevent adhesion. No confirmation of the theory was found. Shooting with a special camera the movement of the legs of the spider through the fibers from a frozen secret gave an explanation of the contact mechanism.

A spider does not adhere to its web in three ways:

• a lot of elastic hairs on its paws reduces the area of ​​contact with the sticky spiral;
• the tips of the spider legs are covered with an oily liquid;
• moving occurs in a special way.

What is the secret to paw structure that helps arachnids avoid sticking? On each leg of the spider there are two supporting claws with which it clings to the surface, and one flexible claw. When moving, he presses the threads to the flexible hairs on the foot. When the spider raises the foot, the claw straightens and the hairs repel the web.

Another explanation is the lack of direct contact between the legs of the arachnid and sticky drops. They fall on the hairs of the paws, and then easily drain back onto the thread. Whatever theories are considered by zoologists, the fact that spiders do not become prisoners of their own sticky traps remains unchanged.

Other arachnids, such as ticks and false scorpions, can weave the web. But their networks can not be compared in strength and skillful interweaving with the works of real masters - spiders. Modern science is not yet able to reproduce the web by the synthetic method. The technology of making spider silk remains one of the mysteries of nature.