Types of spiders - names with descriptions and photos, danger of bite

Spiders are the most numerous order in the class of arachnids. It has 4076 genera and 46986 species (as of November 2021). Spiders are not insects ; according to the taxonomic hierarchy, they are arthropods .

Unlike insects, spiders do not have antennae. They have 6 pairs of limbs. 8 of them are walking legs. In front there are 2 chelicerae with ducts of poisonous glands. To the side of them are the pedipalps, the simplest sensory organs. The head and thorax of the spiders are fused. The cephalothorax and abdomen (opisthosoma) are connected by a thin constriction. There are 2-8 paired arachnoid warts on the abdomen. The tarsi are covered with trichobothria (setae), sensitive to air vibrations.

They eat mainly insects. Spiders have a narrow esophagus. Therefore, they digest food externally. They inject an enzyme into the prey. After a few hours, they drink the insides, which have turned into nutritious juice.

They live on all continents except Antarctica. Their hypodermis produces a chitinous cuticle that prevents moisture evaporation. Therefore, spiders successfully survive in dry areas. The largest representatives can be found in hot places. All spiders are terrestrial animals. The silverback spider is the only species that lives in water. There are also individuals that hunt on the surface of the water.

The main predecessors of modern spiders formed 200 million years ago in the Triassic (the first part of the Mesozoic era). Arachnids capable of producing webs appeared in the Devonian period (386 million years ago).

Appearance and body structure

Spiders are creatures of different sexes, females are much larger than males. The increased size helps them produce more offspring and easily eat the male after mating.

On the back of the underside of the abdomen there are arachnoid warts located in pairs. Between the upper pair there is an anal passage, next to them there are openings necessary for breathing, they are called stigmas (spiracles).

Body

The size varies from 0.3 mm to 10 cm. The smallest (0.37 mm) are males of the species Patu digua from the family Symphytognathae, living in Colombia. The largest are representatives of the tarantula family. For example, females of the species Theraphosa blondi reach 10.4 cm (including paws - 28 cm).

The body of spiders consists of a solid cephalothorax and opisthosoma, connected by a small canal. Like all arthropods, it is covered with an exoskeleton made of chitin. The exoskeleton is updated 5-10 times per life. Moreover, first a new one grows, and then the old one is discarded.

Limbs

Spiders have 4 pairs of legs. Each has hairs that transmit signals about air movement to the brain. With their help, the arachnid representative navigates in space.

In addition to the legs, 2 pedipalps extend from the cephalothorax. They are also covered with bristles. The ends of these limbs have olfactory areas. In some spiders, these body parts are longer, so they can be confused with legs. This means that it is incorrect to identify the animal.

Next to the pedipalps above the mouth there are chelicerae of a curved (like a hook) shape. Inside them are ducts containing poison. Spiders need chelicerae to catch, kill, and tear apart prey.

Vision

The structure of the visual system in spiders is not the same. Therefore, the vision of the world can vary greatly.

Most individuals hardly see further than 30 cm. Eyes are most often 8, but can be from 2 to 12. Simple type. Their location allows for a wide viewing radius (up to 360 degrees). Cave spiders are blind. And the vision of jumping spiders is comparable to that of humans.

Some representatives of this order are able to distinguish colors. For example, a flower spider. They proved that he had color vision through the development of conditioned reflexes. Red, blue and green illumination produced a fly. They gave an electric shock only when the rays were red, when it touched the insect. As a result, the individual no longer tries to capture prey when the lamp with red rays is working.

Pedipalps

Pedipalps are short. With chemical sensors that allow spiders to navigate tastes and smells. The last segment of the pedipalps in sexually mature males is modified. Males use this part of the body to store sexual sperm and fertilize the female. Name of parts of male pedipalps:

1. Cymbium - supports the copulatory apparatus.
2. Embolus is the ejaculatory duct.
3. Bulbus - it contains a reservoir for seminal fluid.
4. Shin.
5. Patella - often has apotella on it. These are outgrowths that, during mating, help arthropod creatures to better gain a foothold.
6. Hip.

The testes do not have a direct connection with the pedipalps. Therefore, before courtship, spiders perform a curious procedure. Males weave webs into nets. The seed is released there. Then the pedipalps are immersed one by one. They suck up sperm. During copulation, an embolus is inserted into the female's reproductive canal and the seminal fluid is released. During copulation, the female is held in place with the help of growths on the front legs.

Color

The color of spiders depends on the pigments bilin (brown tint), guanine (white), etc. The color is also created due to the light reflection of the bristles and hairs.

They lack the most common pigments in the animal world (melanin, carotoid, pterin).

Main differences

With minimal knowledge of biology, one can easily discover that between these species of arthropods there is very little even external similarity, not to mention origin and numbers. Even the appearance of spiders and insects on Earth dates back a hundred million years. The last species appeared on Earth 100 million years later than spiders, which have lived on the planet for more than 400 million Earth periods.

Further differences are even more noticeable:

• there are about 43 thousand species of spiders (42 thousand modern and 1100 fossils), and more than a million insects have been described, and there are suggestions that this is not a complete list;
• spiders are obligate predators, there is only one known species that feeds on acacia, while the feeding of insects varies depending on the stage and species;
• web weavers have eight legs, while their opponents have six; the difference in structure is difficult to compare due to the huge number of varieties of the latter category;
• although spiders are also found with six or 2 eyes, in most cases they have 8 organs of vision, and insects have compound eyes consisting of ommatidia for comprehensive viewing;
• almost all tracheal breathers have digestive organs, even in their infancy, and a mouth for absorbing food, and in spiders, food digestion occurs outside the intestine, after injecting enzymes into the body of the victim;
• insects have an exoskeleton, head, thorax and abdomen, while spiders have only a cephalothorax and abdomen, although there are some species in which the head and thorax are separated by a groove, but still do not constitute separate body segments.

It is difficult to list the structural features, size and dimensions of insects, since there are a myriad of them. But the main differentiation is usually made by the type of digestion.

Spiders, being earlier inhabitants of the Earth, are equipped with hooks and channels for injecting poison into the food they catch. Enzymes that enter the body of the prey dissolve its contents, and the obligate predator can only suck out the contents.

This makes the arthropod dependent on external circumstances - the web, the opportunity to lie in wait, the time required to obtain a kind of soup.

The insect immediately absorbs the food received and digests it inside the body. This gives him the opportunity to get enough faster and not waste precious time, which means a greater chance of survival in interspecies struggle. Therefore, insects became a more branched branch of evolution.

Internal structure

Spiders have a complex internal structure. They have circulatory, excretory, respiratory, digestive, and nervous systems.

Digestive system

The intestinal canal runs directly from the mouth to the anus. Consists of 3 parts. Divided into the esophagus, stomach with five pairs of blind tubes, and intestines. Processing and absorption of nutrients occur in the stomach. The intestines include two branched urinary canals. Liver juice has an effect similar to that of the pancreas of higher vertebrates.

Foregut

Consists of the pharynx, sucking stomach, and esophagus. Covered with chitin. Equipped with powerful muscles. The esophagus is thin and tubular. Forms a right angle with the pharynx. The sucking stomach has the shape of a pyramid with 4 sides. It absorbs part of the food. It also helps with swallowing as it has strong muscles.

Stomach

The stomach of spiders is the anterior section of the midgut. It does not have an internal cuticle. Represents large branched protrusions. It happens: simple, intermediate, classic, complex. Connects to the intestine, which extends through the stalk into the abdomen.

Liver

Large bulge on the intestine at the beginning of the abdomen. Gray or brown. Consists of many blades (lobes). Surrounds all organs except the pulmonary sacs. Releases digestive enzymes and destroys semi-digested food particles.

Cloaca

A voluminous pouch at the end of the intestine. This is where excrement accumulates. The Malpighian vessels flow into it. It continues with the chitinous hindgut. Followed by the anus. Spiders defecate droplets of liquid. After drying, the stains from them become white with a dark center.

Respiratory system

The respiratory organs are unique. The hemolymph of many spiders contains the respiratory pigment hemocyanin. It speeds up metabolic processes. The number of spiracles corresponds to the number of respiratory organs.

Lungs

Consist of many plates. Their appearance resembles a stack of paper. Primitive groups of spiders have 4 lungs. In most spiders, the posterior pair of lungs is transformed into trachea. There are representatives who do not have this body. That is, according to the way they breathe, spiders are divided into:

• Quadruple lungs;
• bipulmonary;
• lungless.

Trachea

Oxygen enters them through air holes. According to development and location, there are local and general significance. The second ones extend into the cephalothorax and limbs. The first ones do not extend beyond the abdomen.

The trachea is more efficient for breathing than the lungs. This has been confirmed by experiment. The stigmata of spider lungs were covered with Vaseline. After 4-7 hours, blood circulation stopped. Then the spider died. Representatives of species with developed tracheae lived significantly longer during the experiment.

Interesting fact. The water spider has predominantly cutaneous respiration. With completely covered spiracles, it lives 4-15 days. Underwater it breathes oxygen, which collects between the hairs on the body.

Circulatory system

The circulatory system is not closed. Heart pulsating. Located in the abdominal cavity. It has lateral stomata that help pump hemolymph (the equivalent of white blood). When the heart contracts, blood enters the artery and the lateral stomata close like valves. Flows through the arteries to the extremities. It rotates around the lung sacs, then returns through the lateral stomata into the posterior vessel.

central nervous system

Consists of the brain and subpharyngeal nerve mass. Concentrated in the cephalothorax. It consists of paired ganglia that act as local control centers for all segments. The brain is created by the fusion of ganglia. Spiders have a centralized nervous system, characteristic of arachnids. There are two visual centers in the brain. One is responsible for the main eyes, the other for the others.

Despite having a relatively small central nervous system, some representatives exhibit complex behavior. For example, the ability to use trial and error.

What class do spiders belong to?

The answer to the question: “Is a spider an insect?” taxonomy gives. What class do spiders belong to? Is a spider an insect or not?

Despite the presence of common characteristics, spiders and insects previously belonged to different classes: arachnids (Arachnida) and insects (Insecta). In modern taxonomy, two classes of insects have been identified: cryptomaxillary and open-jawed, combined into one superclass - six-legged (Hexapoda). The class Arachnida stands apart. Is a spider an insect? The answer is no. However, how is it different from insects?

Nutrition

99% of spiders eat animal food. They prefer insects. On average, they eat 650 tons per year. Digested externally. The esophagus of spiders is very thin. Able to pass only liquid food. The straining apparatus in the pharynx does not allow large pieces (more than one micron) to pass through. The digestive enzyme is secreted by the liver. This function is also performed by the labial gland (located on the upper lip).

Did you know that spiders can distinguish tastes? They do this thanks to a group of receptor cells in the walls of the pharynx. Spiders reject flies coated with table salt and quinine. But they enjoy eating elderberry core soaked in meat broth.

Spiders of different species prepare their prey in 2 ways. Most creatures inject the enzyme into an insect, then knead it and tear it apart with chelicerae. This procedure is carried out several times. After each manipulation, drops of nutritious juice appear on the surface. The spider eats them with its rostrum.

Spiders that feed on hard-shelled insects simply inject secretions into the wound. Then all the nutrient fluid is sucked through one hole.

The tarantula enzyme can dissolve 3-4 grams of mouse meat in 24 hours.

These arachnids are predators. The exception is a species of jumping spider called Bagheera Kipling. They sometimes feed on nectar. But most often with the tips of acacia leaves, as they are rich in proteins. In addition, 60 species were caught occasionally consuming “vegetarian” food.

Is the wasp spider poisonous or not?

The arthropod has poisonous glands that produce a toxic substance. When it enters the victim's body, it causes muscle spasm and immobilization. The poisonous brunette is not distinguished by its aggressive disposition and does not attack unnecessarily. For humans, its presence nearby does not pose a danger. However, if the argiope feels a threat to his own life, the attack will follow.

Due to its unusual color, wasp spiders are kept at home as pets. They live in specially equipped aquariums and feed on insects. Feeding should be done every other day. up to 1.5 years.

The karakurt spider is one of the most dangerous creatures on earth. Despite its small size and non-threatening appearance, the karakurt's venom is 15 times stronger than that of a rattlesnake and 50 times stronger than that of a tarantula. For a horse or camel, a karakurt bite is often fatal.

The karakurt spider is one of the most dangerous creatures on earth

Without prompt medical intervention and professional help, a meeting with a person can also result in death, although such cases are extremely rare. The black spider evokes mystical associations due to the presence of 13 bright red spots on the body and cannibal family traditions. Kalmyk shamans use a dangerous creature in some rituals. There is a common belief that karakurts live only in deserts and do not pose a danger to residents of the central and even southern steppe and forest regions, but this is not true. Recently, the migration of biting “robbers” to the north has been obvious, and climate warming has led to the fact that karakurts are recorded in regions where they have never been observed before.

The poisonous karakurt spider belongs to the order of spiders of the family of web spiders from the genus of black widows. Translated from the Turkic language, the name is literally translated as a black worm. The Latin name Latrodectus tredecimguttatus reflects the external characteristics - 13 points on the back and the essence of the spider (biting robber). Like the karakurt, which is sometimes called the steppe spider? In terms of size, the spider belongs to the medium arachnids. The size of the male is 4-7 mm, the female karakurt is 2-3 times larger and can reach 20 mm. The body of the eight-legged spider is black, with a pronounced abdomen. Both males and females have red spots or dots on the upper side of the abdomen. On the lower part of the abdomen a clear scarlet pattern is visible, similar to the outline of an hourglass. The spot on the abdomen often has a snow-white halo. Adults (males) can be completely black. Karakurt is a predator; it feeds on insects, which it uses a web to catch.

Despite its small size and non-threatening appearance, the karakurt's venom is 15 times stronger than that of a rattlesnake and 50 times stronger than that of a tarantula.

White karakurt, also related to web spiders, has a white or yellowish color. There is no hourglass pattern or spots on the body, but there are 4 indentations forming a rectangle. White spiders are much less poisonous, their bite is not dangerous to people, although the venom of the white karakurt is similar in its toxicological properties and effects on the human body and animals to the venom of the black widow. White karakurts can be found in Russia and neighboring countries, but the main habitat is located further south - in North Africa, the Middle East, and also in Central Asia

Let's focus on the black widow karakurt as the most dangerous representative of the internet, which you can meet at domestic resorts

Karakurts are distinguished by their fertility; in the southern regions there are periodic surges in the birth rate, which entail an increase in the number of casualties among people and loss of livestock. Poisonous spiders in Kazakhstan and Crimea attack dozens of people every year, but serious consequences occur extremely rarely. The female lays more than 1,000 eggs per year, which are placed in a protective cocoon. The newly born spiders continue to live inside the cocoon and emerge from there only next spring. Puberty occurs 2-3 months after the spiderlings leave their original home. Eggs are laid in holes on the ground or in rodent burrows. Fertilization occurs during the hottest months of summer. After mating, the female karakurt eats the male, although there are exceptions - for unknown reasons, the female can either destroy the male before mating or leave him alive after fertilization.

How do spiders weave webs?

All spiders can create webs. In the early days, they used their own yarn as an insurance policy. Then they began to weave carpets in order to recognize the approach of prey by the vibrations of the threads. And finally, we learned how to create clever traps.

The web is produced by the arachnoid glands. They are located in the abdomen (under the liver, near the longitudinal muscles). They emerge as spider warts. Which have hairs called tubules. Their average number is 400-600. The tubes are connected to the glands. Spiders have several types of glands. Each is capable of producing webs with different properties. For example, sticky is never used to weave an egg cocoon.

The spider has complete control over the processes associated with the web yarn. How a spider spins a web:

1. His brain analyzes the task.
2. Sends a signal to the desired gland.
3. It releases a protein mixture.
4. It is directed through the channels to the tubes.
5. Goes outside.
6. The individual presses the warts to the surface, thereby attaching the tip of the future thread.
7. It begins to move, pulling out the web from itself.

Sometimes, during the production of webs, he can comb them with his paw. This entangles the fibers to achieve greater strength.

Distinctive features of arachnids

Due to the fact that arachnids lead a mainly terrestrial lifestyle, their body structure has a number of features. For example:

• the respiratory organs are the pulmonary sacs and trachea;
• appearance of excretory organs;
• a waxy film (lipoprotein) covering the chitinous membrane;
• small body size, which reduces the number of molts;
• the presence of internal fertilization.

Fig.2. Features

The presence of excretory organs and lipoprotein film allow saving internal body moisture. That is why some species of arachnids easily adapted to life even in the driest areas of our planet.

Reproduction and life cycle

All representatives reproduce by laying eggs. Males do not have a penis. They have to drain the seminal fluid into a reservoir made from the web. They pick it up with the pedipalps. How spiders reproduce:

1. Marriage games. If the behavior of the male does not correspond to the species, then the female may mistake the suitor for prey and eat it.
2. The male transfers the seed from the abdominal cavity.
3. Attached to the female with the help of growths on the limbs.
4. Inserts the pedipalp into the female's genital opening and fertilizes. Spider sperm are packed in sacs.
5. The seed capsules end up in a sperm storage container.
6. From there, the fallopian tubes lead to the ovaries, which can be paired or unpaired.
7. The eggs grow on the surface of the ovaries.
8. The ripened ones move inside them.
9. From there they go out through the oviducts.
10. The female wraps them in a web, hides them or carries them with her everywhere.
11. The eggs hatch into completely unformed individuals. At this stage they are called nymphs.
12. Newborns grow and molt up to 3 times.

Many species of spiders care for their young. A South Russian tarantula takes eggs out of a burrow and warms them in the sun. After hatching, it loses interest in children.

Wolf spiders do not abandon their brood even after birth. Small arthropods climb onto their mother. They live under her protection until they get stronger. And the offspring of Coelotes terrestris do not leave their parents for a whole month. There are also cuckoo spiders that drop their eggs into other people's nests.

The life of spiders is very dependent on the weather. They are accustomed to performing important tasks on the same days every year (mating, laying eggs, settling the young). But if they foresee worsening weather, they change plans. They can even hang their web at a different angle, sensing the approach of a hurricane or thunderstorm. Nature has endowed spiders with an amazing sense of smell. These creatures can anticipate bad weather 7-8 hours in advance.

Features of reproduction

During the process of active growth, spiders from time to time shed their tight shell, which consists of a chitinous structure. They gradually acquire a new, stronger one.

Over the entire period of their life, they can molt up to 10 times . Spiders are heterosexual individuals, with the female being much larger than the male.

The mating period lasts quite a long time, its season begins in mid-autumn and lasts until early spring. At this time, the male fills the bulbs, which are located at the ends of the pedipalps, with sperm, then he goes in search of the female.

After performing the “mating dance” and fertilization, the male leaves and dies in the subsequent period.

As soon as 2.5 months have passed, the female lays eggs. After 35 days, spiderlings hatch from them and live in the web until the first molt. Sexual maturity in females occurs at the age of 3-5 years.

Types of spiders

The order of spiders includes 2 suborders: Arthoplastae (97 species) and Opisthothelae. The latter is divided into Araneomorphs (43,834) and Mygalomorphs (2,875). The arthroplasties have changed less during evolution. They have retained clear segmentation and are more similar to other arthropods.

Safe

All spiders have venom. But those whose poison is minimally concentrated are harmless. Due to their size, small individuals cannot produce enough poison to cause a reaction in the human body.

Haymaker

Small spider (2-10 mm). Leg size 40-50 mm. Available on all continents. Has 8 eyes (2 central, 6 lateral). It differs in the way the eggs are packaged. Instead of sealing, it weaves bags like string bags for storage. Places cobwebs in dark, damp places. In people's homes, on the contrary, they like warm, dry places (on windowsills).

House spider

From 6 to 12 mm. Brown with leopard print. Extremely common. But rare in the wild. Prefers to live next to a person. It can easily be confused with the poisonous hobo spider. Can't weave a sticky web. Its networks are loose. Because of this, the victim is easily confused.

South Russian tarantula

Harmless, despite its threatening appearance. Body 2.5-3 cm. Deserts, steppes, forest deserts - these are the zones of its habitat. Lives and hunts in burrows. A female can give birth to up to 50 cubs. At first they live with their mother. The bitten area swells, may turn yellow, and hurt. But a bite is no more dangerous than a hornet attack.

Horse

This family has 5,000 species. Representatives copy the appearance of other animals. For example, ants, false scorpions. Leads a daily lifestyle. It has a viewing angle of almost 360 degrees, as well as claws on its limbs. The jumping spider is a harmless arthropod. It is not capable of biting through human skin.

Argiope Brünnich garden

A spider from the orb weaver family. It hurts. After 2-3 hours, the wound turns red and swells. The bite site becomes numb. The unpleasant feeling usually goes away after 2-3 days. Dangerous for those who are allergic to insect bites. Spiders are helpers; they destroy many pests. The body length of females is 2-2.5 cm, males 5 mm. The color of the body and legs is black and yellow. The spider Agriopa Brünnich is also called the “wasp spider” because of its bright striped color.

Poisonous spiders

In this article, we will call poisonous spiders those whose venom causes discomfort to humans, but is not fatal to him.

Tarantula

The tarantula family includes 143 species. Their bites are not dangerous to adults. But they cause very unpleasant symptoms: fever, cramps, chills, pain. There are fatalities involving cats. Therefore, if a child is bitten by a tarantula, you should immediately consult a doctor.

Cross

Its venom contains a neurotoxin. Causes headaches, joint pain, and weakness. A burning sensation and tissue necrosis appear at the site of the bite. In total, there are 600 species of cross spiders, about 30 are found on the territory of Russia. The spider “Krestovik” owes its name to the spots on its back that form a cross. This color element helps scare away animals.

Tramp

Brown in color, there are yellow spots on the belly. The hobo spider is a close relative of the house spider. It is distinguished by its aggressiveness and the consequences of its bite; its venom causes tissue death. Most common in Europe and America. Size 7-16 cm. Paws are short with a small span.

Deadly poisonous spiders

Females are more aggressive. The poison can be neurotoxic (affects the central nervous system) and necrotic (provokes tissue death).

Karakurt

Spider from the Black Widow genus. The poison is neurotoxic and oily. Only females bite. The fangs penetrate no deeper than 0.5 mm. The pain appears instantly. At the site of the bite, 2 red, inflamed dots form. After 10-15 minutes the poison begins to act actively. Convulsions occur in large muscles, then in the abdominal muscles, severe pain, tachycardia. Further delirium, confusion. Heart failure, respiratory arrest, and death occur.

The paws are shiny (as if varnished) in the shape of a comb. The body is covered with 13 red spots. Sometimes they are inscribed in a white frame. Adult spiders sometimes turn completely black.

Brown recluse spider

On the top of the body there is a pattern resembling a violin. The bite is accompanied by a slight burning sensation. After 3-8 hours, a blister with liquid appears at the site of the bite. It bursts. A hole is formed. This ulcer begins to expand. The temperature rises and nausea appears. There have been deaths from brown recluse spider bites. The poison causes necrosis and has a hemolytic (destroying red blood cells) effect. Found in the USA. Three pairs of eyes. Weaves webs in unpredictable places: clothes, boxes, baseboards.

Classification of arachnids orders

The classification of arachnids includes more than ten orders. The following eight are of greatest importance: 1. Scorpions; 2. Telephons, or flagellated (Uropygi); 3. False scorpions (Pseudoscorpiones); 4. Solifugae; 5. Haymakers (Opiliones); 6. Spiders (Aranea); 7. Acariformes mites; 8. Parasitiformes.

Order Scorpions

Scorpions are common in southern latitudes. These are nocturnal predators. During the day they hide in burrows, under stones, under the bark of trees, and at night they go out hunting. The venom of large scorpions causes painful phenomena in humans not only of a local (tumor), but also of a general (headache, fever) nature. In some very rare cases, injections from large species of scorpions can lead to death. For the small animals that scorpions feed on (other aciformes, millipedes and insects), their injections are fatal.

There are about 600 species of scorpions. A small yellow Crimean scorpion (Euscorpius tauricus) lives in Crimea. It barely reaches a length of 40 mm. Caucasian scorpions are somewhat larger, for example, the Italian scorpion (Euscorpius italicus), found on the Black Sea coast of the Caucasus, or the motley scorpion (Buthus eupeus), common in Transcaucasia and Central Asia. Large scorpions live in the tropics; for example, the African scorpion (Pandinus imperator) reaches 18 cm in length.

Order Telifona, or Flaglegs (Uropygi)

Telifons are tropical predators, somewhat similar to scorpions, with highly developed grasping pedipalps. The front legs are long, rope-like, replacing antennae. The abdomen is strongly dissected (11 segments), the last three segments form a stalk ending in a long segmented caudal filament. There is no poison gland. They breathe with their lungs (2 pairs).

Widely distributed in the tropics. We have one species in the Ussuri region - the Amur thelyphon (Thelyphonus amurensis).

Order False scorpions (Pseudoscorpiones)

False scorpions are small predatory animals that look somewhat similar to real scorpions. The similarity with scorpions is manifested in the shape of the pedipalps, ending in powerful claws with which they catch prey. The strongly developed, wide, segmented abdomen (11 segments) does not carry a sting with a poisonous gland at the end. Pseudoscorpions have arachnoid glands that open at the end of the chelicerae. They breathe only through tracheas, there are no lungs.

False scorpions live under stones, under the bark of trees, and feed on small insects. An interesting book false scorpion (Chelifer cancroides), which lives in bookcases and books, in collections and herbariums. It does not harm books or collections. By destroying insects harmful to libraries, it is rather useful, but the very presence of these animals among the books indicates the presence in the library of some kind of book pests that serve as food for the book false scorpion.

Order Solifugae

Salpugs are fairly large predatory arachnids (some species reach 10 cm in length) and live in southern latitudes. In Russia, salpugs are common in the Azov and Caspian steppes, in Central Asia, the Crimea and the Caucasus. In the Crimea and the Caucasus, the phalanx (Galeodes araneoides) (about 5 cm in length) is common. Salpugs are easy to distinguish from other arachnids by powerful claw-shaped, but not venom-bearing, chelicerae, but pedipalps, similar to highly developed walking legs, as a result of which salpugs give the impression of decapods, and by two free thoracic segments. Salpugs breathe through tracheas.

Although salpugs are not poisonous, however, when they bite through human skin with chelicerae, they contaminate the wound, which can cause an inflammatory process.

Order Harvesters (Opiliones)

Many people know haymakers by their very thin and long walking legs, which easily come off (autotomy) and at the same time retain the ability for convulsive movements. Hence the name “haymaker”. Harvesters are very different from real spiders, despite some external similarities with them. They have small, claw-shaped chelicerae that do not have venom glands. The dismembered abdomen is not separated from the cephalothorax by a deep constriction, like in spiders.

Harvesters do not have lungs, and they breathe through highly developed tracheas. Harvesters can be found on tree trunks, on the walls of houses, sheds, under leaves and in houses, where they hunt for small insects.

Classification of arachnids Order Spiders (Aranea)

Spiders are one of the most numerous orders of arachnids (about 21,000 species), they can be found in a wide variety of environments: in forests and fields, in gardens and houses, and even in water.

The order of spiders is divided into three suborders: 1. Arthroplasty spiders (Liphistiomorphae); 2. Mygalomorph spiders, or tarantula spiders (My galomorphae); 3. Araneomorphae spiders (Araneomorphae).

The first suborder includes only 8 species of the most primitive tropical spiders with a dissected abdomen. Representatives of the second suborder are the largest spiders in the world, sometimes reaching 10 cm in length. The suborder includes about 1,500 species, which are distributed mainly in hot countries and of which only a few are found in our fauna. These are the Central Asian Nemesia sauvagei and others - inhabitants of peculiar hunting burrows. In the steppes, the digger spider (Atypus piceus) is common, which makes long catching tubes from its web, protruding far beyond the flaw. The same group includes the large South American tarantula spider and the even larger (up to 9 cm in length) Javan tarantula spider. The first two suborders of spiders are sometimes combined into the group of four-legged spiders, since they have two pairs of lungs, while the third suborder includes two-legged forms.

Two-lunged spiders have one pair of lungs and, in addition, tracheas. Almost all spiders found in Russia belong to this suborder. Typical representatives are the cross spider (Araneus diadematus), house spider (Tegenaria domestica), tarantula (Lycosa singoriensis), karakurt (Latrodectus tredecimguttatus), silver water spider (Argyroneta aquatica), etc. In the biology of spiders, the most characteristic feature is the formation and spinning webs that have a variety of purposes. We know that the abdomen of spiders often contains a very large number of arachnoid glands, the excretory ducts of which end in holes at the ends of the smallest chitinous tubes sitting on the arachnoid warts. These glands differ in their structure (tubular, pear-shaped, vesicular, etc.) and in the secretion they secrete. Apparently, different types of webs formed by spiders and having various uses are secreted by different glands.

The web is used by a significant part of spiders, called tenet spiders (house spider, cross spider, etc.) to build trapping nets into which prey gets caught and entangled.

The web of a cross spider can serve as an example of a very complex design. It must be borne in mind that an individual arachnoid thread is a product of the secretion of several, often many, glands. Each gland secretes a liquid substance that instantly solidifies in the air into a thin thread. From these the spider spins web threads. Each thread consists of several sticky webs. The spiral threads of the cross spider are sticky. The sticky substance covering them is secreted by tree-like glands. The spider sits, lying in wait for prey, outside its hunting net, hiding in a secluded place near one of the radial threads. It is connected to the hunting web by a special signal web thread. Thanks to the signal thread, the spider senses the slightest vibrations of the net. As soon as the prey has fallen into the net, the spider pounces on it, strikes it with its chelicerae and entangles it with a special web secreted by it at this time.

The spinning of webs and the construction of hunting nets are carried out by the spider using the last segments of its walking legs, especially the legs of the hind pair. The last segment of the posterior pair of legs has special comb-like claws.

The web is used by spiders not only for the construction of hunting nets. Female spiders weave webs around the eggs they lay and make cocoons around them. Some spiders wrap tree leaves on which eggs are laid and also weave webs around them. Burrowing spiders line their home with webs—usually a shallow burrow dug in the ground, often on the bank of a river. The males of some spiders make something like a small hammock out of their web, into which they release sperm, which is then collected in the copulatory appendages of the pedipalps.

Of particular interest is the use of webs by young spiders of many species in early autumn (“Indian summer”) as a flight web. Having climbed the stem of a plant or the end of a branch, the spider releases a web, attaching its end to the branch. When the web is long enough, the spider breaks it off at the point of attachment. After this, it continues to secrete the web for some time, and then draws in its legs and breaks away from the plant, carried away by the web in the wind. The flight web is an interesting adaptation that ensures the dispersal of the species.

Are spiders harmful or beneficial? Since they are predators, destroying mostly harmful insects - flies, mosquitoes, etc. - they, like other arachnids, with the exception of ticks, should be considered useful animals. The fear and hostility they inspire (for residents of middle and northern latitudes) have no basis. The bites of some spiders, although painful, such as tarantula bites, do not pose any serious danger. On the territory of Russia, only the karakurt, found in the Caucasus and Central Asia, is very dangerous for animals and humans. The distinctive features of the karakurt are as follows: the spider is small in size (about 1.5 cm), has a black abdomen covered with small red spots. Lives on the ground, among stones, creating sparse nets that creep along the ground. Karakurt bites are often fatal. Horses, cattle and especially camels die from them. However, sheep are not sensitive to karakurt bites. Therefore, flocks of sheep are sometimes driven to areas inhabited by karakurts, and the sheep trample down spiders and their nests. In humans, karakurt bites cause a severe painful condition, sometimes fatal.

Order Acariformes and order Parasitiformes

Ticks are a collective group that unites two (according to some sources three) independent orders: 1. Acariformes and 2. Parasitiformes.

Ticks are a very large and practically important group of arachnids. Many of them are of great medical and veterinary importance as ectoparasites of humans and animals. They are capable of storing and transmitting pathogens of a number of serious diseases from animals to humans for a long time and can themselves cause diseases by parasitizing the skin of humans and domestic animals. Some mites serve as intermediate hosts for tapeworms. The harmful activity of ticks is also very significant in economic terms. Many groups of mites destroy and spoil grain and flour reserves and parasitize cultivated plants, causing their weakening or death.

Of all arachnids, mites are the smallest animals, often microscopic in size (0.1-05 mm, rarely up to 15 mm). Their organization deviates greatly from the typical arachnid pattern.

The order of acariform mites is the most numerous, it includes more than 6,000 species, among which there are very primitive forms with a dissected cephalothorax, like a salpugs, and a segmented abdomen.

In the most primitive mites, there is a fusion of head segments bearing chelicerae, pedipalps and two pairs of limbs, and the separation of a trunk section, which combines free thoracic segments with two pairs of limbs and a jointed abdomen. Others, like most arachnids, have a cephalothorax bearing six pairs of limbs. However, in many mites, not only body segments, but also its parts merge into a total mass.

In the order of parasitiform mites, segmentation has not been preserved. It includes about 4,000 species, among which there are many parasites that carry pathogens of various infections.

Not all ticks are parasitic on animals and humans. The diversity of habitats and lifestyle of this huge group of arachnids is surprising. Among them are a mass of saprophages that feed on decaying organic remains, herbivorous forms, predators and, finally, various parasites of both vertebrate and invertebrate animals.

Due to different feeding methods and lifestyle characteristics, the chelicerae and pedipalps are greatly modified and are part of a complex “head” (gnathema). In carnivorous and heterovorous forms, the chelicerae bear claws, forming a gnawing-sucking mouthparts. Parasites and herbivorous mites have a piercing-sucking type of mouthparts, and in the former it provides not only a puncture of the host’s tissues, but also a long-term fixation on it. A complexly structured proboscis appears, carrying a kind of anchor device - a hypostome, seated with hooks directed backwards.

Ticks breathe through tracheas, and small forms are characterized by cutaneous respiration.

Postembryonic development of mites, unlike other arachnids, occurs with metamorphosis. A larva emerges from the egg, having, instead of four, only three pairs of walking legs. The larva turns into a so-called nymph, which already has 4 pairs of legs and after one to three molts it turns into an adult tick. The nymphal stage of some ticks can be nonmotile, resembling the pupal stage of insects. In different groups of ticks, metamorphosis occurs differently; the number of nymphal stages may increase or, conversely, decrease, up to viviparity.

Among ticks inhabiting various habitats, natural groups arise, the most important of which we should consider. In ponds and lakes, fairly large, quickly swimming in the water, brightly colored water mites, or hydracarids, are common. However, only in adulthood do they lead a free lifestyle. feeding on crustaceans and insect larvae. Their larvae lead a parasitic life on various aquatic insects and their larvae (aquatic bugs, dragonflies, etc.). When insects fly out of a reservoir, the water mites that parasitize them are dispersed.

Many groups of mites inhabit the soil, being its founders and ancient aborigines. The largest group of soil mites are oribatei mites, named for their characteristic hard shell. making them resistant to changes in external conditions, increasing their durability, and also promoting settlement. Some oribatid mites develop wing-like projections on the sides of their bodies—pteromorphs. The latter can even articulate movably, and the so-called winged mites wave them when moving. It is believed that these formations are similar to the lateral outgrowths of the chest of ancient insects, from which wings apparently developed. Acarologists (mite specialists) jokingly declare that oribatid mites are about to fly. This can be seen as an example of the convergent formation of wing analogues in arachnids.

Oribati mites are typical saprophages, eating various decaying organic remains, including animal droppings. At the same time, they can swallow the eggs of tapeworms Moniezia expansa and others. More than 50 species of oribatid mites serve as intermediate hosts of tapeworms. In ticks, embryos develop and cysticercoids form. Sheep and other domestic and wild ungulates become infected with moniesiosis by eating ticks containing helminth larvae along with grass.

A particularly important group from a practical point of view are various blood-sucking ticks, since when they attack animals and humans, they not only cause irritation and itching, but also carry pathogens of various, sometimes very dangerous, diseases. Blood-sucking ticks are represented by the superfamily of ixodid ticks (Ixodoidea) (from the order Parasitiformes), which includes the largest species of all ticks. Well-fed females reach sizes of more than 15-20 mm.

Of the blood-sucking ticks, the dog tick (Ixodes ricinus) is well known in central Russia. A male dog tick is almost half the size of a hungry female (4 mm). The female, having sucked blood, reaches 1 cm in length. The ability to suck large amounts of blood in blood-sucking ticks is associated with the special structure of the midgut. Blind outgrowths extend from it, which in an animal that has sucked blood fill the entire body cavity. Hungry female ixodid ticks lie in wait for prey on grass, bushes and small trees. The female lays her eggs in a pasture or forest, where she drops from her host to the ground after satiation. Only after being fully saturated with blood is the female capable of laying eggs. Oviposition takes a long time, the female lays several thousand (7-10) eggs, after which she dies. A dog tick, having burrowed into the skin of an animal or person, usually causes itching and redness. Removing a tick is not easy, and before attempting to remove it, you must lubricate the skin with gasoline, kerosene or oil. In this case, the tick's spiracles are blocked, it weakens and can easily be removed. Otherwise, there is a danger that its proboscis will remain in the skin, which can cause inflammation and suppuration.

The epidemiological significance of ixodid ticks themselves (family Iхodidae) is determined by their ability to feed repeatedly during metamorphosis on different hosts, including attacking humans. Thus, in the widespread dog tick (Ixodes ricinus) and taiga tick (I. persulcatus), a six-legged small (about 0.8 mm) larva emerges from the egg; it attacks rodents or other small mammals, birds, and rarely lizards. After saturation, the larva falls off, and after 1-2 months it molts and turns into a nymph, similar to an adult tick, but with a genital opening. The nymph feeds on another host from the same group of hosts, and then after about 2 months it molts and turns into an adult tick. Adult ticks attack cattle and large wild mammals. Thus, these mites suck blood three times, and each time on a new host, for which they are called three-host. If one of the wild hosts (hosts) of larvae or nymphs contains the virus of tick-borne encephalitis or another infectious agent in the blood, then the adult tick can transmit it to humans. The life cycle of ixodid ticks usually extends for 2-3 years, since the larvae or nymphs that appear in the fall overwinter hungry and continue development only the following spring. Thus, ixodid ticks serve not only as carriers of the virus, but also as its long-term keepers.

Tick-borne encephalitis and other infections transmitted by ticks to humans are actually animal diseases—zoonoses. Their pathogens are capable of circulating for a long time in a certain area, transmitted by larvae, nymphs and adult ticks from one susceptible animal species to another. At the same time, some animals may not get sick, but only contain infectious agents. for which they are called a source (reservoir) of infection. Susceptible animals are called recipients of infection, and ticks are called carriers or vectors. The territory in which infectious agents, its sources and recipients simultaneously persist is a natural focus, and the infection will be transmissible (i.e. transmitted through vectors) and natural focal.

All components of a natural focus are members of one community of animals and plants (biogeocenosis), where complex relationships between them support the long-term existence of the focus of infection. Natural foci of infections exist independently of humans and, apparently, arose before his appearance on Earth. A person entering the outbreak area can become involved in the circulation of the virus and get a serious illness.

The theory of natural focality of vector-borne diseases was developed by academician. E. N. Pavlovsky and his students based on the study of foci of tick-borne encephalitis (Far East, Ural, Belarus), tick-borne typhus fevers (tick-borne rickettsiosis), tick-borne relapsing fever (tick-borne spirochetosis), tularemia and many other infections, including transmitted ones insects.

Natural foci of tick-borne encephalitis are found in a vast area of ​​the southern part of the forest zone of Eurasia, from the Mediterranean to the Pacific Ocean. The main carriers of the pathogen are taiga and dog ticks, and another 10 species of ticks are involved in the circulation of the virus in outbreaks. The main hosts and feeders of larvae and nymphs (the main carriers) are bank voles and shrews. Infection control and prevention measures in areas of tick-borne encephalitis are reduced to vaccination of people working in the forest; to individual protection of people from tick attacks through regular inspections of clothing and body after 2-3 hours of work in the forest, wearing special clothing, and using repellents; to exterminate ticks in forests by spraying pesticides from airplanes.

The group of natural focal diseases caused by rickettsia includes tick-borne rickettsiosis of North Asia, in which ticks of the genus Dermacentor are carriers and long-term keepers of rickettsia (the disease is widespread from the Urals to the Pacific Ocean). The same group of diseases includes Marseilles tick fever, the carrier and custodian of which are the ticks Rhipicephalus sanguineus, which parasitize dogs. Ixodid ticks are also capable of maintaining the circulation of the tularemia microbe in natural foci of tularemia. Ticks Boophilus calcaratus are also very important from a veterinary point of view - they are the main carriers of piroplasmosis in cattle.

Argas mites (family Argasidae from Ixodoidca) have a different type of life cycle. These are inhabitants of shelters and pores, common in our country in the deserts and semi-deserts of Central Asia, Kazakhstan and Transcaucasia. They are capable of repeatedly sucking blood in adulthood and fasting for a long time (in experiments up to 8 years). Development takes place with a succession of a large number of nymphal stages (3-5), and the entire cycle can drag on for many years (up to 15-23 years). Argasid ticks can serve as a source of human infection with tick-borne relapsing fever. Persistent foci of this infection in nature are confined to the habitats of tick vectors: caves, grottoes, pores of various mammals that feed ticks. The main vector of tick-borne relapsing fever spirochetes, the tick Ornithodoros papillipes, is often found in livestock buildings and in adobe or stone human dwellings, where local persistent foci of the disease can occur. Ticks attack prey (animals or humans) mainly at night and quickly suck blood. Ticks are capable of storing and transmitting spirochetes pathogenic to humans throughout their lives (up to 18 years).

One of the types of argasid mites - the Persian mite (Argas persicus) - parasitizes poultry and spreads avian spirochetosis among them, causing the death of chickens.

Scabies mites constitute a separate group of mites. Without being carriers of certain diseases, they themselves are the direct culprits of suffering for humans and animals. These mites include various scabies, including human scabies (Sarcoptes scabiei). Fertilized females of this mite, about 0.3 mm in size, penetrate the stratum corneum of the epidermis of human skin and gnaw passages up to 15 mm in length. The introduction of ticks occurs in places with the thinnest skin: between the fingers, on the inside of the bends of the limbs, under the armpits, etc. Here the female lays eggs. The egg develops for 3-3.5 days, and a larva emerges from it, followed by two nymphal stages, and finally an adult tick emerges. The larvae and nymphs do not gnaw through the tunnels themselves, but live in the females’ tunnels. Males gnaw short passages. After the females are fertilized, they die. The entire cycle lasts about 40 days.

Scabies is a very painful and debilitating disease. Once started, it causes great suffering to a person and reduces his performance. In addition, skin damage and inevitable scratching can serve as a gateway to various infections. Humans can also be affected by itching of domestic animals: horses, dogs, pigs, rabbits. Scabies is treated by rubbing in various ointments, using solutions that kill itches and in which animals are bathed, etc.

In conclusion of the review of the harmful activities of various groups of mites, it is necessary to dwell on mites - pests of cultivated plants and grain stocks. Significant damage to agriculture is caused by a large group of pests of vegetable gardens, orchards, cotton and greenhouse crops - tetranychids, or spider mites. These are very small forms (0.2-1.0 mm) with arachnoid glands located in the pedipalps. Ticks suck plant juices from leaves and, when multiplying en masse, greatly weaken and destroy the latter. The most harmful is the widespread common spider mite (Tetranychus telarius). The web protects the ticks themselves and their clutches and greatly complicates the fight against them.

Close to tetranych mites is a group of gall-forming, or four-legged, mites (family Eriophyidae). Microscopically small (0.1-0.2 mm), worm-like mites suck the juices of various plants, which causes the growth of affected plant tissues and organs. This is how galls appear. Living in galls, these mites switched to reproduction in the early stages of development - to neoteny. They do not reach the adult phase, since only two front pairs of legs are developed, and the back two are not formed.

Many species harm cultivated plants: grape felt mite (Eriophyes vitis), currant bud mite (E. ribis), etc.

The group of barn pests is represented by thyroglyphoid mites. These are soil dwellers that feed on rotting vegetation and are capable of reproducing quickly. Thyroglyphoid mites have a persistent hypopus stage, which helps them survive unfavorable conditions and spread widely. With grain, hypopuses end up in granaries and elevators. If the grain moisture content exceeds 17%, the hypopus molts and turns into active mites, which begin to multiply intensively. Ticks eat the germs in grains, thereby reducing their germination, eating and spoiling grain and grain products, causing great damage. The most harmful pest of grain is the flour mite (Tyroglyphus farinae). In the same group of mites there are pests of cheese, wine, dried fruits, etc. (cheese mites, etc.).

Danger to humans

Spiders attack only in case of danger, protecting themselves. A small number of spiders can cause mortal harm to a person, however, a person may develop an allergy to the bite of the most harmless spider. And poisonous representatives can significantly harm health. These animals often live near people. Therefore, there is a risk of getting bitten. You can accidentally disturb them simply by taking out old things.

It is worth remembering that spiders are quite intelligent creatures. They will not attack without a reason. They greatly help people in the fight against insect pests.

Common signs of insects and spiders

Insects and spiders belong to the same phylum of arthropods. Arthropods have the following external characteristics:

1. The body is divided into sections.
2. The limbs are articulated and are the main organs of movement. They are movably connected to each other. Animals are capable of a variety of movements.
3. The chitinous cover protects the body of the arthropod; it also covers the limbs. It protects against mechanical damage, does not allow water to pass through (prevents evaporation in terrestrial arthropods, prevents water from entering the body in aquatic organisms), and also serves as an exoskeleton (muscles are attached to it).
4. Presence of shedding. Due to the fact that the chitinous cover does not stretch.