How long does it take for a spider to spin a web? What knots does a spider use when weaving a web? Secret of the spider glands

Watching insects in the summer, you can admire for a long time the speed and grace with which the spider weaves its web. Not without reason in all world cultures there are references and comparisons to the web, as to something incredibly complex and sinister. But where does the spider get the thread for building its ingenious traps?

10 facts about the web

Below 10 fun facts about the web that these insects produce:

The web is woven by almost all types of spiders.
Only a few of them use it as a trap.
Spiders living in minks still braid the walls with their thread, it’s more convenient for them.
An insect sitting in a web receives all the information about the world around it by vibrating the threads.
Some spiders weave such webs that do not fix the victim that has fallen, but only warn of its approach.
Not all spiders are equally agile. It takes some insects almost a lifetime to learn how to manage their network.
They rarely get tangled in their web, but it is quite possible.
The threads themselves are very durable, they can last for tens and even hundreds of years.
The size of the spider and the web are independent of each other, so do not be afraid if you stumble upon a huge web in your home or yard. Perhaps her little harmless spider wove.
most poisonous and dangerous insects are found in southern latitudes, so that the inhabitants of the northern regions may not particularly worry.

The structure and composition of the web

Having a general idea of \u200b\u200bwhy spiders weave webs, you can try to figure out what is this weaving of threads:

It consists of many single threads.
They are all attached to a solid surface at least at one point.
They travel in the same plane, but in different directions.
Initially, the spider weaves long threads, forming a kind of frame.
Then weaves them with longitudinal threads in a circle, completing the work.
How sticky the web will be depends on the period of its existence and the type of spider.
The insect itself must be extremely careful, because, like its victim, it is not immune from the possibility of falling into its own trap.
The web is only a temporary home, in the event of a change in environmental conditions or increased competition, the spider, without hesitation, will move to another place and begin to weave a new network.

But for any construction it is necessary material. And by its properties spider thread unique:

Mainly made up of proteins.
In terms of properties, it is most similar to nylon.
It has a huge margin of tensile strength. Up to two hundred kilograms per square millimeter.
If humanity could synthesize this kind of fabric, it would be used in many advanced branches of science and production.

A bit of spider anatomy

Let's figure it out how does the spider get this very thread:

As a result, the whole process occurs in three stages:

Activation of the glands located in the abdomen of a spider. This process is accompanied by the synthesis of a sticky protein substance, which is subsequently converted into a web.
The passage of the released secret through the tubes, its accumulation.
Isolation of a cobweb thread through 6 papillae located at the bottom of the abdomen.

More detailed studies have shown that the number of glands, tubules and papillae can vary, depending on the type of spider.

There are varieties with more difficult organized system web production. But it all comes down to the fact that the insect squirts a small amount of web onto a hard surface and begins to weave a thread that dries immediately when exposed to air.

Why can't you kill spiders?

Exists great amount superstitions about spiders and their webs. In most cases it is considered bad sign killing this insect or destroying its house. There is a rationale behind this:

The spider feeds on other insects, killing flies, mosquitoes and other intruders.
One such inhabitant with 8 paws, settled in your house, will work better than a squad of exterminators. And he won't ask for anything for his work.
Once all insects have been eradicated, the spider will have no food options and will be forced to leave your home.

But there are always downsides:

The web collects all the dust and dirt.
Living in southern regions, you may encounter venomous and life-threatening varieties of spiders.
Nobody canceled arachnophobia, the fear of spiders will make you instantly forget about all their usefulness.

Therefore, decide for yourself how to deal with an uninvited guest. If you kill all the other insects without hesitation, it makes no sense to make some kind of indulgence for the owner of eight legs.

On the other hand, pity for harmless creatures should always be present, at least on some level.

Where does the web actually come from?

To dispel a couple of myths, let's say that:

The spider produces its thread through the glands located in the abdomen.
She does not come out of his paws, like a hero of comics and films.
Removal is provided by special papillae located at the bottom of the abdomen.
She comes out of the anus, the web is not a waste of life.
Its composition is not particularly dependent on the diet of the spider. The main thing is that the food is sufficient.
It is difficult to assess labor productivity in spiders, but it is reliably known that spiders can spin a thread without stopping several tens of meters long.
These are all experimental data real life small insects do not need such huge trapping nets.
On the other hand, one can appreciate the scale of the tragedy if one of the plots of horror films about the invasion of these huge insects comes true in real life.
The spider does not have any threads in the abdomen, the web is produced in a semi-liquid form and it freezes only in the air.
It is hard to believe that such a thin thread can be so strong. But it's all about the physical characteristics and chemical composition of the material.

Children often ask seemingly simple questions, but it will not be possible to find an answer to them right away. Now you can in simple words explain to your baby where the spider got the thread from and why he weaves his ingenious webs. Only about the "prospects" of the invasion of giant spiders it is better to keep silent, the fiction of the screenwriters will remain just a fiction.

Video: how does a spider make a thread?

This video will show exactly how the spider produces its thread, how it weaves a web and catches its prey in it:

Candidate of Physical and Mathematical Sciences E. Lozovskaya

Science and life // Illustrations

The adhesive substance covering the thread of the trapping spiral is evenly distributed over the web in the form of droplets-beads. The picture shows the place of attachment of two fragments of the trapping spiral to the radius.

Science and life // Illustrations

Initial stages building a trapping network with a spider-cross.

The logarithmic spiral approximately describes the shape of the auxiliary spiral thread that the spider lays during the construction of the wheel-shaped trapping net.

Archimedes' spiral describes the shape of a sticky trapping thread.

Zigzag threads are one of the features of the spider webs of the genus Argiope.

The crystalline regions of the silk fiber have a folded structure, similar to the one shown in the figure. Individual chains are connected by hydrogen bonds.

Young cross-spiders, just out of a cobweb cocoon.

Spiders of the Dinopidae spinosa family weave a web of cobwebs between their legs and then throw it over their prey.

The spider-cross (Araneus diadematus) is known for its ability to weave large wheel-shaped trapping nets.

Some species of spiders also attach a long "ladder" to the round trap, which significantly increases the efficiency of hunting.

Science and life // Illustrations

This is what spider web tubes look like under a microscope, from which threads of spider silk come out.

Perhaps spiders are not the most attractive creatures, but their creation - the web - cannot but arouse admiration. Remember how the geometric correctness of the finest threads shimmering in the sun, stretched between the branches of a bush or among tall grass, fascinates the eye.

Spiders are one of the oldest inhabitants of our planet, inhabiting the land more than 200 million years ago. In nature, there are about 35 thousand species of spiders. These ubiquitous eight-legged creatures are recognizable always and everywhere, despite differences in color and size. But their most important distinguishing feature is the ability to produce spider silk, a natural fiber unsurpassed in strength.

Spiders use their webs for a variety of purposes. They make egg cocoons out of it, build shelters for wintering, use it as a "safety rope" when jumping, weave intricate trapping nets and wrap the caught prey. The female, ready for mating, produces a web thread marked with pheromones, thanks to which the male, moving along the thread, easily finds a partner. Young spiders of some species fly away from the parent nest on long threads picked up by the wind.

Spiders feed mainly on insects. The trapping devices they use to obtain food are the most different forms and types. Some spiders simply stretch out a few signal threads near their shelter and, as soon as the insect touches the thread, they rush at him from an ambush. Others throw a thread with a sticky drop at the end forward, like a kind of lasso. But the pinnacle of the design activity of spiders is still round, wheel-shaped nets, located horizontally or vertically.

To build a wheel-shaped trapping net, the cross-spider, a common inhabitant of our forests and gardens, releases a rather long, strong thread. A breeze or an updraft of air lifts the thread up, and if the place for building the web is chosen well, it clings to the nearest branch or other support. The spider crawls along it to secure the end, sometimes laying another thread for strength. Then he releases a freely hanging thread and attaches a third to its middle, so that a Y-shaped structure is obtained - the first three radii out of more than fifty. When the radial threads and the frame are ready, the spider returns to the center and begins laying a temporary auxiliary spiral - something like a "scaffolding". The auxiliary spiral fastens the structure and serves as a path for the spider when building a trapping spiral. The entire main frame of the net, including the radii, is made of non-adhesive thread, but for the trapping spiral, a double thread coated with an adhesive is used.

Surprisingly, these two spirals have different geometric shape. The time spiral has relatively few turns, and the distance between them increases with each turn. This happens because, while laying it, the spider moves at the same angle to the radii. The shape of the resulting broken line is close to the so-called logarithmic spiral.

A sticky trapping spiral is built according to a different principle. The spider starts at the edge and moves towards the center, keeping the same distance between the coils, and the spiral of Archimedes is obtained. At the same time, he bites the threads of the auxiliary spiral.

Spider silk is produced by special glands located in the back of the spider's abdomen. At least seven types of arachnoid glands are known to produce different filaments, but none of them known species spiders do not occur all seven types at once. Typically, a spider has one to four pairs of these glands. Weaving a web is not a quick business, and it takes about half an hour to build a medium-sized trapping web. To switch to the production of a different kind of web (for a trapping spiral), the spider needs a minute's respite. Spiders often reuse the web, eating the remains of a trapping net damaged by rain, wind or insects. The web is digested in their body with the help of special enzymes.

The structure of spider silk has been ideally worked out over hundreds of millions of years of evolution. This natural material combines two wonderful properties - strength and elasticity. A web of webs is capable of stopping an insect flying at full speed. The thread from which spiders weave the basis of their trapping web is thinner than a human hair, and its specific (that is, calculated per unit mass) tensile strength is higher than that of steel. If we compare the gossamer thread with steel wire of the same diameter, then they will withstand approximately the same weight. But spider silk is six times lighter, and therefore six times stronger.

Like human hair, sheep wool, and the silk of silkworm cocoons, webs are made up primarily of proteins. In terms of amino acid composition, web proteins - spidroins - are relatively close to fibroins, the proteins that make up silk produced by silkworm caterpillars. Both contain unusually high amounts of the amino acids alanine (25%) and glycine (about 40%). Areas of protein molecules rich in alanine form crystalline regions densely packed into folds, providing high strength, and those areas where there is more glycine are a more amorphous material that can stretch well and thereby give elasticity to the thread.

How is such a thread formed? There is no complete and clear answer to this question yet. The process of spinning the web has been studied in most detail on the example of the ampulla-shaped gland of the orb-web spider and Nephila clavipes. The ampuloid gland, which produces the strongest silk, consists of three main sections: a central sac, a very long curved canal, and a tubule with an outlet. From cells to inner surface small spherical droplets containing two types of spidroin protein molecules come out of the sac. This viscous solution flows into the tail of the sac, where other cells secrete another type of protein called glycoproteins. Thanks to glycoproteins, the resulting fiber acquires a liquid crystalline structure. Liquid crystals are remarkable in that, on the one hand, they have a high degree orderliness, and on the other hand, they retain fluidity. As the thick mass moves towards the outlet, long protein molecules orient themselves and line up parallel to each other in the direction of the axis of the emerging fiber. In this case, intermolecular hydrogen bonds are formed between them.

Mankind has copied many of the design discoveries of nature, but so far it has not been possible to reproduce such a complex process as web spinning. This difficult task scientists are now trying to solve with the help of biotechnological techniques. The first step was to isolate the genes responsible for the production of the proteins that make up the web. These genes have been introduced into bacterial and yeast cells (see "Science and Life" No. 2, 2001). Canadian geneticists have gone even further - they have bred genetically modified goats whose milk contains dissolved cobweb proteins. But the problem is not only in obtaining spider silk protein, it is necessary to simulate the natural spinning process. And this lesson of nature scientists have yet to learn.

What knots does a spider use when weaving a web? Or does it not use nodes at all?

When weaving a web, a spider does not use knots at all. He does not need them: the spider glues the threads of the trapping web together with a special type of web - a connecting one.

The sticky droplet consists of a glycoprotein core and a watery shell of water and peptides. The stickiness of the droplet depends on the humidity of the air: if it is very dry, some of the water may evaporate, and the droplet will lose its properties. This is one of the reasons why in humid climate more variety of spiders. Each spider species is adapted to a specific range of humidity. This is achieved by varying the composition of the sticky droplets from species to species.

In addition to providing stickiness, the droplets perform other functions. For example, in the Australian argiope spider ( Argiope keyserlingi) they can serve as bait for flies - its victims. The sticky droplets of argiope contain putrescine, a substance released during the decomposition of animal corpses. Therefore, carrion flies fly to its smell and fall into a trap (see Argiope spider's web attracts insects by smell, "Elements", 07/17/2017).

So, we figured out the properties of the web thread. Now let's see how the web itself is arranged. The basis of the web is the bearing threads - usually there are three or four of them - which the spider sticks with both ends to the substrate (for example, a tree branch or a grass stalk) using connecting disks. Sometimes they are supported by additional anchor threads (see the picture below). Radial threads are attached to the bearing threads, converging to the center of the web - the “hub”.

The spider puts a trapping spiral on the radial threads. Often the trapping spiral does not reach the "hub" a little, leaving a free zone, the meaning of which is not yet clear. At the intersection of different threads are the above-mentioned connecting disks that support the structure.

Getting into the web, insects stick most often to the trapping spiral. But, of course, not tightly: actively twitching, they can peel off and fly away - so the spider needs to hurry. Having learned about the catch, he immediately runs to the victim, bites him and then, immobilized, entangles him with his web. The secret of the glands that open in its chelicerae jaw contains a poison that paralyzes prey. In addition, the spider injects digestive enzymes into the victim, which break down its insides and turn them into a thick broth. This partially digested soup is then sucked up by the spider. And in order to notice the prey in time, the networks of many species of spiders have special signal threads that lead directly to the spider sitting openly in the center of the web or in a secluded shelter on the periphery. When the caught insect starts to beat, it shakes the web - including the signal threads. According to their vibration, the spider determines that the prey has been caught.

So different strands of the web perform different functions. Spiders can produce up to seven types of arachnoid filaments, which differ in composition and properties and are secreted by different arachnoid glands. The web-bearing threads are the strongest. But the threads of the trapping spiral are the stickiest, because they have the highest concentration of sticky droplets. Therefore, for example, the threads of a trapping spiral cling to a person walking through the forest. In addition, there is a special type of thread for wrapping the victim, a thread for forming a soft inner layer of a cocoon for eggs, and a thread for a strong outer layer of a cocoon. As well as a special connecting web.

But how does the spider itself not stick to its web? During the weaving of the web, he touches the sticky trapping threads only with the very tips of the legs, covered with numerous hairs, which reduces the contact area with sticky drops. In addition, the legs of the spider are lubricated with a special oily substance that prevents sticking. Well, when a spider walks on its web, it moves along less sticky radial threads.

Answered: Alexey Opaev
Picture Ekaterina Volovich

In the abdominal cavity of spiders there are numerous arachnoid glands. Their ducts open with the smallest spinning tubes, which are located at the ends of six arachnoid warts on the spider's abdomen. A spider-cross, for example, has about 500-550 such tubes. Spider glands produce a liquid viscous secret, consisting of protein. This secret has the ability to instantly harden in air. Therefore, when the protein secretion of the spider glands is released through the spinning tubes, it freezes in the form of thin filaments.

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1. Spider-cross (with an open abdominal cavity)
2 Spider Web Warts

The spider begins to spin his web like this: he presses the spider warts to the substrate; at the same time, a small portion of the released secret, solidifying, sticks to it. The spider then continues to draw the viscous secret from the web tubes with the help of its hind legs. As it moves away from the site of attachment, the rest of the secret simply stretches into rapidly hardening threads.

Spiders use the web for a variety of purposes. In the web shelter, the spider finds a favorable microclimate, where it also hides from enemies and bad weather. Some spiders web the walls of the mink. From the web, the spider weaves sticky trapping nets to catch prey. Egg cocoons, in which eggs and young spiders develop, are also made from cobwebs. The web is also used by spiders for travel - small tarzans weave safety threads from it, which protect them from falling when jumping. Depending on the purpose of use, the spider can secrete a sticky or dry thread of a certain thickness.

By chemical composition and physical properties the web is close to silk silkworms and caterpillars, only it is much stronger and more elastic: if the breaking load for caterpillar silk is 33-43 kg per 1 mm 2, then for the web - from 40 to 261 kg per mm 2 (depending on the type)!

Other arachnids, such as spider mites and false scorpions, can also secrete cobwebs. However, it was spiders who achieved true mastery in weaving webs. After all, it is important not only to be able to make a web, but also to produce it in in large numbers. In addition, the "loom" should be located in the place where it is more convenient to use it. In false scorpions and spider mites raw material base cobwebs are located ... in the head, and the weaving apparatus is located on the oral appendages. In the conditions of the struggle for existence, animals whose heads are weighted with brains, and not with cobwebs, gain an advantage. That's what spiders are. The spider's belly is a real web factory and spinning devices - spider webs - are formed from atrophied abdominal legs on the underside of the abdomen. And the limbs of spiders are simply "golden" - they spin so deftly that any lace maker can envy them.

Nowadays, thanks to the achievements of science and technology, you can see and understand how a spider spins a web. Arthropods inherit these abilities from their parents at the genetic level. In other words, all actions are programmed, since no one teaches young spiders such skill. Different kinds spiders weave a web various shapes, different size and different structure, depending on the destination.

Spiders have special glands that produce a special secret. After this substance begins to appear from the glands, the spider stretches it, resulting in thin and strong threads. As a result of curly weaves, a fairly strong construction is obtained. This secret is intended for various, including construction purposes.

The basis of such building material makes up a protein, in complex with alanine, serine and glycine. Being inside the spider gland, the substance is a liquid form. After the substance is used in the form of threads, it hardens in air.

Spider glands, in the form of warts, are located near the genitals. The thread consists of a crystalline protein, which at times increases the strength and flexibility of the dried threads. Depending on the purpose of the web, its thickness and strength can vary markedly.

Interesting fact! The strength of the web is the same as if it were knitted from nylon. At the same time, it retains its characteristics, both in compression and in tension. If you hang an object on a long web and start rotating it in one direction, then the web will not get tangled and will not show any resistance to rotation. Thanks to such unique properties cobwebs, the spider can hang on the web for a long time. The web is not only strong, it is light enough, so spiders often travel long distances with the help of the web under the influence of the force of the wind.

The spider does not just weave a web, where it pleases and when it pleases. He weaves it when necessary and in those places where it can be useful to him. Each spider web has its own purpose. Females spin webs to attract males. That's why:

The spider glands are located near the genitals, which allows the female at the same time to secrete a special secret that attracts males.
Trapping nets are weaved by spinners. Such networks can have a diameter of 2 m, or even more. The strength of the threads is such that a bird can get tangled in the web, not big rodent or amphibian. Most spiders catch insects as well as their larvae.
Spiders living in the ground dig holes with many moves. They do not weave trapping nets, but cover the entrance with cobwebs and weave signal threads. These threads give a signal if the victim is near the hole. In this case, the spider immediately reacts and appears at the entrance to its hole.
Spiders lead a separate way of life and form pairs only for the breeding season. Each spider guards its territory and does not allow outsiders to approach it. In the case of the development of new territories, the spider weaves a long thread, attaching it to some kind of base and waiting for a good gust of wind. Once in the air, under the influence of the force of the wind, the spider is able to overcome tens or even hundreds of kilometers. Such migrations become massive when young spiders are born.
After mating, the female makes a special cocoon from the web and lays up to 1000 cocoons in it. eggs. Some species fix the cocoon in some place, and some species drag it along until the spiders appear.
Some species of spiders, such as the water spider, build their nests underwater using web threads. This house is filled with air, and the female lives in it. AT mating season she lets a spider in, after which offspring is born, which lives in this nest for a certain time. Here she drags the caught victim.
After getting into the web of an insect, the spider wraps it in a web, injecting a toxin before that. After that, he moves away from his victim and watches her. Starts eating after complete death. If the spider is not hungry, then it leaves the next victim until it gets hungry.
There are varieties that wrap the leaves with cobwebs, after which they stretch out a long web. When necessary, the spider pulls the web, thus reviving the leaf. As a result, some predators react to this leaf, but not to the real spider's nest.

There are also crafty spiders who build a raft from improvised means and cobwebs and swim on it, while hunting for fish fry, larvae, crustaceans, etc.

If a trapping net badly damaged, then the spider can leave it and begin to form, somewhere nearby a new canvas.

Important point! Some arthropods eat their trapping nets. Experts explain such actions of spiders by the fact that their body requires replenishment with protein. In addition, moisture always accumulates on the web, which is necessary for the spider.

As a rule, many species of spiders prefer to be nocturnal, therefore weaving a web mainly at night. On average, the spider spends about an hour on this procedure. If you need to repair an insect trap, it takes even less time.

Below you can see in the video how the spider weaves a web and how much time it spends on it. If the web is torn off, then the next morning exactly the same web will appear in the same place. The most beautiful web is obtained from the spinners. With the help of strong threads, the spider forms a triangle, after which it fills it with cells of a certain size.

Interesting to know! AT tropical forests In Brazil, there is a tarantula that weaves a web so strong that local fishermen use it as nets to catch fish. From the threads of spiders, you can weave not only a thin, but also a fairly strong fabric. From the substance of spiders, some companies sew body armor.

In the garden you can see how the spider weaves a web, placing it on 2 trees. It can be an openwork hunting net or a funnel that glitters in the sun, attracting insects. Of course, for many, this process is a mystery. It's even hard to imagine how a spider could pull a web between two trees. As a rule, the spider flies on a web from one tree to another under the influence of wind. Having fixed the second end, the simplest thing remains for him - this is to fill the space with cells.

At the same time, being in a state of flight, the spider controls the distance to a neighboring tree, while adjusting the length of the web. Sometimes, in order to cling to a branch, he simply shoots the web in the right place.