Most species of spiders spin webs, but not all, such as tarantulas. Many tarantulas burrow into the ground and release a little web, covering the entrance to the “cave” to make it easier to catch flying insects. All spiders, whether they spin webs or not, have several things in common: they have eight legs, and they all eat insects. Remember that spiders themselves are not insects.
Spiders belong to arachnids, or arachnids - these are animals in the same group as ticks and scorpions. There are about 40 thousand species of spiders.
What does it consist of and where is it formed?
The composition of the web includes the following substances:
- organic compounds - fibroin protein, which makes up the main internal thread, 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 stronger;
- inorganic substances - chemical compounds of potassium (hydrogen phosphate and nitrate). Their number is small, but they give the web antiseptic properties and protect it from fungi and bacteria, creating a favorable environment in the spider’s glands for the formation of threads.
In the abdomen of the spider there are arachnoid glands, where a liquid substance is formed that comes out through spinning tubes located on the arachnoid warts. They can be observed at the very bottom of the abdomen.
A viscous liquid comes out of the tube and quickly hardens in air. Using its hind legs, the spider pulls out the thread and uses it for weaving. One spider is capable of producing a thread 0.5 km long. Did you know? Our most common spider, the cross spider, weaves the most famous round trapping web. The spider always weaves a structure of 39 rays, on which there are 35 spiral circles with 1245 fasteners. Cross workers do this work at night and update the network every 1–2 days.
Human use
Humanity has copied many constructive natural discoveries, but weaving a web is a very complex natural process, and at the moment it has not been possible to reproduce it qualitatively. Currently, scientists are trying to recreate the natural process using biotechnology based on isolating genes that are responsible for the reproduction of proteins that make up the web. Such genes are introduced into the cellular composition of bacteria or yeast, but modeling the spinning process itself is currently impossible.
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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 secretion of the 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.
Giant death spiders live in the tunnels under Windsor Castle
Have you ever heard about the problems with spiders in the royal castle? Back in 2001, the British press reported that a swarm of poisonous spiders had settled in the tunnels under Windsor Castle, the country residence of the monarchs of England. Stories spoke of thousands of specimens that were twice the size of a normal spider and could kill a person with their venom.
According to Rod Crawford, these messages are overly emotional. The media has been misled by uninformed entomologists, professionals who study insects, not spiders. Crawford said that once arachnologists (who specialize in spiders) saw photographs of the Windsor Castle spider, they quickly determined that it was a European cave spider, which is found not only in Britain but also in most European countries. "It's not a rare species, it's not dangerous, and it's only half the size it's described," Crawford said.
What do spiders eat?
This is a fundamentally important question, since a spider weaves a web primarily to obtain food. Note that all species of spiders, without exception, are predators. However, their diet varies greatly depending on their size, hunting methods, and location. All tenet (web-weaving) spiders are insectivorous, and their diet is based primarily on flying forms.
Although if a crawling character falls onto the web from a tree, its owner will not disdain him. Those who live in burrows and closer to the ground eat mainly orthoptera and beetles, although they may drag a small snail or worm into their shelter. Among the diversity of what spiders feed on, there are also larger objects.
For the aquatic representative of the tribe called Argyroneta, crustaceans, aquatic insects and fish fry become victims. Exotic giant tarantulas prey on frogs, birds, small lizards and mice, although most of their diet consists of the same insects. But there are also more fastidious species. Members of the family Mimetidae hunt only spiders that do not belong to their species.
Where does a spider's web come from?
On the abdomen of the arthropod there are outgrowths - arachnoid warts. In their upper part, the channels of the arachnoid glands open, forming threads. There are 6 types of glands that produce silk for different purposes (moving, lowering, entangling prey, storing eggs). In one species, all these organs do not occur at the same time; usually an individual has 1-4 pairs of glands.
On the surface of warts there are up to 500 spinning tubes that supply protein secretion. The spider spins its web as follows:
- spider warts are pressed against the base (tree, grass, wall, etc.);
- a small amount of protein adheres to the selected location;
- the spider moves away, pulling the thread with its hind legs;
- for the main work, long and flexible front legs are used, with their help a frame is created from dry threads;
- The final stage of making the network is the formation of sticky spirals.
Thanks to the observations of scientists, it became known where the spider’s web comes from. It is produced by movable paired warts on the abdomen.
Interesting fact. The web is very light; the weight of a thread wrapping the Earth along the equator would be only 450 g.
What does a spider look like?
A spider is not an insect, although many people think so. It is classified as a separate class of arachnids, a type of arthropod. This is because he has not 6, but 8 legs. There are other differences from insects, but this is the main thing.
The fact is that there are a great many spiders, more than 40 thousand varieties, and they can differ greatly from each other, but 8 legs are a mandatory sign of a spider. Spiders also do not have whiskers, but they have many eyes—up to 8 in some species. There are no ears either - the spider hears with the help of short hairs on its legs.
Spiders are very easy to draw. Two circles (one larger, one smaller), connected by a thin strip, and 8 legs - 4 on each side. This is a schematic image, but it is very close to the real thing.
The smaller circle is the cephalothorax. The organs of vision and digestion are located here: eyes and mouth. This is where the brain is. Limbs are also attached to the cephalothorax: 8 legs, a pair of jaws (they are called chelicerae and contain poisonous claws) and a pair of pedipalps - they are very similar to legs, but in fact these are tentacles, the spider can lean on them when moving, but the main thing is that they the spider feels and grabs objects.
The larger circle is the abdomen. Strictly speaking, in most spiders the abdomen looks more like an oval than a circle; it can be very elongated, almost to a worm-like state, or have a different shape, even triangular. The abdomen contains the heart, lungs, digestive system and other vital organs. The abdomen also contains special organs for creating webs - arachnoid glands.
How to build a fishing net
The wind is the spider's best assistant in construction. Having taken out a thin thread from the warts, the arachnid exposes it to an air flow, which carries the frozen silk over a considerable distance. This is the secret way a spider weaves a web between trees. The web easily clings to tree branches, using it as a rope, the arachnid moves from place to place.
A certain pattern can be traced in the structure of the web. Its basis is a frame of strong and thick threads arranged in the form of rays diverging from one point. Starting from the outer part, the spider creates circles, gradually moving towards the center. It is amazing that without any equipment it maintains the same distance between each circle. This part of the fibers is sticky and is where insects will get stuck.
Interesting fact. The spider eats its own web. Scientists offer two explanations for this fact - in this way, the loss of protein during the repair of the fishing net is replenished, or the spider simply drinks water hanging on the silk threads.
The complexity of the web pattern depends on the type of arachnid. Lower arthropods build simple networks, while higher ones build complex geometric patterns. It is estimated that the female crosstail builds a trap of 39 radii and 39 spirals. In addition to smooth radial threads, auxiliary and catcher spirals, there are signal threads. These elements capture and transmit to the predator the vibrations of the caught prey. If a foreign object (a branch, a leaf) comes across, the little owner separates it and throws it away, then restores the net.
Large arboreal arachnids pull traps with a diameter of up to 1 m. Not only insects, but also small birds fall into them.
Construction stages
The base of the web is very similar to a snowflake or a point, from the center of which several rays radiate. These central threads-rays are the densest and thickest in their structure. Sometimes the spider makes a warp from several threads at once, as if strengthening its paths in advance.
When the base is ready, the animal proceeds to the construction of “catching spirals”. They are made from a completely different type of web. This liquid is sticky and sticks well. It is from the sticky web that the circles on the base are built.
The spider begins its construction from the outer circle, gradually moving towards the center. He amazingly senses the distance between the circles. Having absolutely no compass or special measuring instruments at hand, the spider accurately distributes the web so that there is an exclusively equal distance between the circles.
Wind to the rescue
The breeze also contributes to the correct distribution of the web. If the spider chooses the right place to place itself, for example between trees or in leaves, then the wind helps to carry the threads where they need to be. If you wanted to answer the question for yourself about how a spider weaves a web between trees, then here is the answer. The wind helps him.
When one thread catches on the desired branch, the spider crawls, checks the strength of the base and releases the next one. The second is attached to the middle of the first and so on.
Formation of building material
So, let's figure out how a spider weaves a web. On the abdomen of the “weaver” there are six glands, which are considered to be transformed rudiments of legs. A special secretion is produced inside the body, which is commonly called liquid silk. As it exits through the spinning tubes, it begins to harden. One such thread is so thin that it is difficult to see even under a microscope. With its paws located closer to the currently “working” glands, the spider twists several threads into one web - approximately the same way women did in the old days when spinning from tow. It is at the moment when the spider weaves a web that the main characteristic of the future web is formed - stickiness or increased strength. And what the mechanism of choice is, scientists have not yet figured out.
Differences in webs by spider species
Depending on the species, spiders can weave different webs, which are a kind of “calling card” of the arthropod.
Round web
This version of the web looks incredibly beautiful, but is a deadly design. As a rule, a round web is suspended in a vertical position and has part of the adhesive threads, which does not allow the insect to escape from it. Weaving such a network is carried out in a certain sequence. At the first stage, the outer frame is made, after which radial fibers are laid from the central part to the edges. Spiral threads are woven at the very end.
This is interesting! A medium-sized circular web has more than a thousand point connections, and its production requires more than twenty meters of spider silk, which makes the structure not only very light, but also incredibly durable.
Information about the presence of prey in such a trap comes to the “hunter” through specially woven signal threads. The appearance of any breaks in such a web forces the spider to weave a new web. Old webs are usually eaten by arthropods.
Strong web
This type of web is characteristic of nephilous spiders, which are widespread in Southeast Asia. The trapping nets they build often reach a couple of meters in diameter, and their strength allows them to easily support the weight of an adult.
Such spiders catch in their strong web not only ordinary insects, but also some small birds. Research results show that spiders of this type can produce about three hundred meters of spider silk daily.
What are the types?
Spiders, depending on the species, can weave different webs.
The form could be as follows:
- Round. This structure is the most common. Thicker threads-rays, which are the base, diverge from the center. The spider then pulls a thinner thread from the outer edge, creating circles that connect to the warp threads and weaves them all the way to the center. Surprisingly, the distances between these circles are approximately the same. Various insects fall into such a sticky trap and serve as food for its owner, who sits motionless on the signal thread. Such a web is not particularly large, but tree spiders that live in the tropics can weave a similar web up to 2 meters in diameter.
- Zigzag. To attract the attention of prey, representatives of the genus Argiope weave noticeable zigzags on the warp threads.
- Cone-shaped. Funnel spiders weave such a network among the stems of grass or other supports, and they themselves sit at the bottom of such a cone, waiting for prey.
- Formless . This web can often be observed at home. The web of house arachnids does not have any shape and is especially noticeable to the eye when covered with dust.
- Between the legs. Representatives of the spider family Dinopidae spinosa hunt by weaving a trapping net between their forelimbs and throwing it over insects.
- Ball on a string. The spider Mastophora cornigera catches insects with this device, similar to a bola weapon. The spider ball is saturated with pheromones and attracts moths, which stick to it and become prey. Because of its hunting method, the spider was nicknamed “bolas”.
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. By striking the web with strong blows with their limbs, the males cause the web to vibrate and, in this unusual way, invite the females to mate.
Home for posterity
Cocoons for eggs are woven from the silky web secretion. Their number, depending on the type of arthropod, is 2-1000 pieces. The females hang the web sacs with eggs in a safe place. The cocoon shell is quite strong; it consists of several layers and is impregnated with liquid secretion.
In their burrow, arachnids weave webs around the walls. This helps create a favorable microclimate and serves as protection from bad weather and natural enemies.
Moving
One of the answers to why a spider weaves a web is that it uses threads as a vehicle. To move between trees and bushes, quickly understand and fall, it needs strong fibers. To fly over long distances, spiders climb to elevated heights, release a quickly hardening web, and then with a gust of wind they fly away for several kilometers. Most often, trips are made on warm, clear days of Indian summer.
Hunting for prey
Building webs to catch prey is one of the reasons why spiders need to make webs. Its ability to immobilize the victim depends on the structure of the web. Some species of predators are so small that they themselves become prey to large insects. The poison introduced by the spider into the body of the victim does not act immediately. To prevent the prey from escaping, the predator takes it and wraps it in fiber, after which it waits for the prey’s insides to turn into a liquid state.
If you compare a spider's web and human hair, the former will be thinner. It is comparable in strength to steel wire.
Attracting males
Some types of female arachnids secrete a web secretion containing pheromones during the breeding season. This “mark” attracts the male. Signaling fibers are formed by most species, but in some the initiative comes from the male.
In search of a female for reproduction, males weave a sperm net onto which they first secrete a drop of seminal fluid. To attract a female, males attach their threads to the female’s web and set it in motion. This is how they tell her the purpose of their stay. To mate, the female goes into the male’s web space.
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 for a sufficiently strong wind, the small spider releases 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.
Distracting the attention of predators
Orb-weavers create distracting dummies from nets by gluing leaves and twigs with cobwebs. They place a “decoy” on their web, thereby trying to mislead the predator. The animal hides not far from the dummy and pulls the threads, making deceptive movements with them.
For the first time, a spider capable of making its own double was discovered in the Amazon forests by biologist Phil Torres. He came across a web with what he thought was a strange spider. At first the biologist thought it was dead, but when he got closer, he discovered that it was an elaborate replica made from leaves. The creator of the bait was waiting for prey in another place.
Design features of the web
Design features of the web
The purpose of a spider's life is to obtain protein food. The answer to the question “Why do spiders weave webs” is obvious. Primarily for hunting insects. They make a trapping net of complex design. The appearance of the 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're lucky, the thread will quickly catch on 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 begins to create radial bases. When they are ready, all that remains 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 likelihood that the victim will not get out of such a pattern is much greater;
- The spider called “bola” does not bother itself; it weaves only one thread, which has a drop of glue at the end. The hunter shoots a thread at the victim, gluing it tightly;
- Spider-ogres turned out to be even more cunning. They make a small net between their paws, then throw it over the desired object.
Designs depend on the living conditions of insects and their species.
The role of the web in the life of a spider
A web is not only a trapping net with which a spider entangles its prey. Her role is much more important. Realization of the reproductive instinct is one of the main goals, which is why spiders weave their webs. Females use it to attract a male, leaving pheromones on the threads.
Male araneomorph spiders, on the eve of the mating season, weave a special spermatic net onto which they secrete seminal fluid for subsequent transfer to a special reservoir on the forelimbs-tentacles (pedipalps). They are also the organ of copulation.
Egg cocoons are also woven from the web. Some of them have a very complex barrier structure. The bacteriostatic properties of the web protect the eggs from the effects of mold, bacteria and drying out.
Another reason why spiders need webs is for protection. Adults hide in web cocoons during molting periods. At this time they are most vulnerable, and the dense, breathable cover reliably protects them from external factors.
Water spiders create a cocoon from web threads to collect air bubbles. Many species cover the walls of their home with fibers and weave around the entrance to it.
Spiders use web threads to create safety structures in their habitat and hunting area in order to cling in case of a fall. Orb-weaving spiders roll up a dummy from webs and small debris and hang it on a fishing net as bait.
The spider periodically eats the web (usually when repairing damage). There are 2 versions of why he does this: 1 – replenishing protein in the body, 2 – obtaining water that settles during precipitation.
The web also serves to spread the population. Young spiders of some species leave their nests in the fall on thin spider webs carried by the wind.
Upon closer inspection, the spider is a unique spinning mini-factory and an interesting object to observe.
These are predators that could not be forced to produce silk for human use, like silkworms. Scientists are close to creating such threads in artificial conditions, but this goal has not yet been achieved.
What is it for?
If you ask a person why a spider needs a web, he will answer without any doubt: for hunting. But this does not exhaust its functions. Additionally, it is used in the following areas:
- for insulating minks before wintering;
- to create cocoons in which offspring mature;
- for protection from rain - spiders use it to make a kind of canopy that prevents water from entering the “house”;
- for traveling. Some spiders migrate on their own and send children away from the family on long webs blown by the wind.
Web weaving technology
As a rule, many species of spiders prefer to be nocturnal, so they weave webs mainly at night. On average, a 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 a spider weaves a web and how much time it takes him to do it. If the web is torn off, then the next morning exactly the same web will appear in the same place. The most beautiful webs are produced by orb weavers. Using strong threads, the spider forms a triangle, after which it fills it with cells of a certain size.
Interesting to know! In the tropical forests of Brazil lives a tarantula spider that weaves such a strong web that local fishermen use it as nets to catch fish. From spider threads you can weave not only a thin, but also a fairly strong fabric. Some companies make body armor from spider substances.
In the garden you can see how the spider weaves a web, placing it on 2 trees. This could be an openwork fishing net or a funnel that glitters in the sun, attracting insects. Of course, for many this process is a mystery. It is even difficult to imagine how the spider was able to stretch its web between two trees. As a rule, a spider flies on a web from one tree to another under the influence of the wind. Having secured the second end, the simplest thing he can do is fill the space with cells.
At the same time, while in a state of flight, the spider controls the distance to the neighboring tree, while adjusting the length of the web. Sometimes, in order to catch on to a branch, he simply shoots a web at the right place.
The spider weaves a web. Watch this video on YouTube
Why doesn't the spider stick to its web?
For a successful hunt, the spider must be able to move quickly and unhindered along the woven web. And he succeeds very well. Unlike its victims, the hunter does not stick to the threads and easily moves along them.
Spider's foot
He succeeds due to several factors:
- The spider's legs have many elastic hairs and claws. Moving along the web, the arthropod clings with its claws, pressing the thread to the hairs. When the spider lifts its leg, the claw unclenches and the hairs straighten, pushing away the web.
- The tips of the spider's legs are covered with a special oily substance.
- The predator moves along dry threads, which it specially weaves into a network to facilitate its movement.
Most often, in the center of the web there is a safe area where the spider waits for its victim.
