Who is a spider? The most interesting facts about spiders: description, types and features. Spider with a happy face

The first spiders appeared about 400 million years ago. They descended from a crab-shaped ancestor. Today there are more than 40 thousand species of spiders.

Many people are sure that spiders are insects. In fact, spiders are a separate order and class - arachnids (Arachnida, subphylum Chelicerata - Chelicerata, phylum Arthropods). Noticeably different from insects.

First of all, it is worth noting that spiders have not 6 legs, but 8. In front there are special limbs with poisonous claws - chelicerae. However, in Middle lane In Russia, the presence of spiders that are deadly to humans has not been registered. From a big bite
the spider can only be felt as a burning sensation, fever and pain. Spiders will not attack first. If a small spider accidentally falls from the web onto a person, you should carefully blow it away and not hit it - otherwise it may get scared and bite.

Spiders usually have three pairs of arachnoid warts on their abdomen. Digestion in these arthropods is extraintestinal. Unlike, for example, predatory mantises, which chew a caught fly with appetite, the spider injects digestive enzymes into it, transforming
the insect enters the “soup” after a few hours, after which it sucks out the contents. Spiders have very strong webs; if a plane hits a pencil-thin web, it will not break.

Spiders usually have 8 eyes, sometimes 6, or very rarely - 2. Males have bulbs on their forelimbs, into which he places sperm to fertilize the female. Some males are already prepared for death after mating - they allow the female to eat them, others intend to fight for their lives and try to escape. In any case, males do not live long, but females need to raise offspring, so they live longer. Males are smaller, females are huge. Many females are caring mothers. They weave a ball-cocoon from a web and carry spiderlings in it.

Almost all spiders are predators. An exception is the Kipling's bagheera spider (Bagheera kiplingi). Biologists discovered this jumping spider in the forests Central America, on the branches of an acacia. Spiders live on acacia trees along with ants. Ants protect these trees for the nutritional Belt bodies (named after the naturalist Thomas Belt), sweet shoots at the ends of the leaves. tropical species acacia Spiders also feed on these formations.

The first thing that catches your eye when meeting insects is their long, constantly moving antennae. Spiders don't have antennas. Their eyes are also simpler, but there are many of them - most often eight. The body is covered by an external skeleton (exoskeleton). It consists of a cephalothorax and abdomen, connected to each other by a stalk.

The flora and fauna of our planet is so diverse that it can be quite difficult to determine the species identity of creatures living next to humans. Sometimes individuals that are similar at first glance turn out to be representatives of different biological classes. This similarity gives rise to a lot of misconceptions. So, many people believe that spiders are insects.

Many people mistakenly classify spiders as insects.

Basic Concepts

Biologists classify living organisms according to the characteristics that unite them. Animals are creatures that move from place to place on their own and do not produce their own food from raw materials in their habitat. Those that cannot move of their own free will, but have the ability to move by the forces of nature or other means, synthesize food from environment, are considered plants.

Within the numerous animal kingdom, there are organisms that lack a backbone - invertebrates. Representatives of this group are mostly small in size. Some of them are land dwellers, while for others the water becomes their home. They are all very different - they crawl, wriggle, walk and even fly. Since everything in science must be structured, then scientists classified insects and spiders as a separate type - arthropods, or arthropods.

The main difference from insects is a more complex structure internal organs

Among the huge number of invertebrates there are more than a million various types have bodies with three main parts - head, thorax and abdomen. On the head there are eyes, antennae and mouthparts. The thoracic region has three pairs of legs. The entire body is protected by a hard outer covering called an exoskeleton. Organisms that have these characteristics belong to the class of insects.

Another, smaller group has only two main body parts - a combined head and chest (cephalothorax) and a belly. The cephalothorax contains eyes, mouth parts (without antennas) and four pairs of legs.

Animals that fit this description are grouped into the class Arachnidae. This includes the spider, as well as the scorpion and the tick.

In this video you will learn about the structural features of spiders:dodo

Features of arachnids

Obviously, not all arachnids are the same. Biologists have found differences among representatives of this type of arthropod. Several main signs that spiders are not insects and also differ from other arachnids:

• the cephalothorax has no antenna, there are only 4 pairs of simple eyes, a pair of jaws and 2 pedipalps;
• basically have no wings;
• 4 pairs of articulated legs are attached to the cephalothorax;
• the abdomen is not segmented and is connected to the cephalothorax by a thin “waist”;
• the body is covered with an exoskeleton, and sensory hairs grow from the skin.

Interestingly, spiders have claws located at the end of each limb.. The spider leg consists of seven segments: cox, trochanter, femur, patella, tibia and finally the tarsus, which may end in two or three small claws. Such features are necessary in order to help the animal cling to its web.

All 4 pairs of legs have muscles that attach to the inner wall of the cephalothorax and intestines. Surprisingly, that's exactly what it is internal structure helps the spider suck out food. The circulatory system of these arthropods consists of a heart, arteries and veins, but does not have capillaries. The heart muscle has one cavity and, with the help of valves, moves blood in one direction. By the way, the color of spider blood is blue; it received such an unusual coloring due to hemocyanin dissolved in the lymph.

Spiders (like insects and animals) have a respiratory system, represented in these creatures by the trachea and lungs. The structure of lung tissue, of course, is very different from the human respiratory organs. All arachnid families do not have a muscular respiratory mechanism.

Silk nets

Almost all arachnids produce webs, but some do not weave webs from them. These protein strands are used for climbing, hunting, reproduction, protection and other needs of the animal. If you look at a frozen web, it may seem that it is monolithic, but in fact it can be 3-4 separate threads that stuck together when drying.

Surprisingly, the webs are so strong that some spiders use them for travel.. One end of the thread is attached to a tree branch, and the animal hangs on the other end and, with the help of the wind, sometimes moves for many kilometers. It is interesting that the owner disposes of the unnecessary network - simply eats it.

Spiders treat insects as food; some large specimens are able to catch and eat even bats, small birds or small fish.

Representatives of the orb weaver class catch fish by weaving a kind of fishing net from a web. These creatures hunt prey in very different ways:

• spiders that live in holes jump out of them to catch a passing or flying victim;
• some, having placed sticky snares, sit in ambush on plants, tree bark, under stones and wait for the victim to fall into their clutches;
• more active individuals go in search of prey on their own.

All spiders are carnivorous. Their digestion begins long before food enters the stomach. Some representatives inject enzymes directly into the body of the victim, others first break the food with their jaws. Partially digested food is absorbed into the intestines.

Disputes on the topic “are spiders insects, and if not, then why” arise to this day. Although there are huge differences between these groups of living organisms.

In fairness, it should be noted that until the middle of the last century, these classes were indeed united by one biological type.

The first spiders appeared about 400 million years ago. They descended from a crab-shaped ancestor. Today there are more than 40 thousand species of spiders.

Many people are sure that spiders are insects. In fact, spiders are a separate order and class - arachnids (Arachnida, subphylum Chelicerata - Chelicerata, phylum Arthropods). Noticeably different from insects.

First of all, it is worth noting that spiders have not 6 legs, but 8. In front there are special limbs with poisonous claws - chelicerae. However, in central Russia the presence of deadly substances for people has not been registered. From the bite of a large spider, you can only feel a burning sensation, fever and pain. Spiders will not attack first. If a small spider accidentally falls from the web onto a person, you should carefully blow it away and not hit it - otherwise it may get scared and bite.

Spiders usually have three pairs of arachnoid warts on their abdomen. Digestion in these arthropods is extraintestinal. Unlike, for example, predatory mantises, which chew a caught fly with appetite, the spider injects digestive enzymes into it, turning the insect into “soup” after a few hours, after which it sucks out the contents. Spiders have very strong webs; if a plane hits a pencil-thin web, it will not break.

Spiders usually have 8 eyes, sometimes 6, or very rarely – 2. Males have bulbs on their forelimbs into which he deposits sperm to fertilize the female. Some males are already prepared for death after mating - they allow the female to eat them, others intend to fight for their lives and try to escape. In any case, males do not live long, but females need to raise offspring, so they live longer. Males are smaller, females are huge. Many females are caring mothers. They weave a ball-cocoon from a web and carry spiderlings in it.

Almost all spiders are predators. An exception is the Kipling's bagheera spider (Bagheera kiplingi). Biologists discovered this jumping spider in the forests of Central America, on the branches of an acacia tree. Spiders live on acacia trees along with ants. Ants protect these trees for the nutritional Belt bodies (named after the naturalist Thomas Belt), sweet shoots at the ends of the leaves of tropical acacia species. Spiders also feed on these formations.

The first thing that catches your eye when meeting you is– their long, constantly moving whiskers (antennas). Spiders don't have antennas. Their eyes are also simpler, but there are many of them - most often eight. The body is covered by an external skeleton (exoskeleton). It consists of a cephalothorax and abdomen, connected to each other by a stalk.

SO DIFFERENT SPIDERS

A big mistake is made by those who call spiders insects.In fact, spiders belong to the order of arthropods of the phylum Arthropoda. The main difference between spiders and insects is the number of legs. Insects usually have only 6 of them, while spiders have as many as 8 legs. In general, of course, they are close relatives, because both spiders and insects belong to the phylum arthropods.

There are about 41,000 species of spiders in nature!

The spider's body consists of two parts connected by a stalk: the cephalothorax and abdomen (opisthosoma).

Located on the cephalothorax oral apparatus, consisting of chelicerae, lower lip and chewing lobes, pedipalps and four pairs of legs. All spiders have arachnoid warts on their abdomen, in most cases there are three pairs of them.

The abdomen generally has an oval shape, less often round, angular, and sometimes has a very elongated, worm-shaped shape.

Spiders have 8 or 6 eyes, very rarely some species have 2 eyes.

The cephalothorax contains two nerve ganglia, which form many brain nerves and they diverge from the brain to the legs, eyes and other organs of the spider. The brain can occupy from 20% to 30% of the volume of the cephalothorax.

The only spider for which plant food is the jumping spider, which lives on acacia trees (it is this tree that it feeds on). But in generalVegetarian spiders do not exist; they are all predators. They usually feed on their relatives - insects.

Having caught prey with the help of a web, the spider kills it with poison and injects digestive juices into it. After some time (usually several hours), the spider sucks out the resulting nutrient solution.

The web is a protein mass secreted by special glands of the spider. At the moment of release, the web is a liquid mass that quickly hardens in air, forming threads. Spider web is a very durable material; in its stability it surpasses even steel of equal thickness. The main components of the web are proteins, one of which is responsible for strength, and the second for elasticity. Each thread of the web is coated with a special adhesive substance that holds the prey in case it tries to escape.

The spider is capable of reproducing different types of threads, so not all webs are the same. Behind different types different glands are responsible for the threads. The main type of web is the one along which the spider descends to any place, and along which it returns to its original position. Young spiders can create such a web, which they use as a parachute; the wind picks it up and carries the spider in the desired direction.

Spiders' nests are also built from cobwebs.

U a separate type In spiders, all types of glands are not found at the same time.

Spiders often use spider silk repeatedly, eating fishing threads damaged by rain, wind or insects. It is digested with the help of special enzymes.

Male spiders tend to be significantly fewer females, and their coloring is different.Many females eat males after fertilization.

Most species of spiders bite people only in defense, and few species can cause more harm than a mosquito or bee.

The science that studies spiders is called arachnology. And the fear of spiders is arachnophobia.

1. The largest spider

Theraphosa Blonda or Goliath tarantula is the most big spider in the world. Capable of huntingfrogs, toads, lizards, mice and even small snakes.

It was first described by the French entomologist Latreille in 1804. Distributed in tropical forests South America. Lives in deep burrows, entrance towhich are lined with cobwebs.

The size of the body of the female Theraphosis Blonda reaches 90 mm, and the male - 85 mm, with the legs straightened, the dimensions of Theraphosis Blondareach up to 25 centimeters. The size of the dorsal shield is the same in both length and width. The body is dark browncolor. The legs are covered with a mass of reddish-brown hairs.

Most major representative this species was discovered in Venezuela in 1965: the span of its paws reached 28 centimeters(according to the Guinness Book of Records).

In Cambodia, fried tarantula spiders are considered a delicacy. Before preparing the tarantula, its stinging hairs are removed.

2. The smallest spider- Patu digua reaches only 0.37 mm.

3 . The most poisonous spider

Brazilian wandering spider, considered the most poisonous in the world.Sometimes it is also called banana spider or a Brazilian hunter.This spider has the largest venom glands, they reach 10 millimeters in length. The amount of one portion of poison is enough to kill 225 mice. Hundreds of accidents involving spider bites are reported every year.Fortunately, there is an antidote for its poison.

In South In America, these spiders are usually found in houses, hiding in boots, hats and other clothing, and if they are disturbed, they bite. In addition to the fact that they have the most dangerous poison, they also differ from other spiders in their increased aggressiveness and speed of movement.

These spiders got their main name becausethat they do not sit still and do not weave webs, but are in constant motion, moving from place to place.Young individuals eat fruit flies and small crickets. Adults eat crickets and other large insects, Aalso small lizards and mice.

Wandering Spider entered into the Guinness Book of Records.

4. The most famous spider - Black Widow .

Black Widow Spider, a common name for any of several long-legged, smooth-bodied spiders found in the Tropics,in the southern United States, and also found in northern Canada.They spin simple webs in places protected from the sun, often in crevices. Adult female has a glossy black color (hence the name Black), body diameter is approximately 1 cm, legs length is up to 5 cm.the dorsal side of the abdomen has a characteristic red mark,similar to hourglass. The female is very poisonous spider.

Males are less common and are harmless. Males have four pairs of red dots located along thesides of the abdomen. After mating, the female devours the male, hence the name “black widow”.

The black widow spider is dangerous to humans - it produces a neurotoxin that causes severe pain, muscle cramps and evenparalysis. Their bites are very dangerous, butAntidotes have long been created that allow you to recover from poison in a few days. But insectsneurotoxins paralyze so quickly that the spider often starts eating when the victim, although not moving, is still alive.

By the way, most species of “black widow” behave rather timidly, preferring flight to attack. Disturbed spideroften pretends to be dead, with its paws tucked in, and runs away only if it considers that the danger has passed. Per person"black widows" attack only if they are teased or frightened, and the spider itself is not aggressive and attacks people exclusively whencase of their defense.

5. Karakurt

Karakurt - close relative Black widow, these spiders belong to the same speciesLatrodectus, and are similar in appearance.

In the photo: a young female karakurt. With age, the spots on the abdomen first become white, and thencompletely disappear. Photo taken in Russia, Astrakhan region

Karakurt, unlike the Black Widow, is quite common in steppe zone Central Asia, andin the Caucasus and Crimea. Karakurt is a small spider, its length usually does not exceed twenty millimeters (this is the maximumthe length of females, males do not exceed seven millimeters in length).

The habitat for karakurts is virgin lands, wastelands, banks of irrigation canals, and so on. The female findsmakes a hole in the soil and makes a den there. Very often karakurts settle in rodent burrows. Before entering the lair, the femalestretches a catchy, incorrectly woven web.

Karakurt eggs spend the night in cocoons previously suspended in the lair. In April, young spiders are selected forsurface and scatter in the wind along with the cobwebs.

Karakurt is a prolific spider,outbreaks occur every ten to twelve years mass reproduction. Adults are the most poisonousfemales. Let us recall that the poison of karakurt is fifteen times stronger than poison rattlesnake.

After a bite, a small spot remains on the body, which quickly disappears. Within fifteen minutes sharppain in the abdomen, lower back and chest, then numbness in the legs. The patient becomes lethargic and cannot sleep due to severe pain.

Recovery occurs in about three weeks, or even more.Most effectiveAntikarakurt serum is considered a medicine.

It does not attack animals or humans; it can bite only if someone literally steps on it.

6. Tarantula

Tarantula, a spider that is very widespread in America and southern Europe, whose bite is not dangerous.Tarantulas live in deep(about 50 centimeters deep) minks. At night they hunt insects.

The tarantula's body length is about three centimeters.

They feed on insects and a variety of small animals. A large species of this group can bite people, suchthe bites are often painful but not fatal.

7. The most strange spiders - "horns".

The belly of these spiders is amazingbright yellow, white and black colors. Six strong spines, long and smooth, emanate from the border of the abdomen.The female's abdomen is wide, flattened, angular, with six spines, two of which are very long. Probably the spikes are needed forprotection from predators. Bright yellow or red stripes run across the abdomen. Spider warts are raised. Malesmall, without noticeable spines.

Size: female - up to 10 mm (body width - up to 20 mm), male - up to 4 mm.

Habitat: forest edges and gardensIndia and South-East Asia, Australia.

Horned spiders weave excellent webs and make a trap loop for the victim. Their webs are usually woven at a distance of two metersfrom the earth. Their victims are most often small insects. Interestingly, if these spiders live in a community, thenThey share the caught prey regardless of whose net it fell into.

A distinctive feature of these spiders is bright color and thorns are needed to save them from other predators.

8. Most dangerous for children- Sydney leukoparachnoid spider.

Belongs to the most dangerous spiders in the world, but fortunately they live very far from Russia - in Australia.They weave (as can be seen from theirnames) watering-like or pipe-like web and live in a burrow up to 40 cm deep. They are very aggressive and alwaysready to attack. Their massive fangs can even bite through children's nails. Unfortunately, adult males leavetheir burrows and begin to travel, often “visiting” human dwellings, especially after a summer rainstorm. So, when traveling around Australia, be careful and careful - thesespiders cannot climb into a bed or table along a smooth metal or wooden leg, but they can “climb” intoclothes, shoes or towels thrown on the floor.

9. Spiders are spider hunters- are called "wolf spiders".

Wolf spider, a common name for any group of spiders that have a ground dwelling and hunt spiders. Wolf spidersare among the most common and visible spiders.

There are more than 2000 species of wolf spiders. These are brownish spiders that run (prowl) back and forth in whole “flocks”, like real wolves. This is quite unusual among spiders, as most spiders can't stand each other.

Probably because they often gather in packs and are brownish in color, they were given the name wolf spiders. In EuropeThere are several hundred species of wolf spiders. Most wolf spiders have strongbodies and long legs. Their bodies are low to the base for easy yaw. Wolf spider species are similar ingeneral shape, but their bodies vary in size, ranging from 2 mm to 40 mm in length. They typically have two verylarge eyes in the middle of their heads.

Wolf spiders have very good eyesight,which they need to hunt during the day.Wolf spiders generally determinelocate their prey by sight, but can also use contact to determine the nature of the prey. Theyuse their front legs to grab prey, then bite and crush it with strong fangs.

Wolf spiders are very common in any region of Russia. They can winter infield, prefer sparse vegetation. IN summer months leave the field to the side of the road, although the vegetation there is morethicker than in the field. This is probably due to low humidity and high temperatures in the field in the summer.

The female wolf spider lays her eggs in a large sac that can be almost as big as her own body.

She attaches the egg sac to her body and wears it until the eggs hatch. Then she tears the bag and takes itinto the burrow, where the offspring remain for another week. Many female wolf spiders are very good mothers: theylay their eggs in a cocoon, which they carry with them almost until the young hatch. Some species have young spidersclimb onto the mother's back and travel in this way for one to two weeks.