Orb-web spider: what it looks like, where it lives, what it eats. Orb-weaver spider: photo of appearance and description of the life cycle Spider is one of the types of orb-weavers

P Darwin's spider (Caerostris darwini) is a very interesting specimen of spiders from the orb weaving family. The Darwin spider is named after the naturalist Charles Darwin. His main feature is the web, which is of particular interest to scientists.

How Darwin's spider was discovered

Darwin's spider was discovered on the island of Madagascar in national park Andasibe-Mantadia. This discovery was made in 2001, but the spider was described only in 2009. Such a delay in the description of this species is due to the fact that its name is timed to coincide with the 150th anniversary of the publication of Charles Darwin's On the Origin of Species. In 2009 Caaerostris darwini was first described by Matjaž Kuntner and Ingi Agnarsson, but the description was published in 2010.

Where does it live Caaerostris darwini

As mentioned above Caaerostris darwini was found on the island Madagascar. This island is considered the only habitat of this species of spiders. Only 12 species of spiders of this family were found on this island. In principle, it can be found everywhere, but Darwin's spider gives the greatest preference to places with water areas. He weaves his nets mainly over the surface of the rivers, but you can run into his web and on a regular path.

Description and behavior

For spiders of the species Caaerostris darwini characterized by sexual dimorphism. Females are usually much larger than males. Females have a body length of 18 to 22 millimeters, while males have a body length of about 6 millimeters. Females are usually black with white hairs on abdominal cavity and appendages. The limbs are about 35 millimeters long, while in males the limbs are about 15 millimeters. Males are usually either red or light brown. The behavior of spiders is also individual character, since the hunting of spiders for prey is different from its relatives. They hang a ball over a river or lake and release a web in the wind until it touches the other side. In this way, they form a kind of bridges, which are the basis of their trap.

Scientists' interest

The interest of scientists in this type of spider is that Darwin's spider, which in itself is not large sizes, weaves just a giant and very strong web. Giant, because the area of ​​\u200b\u200bthe web is from 900 to 28,000 square centimeters. The length of the web of the "cable" is about 25 meters. But the main interest is the web itself. The tensile strength of this type of web is between 350 and 520 MJ/m³, while the tensile strength of Kevlar is 36 MJ/m³. So that you understand, bulletproof vests are made from Kevlar for special units. The web of Darwin's spider is a very complex mixture of elements that scientists from all over the world are studying.

In the world of spiders, it is the orb weavers that have earned a reputation the best craftsmen for weaving webs! Moreover, in 1973, two members of the orbweb family, Anita and Arabella, were sent into space aboard NASA's Skylab orbital station so that scientists could study the process of weaving webs in zero gravity.

It turned out that even in space, the design of the web did not change; it still had the same characteristic circular shape. In the skill of weaving nets, the round rows have left their relatives far behind: in other spiders, the web does not have such a clear shape, but is only sloppy "funnel" or panels of tangled threads.

Orb-weaving spiders form a whole family Araneidae, which includes about 3000 species.

But uloboride spiders are sometimes mistakenly called orbs ( Uloboridae, several hundred species) - due to the similarity of the web. Both orb weavers and uloborids are widely distributed in various parts of the world. the globe and weave very similar trapping nets, but these hunters kill their victims in different ways.

Insect hunters

Spiral webs of orbweavers are one of the engineering marvels of nature. The diameter of the web can vary from a few centimeters to a whole meter, but all networks have a common basic structure: a “bridge” line stretched between the stems forms a triangle along with two “anchor” threads that “tie” the web to the ground. Inside the web - a series of threads - "radii", diverging from the center and forming the frame of a radial spiral, itself characteristic feature circular web.

It takes about an hour for a spider (more precisely, a spider, since males do not weave webs) to create this miracle.

The circular web of the orb-weaver is a real trap for insects, which, without suspecting anything, fall into it right on the fly. The orbworm is a passive predator. He sits in the center of a shiny silky spiral and waits until the "lunch" itself will fly to him.

The orb weaver has eight eyes that provide great review, although the spider does not need to look for prey at all. He learns about the replenishment of his food stocks thanks to the vibration of the threads of the web. In anticipation of prey, the orbworm clings to the web with tenacious claws, which are located at the ends of the legs. He usually sits upside down, clinging to non-sticky threads emanating from the center of the trapping Web.

Once in the web, the unlucky insect sticks to the main spiral of threads, covered with a kind of "glue". Trying to escape from the nets, the victim becomes even more entangled in the sticky mass. The spider catches the trembling of the threads and hurries to the prey along the dry threads.

If the spider gets on the wrong thread, it will free itself, but the victim can no longer get out of the sticky web.

The orb-weaver is cautious about insects caught in the web. If it is a dangerous catch, such as a wasp, it will usually snap the threads around it. Some orbweavers are armed with spikes that protect the spiders if the prey resists. When the insect is not dangerous, the spider kills it by biting it with poisonous "fangs".

The poison not only kills, but also digests the prey. The spider rarely starts eating immediately after catching a prey. First, he wraps the insect with thread and waits. The spider feeds on liquid food and cannot chew, so it injects digestive juices into dead body or dying prey. Enzymes corrode the tissues of the insect, turning them into a thick "soup", and the spider sucks it out.

cunning predator

Orb-weaving spiders hang their webs on the routes of insects - between plants, where they most often fly. Usually spiders come out of their lair at night, although in autumn, when the females, as they say, work tirelessly to lay enough eggs, orbs can be seen both at night and during the day. Construction begins with one thread, a kind of "bridge", which the spider stretches, climbing onto a branch.

If the spinner is lucky, this thread, fluttering in the wind, will catch on the second support - the plant on the opposite side. This process is similar to starting kite. The spider tries to keep the first thread as long as possible, and it remakes the rest of the web almost every day.

After that, under the “bridge”, the spider attaches a second, not so tight thread and runs to the center, in order to then go down on a new thread. It turns out a U-shaped frame - the basis of the web. Two "anchors" connect the base of Y with each stem, thereby forming a triangle together with the "bridge" - outer part cobwebs. Then the spider begins to weave dry radial threads, diverging from the center to the edges. There are about 20 such threads.

When the work comes to an end, the spider weaves a wide auxiliary spiral from the center to the edge. This is dry silk, which serves as a platform for the spinner during the construction of a trapping spiral going to the center. The trapping spiral has more turns than the auxiliary one, which the spider removes in the course of work.

Building a web takes about an hour, maybe two. After the spider has caught and eaten the prey, the hunter returns to his lair, hidden among the foliage. The spinner sits there all day until the next evening. Then the spider, or rather the spider, leaves the shelter to inspect the net. If the web is beyond repair, the orb-weaver eats it, and processes the absorbed proteins into silk, from which weaves a new web.

Some types of spinners add thin threads to the design, forming a zigzag pattern. They probably distract the attention of potential prey, which, thanks to them, do not notice the trapping net until it is too late. Uloborid spiders do not weave sticky trapping coils. Their web is an unusually thin thread that clings to prey, like one half of a Velcro fastener is attached to the other. In addition, uloborids suffocate the victim with a tight cocoon.

careful courtship

Orb weaver males are much, about 10 times smaller than females. Adult spiders, obsessed with the goal of finding a mate, stop caring about food. But, having found the web of the female, the spider must exercise maximum caution.

One wrong move - and the female will take him for prey! After mating, the male looks for a new pair, while the female takes care of the production of eggs. The spider lays them in a dense silk bag. The offspring of orb-weavers, having wintered in their "cocoon", will be born in the spring.

The web has incredible elasticity. Its thread can be stretched five times without breaking!

The Circular Web is virtually invisible unless its shiny silk is hit sun rays will not illuminate the intricate spiral of threads, each of which is a fraction of a millimeter thick.

Spider silk is not only used for weaving webs. The spider wraps its prey in a silken blanket and waits for the poison to take effect before eating.

It is said that Carpathian peasants used pieces of cobwebs as an antiseptic, treating wounds with them. Well, in the near future, spider silk may well become a fairly familiar material.

In terms of such a parameter as tensile strength, the web thread can be compared with steel, and the fabric woven from the web of orb-weavers is stronger than Kevlar ™ fiber. In addition, the moistened web shrinks, so it is likely that it will be possible to make artificial muscles from it.

Scientists are working on deciphering the genetic code of the proteins that make up the orb weaver's web
Araneus ventricosus to learn how to produce such strong threads industrially.

In the world of arthropods, the real masters of weaving the web, by right, are the orb-weaving spiders. Where do members of this family live? What common species are found in domestic latitudes? What does the orbweb spider look like? The answers to these and other questions can be found in our article.

general description

Orb-weaving spiders, photos of which can be seen in the article, are insects whose body length reaches a maximum of several centimeters. Most members of the family have a dirty brown color. Among the orbs, spiders of a reddish and greenish hue are occasionally found.

Such insects have four pairs of legs, symmetrically located on both sides of the body. The extreme limbs have the greatest length. They are used for weaving nets.

The female orb-weaving spiders are much larger than the males. In addition, they are more aggressive behavior. For this reason, miniature males have to constantly be careful. Since an angry female is able to pounce on a representative of her own species at any time, mistaking him for a suitable victim.

Web

Giant orb-weaving spiders are capable of weaving webs that are a real engineering marvel of nature. The diameter of the web can reach the order of a meter or more. However, regardless of the size of the spider, the webs always have an identical structure.

Such insects stretch a horizontal line between the stems of plants, which acts as the base of the web. Two threads depart from it, which connect the frame to the soil. A whole series of so-called radii diverges from the center of the fundamental line. The latter form spirals, which actually form a circular web.

The creation of the above traps is carried out exclusively by female orb-weaving spiders. On average, it takes them about an hour. Males do not waste time weaving webs.

Hunting features

Orb-web spiders are passive predators. Representatives of this family are located in the central part of the spiral web and wait until the prey itself falls into their trap. Despite the fact that such arthropods have as many as eight keen eyes, which provide excellent all-round visibility, they absolutely do not have to look out for victims. Spiders react to the vibration of the threads of the nets by placing the claws of their tenacious paws on them.

Once in the web, the victim sticks to the threads, which are covered with a sticky substance. The more movements the prey of the orb-weaving spider makes, the less chance it has for salvation, since the body becomes more entangled in the sticky mass with each vibration. Having caught the vibration, the hunter hurries to the prey, moving along the dry threads. However, the spider is able to free itself even if it gets on the sticky part of the web.

Representatives of the family are sensible about the victims who were in the networks. If a bee or a wasp is in the web, the hunter carefully cuts off individual threads until the dangerous catch is taken away.

There are spiny orb-weaving spiders. The body of the latter is covered with hard outgrowths that protect them from victims who are able to resist. If the prey does not pose any potential danger to the spider, the hunter injects poisonous enzymes into its body through special fangs. Such substances not only reduce the activity of the prey, but also lead to the gradual digestion of its entrails.

Orb-weaving spiders do not have chewing organs. For this reason, they start “lunch” only after some time has passed, when the victim’s insides turn into a liquid state. The enzymes of the spider's venoms turn the victim's tissues into a thick mass, which the hunter happily absorbs.

Reproduction of offspring

Male orb-weaving spiders are several times smaller than females. Sexually mature individuals are especially active in finding a pair. Males obsessed with mating do not care about their own food. It is for this reason that they do not create a web.

Having found a female, males are cautious. There is a high chance that they will be eaten. After all, females quite often mistake them for prey.

After a successful mating, the males go in search of a new pair. At this time, fertilized females begin to prepare for the reproduction of eggs. Spiders form a special silk bag, where they lay their offspring. Orbweaver eggs are in a cocoon throughout the winter. With the advent of heat, young individuals appear from them.

Common members of the family

In domestic latitudes, the following orb-weaving spiders can most often be found:

1. Common cross- has an abdomen that expands closer to the head. In this place there are light marks that resemble crosses. The back contains a leaf-like pattern of a dark brown hue. Representatives of the species reach a size of about 16 mm. Inhabits forest clearings, edges and clearings. Scatter the net at a height of about 2 m.
2. Marble cross- has an oval abdomen, which expands in the middle part. On the surface of the body there are white spots that form oval patterns. There are reddish markings on the legs. The size of adults, on average, ranges from 15 to 20 mm. Representatives of the species build shelters in the form of rolled leaves, in which they wait for prey.
3. Four-spotted cross- has a spherical abdomen, painted with four dark dots, which are located on a light background. In the back of the body is a blurry leaf-like pattern. Such spiders inhabit humid areas, living in meadows, along the banks of water bodies and wherever there is high grassy vegetation.
4. striped orbworm- representatives of the species have a smooth, rounded body. The size of such insects is no more than 6 mm. The body is presented in the form of a brown cephalothorax and a light abdomen, which contains wide longitudinal black lines. Such spiders settle in places with grassy, ​​wet vegetation. Striped spinners stretch the web low above the soil, among the grass.

Finally

So we found out what the orb-weaving spiders are. About 20 species of such insects are found on the territory of our country. We often stumble upon their large complex networks in parks, gardens and forests.

Despite the intimidating appearance of the orb-web spider in the photo, the description life cycle it is debunked by the myth of the extreme rapacity of the animal and the danger to humans.

According to the international taxonomy of animals, the genus of Nephila spiders (Nephila) is included in the family, which has two synonymous names at once:

1. ancient Greek Nephilidae;
2. latin

In the Russian-language version of the classification of arthropods, they are called Orb-weavers.

Any of the names of these spiders fully corresponds to their abilities: if the Greek nema- and -philos are literally translated as “loving to weave”, then the Russian one indicates the circular shape of the trapping network of this category of arachnids.

The appearance of a typical representative

The entire structure of the spiders of the genus Nephila (hereinafter in the text: spiders-nephiles, or nephiles) is adapted for unhindered, easy and rapid movement.

Spider-web spider according to the photo and description has:

• incredible long legs allowing you to take huge steps;
• extremely light weight relative to the huge total area supports with widely spread paws.

The area of ​​the end segment of the leg is so small that for it the thin fiber of the cobweb serves as a completely reliable support.

Spider weaver

Given the fantastic strength and degree of elasticity of the threads of the trapping net, it is not surprising that the orb-web spider walks along the structure it has built as easily as a person skis on snow.

When looking at its narrow and as if streamlined body, a comparison with a racing car suggests itself, next to which the sometimes huge body of a caught victim seems like a clumsy bulldozer or excavator.

A scattering of small spots of bright color on the abdomen and legs, visually splitting the body into separate fragments, perfectly masks the predator, even located in the very center of its trap.

Where are the nephiles found

Despite the prevalence of nephil in the world, each species lives in conditions that are comfortable for it. Thus, the garden orb-web spider is considered a typical representative of the fauna of Australia.

And if spiny orb-web spider(also called the horned orb weaving spider) cannot meet a Russian citizen either (because it lives in the humid and hot tropics), then for the orb weaving spider Argiope lobata, the semi-deserts and steppes of the Crimea are the habitat, Central Asia and the Caucasus.

At the same time, the green orb-web spider (or Araniella cucurbitina) is a rare but common inhabitant of the forest, where it can be found at the very beginning of summer.

Spider Araniella cucurbitina

The most common orb-web spider found near human habitation is common cross, the details of whose life are well studied by arachnologists - biologists specializing in the study of arachnids.

About the life cycle and reproduction of nephil

males different types Nephil spiders can be up to 10 times smaller than the female. Their life also does not differ in duration - after mating, they are usually killed and eaten by recent sexual partners, with special luck, the male manages to fertilize several spiders during the season.

Sometimes they have to patiently wait a few weeks until the future "wife" sheds, during this period of life she is less belligerent.

An example of spider eggs

Carefully sealed in a dense and warm cocoon, laid and hidden in a secluded place, the eggs overwinter, so that offspring hatch from them in the spring.

Being passive predators, spiders wait for a small animal to get into the network they have built, which is killed by the secretion of poisonous glands. Its enzymes, injected upon bite, cause the body of the victim to be digested while the spider rests in the nest.

Orb-spin tetragnathoides catching a hornet in its web

After the required time has passed, it returns to suck out the liquid formed inside the chitinous shell of the prey from the action of the poison's enzymes.

About traps and catchers

Home distinctive feature nephil from other families of spiders is the ability to build within 1 hour a trapping network of a huge area (up to 1 m in diameter), which has a regular radial-spiral structure (hence the name "orb-web spider").

The weaving of trapping nets and their skillful use is the main occupation of the life of the Nefil. So, if stuck to the web poisonous insect(wasp, bee), the threads around the dangerous prey break. The threads that have become unusable are eaten by the spider to serve as material for a new trap.

It is a spider, because, given the preoccupation of males with the abandonment of offspring, they themselves do not knit a web, or they have it in the form of a disorderly structure with randomly tangled threads.

Ladybug caught in a web

But built by the female, it is distinguished by impeccable proportions, and the shape, size of the cells, the thickness of the thread is adjusted to the expected size and resistance of future prey. The shape and size of the grid also depends on the weather and the time of year.

In addition to sticky threads, the design of the trap also includes dry silk threads - spiders run along them without sticking.

Spider of the family araneidae

The unheard-of strength of spider silk proteins (with 5 times the tensile strength of steel wire) and its elasticity (greater than that of nylon) serve as the basis for the existence of both individual members and the entire Araneidae family.

On the danger to humans and the value of spiders for wildlife

The toxicity of the venom of orb-weaving spider species (any) is designed only for killing prey, therefore chemical substances, which are included in it, are not dangerous for human life, although they can cause sensitive pain.

In addition to ensuring their own survival, arachnids provide wildlife with an essential service.

They participate in the process of evolution, regulating the number of some animal species, among which the strongest and most adapted to living in given conditions survive.

As for a person, the number of certain types of insects (planting pests, disease vectors and other categories) is also important for his activities, especially when living in hot tropical countries.

Video: Amazing Spiders (Spider-web)

Orb weavers are spiders whose weaving technique can delight even a professional weaver. Once, scientists even conducted a funny experiment - they sent two representatives of this species to one of them. What was their surprise when these creatures, even in conditions of complete weightlessness, managed to create a web of ideal shape and structure.

What else do we know about these spiders? For example, where do they live? What do they eat? And how dangerous are they for people?

general information

Orb weavers are spiders, whose family includes more than 3 thousand species. Considering this, it is safe to say that they are in the lead among similar creatures. However, this also means that it is quite difficult to give them general characteristics. Indeed, despite some similarities, their external differences can drive even an experienced researcher into a stupor.

What unites them all? The correct answer is a web, all spinners weave it. Spiders of this species, despite all their differences, create networks of a similar shape. It is difficult to confuse it with the creations of other arachnids, since it has almost perfect shape. Looking at it, you can clearly distinguish both the main threads and additional ones, in the form of circles.

The appearance of spiders

These representatives of arachnids boast the richest set of skin tones. They can be both snow-white and poisonous green. In general, the color of their body depends on the habitat and serves as a kind of natural camouflage.

But there is also something that does similar friend on each other of all representatives of the species Orbweavers. Spiders of this family have a large abdomen, which in its volume greatly exceeds the cephalothorax. Also on the front pair of paws there is a special process, thanks to which they weave their web.

habitats

The trapping webs of orbweb spiders are scattered all over white light. They can be found in both Northern and South America, in Africa, Europe and even Australia. Some representatives of this species feel quite confident on the territory of Russia. In particular, the most common is the cross-spider.

If we talk about the preferences of these arachnids, then we can say with confidence that they like quiet and cozy corners, hidden from prying eyes. Therefore, they try to weave their web in those places where contact with human world minimum.

However, sometimes they can change this rule. The reason for this is the desire to find lands rich in food. Therefore, do not be surprised that the orb-web spider decided to settle in the garden or in the garden. Indeed, in such places there is a lot of prey, which, by the way, is often a pest.

How does a spider spin its web?

As you might have guessed, the web of the orb is needed not only for the sake of aesthetic pleasure. In practice, this is a powerful trapping mechanism, honed over many centuries by evolution. How does it work?

The construction of a new network begins with the fact that the spider sends one end of its web behind the wind in the hope that it will catch on, for example, a tree. After the goal is reached, the spinner, using the newly made bridge, begins to weave other branches of the web.

At the same time, he has two types of threads in stock. One is strong and elastic, the second is sticky. The first he uses to build the frame of the web. The second one is wound in circles in a spiral in order to cover as large an area as possible.

A signal thread runs along the entire web, the vibrations from which are able to inform the hunter that the victim has flown into a trap. After that, he only has to wait a little while the prey is finally entangled in the network.

What do Orb Weavers Eat?

The basis of the diet is made up of insects that managed to get into the net. In this case, the spider will rarely attack immediately. In most cases, he will wait until the victim is a little tired and stops fluttering, after which he will approach him.

The orbworm does not eat the whole prey. He injects special toxins into her, which corrode the victim from the inside. Then he simply drinks the contents like a thick soup, and dumps the rest down.

or not?

Many are interested in how dangerous it is for others, including people. Well, this arachnid has poisonous glands. But its toxins are only dangerous for insects and small mammals. In particular, it can cause paralysis in them.

As for people, it is not fatal for them. But the pain from him will haunt the poor fellow for a long time. True, spiders rarely bite people, it is much easier for them to jump to the ground and run away than to get involved in a senseless fight with a giant.

Spider-cross

In Russia, there is also a spider-web. Photos of this arachnid are presented in the article. His name is a cross. In general, this species of orbweaver is not much different from its relatives. He got his name thanks to the pattern on his belly in the form of a cross. You can meet him both in the forest and in an ordinary park.

They are often hard to spot because they hide from people. But with the advent of autumn, everything changes - they begin mating season. At this time, the females weave webs in the most prominent places so that the male does not miss them. And only with the advent of the first cold weather, they again hide in their shelter.