General characteristics of insect orders. General characteristics of insect orders with complete metamorphosis Some more species of individuals with incomplete metamorphosis

No living being is born into the world in vain. And even in relation to mosquitoes and insects, this statement is true. But there are so many of them - a whole table. Squads of insects, however, also in their own way bring both benefit and harm. Their features will be discussed today.

The fantasy of nature is limitless

It is not easy to classify all the insects that exist on our planet. And all because it is the most numerous group of organisms. Moreover, its diversity is so great that systematic entomologists have to do a tremendous job of distributing all this crawling, flying and jumping diversity into groups and classes.

Usually used to facilitate the recording and sorting of the characteristics possessed by insect orders, table. It is not surprising that it is so easy to get confused, because in nature there are more than a million varieties of individuals, and from 3 to 10 thousand new species are added annually, not yet included in the "registry" and not yet known to science.

Live and breed even in the cold

The greatest number of discoveries falls to the share of little-studied and insect-rich tropical regions. But oddly enough, in cold places, for example, in the north of our country, there are also a lot of them, judging by the list growing every year. And therefore, using various groups, subsections, and so on, scientists are trying to bring this numerous brethren to a system that is understandable for study. For example, the biology table (grade 7) "Insect Squads" subdivides all new species according to common features which are listed below.

List for compiling characteristics

1. body segmentation.
2. Mouth organs.
3. Limbs.
4. The presence of a molt.
5. Sections of the body.
6. Symmetry.
7. Ways of movement.
8. Development of the sense organs.
9. Separate cavity.
10. Development.
11. Circulatory system.
12. Having a heart.
13. The number of wings.
14. Nervous system.
15. Respiratory system.
16. excretory organs.

For such an impressive species diversity insects for several reasons. And first of all, it should be noted that, having a typically terrestrial organism, as can be seen even from the points classifying insect orders (table, class 7), they are perfectly adapted to the living conditions of land.

Causes of a large-scale species extravaganza

The entire life organization of insects is closely intertwined with protection from drying out and rational economy moisture. The surface of the integument is like a long time ago known to science, and in only discovered individuals, it is protected by a thin wax-like film called the epicuticle. This is what prevents the evaporation of water. In addition, tracheal respiration in insects is very effective in terms of saving moisture, in comparison with pulmonary respiration. This is explained by the fact that spiracles, and this is how the respiratory openings are called in the representatives of the fauna we are considering, are very small in size and differ in their ability to close.

Protective system

The excretory system, which is considered in the 16th paragraph of the above-mentioned classification of insect orders (class 7 school curriculum), represented by Malpighian vessels. The bottom line is the production of uric acid crystals, which can bind small quantities water.

The anus in insects is distinguished by the presence of special rectal glands that are able to draw moisture from the forming excrement and return it back to the body cavity. In addition, in most individuals, even the eggs they lay are also perfectly protected from moisture loss. Conclusion: insects are perfectly adapted to living in a terrestrial environment, as they easily cope with one of the most important tasks - protection from drying out.

Stormy evolution

The ancestors of modern insects were already terrestrial organisms, and therefore there are no inhabitants of the seas and oceans among them. There is, of course, a part of insects that is associated with fresh water bodies, where the larvae laid by them develop. These include caddisflies, mayflies, dragonflies, stoneflies, and some other species of beetles and Diptera. But scientists believe that this is just a secondary connection with aquatic environment. And their formation as a class itself took place about 350 million years ago (Devonian period). Rapidly proceeding evolution allowed them already in the next, Carboniferous period to form all modern and adapted to the environment (as the table indicates) orders of insects.

Influence of plant evolution

The process of evolution in all these jumping-flying and biting hordes is closely intertwined with the time of plant development. When some mastered the land, others settled further from the drive areas, conquering the hills. The Cretaceous period, marked by the appearance of flowering plants, also marked the close relationship between insects and plants. They pollinate the majority of modern flowering representatives of the flora.

And for the class of phytophages, this particular plant species is the main food object. The features of the insect orders, the table of which is presented in the article, their formation and differentiation as separate groups occurred during the period of transition from living in the soil to living on hills, which is what the emergence of flight is associated with.

Fly - don't crawl

If we consider all invertebrates, then only the class of insects acquired wings and mastered air environment. It is clear that the flight is not comparable in efficiency with movement on land. This is an opportunity to choose the most attractive place from above and, moreover, a significant saving of forces. For example, scientists have calculated that a bee spends an amount of energy equal to a flight of 78 meters for a 3-meter walk. Agree, a noticeable difference. In general, the very ability of insects to settle over long distances can impress anyone. Even the Bible describes cases of global migrations migratory locust. Surprisingly, this species is able to cross the Mediterranean Sea with ease, their hordes have been seen from ships at a distance of at least 1000 km from land. And laboratory tests and experiments show that locusts can spend 6 days in flight without landing for a second, while rotating a small mini-carousel to which they are tied with a thread.

Traveler

Of those individuals described in the table "Orders of Insects", perhaps the most famous American migratory butterfly, called the monarch, occupies a leading position. This representative of the species makes regular flights from America to Mexico for the winter, after which it returns to its homeland ready to breed.

Separate specimens of monarchs were found even on the coast of England and France. There they were carried away by air currents, which is why they had to cross the Atlantic Ocean.

The main and main orders of insects (table)

The class of insects includes up to 40 orders, which, in turn, are divided according to the type of development into 2 separate groups:

1. Units with full transformation.
2. Orders of insects (table below) with incomplete transformation.

Group of units with full transformation

Now let's pay attention to how the table classifies insect orders with complete metamorphosis. This group includes Coleoptera, Diptera, Lepidoptera, Hymenoptera and Fleas.

Some more species of individuals with incomplete transformation

The most common individuals representing the orders of insects with incomplete transformation, the table of which is presented above, are red cockroaches. These individuals help people, hinting that it is time to pay attention to your home. Their appearance in dwellings has always been considered a sign of carelessness. Cockroaches quietly come out of their hiding places at night and feed on leftover food left on the tables, crumbs and carelessly stored food, while polluting them.

termites

This order includes insects living in large families. These are organized communities in which there is a dividing labor hierarchy - from simple workers to a female queen. The nests of these individuals, called termite mounds, are, as a rule, large sizes sometimes even quite significant.

For example, their height in African savannas reaches 10-12 m, and the diameter of the underground base can reach up to 60 m. Termites eat mainly wood, causing harm wooden buildings. In addition, their diet includes agricultural plants. To date, approximately 2,500 species of termites are known and recorded. If in the school textbook was included Comparative characteristics orders of insects, a table even for these individuals alone would take up half of its pages.

A little more about beetles

Beetles, or beetles, are the most numerous army among insect orders. Today they number up to 300,000 species. Most of their representatives are large and extremely beautiful. For example, the stag, listed in the Red Book, popularly known as the "stag beetle", reaches a length of up to 8 cm, and its larvae, falling into a favorable development environment - rotten stumps - can stay there for up to 5 years and grow into length up to 14 cm.

The biology table (Grade 7) "Insect Squads" divides these representatives into many more subgroups according to the characteristics given in it. Beetles also live in water bodies, they also differ from each other in size and way of feeding. For example, swimming beetles are predators, and black water beetles are herbivores.

The role of beetles on the planet

Beetles, as already known, are included in the main orders of insects (their table is presented above). They bring both harm and benefit in their own way. The individuals of this group that spoil food products include beetles, which are called "bread grinder" and "pea weevil". The kozheed beetle spoils woolen and leather products. And its small brother, called a pipe-roller, spoils the leaves of plants. In spring, he cuts them to the main vein. Starting to fade, the incised part ceases to be elastic, which is what this beetle needs. Then he folds it in the form of a bag and lays eggs there. Such a folded leaf resembles a small cigar. Such is his nature, so he takes care of the offspring.

But there are beetles that can be called orderlies, because they feed on the rotting remains of plants and living creatures. The names of these representatives correspond to their functions: coffin and gnoevik. Here is a characteristic of insect orders. A table of such individuals is compiled by scientists separately. Because such representatives can be used to strike a balance where harmful insects too much has bred, and this poses a threat to the future harvest. For example, ladybugs destroy aphids, and beetles kill caterpillars.

Diversity in nature

What kind of individuals does not study biology! Table "Squads of insects" - brightest to that example. It was impossible even to imagine the existence of such a generous variety. For example, butterflies, or Lepidoptera, are distinguished by the magnificent coloring of their wings. Among them there are nocturnal representatives living on Far East, whose wingspan is equal to the width of the unfolded notebook. And mulberry and oak silkworms have been bred by people since ancient times in order to obtain silk from their cocoons. Most butterflies are extraordinarily beautiful, for example Apollo, Swallowtail and the like. They represent the class "Insects". Units, the table of which is quite impressive, have their own characteristics. Just remember how attractive a large butterfly called the night peacock eye looks. On its wings there are oval spots resembling an eye.

Conclusion

Insects, no matter what is said about them, are not considered large representatives of the natural world. Many of them benefit by pollinating flowering plants and destroying crop pests. Most of this large brethren have a fairly organized way of life, where the hierarchy is strictly observed. Even those that do not have obvious benefits, still inform us of something by their existence, warn us about something. Perhaps someday all living beings on the planet will learn to understand each other without words, and then the representatives of this class will tell us a lot of interesting things.

Systematic position of the class, division into orders and families.

Insects are the highest invertebrates.

The class has more than 1 million species.

Habitat: soil, air-ground, organisms of other living beings

The body is divided into sections: head, chest, abdomen.

The thoracic region consists of three segments; each carries one pair of legs. Therefore, insects are characterized by the presence of 3 pairs of limbs. The second and third segments, in addition, can carry a pair of wings. In some insects, both pairs of wings are well developed, but wingless insects are also known. The abdomen consists of 6 - 12 segments. The type of complexly arranged oral apparatus of insects is determined by the method of feeding and can be gnawing (beetles), sucking (butterflies), piercing-sucking (lice), licking (flies).

Integuments of the body and muscular system: have a chitinous cover, under which lies a single-layer hypodermal epithelium. The skin is rich in various glands: odorous, waxy, molting, etc. Muscles are striated.

Digestive system: mouth, pharynx, esophagus, goiter, stomach, midgut, hindgut ends with anus. There are salivary glands and a gland that performs the functions of the liver and pancreas. Digestion and absorption of food takes place in the midgut.

Respiratory organs: trachea.

excretory organs: Malpighian vessels and fat body.

Circulatory organs: the circulatory system is not closed, the tubular heart and aorta are located on the dorsal side. Due to the fact that there is an extensive network of tracheae, the circulatory system is poorly developed and lacks the function of an oxygen carrier. Hemolymph circulates through the vessels.

Nervous system: abdominal nerve chain with a strong tendency to concentrate ganglia in the head region, so the supraesophageal ganglion is transformed into a "brain" with three sections (anterior, middle, posterior). There are sense organs: eyes (faceted, but may be simple), balance, taste, touch and smell, in some - hearing.

Reproductive system: insects are dioecious, sexual dimorphism is often expressed. Gonads are paired (ovaries in females, testes in males). Sexual reproduction: with fertilization or parthenogenetic. Development is not direct: with complete metamorphosis (stages: egg - larva - pupa - imago) or incomplete metamorphosis (stages: egg - larva - imago).

The practical importance of insects is very great: pollinators of flowering plants, participate in soil formation processes, etc.

Among insects of medical importance, the following groups are distinguished:

The class Insects is divided into big number detachments.

Spreading: ubiquitous

Morphology: Its body is dorsally flattened and covered with highly extensible chitinous cover. The wings are completely reduced. Bedbugs attack a person at night, and spend the day in shelters - in furniture, behind wallpaper. The saliva of the bed bug contains a poisonous secret, so its bites are painful, the transfer of pathogens of any infectious diseases by the bed bug has not been proven.

Medical and epidemiological significance:

Locally with a bite: hyperemia, swelling, itching, blisters. Absorb for 1 time up to 7 ml of blood. Bed bugs living on birds and mammals can also attack a person - it is possible that viruses that cause psittacosis are transmitted. In tropical countries, bedbugs can transmit trypanosomes and a number of other pathogens.

Prevention : sanitization dwellings.

Insect with complete transformation (with metamorphosis) goes through four stages in its development: egg - larva - pupa - adult insect (adult).

Pay attention!

Orders of insects with complete metamorphosis: butterflies (lepidoptera), beetles (coleoptera), diptera, hymenoptera, fleas.

Most insect species are characterized by development with complete transformation. In insects with complete metamorphosis (butterflies, beetles, flies, wasps, ants), the larvae do not look like adults at all. They lack compound eyes (there are only simple eyes, or organs of vision are completely absent), antennae are often absent, there are no wings; the body is most often worm-like (for example, butterfly caterpillars).

In insects with complete metamorphosis, the larvae often live in completely different places and feed on different food than adult insects. This eliminates competition between different stages the same types.

Insect larvae with complete transformation molt several times, grow and, having reached the limiting size, turn into chrysalis. The pupa is usually immobile. An adult insect emerges from the pupa.

Watch a video that demonstrates the release of the Monarch Butterfly from the chrysalis.

Order Butterflies, or Lepidoptera

Butterflies differ from other insects mainly in two ways: scaly cover of wings and sucking mouthparts coiled up.

Butterflies are called Lepidoptera because they have small chitinous cells on their wings. scales. They refract the incident light, creating a bizarre play of shades.

The coloration of butterflies' wings helps them to recognize each other, camouflages them in the grass and on the bark of trees, or warns enemies that the butterfly is inedible.

The mouthparts of butterflies sucking- this is a proboscis rolled into a spiral. Butterflies feed on the nectar of flowers.

Butterfly larvae (caterpillars) have a gnawing mouth apparatus, they feed on plant tissues (most often).

When pupating, the caterpillars of some butterflies secrete silk threads. The silk thread is secreted by a special silk-separating gland located on the lower lip of the caterpillar.

Detachment Beetles, or Coleoptera

Representatives of this group have dense hard elytra covering the second pair of leathery wings with which they fly. The oral apparatus is gnawing.

Among the beetles there are many herbivores, there are predators and scavengers.

Beetles live in the ground-air environment (on plants, the surface of the earth, in the soil) and in water.

Beetle larvae are both very mobile predators living openly, and inactive, similar to worms, living in shelters and feeding on plants, fungi, and sometimes decaying remains of organisms.

Order Diptera

These insects have only one pair of wings. The second pair is greatly reduced and serves to stabilize the flight. This group includes mosquitoes and flies. They have piercing-sucking or licking mouthparts. Some dipterans feed on pollen and nectar of flowers (syrphid flies), there are predators (ktyrs) and bloodsuckers (mosquitoes, midges, midges, horseflies). Their larvae live in the decaying remains of cesspools, composts ( house flies), in the water (mosquitoes and midges) or lead a vagrant lifestyle and prey on small insects.

Order Hymenoptera

The group includes such well-known insects as bumblebees, wasps, bees, ants, sawflies, riders. They have two pairs of membranous wings (some do not have wings).

Habitat, structure, lifestyle

Insects are the largest class of animals. It includes over 1 million species. Insects live everywhere: in forests, gardens, meadows, fields, orchards, on livestock farms, in human dwellings. They can be found in ponds and lakes, on the body of animals.

The body of insects consists of a head, thorax and abdomen. On the head there are a pair of compound eyes, a pair of antennae, on the chest - three pairs of legs, and most have one or two pairs of wings, on the sides of the abdomen - spiracles.

Insects differ in the shape of the body parts, the size of the eyes, the length and shape of the antennae, and other features. Their antennae, mouth organs, and legs are especially diverse. Some of the insects have lamellar antennae (many beetles), others are filiform (grasshoppers), others are pinnate or club-shaped (butterflies), etc. like butterflies, etc. The hind legs of grasshoppers are jumping, those of swimming beetles are swimming; The front legs of the bear are digging. All these and other structural features have developed in insects in connection with adaptation to certain living conditions.

Rice. Bombardier (beetle). Family - ground beetles

Peculiarities internal structure insects are associated mainly with the respiratory, excretory and nervous systems. The respiratory organs of insects - the trachea - are highly branched. In small insects, gas exchange occurs by diffusion. large insects ventilate the trachea (when the abdominal walls relax, air is sucked into the trachea, and when it contracts, it exits into external environment). The excretory organs of insects are numerous tubules, the free ends of which are closed. The excretory products that enter them drain into the posterior intestine. Insects have fat cells with a margin nutrients and water. They also deposit some substances that are unnecessary for the body.

Differences in the nervous system of insects are associated with enlargement of the supraesophageal ganglion (it is often called the brain), a decrease in the number and enlargement of the nodes of the abdominal nerve chain. A more complex structure of the nervous system is manifested in the complexity of the behavior of insects. A bee, for example, having found flowering nectar-bearing plants, upon returning to the hive, crawls on the combs, "dances", describing certain figures, by which other bees set the direction to the place of honey collection. Ants close the entrances to the anthill at night, bring wet needles to the surface, and after drying they drag them deep into the anthill.

Types of insect development

Insects are dioecious animals. In some insects (locusts, bugs), from fertilized eggs laid by females, larvae develop that look like adults. Eating intensely, they grow, molt several times and become adult insects. In other insects (butterflies, beetles, flies), the larvae are not similar in appearance and nutrition to adults. The larvae of the cabbage butterfly, for example, are worm-like and feed not on nectar, like butterflies, but on cabbage leaves. Their oral apparatus is not sucking, but gnawing. After a few molts, the caterpillars turn into pupae that do not feed and do not move, but complex changes occur under their chitinous cover. After some time, the cover of the body of the pupa bursts and an adult insect emerges from it.

Development that occurs in three phases, and insect larvae at the same time look like adults, is called incomplete transformation. The development of insects, which proceeds in four phases (including the pupal phase), and the larvae do not look like adults, is called complete transformation.

Development with transformation enables insects to survive under adverse living conditions ( low temperature, lack of food) at one or another less vulnerable stage of development. BIGGEST BENEFITS possess insects with complete metamorphosis. Their larvae do not compete with adults: they usually use different food and develop in other habitats.

Major orders of insects

In the class of insects, from 30 to 40 orders are distinguished. The largest of them are the orders of Orthoptera, Homoptera, Hemiptera, Coleoptera, Lepidoptera, Hymenoptera, Diptera.

Squads of insects with incomplete metamorphosis. The Orthoptera order includes locusts, grasshoppers, crickets, and bears. They are characterized by gnawing mouthparts, two pairs of longitudinally veined wings, and a (usually) hopping hind pair of legs. Many orthopterans make and perceive sounds (in grasshoppers, the sound apparatus is located on the front wings, and the auditory apparatus is on the shins of the front legs). Their antennae are filiform. The females of many species have an ovipositor. The order Homoptera includes aphids, cicadas, etc., feeding on plant sap, having a piercing-sucking proboscis and 2 pairs of transparent wings.

The order Hemiptera, or bugs, includes terrestrial and aquatic insects with piercing-sucking mouthparts, two pairs of wings (semi-rigid upper and membranous lower), highly developed odorous glands. Of the representatives of this order, the most common are green forest bugs, long-legged water strider bugs. The bed bug, which feeds on the blood of people and animals living in human housing, belongs to the same detachment.

Squads of insects with complete metamorphosis. The order Coleoptera, or beetles, includes insects with rigid anterior wings and membranous hind wings. In most beetles at rest, the rigid wings completely cover the membranous and protect them from damage. The mouthparts of beetles are gnawing. The Coleoptera order includes May beetles, ground beetles, ladybugs, weevils.

Butterfly Papilio demoleus. Photo: Jeevan Jose

For the vast majority of insects of the order Lepidoptera, or butterflies, two features are characteristic: a scaly cover on two pairs of wings and a sucking mouth apparatus, usually coiled. The antennae of diurnal butterflies are usually club-shaped, those of nocturnal butterflies are feathery. Worm-like butterfly larvae (caterpillars), in addition to three pairs of jointed legs, have false legs - outgrowths of the body. Caterpillars have chewing mouthparts.

Diptera - flies, mosquitoes, horseflies, etc. - have one pair of membranous wings. The hind wings are transformed into flask-shaped organs - halteres. Mouthparts of Diptera are piercing-sucking or licking. The larvae do not have legs. They develop in water, soil, in the decaying remains of plants, living animals and corpses.

Insects are the most numerous class of animals, there are more than 1 million species. There are about 40 orders of insects, which are divided into two groups - insects with incomplete transformation and insects with complete transformation.

Examples of insect orders with incomplete metamorphosis are orthoptera, homoptera, and hemiptera. Examples of orders with complete metamorphosis are Coleoptera, Diptera, Lepidoptera, Hymenoptera.

Features of the order Orthoptera

Representatives: grasshoppers, locusts, crickets.

• Gnawing mouth apparatus.
• The wings of the first pair are narrow with longitudinal venation, the wings of the second pair are fan-shaped.
• Hind legs jumping type (not all).
• Many can make sounds and perceive them (grasshoppers make sounds with their front wings, and the hearing organ is on their feet).

Features of the order Homoptera

Representatives: aphids, suckers, shield insects.

Aphids live on the shoots of trees, shrubs and grasses, forming clusters. There are usually a lot of suckers on the leaves of fruit trees.

• They feed on plant sap.
• A piercing-sucking mouthpart with a proboscis.
• Two pairs of soft transparent wings (not all).

Features of the order Hemiptera (bugs)

Representatives: green forest bugs, water strider bugs, bed bugs.

• They lead a terrestrial or aquatic lifestyle.
• Piercing-sucking mouthparts.
• A pair of semi-rigid upper wings and a pair of membranous lower wings.
• Developed odorous glands.

Features of the order Coleoptera (beetles)

Representatives: ladybugs, weevils, dung beetles, ground beetles, May beetles.

• Rigid forewings protect the hind wings from damage.
• Mouth apparatus gnawing type.

Features of the order Diptera

Representatives: flies, mosquitoes.

• One pair of membranous wings. The hind ones are modified into halteres.
• Mouth-apparatus piercing-sucking or licking.

  Characteristics of the insect squad

• Legless larvae that develop in soil, water, plant and animal remains.

Features of the order Lepidoptera (butterflies)

• Scale cover of wings.
• The sucking mouthparts are coiled.
• Cirrus (in nocturnal) or club-shaped (in diurnal butterflies) antennae.
• Butterfly larvae are caterpillars.

  They have outgrowths of the body - false legs. Mouth apparatus gnawing type.

Features of the order Hymenoptera

Representatives: bees, wasps, ants, riders.

• Two pairs of membranous transparent wings.
• Mouth apparatus gnawing or licking.
• Females have an ovipositor at the end of the abdomen, which in some species is turned into a sting and is associated with venom glands.
• Worm-like, most often legless, larvae.

Detachment Coleoptera, or beetles

The front wings, or elytra, are very rigid and strong.

They cover the upper side of the abdomen and the membranous wings of the second pair located here. It is these membranous wings that are used for flight.

They are slightly longer than the elytra and are folded and hidden under them when at rest.

The mouth organs of beetles are of the gnawing type. The main tools for crushing food are the upper jaws, often called mandibles, or mandibles. Sometimes they turn into ornaments, reaching extraordinary development in males ( bug—deer).

The elytra and wings of beetles are attached to the mesothorax and metathorax. The prothorax forms a wide ring, top part which is called the pronotum.

From below, three pairs of legs are attached to the three thoracic segments, which are extremely diverse in beetles. Usually they are long, running, in aquatic forms - swimming, in those living in the soil - digging; sometimes the hind legs increase in size, their thighs thicken - the legs become jumpy. The legs end with paws, the segments of which bear pads from below, and in some species - suckers.

Beetles are fully metamorphosed insects that lay eggs after mating.

The larvae emerge from the eggs, the body of which consists of 3 thoracic and 10 abdominal segments. The development of larvae is completed in a few months, rarely stretches for three to five years. Further, the larva turns into a pupa, and from a pupa into an adult insect.

This order includes beetles that damage a wide variety of cultivated plants ( Chafer, bread beetle, clickers, whose larvae are called wireworms, Colorado beetle , apple beetle), forest plants ( beetles—bark beetles, beetles—lumberjacks,); beetles destroy food barn weevil, bread fleas).

Predatory bugs destroy pests Agriculture (ground beetles, ladybugs), beetles that eat animal excrement and dead parts of plants are of great sanitary importance ( beetles—dung beetles) and animal carcasses ( beetles—dead eaters). Some beetles have moved to life in fresh water ( beetles—swimmers, beetles—water lovers).

Over 30 thousand species.

Lepidoptera order, or butterflies

Of all insects, butterflies are the most famous. The most important sign detachment - they are covered with scales, the structure and location of which determine the quirkiness and variety of colors. Therefore, butterflies are called Lepidoptera.

Insects. Troops Dragonflies, Mayflies

Scales are modified hairs. Along the edge of the wing are very narrow scales, almost like hairs. Closer to the middle they are expanded, but their ends are sharp. And even closer to the base of the wing, wide scales sit in the form of a flattened, hollow pouch attached to the wing by means of a short stalk.

The scales are arranged on the wing in regular rows across the wing: the edges of the scales face the lateral margin of the wing, and their bases are covered in a tiled manner by the ends of the previous row.

Usually, all four wings are developed in Lepidoptera; however, in females of some species, wings may be underdeveloped or absent altogether.

The forewings are always larger than the hindwings. In many species, both pairs of wings interlock with each other using a special hook, or “bridle”.

The mouthparts are sucking. They are represented by a soft proboscis that can coil and unfold like a clock spring. The basis of this oral apparatus is made up of strongly elongated inner lobes of the lower jaws, which form the flaps of the proboscis. The proboscis is elastic and mobile.

Lepidoptera are insects with complete metamorphosis.

Their larvae are very diverse in shape. Butterfly larvae are called caterpillars, their body consists of a head, 3 thoracic and 10 abdominal rings. They use a silky thread to build a cocoon, inside which pupation takes place.

And only after a few weeks the butterflies fly out.

This group includes silkworm, leaf rollers, glassware, moth, scoops, pigeons, cabbage, moths, hawk moths and others. About 140 thousand species.

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All about insects

Insect - what does this name mean? It says that his torso is divided into parts. Insecta is a Latin word that literally means "divided, dissected." Russian word"Insects" is also explained by the fact that the wasp's body is divided into three segments (parts of the body) - notches.

Class Insects, their orders, main features and significance (Table)

The ancient Greek word entomon, with a similar meaning "divided", is preserved in the name of the science of insects - entomology. The scientific name of species is based on the principle of binary nomenclature: genus name + species name. For example, the name of the honey bee is made up of the name of the genus Apis and the name of the species mellifera. Thus, the scientific name of the honey bee is Apis mellifera.

In the tropics there are many species of insects, but in Europe there are currently at least 30,000 species.

In order to somehow understand this diversity, biologists 200 years ago began to systematize knowledge about animals, based on their typical features. Similar to each other and capable of reproduction, they attributed to the same species. Species that had a common ancestor and are thus related were grouped into genera.

Many genera form a family, several families - a detachment, several orders - a class, classes are combined into types, which, in turn, belong to the animal kingdom. Thus, each species gets its own place in the natural system.

In 2002, scientists discovered an unknown insect in the rocky canyons of Namibia. It looked like a cross between a praying mantis, an Annam stick insect, and a grasshopper. Shortly before this, similar insects were discovered in amber that had solidified 45 million years ago; they were classified as extinct species.

Squads of insects

At present, the class of insects is subdivided into more than 30 orders.

At the same time, the orders of cockroaches, zorapters and large-winged ones include less than a hundred species, hymenoptera, butterflies and beetles - more than a hundred thousand species. The first two orders are not found in Europe. Representatives of other, less well-known detachments, although they are found in our area, live secretly, and their size is so small that in order to see them, you need a microscope.

The insects presented here can be found during a normal walk in the field and forest.

Fly - mayfly

Mayflies die a few hours after birth; maximum term The life of a fly is a few days.

Adult mayflies do not feed. Their only task now is to find a partner and lay eggs. As larvae, mayflies spend one to three years at the bottom of streams, rivers and lakes. All this time they feed on algae, parts of plants and small invertebrates (crustaceans).

beetles

Coleoptera are the largest order of insects, with over 300,000 species.

They have mastered all spheres of habitat - from earth to fresh water. Among them there are herbivores and predators, some feed on manure and carrion. In beetles, the rigid forewings (elytra) cover the flying hindwings. Usually, before taking off, the beetles raise their rigid elytra and spread their hind wings.

Common silverfish and forktails

In many orders of insects, there are wingless species that have lost wings in the process of evolution.

These are, in particular, forktails and silverfish. Forktails are no more than 1-2 millimeters long, live in the ground, where they feed on rotting plant and animal remains. These insects owe their name to a special jumping fork on the underside of the abdomen. If they are disturbed, they can jump far in an attempt to protect themselves.

The most famous representative of silverfish is the common silverfish, Lepisma saccharina, which can sometimes be found in our kitchens and bathrooms.

Locusts and Grasshoppers

Locusts and grasshoppers need strong hind legs in order to quickly hide from the enemy.

When locusts use their wings, they are able to cover noticeable distances with lightning speed. By their long hind legs, powerful body, strong head and leathery wings, locusts and cicadas are easy to distinguish from other insects.

The Italian locust feeds almost exclusively on plants; true grasshoppers and crickets are omnivores. For them, animal food (insects and their larvae) can make up more than half of the diet.

Characteristics of insect orders with various variations of sucking mouth organs.

Order Diptera (diptera) The external appearance of Diptera is characteristic, primarily due to the reduction of the hind wings, which are turned into short halteres.

However, these are not useless rudiments. covered a large number sensitive receptors, halteres stimulate the nervous system and ensure the rapid activation of the forewings and the launch of Diptera, while at the same time being flight stabilizers.

Diptera usually have a large, often spherical head with large eyes, which in males may touch on the forehead.

The most common orders of insects

Antennae are of two types - multi-segmented in the suborder of long-whiskered dipterans and three-segmented in the suborder of short-whiskered dipterans. Mouth organs are transformed into various proboscis. In those who feed on liquid organic substances, these are sucking or licking-sucking organs, in bloodsuckers they are piercing-sucking.

In connection with the diptera, the mesothorax is especially developed.

Noticeable costalization of the wing is observed; thickening of the anterior veins and shifting them to the anterior margin. The flight of Diptera is very perfect, especially in hoverflies, with a quick start and hovering in the air.

Mosquitoes can make up to 1000 wing beats per second, although they fly relatively slowly.

Diptera larvae are legless and rarely have false ventral limbs. In long-whiskers with a separate head, however, in most fly larvae, the head capsule is reduced, and the oral appendages are represented by a pair of retractable hooks. Pupae are free, or in a false cocoon - puparia. When the fly emerges from the puparium, its shell at the top is either torn longitudinally (in straight-sutured dipterans) or in a circle, and folds back in the form of a small lid (in round-sutural dipterans).

Order Hymenoptera (Hymenoptera). This order includes both rather primitive sawflies, whose caterpillars, similar to butterfly caterpillars, feed on plants, and insects with the most highly organized nervous system and extremely complex biology - ants, bees and wasps.

Adult insects have two pairs of membranous wings covered with relatively sparse veins, and small forms are usually almost or completely devoid of venation. The hind pair of wings is smaller and is of secondary importance in flight.

In living insects, both pairs of wings are usually fastened with hooks to each other and work as a single plane. The mouthparts are gnawing or licking-gnawing. In the latter case, the lower lip and lower jaws are extended and form a proboscis with a tongue at the end.

Such a mouth apparatus serves to suck nectar from flowers. Mandibles are well developed in all species and are used not only for feeding, but also for building nests, digging soil, etc.

d. Antennae are simple, club-shaped, comb-shaped, pinnate, are both straight and geniculate. The tibia and tarsus of the fore leg sometimes bear a special apparatus for cleaning the antennae and tarsi, formed by a pectinate spur at the end of the tibia and a notch on the first segment of the tarsus.

Lepidoptera, or butterflies (Lepidoptera) differ from other orders of insects in such features as sucking mouth organs that look like a thin, coagulating proboscis, a colored scaly cover of the wings, as well as development with complete transformation, i.e.

the presence in their development of a caterpillar, which is a worm-like larva, and a pupae.

The smallest scales located on the wings of butterflies served as the basis for assigning the name to the detachment of these insects - "Lepidoptera", since they are their main distinguishing feature.

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Habitat, structure, lifestyle

Insects are the largest class of animals. It includes over 1 million species. Insects live everywhere: in forests, gardens, meadows, fields, orchards, on livestock farms, in human dwellings. They can be found in ponds and lakes, on the body of animals.

The body of insects consists of a head, thorax and abdomen. On the head there are a pair of compound eyes, a pair of antennae, on the chest - three pairs of legs, and most have one or two pairs of wings, on the sides of the abdomen - spiracles.

Insects differ in the shape of the body parts, the size of the eyes, the length and shape of the antennae, and other features. Their antennae, mouth organs, and legs are especially diverse. Some of the insects have lamellar antennae (many beetles), others are filiform (grasshoppers), others are pinnate or club-shaped (butterflies), etc. like butterflies, etc. The hind legs of grasshoppers are jumping, those of swimming beetles are swimming; The front legs of the bear are digging. All these and other structural features have developed in insects in connection with adaptation to certain living conditions.

Rice. Bombardier (beetle). Family - ground beetles

Features of the internal structure of insects are mainly associated with the respiratory, excretory and nervous systems. The respiratory organs of insects - the trachea - are highly branched. In small insects, gas exchange occurs by diffusion. Large insects ventilate the trachea (when the abdominal walls relax, air is sucked into the trachea, and when contracted, it goes out into the external environment). The excretory organs of insects are numerous tubules, the free ends of which are closed. The excretory products that enter them drain into the posterior intestine. Insects have fat cells with a supply of nutrients and water. They also deposit some substances that are unnecessary for the body.

Differences in the nervous system of insects are associated with enlargement of the supraesophageal ganglion (it is often called the brain), a decrease in the number and enlargement of the nodes of the abdominal nerve chain. A more complex structure of the nervous system is manifested in the complexity of the behavior of insects. A bee, for example, having found flowering nectar-bearing plants, upon returning to the hive, crawls on the combs, "dances", describing certain figures, by which other bees set the direction to the place of honey collection. Ants close the entrances to the anthill at night, bring wet needles to the surface, and after drying they drag them deep into the anthill.

Types of insect development

Insects are dioecious animals. In some insects (locusts, bugs), from fertilized eggs laid by females, larvae develop that look like adults. Eating intensely, they grow, molt several times and become adult insects. In other insects (butterflies, beetles, flies), the larvae are not similar in appearance and nutrition to adults. The larvae of the cabbage butterfly, for example, are worm-like and feed not on nectar, like butterflies, but on cabbage leaves. Their oral apparatus is not sucking, but gnawing. After a few molts, the caterpillars turn into pupae that do not feed and do not move, but complex changes occur under their chitinous cover. After some time, the cover of the body of the pupa bursts and an adult insect emerges from it.

Development that occurs in three phases, and insect larvae at the same time look like adults, is called incomplete transformation. The development of insects, which proceeds in four phases (including the pupal phase), and the larvae do not look like adults, is called complete transformation.

Development with transformation makes it possible for insects to survive under unfavorable living conditions (low temperature, lack of food) at one or another less vulnerable stage of development. Insects with complete transformation have the greatest advantages. Their larvae do not compete with adults: they usually use different food and develop in other habitats.

Major orders of insects

In the class of insects, from 30 to 40 orders are distinguished. The largest of them are the orders of Orthoptera, Homoptera, Hemiptera, Coleoptera, Lepidoptera, Hymenoptera, Diptera.

Squads of insects with incomplete metamorphosis. The Orthoptera order includes locusts, grasshoppers, crickets, and bears. They are characterized by gnawing mouthparts, two pairs of longitudinally veined wings, and a (usually) hopping hind pair of legs. Many orthopterans make and perceive sounds (in grasshoppers, the sound apparatus is located on the front wings, and the auditory apparatus is on the shins of the front legs). Their antennae are filiform. The females of many species have an ovipositor. The order Homoptera includes aphids, cicadas, etc., feeding on plant sap, having a piercing-sucking proboscis and 2 pairs of transparent wings.

The order Hemiptera, or bugs, includes terrestrial and aquatic insects with piercing-sucking mouthparts, two pairs of wings (semi-rigid upper and membranous lower), highly developed odorous glands. Of the representatives of this order, the most common are green forest bugs, long-legged water strider bugs. The bed bug, which feeds on the blood of people and animals living in human housing, belongs to the same detachment.

Squads of insects with complete metamorphosis. The order Coleoptera, or beetles, includes insects with rigid anterior wings and membranous hind wings. In most beetles at rest, the rigid wings completely cover the membranous and protect them from damage. The mouthparts of beetles are gnawing. The Coleoptera order includes May beetles, ground beetles, ladybugs, weevils.

Butterfly Papilio demoleus. Photo: Jeevan Jose

For the vast majority of insects of the order Lepidoptera, or butterflies, two features are characteristic: a scaly cover on two pairs of wings and a sucking mouth apparatus, usually coiled. The antennae of diurnal butterflies are usually club-shaped, those of nocturnal butterflies are feathery. Worm-like butterfly larvae (caterpillars), in addition to three pairs of jointed legs, have false legs - outgrowths of the body. Caterpillars have chewing mouthparts.

Diptera - flies, mosquitoes, horseflies, etc. - have one pair of membranous wings. The hind wings are transformed into flask-shaped organs - halteres. Mouthparts of Diptera are piercing-sucking or licking. The larvae do not have legs. They develop in water, soil, in the decaying remains of plants, living animals and corpses.