What kind of spiders weave webs. Description of how a spider weaves a web - features of the process and functions of the web

Most people don't like spiders. They look rather unpleasant, and prejudices do their job. At the same time, not only children, but also adults have a keen interest in how a spider weaves its web. Why he does this is clear to everyone. But how, remains a mystery. Let's try to open it.

You won’t believe it, but not all spiders are capable of creating such an elegant lace, but only those that use it to catch small insects that serve them as food. These representatives of the spider family are called snails. They also include poisonous individuals, such as karakut and black widow. The same spiders that are actively hunting can also weave a web, but they use it purely for other purposes.

In humans, lace woven by spiders often causes a feeling of envy, they are so skillfully woven. The threads from which they are made are incredibly durable. From its own weight, the web never breaks. This can only happen if the length of the thread is more than fifty meters. As you can see, the margin of safety of cobwebs is very high. If you pay attention to their subtlety, then this fact can really be envied. If you take a separate cobweb and try to stretch it, then it will break only after it has quadrupled in length.

Threads woven by a spider have another exceptional property. They are transparent and almost invisible. Depending on the conditions of use, the spider can weave a web of three types: strong, household, sticky. A strong web is used to create a framework for trapping nets. Jumpers in the frame are made of sticky threads. With a household web, the spider closes the entrance to its mink or entangles cocoons with larvae. Some types of spiders can spin webs that reflect ultra-violet rays. It is used to attract butterflies.

Do all spiders weave patterned webs?

As it turns out, not all. Only araneomorphic arthropods are capable of creating real masterpieces.

Now let's get back to the question of why a spider needs a web. It is clear that the answer suggests itself - of course, for hunting. However, these are not all of its functions. The web can be used for the following purposes: for masking and warming the entrance to the hole, for cocoons, for protection. Paradoxically, the cleverly crafted web protects the spider's burrow from the rain. Spiders move along the web, their offspring leave the nest along it.

And yet, what is the basis of the web?

The spider has six glands located on its abdomen. With their help, he produces a secret called liquid silk. When it comes out, it starts to harden. Incredibly thin threads emerge from the glands, which the spider twists together with its paws. The result is a web. This is how he weaves his lace.

If this is a trapping net, then he stretches it between the branches of the tree. Having fixed one side of the thread, he stops spinning and waits for a breath of wind, which should carry the second side of the web to the second branch. After that, the next stage of weaving begins, which is similar to the first. This continues until the framework of the future network is woven. After that, a sticky web is woven into it. All unused remnants of the web are eaten by the spider.

Almost all spiders are predators and use their webs to catch insects. Shadow spiders catch flying insects. Those who live in earthen burrows are content with beetles, worms and snails. Water spiders catch small fish, crustaceans, insects. The tarantula does not disdain frogs, lizards, birds, small rodents. However, there are those who eat their own kind.

All spiders, regardless of species, spin webs. It is a net into which small insects fall. They serve as food for animals. The threads that make up the web are sticky, but the spiders don't stick to it.

The fact is that the web has its own structure. Some threads serve as a trap, while others are designed to support the fabric web. They have less adhesive.

The spider moves along a woven web, barely touching its limbs. The tips of the hairs are lubricated with a gel that prevents the individual from getting into its own webs. Why does a tarantula spider weave a web? What are threads made of?

Tarantulas also weave webs, but not to set a trap to catch insects. Animals hunt, wait for their prey in a shelter. They scatter threads around their shelter. They are thin, imperceptible to the human eye.

Males spin sperm webs during the breeding season.

During the construction of a tissue web from the sex glands, which are located on the abdomen of the spider, seminal fluid is released. In the future, individuals collect fluid in the bulbs, which are located at the ends of the pedipalps; bulbs function like a pump.

Some types of spiders spin webs to collect water. Dew is formed on the threads, which is consumed by both adults and young animals as a drink. This is especially true in the hot season. The fabric will not hold a lot of water, but dew drops settle on it.

The thickness of the spider web is 10 microns. In tarantulas, it has greater strength than the silk thread of the silkworm. A canvas with an area of ​​1 mm2 withstands a breaking force of 260 kg.

At the end of the 17th century in France, developments were underway to create web fabrics that were supposed to replace silk. Gloves and stockings were sewn on. Products were presented at the Royal court.

The web is a secret that is secreted by the spider glands. They are located in the abdomen, connected by thin tubules with outlets. Holes are located in arachnoid warts. They are at the end of the abdomen. In the tarantula, this is a paired organ.

There are several spider glands in arthropods. Each has its own function, highlights the secret to create a specific section of the web and for the fabric that performs a specific function; construction of dwelling and cocoon, alarm system, cleaning of the territory.

Spiders have the following glands:

• lobular - responsible for creating a soft layer of a cocoon; threads are also used to wrap the victim so that it is easier to hold it with chelicerae;
• tubular - the secret is allocated for the manufacture of the upper layer of the cocoon; it is more durable and rigid;
• coronal - the outer contour of the web is built from the threads and its attachment to any object: tree bark, branches, to the ground; tarantulas use threads of this nature to strengthen their holes, to create "air" tunnels on a tree;
• the arborescent gland secretes a secret from which the threads of the internal contour of the web are derived; there are drops of glue on the threads; they are distributed along the entire length clearly at a certain distance; spiders do not use knots for weaving;
• a large ampuloid gland secretes a secret for making the main "body" of the canvas; the threads lie exactly on the sticky droplets;
• there is also a small ampuloid gland, but in tarantulas it is poorly developed; spiders make an additional spiral from threads for the trapping zone, which is unusual for tarantulas.

The filaments are made up of a protein, fibroin, which is a chain of amino acids. The main part is occupied by alanine and glycine. In small quantities in cobweb secret contains glutamic acid, leucine, tyrosine, serine. 13% falls on the protein.

This is a complex protein. It consists of amino acids and compounds that belong to the non-amino acid nature of origin.

The composition of the secret of the female and male tarantula is not the same. During the breeding season, males find spiders on their webs. The secret is removed from the spider warts at high speed.

It looks like it's being shot by a spider. It is liquid, but in contact with air, it quickly crystallizes, turning into a strong and elastic thread.

Each tarantula weaves its own web design. The web is distinguished by an individual pattern, the way the threads are arranged, and the fastening.

According to the canvas, arachnologists can only determine the sex and type of arthropod. For weaving, individuals use the front and hind limbs. Arachnologists continue to study the world of insects, and in early 2000 they found that arthropods also have spider microglands on the limbs of arthropods. Which are actively used to create a canvas.

The web of arthropods has a complex structure. The weaving of the web is an unconditioned reflex of the spider. Bird-eaters do not teach their offspring to create webs. The ability is laid down by nature.

The larvae can already lead an independent lifestyle. They dig small holes in which they strengthen the soil with thin threads or equip a dwelling under the bark of a tree, densely braiding the nearby area.

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Indian summer is a great time of autumn, when you can soak up the last warm rays of the sun of the year, enjoy the excellent weather, and see the past summer. But, as usual, a barrel of honey should spoil something. Web. She is everywhere. It poisons my happiness, scares and spoils the mood. She's annoying! The web hurries to meet me in the most unexpected places, even where someone passed in front of me a minute ago, even where there is no vegetation nearby.

And they also say that the web is an incredibly strong and durable material. How does a spider weave a web that spreads it everywhere?

Spider web weaving algorithm

I read it, it turns out creating gossamer lace is a very laborious process for eight-legged creatures (spiders, by the way, cannot be called insects). They work like this:

• having chosen a suitable place, a special secret is isolated from the spider web warts located on the abdomen, which, congealing, is transformed into a long, thinnest thread;
• waiting when the breeze will pick up this thread and carry it to some kind of support - twigs, blades of grass, leaves, etc. and crawl to the place where the thread is hooked, securely fasten it;
• form another thread repeating the first, fix it;
• crawl to the middle of the second thread and form the third thread, placing it perpendicular to the first two, and fix it so that a figure resembling the letter Y is formed.

This is the basis of the future web. Then the spider stretches several more radii from the point of intersection of the threads, connecting their ends with segments of the thread. It turns out the skeleton of the web, peculiar ribs with edging. Further, fluttering over this blank, the spider quickly knits a lace pattern on it.

Patterns are created using two spirals. The first, not sticky, spider weaves from the middle of the warp, and it exactly repeats the shape of the logarithmic spiral. The second, sticky, weaves in the opposite direction and exactly repeats the shape of the Archimedean spiral.

Web types

There are 35 thousand varieties of spiders on the planet. Not all eight-legged creatures weave tight webs.

Some representatives weave a tiny mesh of cobwebs between its paws, they wait for the prey and throw a prepared sticky net on top of it. And there are representatives who do not bother with weaving at all. They catch the prey homemade spider web lasso with a drop of sticky substance at the end. There are species that work together weaving cobwebs over vast areas.

What is web used for

The most common web function is catching prey for food. But this is far from its only purpose.

Another web is used:

• to protect the home;
• as a home decoration;
• for cocoons in which females lay eggs;
• as a means of transportation.

It is the last point that explains the fact of the autumn invasion of the flying web. So young spiders settle in the area.

Appearance

In general, female goliath tarantulas are usually larger than males. The size of their soft body reaches 9 cm, while in males it is no more than 8 cm. The leg span of these giant spiders ranges from 25 cm to 28 cm. The largest individuals weigh about 150 grams.

The protective color of tarantulas varies from black to yellow-orange. This usually happens just before the molt. The cephalothorax of these creatures, as well as their abdomen, are covered with short but dense hairs. The paws are covered with long and reddish hairs.

Where does the world's largest spider live?

The favorite places of these creatures are mountainous areas with dense and wet forests. The optimal habitat for these "giants" is humid and swampy areas, mainly located in Venezuelan tropical forests. In addition, goliath tarantulas are widespread in the rainforests of Guyana, Suriname and Brazil.

Goliath tarantulas inhabit entire burrows up to 1 m deep. Outside, they braid them with thick cobwebs to prevent strangers from getting inside. Females spend most of their lives in burrows. They only come out to hunt at night. And this despite their impaired vision.

Hunting

The goliath tarantula is a carnivorous spider. Before attacking a potential victim, this creature lurks in an impromptu ambush. So the spider lies in wait for his "dinner". As soon as the future prey has approached a distance sufficient to attack, the tarantula pounces on it, using its fangs.

Contrary to its name, the tarantula does not eat birds at all. This was apparently an isolated case. The fact is that this type of spider from the order of arachnids was first noticed precisely when, for some reason, it ate a bird. Zoologists who have been observing goliaths for a long time have come to the conclusion that the favorite and main food of these creatures are both invertebrates (butterflies, beetles) and vertebrates (mice, small snakes, frogs).

Lifespan

In general, zoologists call adult tarantulas individuals who have reached three years of age. The average life expectancy of a male goliath is 6 years. The female lives twice as long - up to 14 years. It is curious that often the life of males ends after mating with a female.

The fact is that during mating games, goliath tarantulas, like praying mantises, have a ritual: after mating, the female simply eats her “groom” without his consent. However, not all spider suitors are willing to put up with this state of affairs. That is why nature rewarded them with sharp spikes located on the first pair of limbs. They serve as protection against aggressive females.

What is it made of and where is it formed

The composition of the web includes the following substances:

• organic compounds- protein fibroin, of which the main internal thread consists, and glycoproteins that form nanofibers located around the main thread. Thanks to fibroin, the web is similar in composition to silk, but much more elastic and durable;
• inorganic substances - chemical compounds potassium (hydrophosphate and nitrate). Their number is small, but they give the web antiseptic properties and protect it from fungi and bacteria, create a favorable environment in the glands of the spider for the formation of threads.

In the abdomen of the spider there are arachnoid glands, where a liquid substance is formed, which exits through the spinning tubes located on the arachnoid warts. They can be observed at the very bottom of the abdomen.
A viscous liquid exits the tube and quickly solidifies in air. With the help of its hind legs, the spider pulls the thread and uses it for weaving. One spider is capable of producing a thread 0.5 km long.

What are the types

Spiders, depending on the species, can weave a different web.

The form may be as follows:

How and how long do spiders weave a web

The spider weaves the most famous round web for 0.5–3 hours. The duration of weaving depends on the size of the net and the weather. In this case, the wind usually becomes the best helper, carrying the thread released by the spider to a decent distance.

It is downwind that the web stretched between the trees is located. A thin thread is transferred air flow, clings to a nearby tree and perfectly withstands the movements of its creator.

He periodically renews the woven net, as over time it loses its ability to hold prey.

The spider usually eats old webs to provide for itself. building material necessary for weaving a new product. Automatic actions for building a network are laid down at the genetic level and are inherited.

Properties and functions

The web has the following properties:

1. Very durable. Due to its special structure, its strength is comparable to nylon, it is several times stronger than steel.


2. Internal hinge. An object suspended on a gossamer thread can be rotated in one direction for as long as you like without twisting.
3. Very thin. The spider thread is extremely thin compared to the threads of other living beings. In many families of spiders, it is 2-3 microns. For comparison, the thickness of the silkworm thread is in the range of 14-26 microns.
4. stickiness. The threads themselves are not sticky, they are dotted with drops of sticky liquid. However, to create a web, a spider emits not only a sticky, but also a thread devoid of glue particles.

The web is necessary for the life of the spider.
It performs the following functions:

1. Refuge. The woven web serves as a good shelter from bad weather, as well as from enemies in the natural environment.
2. Creation of a favorable microclimate. For example, in water spiders, it is filled with air and allows them to be under water. They also close the shells in which they live at the bottom with it.
3. Trap for food objects. The spider is carnivorous, and its diet consists of insects entangled in a sticky web.
4. Material for creating a cocoon from which new spiders emerge.


5. An adaptation that plays a role in the process of reproduction. During mating season females weave a long thread and leave it hanging so that a passing male can easily reach them.
6. Deception of predators. Some orb-weaving spiders use it to glue garbage and make dummies to which the thread is attached. In case of danger, they pull the thread and divert attention from themselves with a moving dummy.
7. Insurance. Before attacking the prey, spiders attach a web thread to some object and jump on the prey, using the thread as insurance.
8. Vehicle. Young spiders leave the "father's house" with the help of a long thread. Spiders that live in water bodies use web weaving as water transport.

How can a person use the web

In China, the amazing strength and lightness of the web fabric is called "fabrics of the eastern sea." Polynesians use the cobwebs of large web spiders for sewing, and besides this, they also weave nets for catching fish.

Scientists in Japan have been able to create spider silk violin strings. Nowadays, scientists are striving to synthesize a material that has the properties of a spider web for use in various fields - from the production of bulletproof vests to the construction of bridges.

But science is not yet capable of creating an analogue of the substance that the spider produces. To do this, some researchers are trying to introduce spider genes to other living organisms.

Dutch biologist Abdul Wahaba El-Khalbzuri and artist Jalil Essaidi research activities synthesized a super-strong fabric, which is an organic combination of cobwebs and human skin.

The web is remarkable not only for its strength. The antibacterial properties of such a spider product have been used for a long time. Even in ancient times, a person used a cobweb mesh as a bandage bandage.

Such a sticky material adjoined the skin and created a barrier for bacteria and viruses to enter the wound. Many research institutions are working with the web, trying to apply its properties in medicine to create a material that can regenerate limbs.

European scientists say that within 5 years they will be able to synthesize artificial tendons and ligaments from spider webs.

AT modern world cobweb threads are used in the optical industry to designate crosshairs in optical devices, as well as threads in microsurgery. It is also known that microbiologists have created an air analyzer using the properties of spider filaments to capture microparticles from surrounding traces.
It should be noted that the study of the properties of the web will allow in the future to achieve great results in many industries, as well as contribute to the development and emergence of advanced technologies that are important for mankind.

Why doesn't a spider stick to its web?

Hunting for its victims (flies, midges and other insects), which are entangled in sticky nets, the spider itself does not stick to its own trap.

Consider the factors due to which the spider does not stick to its product:

1. Not all spider webs are covered in adhesive liquid, but only some areas that are well known to its creator. It is the circular threads that are sticky, and the central threads are not impregnated with a sticky substance.
2. The legs of the spider are completely covered with short and thin hairs. These hairs quickly remove droplets of glue invisible to the eye from the threads of the web. When the paw is located on the site of the arachnoid network, the particles of glue are on the hairs. When the spider removes the paw from the area without glue, the hairs, when sliding on the thread, return the glue particles back.
3. A special substance that coats the legs of the spider reduces the level of interaction with the adhesive, which further helps with sticking.

Video: about the web of spiders So, the web is synthesized in the spider glands located on the abdomen of spiders, and has a predominantly protein composition. These arthropods weave it for various needs, and it happens various forms. Moreover, it has extraordinary properties that humanity can use for its own purposes. Scientists different countries trying to synthesize a substance similar to it.

Arachnids stand out from all insects with the ability to weave amazing cobweb patterns.
How a spider spins a web is unimaginable. A small creature creates large and strong networks. Amazing Ability formed 130 million years ago.

All possibilities in animals appear and are fixed when natural selection not by chance. Each action has a strictly defined purpose.

The spider spins a web to achieve vital goals:

• catching prey;
• breeding;
• strengthening their minks;
• fall insurance;
• deception of predators;
• facilitate movement on surfaces.

The order of spiders consists of 42 thousand species, each of which has its own preferences in the use of the arachnoid structure. To hold the victim, the grid is used by all representatives. Males - aranemorphs on the grid leave secretions of seminal fluid. Then the spider on the web walks, collecting secretions on the organs of copulation.

After fertilization, the babies are formed in a protective web cocoon. Some females leave pheromones on the net - substances that attract partners. Spinners wrap threads around leaves and twigs. The result is dummies to distract predators. Silverfish living in the water make houses with air cavities.

The size of the web depends on the type of spider. Some tropical arachnids create "masterpieces" with a diameter of 2 m, capable of holding even a bird. Ordinary spider webs are smaller.
It is interesting to know how much a spider weaves a web. Zoologists managed to find out that the cross-piece copes with the work in a few hours. Representatives of hot countries take several days to create patterns of a large area. main role in the process are carried out by special bodies.

The structure of the spider glands

On the abdomen of the insect there are outgrowths - arachnoid warts with holes in the form of tubes.
Through these ducts, a viscous liquid flows out from the arachnoid gland. When exposed to air, the gel turns into thin fibers.

The chemical composition of the web

The unique ability of the released solution to solidify is explained by the structural components.

The composition of the liquid contains a high concentration of protein containing the following amino acids:

• glycine;
• alanine;
• serine

The quaternary structure of the protein, when pushed out of the duct, changes in such a way that filaments are formed as a result. From the filamentous formations, subsequently, fibers are obtained, the strength of which
4 to 10 times the strength of a human hair.,
1.5 - 6 times stronger than steel alloys.

Now it becomes clear how a spider weaves a web between trees. Thin strong fibers do not break, they are easily compressed, stretched, rotated without twisting, connecting the branches into a single network.

The purpose of the life of a spider is the extraction of protein food. The answer to the question "Why do spiders weave webs" is obvious. First of all, for hunting insects. They make a trapping net complex design. Appearance patterned structures is different.

• Most often we see polygonal networks. Sometimes they are almost round. Weaving from spiders requires incredible skill and patience. Sitting on the top branch, they form a thread that hangs in the air. If you are lucky, the thread will quickly catch on to a branch in a suitable place and the spider will move to a new point for further work. If the thread does not catch in any way, the spider pulls it towards itself, eats it so that the product does not disappear, and begins the process again. Gradually forming a frame, the insect proceeds to create radial foundations. When they are ready, the only thing left is to make connecting threads between the radii;
• Funnel representatives have a different approach. They make a funnel and hide at the bottom. When the victim approaches, the spider jumps out and pulls it into the funnel;
• Some individuals form a network of zigzag threads. The probability that the victim will not get out of such a pattern is much greater;
• The spider with the name "bola" does not bother itself, spins out only one thread, on which there is a drop of glue at the end. The hunter shoots the thread at the victim, sticking it tightly;
• Spiders - ogres were even more cunning. They make a small mesh between the paws, then cast on the desired object.

Designs depend on the living conditions of insects, their species.

Conclusion

Having found out how a spider weaves a web, what are its features, it remains to admire this creation of nature, to try to create something similar. In delicate patterns of knitted shawls, craftswomen copy patterns. Antennas, nets for catching fish and animals are made according to similar schemes. So far, a person has not been able to fully simulate the process.

Video: Spider weaves a web

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

Science and life // Illustrations

Science and life // Illustrations

Science and life // Illustrations

Initial stages building trapping net 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.