Candidate of Physical and Mathematical Sciences E. Lozovskaya

Science and life // Illustrations

The adhesive substance covering the thread of the catching spiral is evenly distributed throughout the web in the form of bead droplets. The picture shows the place where two fragments of the catcher spiral are attached to the radius.

Science and life // Illustrations

Science and life // Illustrations

Science and life // Illustrations

Science and life // Illustrations

The initial stages of building a catching net by a cross spider.

The logarithmic spiral approximately describes the shape of the auxiliary spiral thread that the spider lays when constructing a wheel-shaped catching net.

The Archimedes spiral describes the shape of the adhesive trapping thread.

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

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

Young cross spiders that have just emerged from their web cocoon.

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

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

Some types 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 the spider tubes from which the threads of spider silk emerge look like under a microscope.

Spiders may not be the most attractive creatures, but their creation, the web, is nothing short of awe-inspiring. Remember how the geometric regularity of the finest threads shimmering in the sun, stretched between the branches of a bush or among tall grass, captivates the eye.

Spiders are one of the oldest inhabitants of our planet, having settled on land more than 200 million years ago. There are about 35 thousand species of spiders in nature. These eight-legged creatures, which live everywhere, are recognizable always and everywhere, despite differences in color and size. But the most important thing is distinctive feature- is the ability to produce spider silk, a natural fiber unsurpassed in strength.

Spiders use webs for a variety of purposes. They make cocoons for eggs from it, build shelters for wintering, use it as a “safety rope” when jumping, weave intricate trapping nets and wrap up caught prey. A 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 parental nest on long threads carried by the wind.

Spiders feed mainly on insects. The hunting devices they use to get food are of the most different forms and types. Some spiders simply stretch out several signal threads near their shelter and, as soon as an insect touches the thread, they rush at it from 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 catching net, the cross spider, a common inhabitant of our forests and gardens, produces a fairly long, strong thread. A breeze or rising air flow lifts the thread upward, 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 frame are ready, the spider returns to the center and begins to lay out a temporary auxiliary spiral - something like "scaffolding". The auxiliary spiral holds the structure together and serves as a path for the spider when constructing a catching spiral. The entire main frame of the net, including the radii, is made of non-adhesive thread, but for the catcher spiral, a double thread coated with an adhesive substance is used.

What's surprising is that these two spirals have different geometric shapes. The temporary spiral has relatively few turns, and the distance between them increases with each turn. This happens because, when 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.

The 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 turns, creating an Archimedes spiral. At the same time, it bites off 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, producing different filaments, but none of them known species All seven types of spiders are not found at once. Usually a spider has from one to four pairs of these glands. Weaving a web is not a quick task, and it takes about half an hour to build a medium-sized trapping net. To switch to the production of a different type of web (for the catching spiral), the spider needs a minute's respite. Spiders often reuse webs by eating leftover webs that have been 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 perfectly developed over hundreds of millions of years of evolution. This natural material combines two wonderful properties - strength and elasticity. A web made of cobwebs can stop an insect flying at full speed. The thread from which spiders weave the base of their hunting 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 you compare spider thread with steel wire of the same diameter, they will support approximately the same weight. But spider silk is six times lighter, which means six times stronger.

Like human hair, sheep wool, and silk from silkworm cocoons, spider webs are composed primarily of proteins. In terms of amino acid composition, the spider web proteins - spidroins - are relatively close to fibroins, the proteins that make up the 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 represent a more amorphous material that can stretch well and thereby impart elasticity to the thread.

How is such a thread formed? There is no complete and clear answer to this question yet. The process of web spinning has been studied in most detail using the example of the ampullaid gland of the orb-weaving spider Nephila clavipes. The ampullaid gland, which produces the strongest silk, consists of three main sections: a central sac, a very long curved canal, and a tube with an outlet. From the cells on the inner surface of the sac emerge small spherical droplets containing two types of spidroin protein molecules. This viscous solution flows into the tail of the sac, where other cells secrete a different type of protein - 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 of order, and on the other, they retain fluidity. As the thick mass moves towards the outlet, the long protein molecules are oriented and aligned parallel to each other in the direction of the axis of the forming fiber. In this case, intermolecular hydrogen bonds are formed between them.

Humanity has copied many of nature's design discoveries, but such a complex process as spinning a web has not yet been reproduced. Scientists are now trying to solve this difficult problem using biotechnological techniques. The first step was to isolate the genes responsible for the production of the proteins that make up the web. These genes were introduced into the cells of bacteria and yeast (see "Science and Life" No. 2, 2001). Canadian geneticists have gone even further - they have bred genetically modified goats whose milk contains dissolved spider web proteins. But the problem is not only in obtaining the spider silk protein, it is necessary to model natural process spinning. But scientists have yet to learn this lesson from nature.

Spiders are small weaving factories; they can produce thin threads from which they skillfully weave lace. Their speed and skills can be the envy of experienced lacemakers. Where do spiders get their webs from?

If you turn the insect over and look closely, you will see tubercles on the abdomen. These are arachnoid warts that were formed in the process of evolution from atrophied hind legs. The abdominal cavity of the spider contains numerous arachnoid glands, the ducts of which open and close with tiny spinning tubes. Each type has them different quantities, some specimens have up to 500 such tubes. This is a miniature “weaving factory”. The glands tirelessly produce fluid. The viscous secretion consists of protein, which instantly hardens when it comes into contact with air. The liquid passes through thin tubes and, when frozen, forms a web.

The spider presses the arachnoid warts to the surface, a sticky secretion flows out of them and sticks to it. Liquid continues to flow from the arachnoid tubes. Using its hind legs, the spider stretches the liquid into a thin stream, which quickly hardens, forming a web.

The web is a thin thread tens of times thinner than a human hair. It is highly durable and elastic. For example, a thread of natural silk is six times weaker than spider web in terms of strength.

The spider uses its web for various purposes. By carefully wrapping the clutch of its eggs, the spider protects its future offspring from predators and drying out. For cocoons, the spider uses a special web that contains an antibiotic. This is what protects the masonry from fungi and pathogenic bacteria.

Spider nets are an excellent hunting device. Woven nets have a sticky middle. The insect, caught in the snare, sticks and desperately resists, becoming entangled. The spider calmly watches what is happening from the side. The spider learns that the net has caught its “lunch” by the movements of the signal web, which it prudently brought directly to its hole. The spider eats exhausted prey.

Catching nets are a marvel of engineering. The arachnids thought through everything to the smallest detail. First, they weave a frame - longitudinal and transverse threads at a certain distance. The borders of the frame are attached to a stationary surface, it can be wood, stone, wall, etc. The radial support threads are shaped like a snowflake. The insect weaves them from non-adhesive material, along which the spider will come to the caught victim.

The second stage of weaving catch nets involves laying spiral threads. For these purposes, spiders use adhesive material; an unwary insect will stick to these threads. The coating loses its ability to stick over time, so many spiders coat it with a fresh layer of “glue” from time to time. To weave such a structure, the spider will spend minimal amount web and time.

Spiders braid the entrance to the hole with a thick layer of cobwebs. Firstly, it saves from bad weather, secondly, it protects from enemies, and thirdly, the desired microclimate is created inside the hole. If an insect is cold in its home, it hangs “carpets” on the walls of the burrow.

Spiders do not spend all their time in the hole; sometimes they travel. While producing a web, they descend along it like a tightrope.

Life would not be sweet for a spider without a web. In order for arachnids to survive, Mother Nature awarded them a gift - the ability to produce miracle threads. Insects use their skills everywhere and, in my opinion, do not complain about their lives.

To study how a spider weaves a web, scientists chose Nephila. This species of tropical spider is famous for its unusually strong silk thread, which is even used to make fishing bait. Nephiles weave huge webs of cobwebs and have voracious appetites. They mainly feed on flies and other insects. Flies are their favorite food, but sometimes small birds also get caught in the nets.

Nephil spiders are poisonous, and their poison is comparable in toxicity to that of the karakurt. But this did not stop anachronists from trying to find out where the spider’s web is formed and how it is used. Spider silk is an incredibly durable material. It surpasses in strength all synthetic polymer materials invented by man. From it, spiders manage to weave a web that can withstand not only its own weight, but also absorb the energy of a blow from a flying insect.

To build its web, the spider uses a thread thirty times thinner than a human hair. Spiders are notable for the fact that, unlike other animals that look for building materials for nests in environment(for example, birds look for twigs to build nests) manage to store a lot of building material inside their body.

Where do spiders' webs come from? The material for the web is silk, stored in the body of the spider. Only there it looks like a kind of protein mass, like a soup, where two types of proteins float randomly. When this soup is released through the special glands of a special shape with which his body is equipped, it almost immediately undergoes changes and becomes hard. The spider has several silk glands. They allow the spider to change the thickness, strength and density of the web. An adult spider has enough material to weave three webs in a row. During the experiments, scientists pulled a silk thread 30 meters long from the spider.

How does a spider weave its web? Weaving a web is a very complex and well-calibrated process. The first thread that the spider pulls out from the back of the body serves to create the basis of the web, and it is the strongest, since it consists of the first, ordered type of proteins. Then a temporary frame is made, for which the spider lays paths of threads of a completely different quality from the center of the web to the outer edges. Then the spider begins to weave the web in a circle from the outer edge to the center. The spider eats the temporary frame and replaces it with very elastic and sticky silk. This deadly weapon for the trap - sticky silk, scientists examined it under an electron microscope. There were tiny droplets of glue on it. But why the spider does not stick to its web is the topic of another article.

In the summer, starting from July, and especially in the fall, on the grasses, even on the lawns of parks, on low bushes and young pines, dew glitters, sprinkled between the branches, like silk scarves - the finest work! Delicate, graceful and densely woven web. It is different, very different, and because the trapping net is designed, you can immediately decide which spider wove it. Spiders produce different types of web: inextensible and elastic, dry and sticky, with sticky droplets, straight and corrugated, colorless and colored, thin and thick, and some even weave real ropes.

Many researchers sat hour after hour, day after day at the web constructed by the spider. Andre Tilkin, a French philosopher, devoted 536 pages to the web, although 11 years before him, the German G. Peters seemed to have seen and told everything that was possible. see and talk about the web of the cross. And to this day, for the inquisitive mind, the web is fraught with so many new and unexpected things that it is worth sitting in front of it for more than one hour. T. Savory said that: “Weaving circular nets is a performance that can be watched and watched.”

One day I saw an amazing web, and next to it a small spider, I began to wonder how such small spiders can create such beauty and how do they do it? Conducting observations of spiders and webs, I set myself a goal: to study the features of spider networks, the adaptations of spiders for creating webs.

I was interested in the following questions:

1. Is it true that spider webs are pure protein?

2. Do all spiders have the same web?

3. How does a spider weave its web?

4. What properties does a spider's web have?

5. Find out what a “signal thread” is. And its meaning.

To find answers, I set myself the following tasks:

1. Study the literature.

2. Conduct observations of spiders and webs in nature (take photographs).

3. Carry out the simplest chemical experiments in the school laboratory.

4. Find similarities in the schematic drawings of webs with those found in nature.

1. MAGIC WEB

1. Skilled weavers

From what and how does a spider draw its web? On the spider's abdomen, at the very end, there are arachnoid warts. This is what made a spider a spider.

Nature works wonders by turning the juices of a spider's body into a web. Five or six different types of arachnoid glands - tubular, saccular, pear-shaped - produce several varieties of web. And its purpose is truly universal: a spider makes a net and snare from it, a cocoon for eggs and a house for living, a hammock for mating purposes and a bola for throwing at a target, a diving bell and a bowl for food, lassoes for flies, ingenious doors for holes , and for a kind of parachute when moving in the wind. The ducts of the arachnoid glands open on the hind limbs of the abdomen. These stalks are called spider warts. With their help, the spider weaves its wonderful trapping webs. Each arachnoid gland releases its product - a sticky liquid that quickly hardens - through a thin chitinous tube. There are half a thousand of these tubes in the cross tree, and only a hundred in the spider that lives in the cellar. The spinning tools of spiders are not the same. The first pair of walking legs is the longest. With its help, the spider weaves a web and communicates with its fellows. Spider thread bases are silk proteins.

Weaving: true art

The circular web of spiders is a very intricate thing, and its construction is not at all easy. Here, special materials and special, well-thought-out methods of weaving are used. The spider itself thinks little about weaving its web: all its actions are entirely instinctive. The network woven by each of them has an individual, expressed character. By looking at the web, you can find out which spider has woven it. The methods and main principles of building a network are almost the same for everyone. First of all, what structures is it made of?

There are eight of them: a first-order frame, a second-order frame, radii, a center, fastening spirals, a spiral-free zone, catching spirals and auxiliary spirals, from which only knots remain on the radii of the finished network - in the places where the radii and auxiliary spirals formerly intersected. The frame threads, especially the upper ones, are thick and low-elastic. The radii are also inelastic, but the catching spirals, on the contrary, are very elastic - they can be stretched twice or four times, and then, as soon as the deforming force has weakened, they are again shortened to their previous length. All threads are dry, except for the catching spirals, thickly hung with glue droplets. That's why when I touched the web with my hands, it stuck to my fingers.

First he tensions the first order frame. Its base is usually two threads. They converge at a wide angle at one point, and from there they can diverge up or down - it all depends on the location of the spider. The spider, having glued a thread at the top, descends vertically, weighing on it, to a solid object at the bottom, gluing the thread to it, and crawls up along it again, not forgetting to pull the second thread behind it from the warts. To prevent it from sticking together with the first one on which he crawls, he holds an additional claw of one of his fourth legs between them. Having risen to the starting point, he runs to the side - the width of the upper base of the frame - and there he glues the thread that he was pulling behind him. The cornerstone of the network, or the first-order frame, is ready. All that remains is to weave additional threads into it to make it stronger: after all, the whole network hangs on it. How do radii weave?

The spider climbs to the very top high point constructed frame, there glues the beginning of a new thread, which will be the first diameter of the circle. It falls, pulling it down with its weight from the glands to the bottom edge of the frame. Glues a thread - an elevator - to the frame and crawls along it up to the future center of the circle. Here the thread that he pulled behind him is crumpled and pressed into a ball and hangs it on the thread along which he crawled - this is the center of the center of the web. It crawls up again, inserting a claw between the threads (along which it crawls and pulls along), runs to the side and glues the towed web to the frame - the first radius is pulled from the center of the diameter to the frame. It crawls along it again to the center, from the center - along the diameter it pulls down along with itself. The thread that it pulls along with it does not allow it to now stick together with the ones drawn before. Having reached the bottom edge of the frame, he runs to the side and ties the second radius there, on the frame. So, running alternately down and sideways, then up and sideways, it tightens the entire frame with radial threads with equal angles between them. The third and, incidentally, the fourth (the center crossed randomly by threads) composite structures of the catching net are completed.

The spider does the fifth - fastening spirals - quickly: returning to the center and throwing them from radius to radius. The sixth zone, free from spirals, arises by itself, since there is no need to work on it, just make sure that it is not braided by mistake. But the seventh and eighth structural elements require a lot of effort and attention.

The spider weaves trapping spirals from the outside to the center. To do this, he needs scaffolding on which he can move in a spiral manner. They serve as auxiliary spirals; the spider weaves them from the center to the edges. Moving along the auxiliary spirals from the frame to the center, he uses the first pair of legs to measure the distance between the turns of the catcher spirals, which he pulls and secures on the radii with the legs of the fourth pair. On the second and third legs it runs along the web. Catching spirals are woven from a special material - cobwebs, thickly coated with glue. As soon as the scaffolding-auxiliary spiral fulfills its purpose, the spider, after running approximately one circle along it, bites it and eats it (so that the protein from which they are made does not go to waste). Therefore, by the end of the work, only knots remain from the spirals.

Spiders are forced to carefully handle the arachnoid fluid, since it is produced in spiders only with good nutrition and is expensive for the animal’s body. Once released and hardened, the web can no longer be retracted. Sometimes you can see that the spider, rising upward, seems to absorb a web that is becoming shorter and shorter; but upon closer examination it turns out that the spider simply wraps it around its legs or around its body.

1. 3. As strong as steel!

Spider webs, or nets, are extremely diverse in design, but the principle of their operation is the same: the insect is delayed, which is signaled by the vibration of the web threads, their displacement or even rupture. In the flat wheel-shaped network of the cross spider there is no such a dense plexus of threads as in a three-dimensional network, so it is possible to retain prey thanks not to the structure, but to special properties fibers They are strong enough and do not tear under strong stretching, and do not spring back. The fibers of such a web can quickly contract and stretch 4 times or more.

What is the reason for such amazing properties of threads? It is based on the protein keratin, which is part of the hair, wool, nails and feathers of animals. The structure of the fibers of the web when stretched, the threads straighten, and when it is released they return to their original position, i.e. the elasticity of the spring.

We can say that spider fiber is superior in strength and elasticity natural silk. Its tensile strength, according to D.E. Kharitonov, is approximately 175 g/mm2 versus 33-43 g/mm2 for natural silk and 18-20 g/mm2 for artificial silk. A spider's web is thousands of times thinner than a human hair. Fiber fineness and strength are measured in units called denier. Denier is the weight in grams of a thread 9 kilometers long. The thread of a silkworm weighs one denier, a human hair weighs 50 denier, and the thread of a spider's web weighs only 0.07 denier. This means that the spider thread, which can be used to encircle the globe at the equator, weighs a little more than 300 grams. The tensile strength of gossamer is twice as strong as steel, stronger than Orlon, viscose, ordinary nylon and almost equal to special high-strength nylon, which, however, is even worse because it is much less stretchable and, therefore, breaks faster under the same load. Silk thread is one of the strongest chains in the world. Elastic, it can stretch, becoming twice as long as before, without tearing. Despite such a tiny diameter, it is as strong as steel! The spider synthesizes its web from amino acids. This is pure protein!

2. PRACTICAL PART

EXPERIMENT No. 1. Purpose: to determine whether the web sinks in water.

Equipment and materials: container with water, spider web.

Progress of the experiment: lowered the web into cold water. The web did not sink.

Conclusion: She protein origin and belongs to the group of globular proteins that are insoluble in water and are not wetted by it.

EXPERIMENT No. 2 Purpose: to determine whether spider webs dissolve in 70% acetic acid.

Equipment and materials: glass cup, 70% acetic acid, spider web.

Procedure of the experiment: the web was placed in a glass cup, 70% acetic acid was dropped. The web did not dissolve. 15 minutes passed, the web did not dissolve, after 30 minutes the web also did not dissolve. After 6 hours of experiment, the web did not dissolve. Another 18 hours passed and the web did not dissolve.

Conclusion: spider webs do not dissolve in 70% acetic acid. But the material (web) is curled into a ball, which means it is pure protein.

EXPERIMENT No. 3 Purpose: to determine whether spider webs dissolve in baking soda.

Equipment and materials: glass cup, baking soda diluted with water, spider web.

Procedure of the experiment: the web was placed in a glass cup, and baking soda was added with diluted water. The web did not dissolve. 5 minutes passed, the web did not dissolve, after 30 minutes the web did not dissolve either. After 4 hours of experiment, the web did not dissolve. Another 12 hours passed and the web did not dissolve.

Conclusion: spider webs do not dissolve in an alkaline environment.

EXPERIMENT No. 4 Goal: to determine that spider web is really a pure protein.

Equipment and materials: test tube, transparent nitric acid, pure white spider web.

Procedure of the experiment: the web was placed in a test tube, nitric acid was dropped. the cobwebs dissolved and the nitric acid turned slightly yellow.

Conclusion: spider web is pure protein.

EXPERIMENT No. 5 Purpose: to determine whether the web decomposes without access to air.

Devices and materials: sealed plastic bag, branch with cobweb

Procedure of the experiment: placed a branch with cobwebs in a transparent bag. The package was sealed and hung on the balcony in the sun. We observed the web for a month. Despite the fact that the air temperature changed, the web did not change either in color or shape, it remained the same.

Conclusion: the web is woven from dense material. Air temperature does not affect the quality of the fiber. The substance from which the web is formed does not oxidize in air and does not decompose without access to air. This means its chemical composition is pure protein.

EXPERIMENT No. 6 Purpose: to determine whether the cobweb is of natural origin.

Equipment and materials: matches, metal rod, cobweb.

Procedure for the experiment: we attach the web to a metal rod with a wooden tip and set it on fire. She's burning.

Conclusion: the web burns, not melts. This means that this is a completely natural product, without chemical impurities. With a specific smell of burning protein.

EXPERIMENT No. 7 Purpose: to determine whether the web really does not deform when stretched. And does the web have a signal thread?

Equipment and materials: ruler, branches, cobwebs.

Progress of the experiment: we move the branches on which the web, 2 cm in diameter, is attached, to the sides. The web stretched 0.5 mm in width. When we release the branches, the web returns to its previous position. We measure the web, it remains the same size and is not deformed.

Conclusion: the web is elastic, does not deform or break when stretched. This means that the thread consists of a long fiber that the spider synthesizes from amino acids. In addition, the spider reacted to the movement of the branch - it appeared on its web, which means that the web really has a signal thread.

EXPERIMENT No. 8 Purpose: to determine whether it affects the quality and appearance spider web temperature difference.

Equipment and materials: sealed plastic bag, freezer, thermometer, spider web.

Procedure of the experiment: put the web in a sealed plastic bag and put it in the freezer, where the air temperature is minus 10ºC, for 24 hours. In appearance and quality (remained sticky), the web did not change.

We hung the same bag in the sun, where the air temperature was plus 20ºС, the appearance of the web did not change, it remained the same. The quality of the web did not change - it remained sticky.

Conclusion: the appearance of the web and its quality (stickiness) are not affected by a sharp change in air temperature.

Experiment: I caught a fly, carefully placed it on the web, the fly stuck, buzzed and tried to escape. The signal thread twitched, the spider instantly jumped out, ran up to the fly and approached from one side, then from the other side, doing something to the fly, and the fly began to subside, swaddled in spider threads. Less than a minute passed, and the fly was already tied up and not twitching.

Conclusions: After conducting my observations and research, I learned that the spider never sits in the very center of its trapping network, it hides in some shelter nearby. And from the net to the shelter there is always a cobweb stretching - a signal thread.

CONCLUSION.

Conducting experiments and observations, I came to the conclusion that the web is a protein. I learned that fiber contains amino acids that are highly hygroscopic. Protein chains are located along one axis and form long fibers, their amino acid composition resembles silk proteins. By its origin, the web belongs to the group of globular proteins; it does not dissolve in water and is not wetted by it. This is a completely natural product of animal origin; it burns and does not melt.

While working, I learned that cobwebs vary not only in size, but also in the woven pattern. The spider squeezes out the web from at different speeds. That the web freezes instantly. The spider weaves a thread intermittently, since the production of a web takes a lot of energy: after producing 30-35 meters of thread, it recovers its strength within several days. All krestoviki have different networks, although all krestovik networks are round and look like lace. But the webs of house spiders are completely different; they are stretched in a corner, from wall to wall, without any order. Like thin gray shreds. For those spiders that live in trees, bushes, and grass, the web threads stretch from branch to branch, from leaf to leaf, from blade of grass to blade of grass, also in no particular order.

I learned that spider fiber is stronger than steel and more elastic than natural silk. Spider nets are used in different areas creating a wide range of items from socks to fishing nets, and was previously used as a dressing material.

You can tell a lot more interesting things about the web and spiders. After all, spider webs and the silk fibers from which they are made have not been sufficiently studied. But for starters, I think that's enough.

And now every summer I will watch them weaving lace and take photographs. Since in the future I dream of connecting my activities with medicine, my work and my observations will be useful to me in the future, both in my studies and in choosing a profession.

Maybe in the future there will be spider farms created to create eco-friendly and harmless baby clothes for newborns. We won't ever use chemical compositions to kill flies, we will use cobwebs, which do not need to be disposed of (burned, buried in the ground) and harm nature.

The web is a kind of secret produced by the arachnoid glands. Such a secretion, after a short time after release, is able to solidify in the form of strong protein threads. Cobwebs are produced not only by spiders, but also by some other representatives of the arachnid group, including pseudoscorpions and mites, as well as labiopods.

How spiders make webs

A large number of arachnoid glands are located in the abdominal cavity of the spider.. The ducts of such glands open into tiny spinning tubes that have access to the end part of special arachnoid warts. The number of spinning tubes may vary depending on the type of spider. For example, the very common cross spider has five hundred of them.

This is interesting! The arachnoid glands produce a liquid and viscous protein secretion, the peculiarity of which is the ability to almost instantly harden under the influence of air and turn into thin long threads.

The process of spinning a web involves pressing the spider warts onto a substrate. The first, insignificant part of the released secretion hardens and reliably sticks to the substrate, after which the spider pulls out the viscous secretion using its hind legs. In the process of removing the spider from the site of attachment of the web, the protein secretion stretches and quickly hardens. To date, seven are known and fairly well studied. different types arachnoid glands that produce different types threads

Composition and properties of the web

Spider web is a protein compound that also contains glycine, alanine and serine. The inner part of the formed threads is represented by hard protein crystals, the size of which does not exceed several nanometers. The crystals are held together by highly elastic protein bonds.

This is interesting! An unusual property of the web is its internal articulation. When hung on a spider's web, any object can be rotated an unlimited number of times without twisting.

The primary threads are intertwined by the spider and become thicker spider fibers. The strength indicators of the web are close to those of nylon, but are much stronger than the secret silkworm. Depending on the purpose for which the web is intended to be used, the spider can produce not only sticky, but also dry thread, the thickness of which varies significantly.

Functions of the web and its purpose

Webs are used by spiders for a variety of purposes. A shelter woven from a strong and reliable web allows you to create the most favorable microclimatic conditions for arthropods, and also serves as a good shelter both from bad weather and from numerous natural enemies. Many arthropod arachnids are capable of weaving their web around the walls of their burrow or making it into a kind of door into their home.

This is interesting! Some species use webs as transport, and young spiders leave the parental nest on long web threads, which are picked up by the wind and transported over considerable distances.

Most often, spiders use webs to weave sticky trapping networks, which allows them to effectively catch prey and provide food to the arthropod. No less famous are the so-called egg cocoons made from webs, inside which young spiders appear. Some species weave web-like safety threads that protect arthropods from falling while jumping and for moving or catching prey.

Web for reproduction

The breeding season is characterized by the release of arachnoid threads by the female, which make it possible to find the optimal pair for mating. For example, male web-slingers are capable of constructing, next to the nets created by females, miniature mating web laces into which spiders are lured.

Male cross spiders deftly attach their horizontal webs to radially arranged strands of trapping webs made by females. Applying along the web strong blows limbs, the males cause the net to vibrate and, in this unusual way, invite the females to mate.

Web for catching prey

In order to catch their prey, many species of spiders weave special trapping nets, but some species are characterized by the use of peculiar web lassos and threads. Spiders that hide in burrow dwellings place signal threads that stretch from the arthropod’s abdomen to the very entrance to its shelter. When prey falls into the trap, the vibration of the signal thread is instantly transmitted to the spider.

Sticky spiral trapping nets are built according to a slightly different principle. When creating it, the spider begins weaving from the edge and gradually moves towards the central part. In this case, the same gap between all turns is necessarily maintained, resulting in the so-called “Archimedes spiral”. The threads on the auxiliary spiral are specially bitten by the spider.

Web for insurance

Jumping spiders use web threads as insurance when attacking a victim. Spiders attach a safety thread of the web to any object, after which the arthropod jumps on the intended prey. The same thread, attached to the substrate, is used for overnight shelter and protects the arthropod from attacks by all kinds of natural enemies.

This is interesting! South Russian tarantulas, leaving their burrow home, pull behind them a thin web thread, which allows them to quickly find the way back or the entrance to the shelter if necessary.

Web as transport

By autumn, some species of spiders hatch their young. Young spiders that survive the process of growing up try to climb as high as possible, using trees, tall bushes, roofs of houses and other buildings, fences for this purpose. Having waited long enough strong wind, a small spider produces a thin and long web.

The distance of movement directly depends on the length of such a transport web. Having waited for a good tension of the web, the spider bites off its end and takes off very quickly. As a rule, “travelers” are able to fly several kilometers on a web.

Silver spiders use webs as water transport. To hunt in bodies of water, this spider requires breathing atmospheric air. When descending to the bottom, the arthropod is able to capture a portion of air, and on aquatic plants, a kind of air bell is constructed from the web, which retains air and allows the spider to hunt its prey.