The cobweb is the secret of the cobweb glands, which, soon after being excreted, solidifies in the form of threads. By its chemical nature, it is a protein similar in composition to silk. It is woven mainly by arachnids and is used for hunting.
Spiders do not stick to the sticky strands of their own web thanks to the special hairs on their legs. They, firstly, reduce the contact area of the limb with drops of glue on the threads, and, secondly, they are covered with a special substance that sharply reduces the sticky properties of the glue. When the spider puts its paw on the thread, a drop of glue envelops the hairs, sliding back as soon as the spider rearranges its paw.
If you weigh the mass of the cobweb. which could entangle the entire globe along the equator, then this mass would be only 340 grams.
The web is much tougher than any known natural or man-made material. The strength of a material is measured in units called dernier (1 dernier = 1 g per 9000 m). So the spider thread has a strength of 5 to 8 dernier. Only glass and nylon have similar characteristics. Known for its durability, the steel only lasts 3. Scientists have calculated that a thread woven from spider silk, as thick as a pencil, can stop a flying Boeing 747.
To date, the cobweb has not yet been learned to recreate in the laboratory.
Once the king of France, Louis XIV, received a souvenir from the parliament of the city of Montpellier - stockings and gloves knitted from spider silk.
The spider Nephila lives in Madagascar and East Africa. The animal itself is far from the leader among spiders in size - only 7 centimeters, but the diameter of its trapping net reaches 8 meters.
Most spiders eat their old cobwebs, as well as the pollen of flowers that has settled on it. Everything, except for the main thread, and then weave it again, such is their waste-free production.
The spider Araneus, the common cross among the people, has proved to be a brilliant mathematician who repeats the formula of his own web with amazing accuracy. The web of the female of this spider always has strictly 39 radii, 39 spiral curls and 1245 nodes connecting the radii and spirals.
The filament of the orb-web spider Araneus diadematus is very elastic and can be stretched 30-40% before it breaks. Steel can only be stretched 8%, and nylon somewhere around 20%.
Thanks to the web, side walk spiders can be transported through the air over long distances. Such travels are undertaken in the fall during the "Indian summer", when the spiders reach their full bloom. By the way, they do not weave a web for hunting, but use it only for keeping offspring (the female weaves a bag for laying eggs) and travel.
Another unusual property of the web is its internal hinge: an object suspended on a spider web can be rotated indefinitely in the same direction, and at the same time it will not only not twist, but will not create a noticeable reaction force at all.
Interestingly, the primary function of the spider's web is related to reproduction, and not to the extraction of food. During the mating season, female spiders release a web with pheromones, which the male uses when searching for a mate.
There are over 40, 000 spider species, each of which can weave up to 7 different types of threads. Thus, 99.99 percent of spider silk threads are still unexplored.