"The importance of insects in nature and human life"

1. Abundance of insects

Insects are the most numerous class of animals; more than a million species are known. Calculations made by scientists have shown that about 1017 (100000000000000000) insects live on Earth at the same time. Due to their abundance, insects play a very important role in nature and in human life.

In addition to the studied orders of insects, the most common in nature are beetles, or Coleoptera, which have rigid fore wings. Based on the nature of their diet, they are divided into three main groups. Firstly, they are predators that feed on various small animals, mainly insects.

Such are, for example, brightly colored ladybugs. Some ladybugs are bred in laboratories and released into greenhouses and gardens to combat aphids that damage agricultural plants. Secondly, they are consumers of decomposing plant and animal residues. These include, for example, carrion eaters and gravediggers, who use animal corpses as food. Their larvae also feed on the same food. They are among nature's orderlies: without them, animal corpses would decompose and contaminate the surrounding area. Thirdly, these are herbivorous beetles, consuming all kinds of plant parts, including wood. This includes, for example, the cockchafer and other beetles and leaf beetles. The leaf beetle, the Colorado potato beetle, settles en masse on potatoes, often eating all the tops on the bushes. It was brought to Europe and our country from North America. There are more than 300,000 species of beetles known on Earth.

2.The importance of insects in nature

The life of many insects is closely related to the life of plants. Bumblebees, bees and flies pollinate flowering plants.

An important link in food chains.

A huge army of these arthropods feeds on leaves, roots, stems and other organs and parts of plants, fruits and seeds, limiting their growth and development.

Soil-forming role of insects.

They feed on other insects and limit their numbers.

Biological suppression of insect pests.

Food for other animals: fattening up on plant foods, they themselves become prey for other animals.

Aesthetic meaning: beautiful forms evoke feelings of joy and admiration.

By destroying corpses and manure, they perform a sanitary role.

Insects make up about 80% of all animals on Earth; according to various estimates, there are from 2 to 10 million species of insects in the modern fauna, of which just over 1 million are known so far. Actively participating in the cycle of substances, insects play a global planetary role in nature.

More than 80% of plants are pollinated by insects, and it is safe to say that a flower is the result of the joint evolution of plants and insects. The adaptations of flowering plants to attract insects are varied: pollen, nectar, essential oils, aroma, shape and color of the flower. Adaptations of insects: sucking proboscis of butterflies, gnawing-licking proboscis of bees; special pollen-collecting apparatus - in bees and bumblebees there is a brush and a basket on the hind legs, in megachila bees - an abdominal brush, numerous hairs on the legs and body.

Insects play a huge role in soil formation. Such participation is associated not only with loosening the soil and enriching it with humus by soil insects and their larvae, but also with the decomposition of plant and animal residues - plant litter, corpses and animal excrement, while simultaneously fulfilling a sanitary role and the circulation of substances in nature.

The following types of insects perform a sanitary role:

· coprophagous - dung beetles, dung flies, cow flies;

· necrophages - carrion beetles, gravediggers, skin beetles, meat-eating flies, carrion flies;

· insects - destroyers of dead plant debris: wood, branches, leaves, pine needles - borer beetles, longhorned beetle larvae, golden beetles, horntails, long-legged mosquitoes, carpenter ants, fungus gnats, etc.;

· insects - orderlies of reservoirs feed on suspended or settled rotting organic matter (detritus) - the larvae of mosquitoes, or bells, mayflies, caddis flies, purify the water and serve as a bioindicator of its sanitary condition.

3. Soil-forming role of insects

In the process of their life activity, insects enrich the soil with organic and mineral substances. The larvae of beetles, butterflies and flies living in the soil take part in loosening the soil and mixing its layers.

A significant number of insects (beetles, ants, etc.) live in the soil, which have a significant impact on the soil-forming process. By making numerous moves in the soil, they loosen the soil and improve its physical and water properties. Insects, actively participating in the processing of plant residues, enrich the soil with humus and minerals.

.Plant pollinators

Many flowering plants cannot exist without insect pollination.

The most important in the development of the evolution of entomophilous plants were the most diverse representatives of Hymenoptera, in particular bees. Bees have retained their leading role in cross-pollination of plants cultivated by humans.

Not all insects that visit flowers for nectar are useful for cross-pollination. Insects such as beetles, bedbugs, aphids and others, although they feast on nectar, do more harm to plants than good.

Butterflies play a very minor role in the pollination of flowers, and among the hymenoptera, short-proboscis wasps, glitterworts, gall moths, wasps and sawflies. Among wild representatives of the entomofauna, bumblebees, solitary bees, certain species of true wasps and flower flies are of significant importance as pollinators. Moreover, each of these groups is of interest for pollinating plants of certain species. For example, long-proboscis bumblebees are more successful than other insects in pollinating red clover flowers. Some representatives of solitary bees are well adapted to opening flowers and pollinating alfalfa. Flower flies are most successful at pollinating carrot seeds. However, the number of wild insects changes dramatically from year to year, not to mention the fact that due to the plowing of borders, empty lands and the massive introduction of chemical measures to combat pests and plant diseases, the number of wild pollinators is sharply declining. Currently, especially in areas of intensive agriculture, their role as pollinators is reduced to almost zero.

The main role in the pollination of agricultural entomophilous crops belongs to honey bees, whose structure and lifestyle in the process of evolution are best adapted to perform this function. They live in large families, the number of which reaches several tens of thousands during the flowering period of the most important honey plants.

Each bee colony spends about 200 kg of honey and about 20-25 kg of plant pollen on its nutrition and raising brood throughout the year. To collect such an amount of honey, bees from each colony must visit over 500 million flowers, each of which contains 0.5 mg of nectar. Almost the same number of flower visits are required to collect pollen. Thus, a strong bee family visits over a billion flowers per season - this is the real amount of pollinating work of each strong family during the year. No other insect species can compare with the honey bee in terms of the amount of pollinating work it does. But it's not just about quantitative indicators. It is very important that honey bees spend the winter in large families. In the spring, when the number of wild pollinating insects is very small (in a bumblebee family, for example, only the queen remains), and the bee family can send a 10,000-strong army of flying bees to collect nectar and pollen, the number of which increases as the number of flowering plants increases is increasing every day.

While many species of solitary bees are monotrophic insects (they visit the flowers of plants of only one genus or species) or oligotrophic (they visit the flowers of several species of the same family), the honey bee, as a polytrophic insect, collects nectar and pollen from all entomophilous plants available to it, belonging to different families, genera and species. At the same time, worker bees quickly switch to visiting entire tracts of plants of one or another species during the period of their mass flowering, that is, at the time of greatest need for pollinators. To load the honey crop in one flight, the bee must visit 80-150 flowers, depending on the nectar productivity of the plants. The bee must visit the same number of flowers to collect pollen and form pollen. Two bee pollen weighing about 15-20 mg contain over 3 million pollen grains. During repeated visits to flowers, thousands of pollen grains of different quality stick to the body of a bee, which is covered with hair, and are transferred on the stigma of the pistils. Moreover, each flower is visited by bees during its life, usually not just once, but many times. This ensures the best conditions for selective pollination and fertilization. That is why, in the conditions of modern intensive farming, only the correct organization of pollination of entomophilous crops by bees serves as a necessary element of the agrotechnical complex for obtaining high yields, improving product quality and reducing its cost.

5. The importance of insects in human life

In human life and economic activity they have both positive and negative meanings.

Of the more than 1 million insect species, only about 1% are actual pests that need to be controlled. The bulk of insects are indifferent to humans or beneficial. Domesticated insects are the honey bee and the silkworm; beekeeping and sericulture are based on their breeding. The honey bee produces honey, wax, propolis (bee glue), apilak (bee venom), royal jelly; silkworm - a silk thread secreted by the spinning glands of a caterpillar during the construction of a cocoon; the silk thread is continuous, up to 1000 m in length. In addition to these insects, valuable products are produced by: caterpillars of the oak cocoon moth, their coarser silk thread is used to make tussock fabric; lac bugs secrete shellac, a wax-like substance with insulating properties used in radio and electrical engineering; carmine bugs (Mexican and Ararat cochineal) produce red carmine dye; Blister beetles secrete a caustic substance called cantharidin, which is used to make blister plaster.

Insect pollinators, representatives of many orders, among which Hymenoptera occupy an important place, increase the yield of seeds, berries, fruits, and flowers of many cultivated plants - fruits and berries, vegetables, fodder, and flowers.

The Drosophila fruit fly, due to its fertility and reproduction rate, is not only a classic object of genetics research, but also one of the ideal experimental animals for biological research in space. Fossil insects are used in stratigraphy to determine the age of sedimentary rocks.

6.Insects that cause damage to humans

Of the huge number of described insect species (about 1,000,000), only a small part, about 1%, directly or indirectly causes harm to humans.

The aesthetic significance of insects lies in the fact that many striking beautiful butterflies, beetles, dragonflies, bumblebees and others evoke feelings of joy and admiration.

Insect pests are insects that can cause death or harm to humans, their pets, food supplies or other plant products. The term also applies to many insects that are more of a nuisance to people than a serious threat. Insect pests that cause serious harm to human health are of particular importance in countries with warm climates and in the tropics, of which mosquitoes are the most dangerous. They carry pathogens of various forms of malaria, yellow fever and other dangerous diseases. Fleas transmit bubonic plague to humans from rats. Insects that harm domestic animals include tsetse flies, gadflies, lice, and lice. Each type of plant used by humans has its own insect pests, which eat either the entire plant or parts of it. The roots feed on beetles, wireworms (larvae of click beetles) and other insects. Among insect pests that feed on above-ground parts of plants, the most important are aphids, scale insects and locusts, but many caterpillars also cause significant damage.

Examples of insects that annoy humans include summer-biting mosquitoes, midges and stinging wasps. Household insect pests include cockroaches, silverfish, clothes moths and bedbugs; none of them are dangerously fatal, but almost all of them are considered to threaten human health.

7. Beneficial insects

Seven-spotted ladybird (Coccinella septempunc-tata L.). A small black beetle, 6-8 mm long, with red elytra, on which 7 black caugled spots are clearly visible, which is how the insect got its name. The beetles fly well and with amazing accuracy find colonies of aphids, which they greedily eat. Here, on leaves or branches, females lay piles of yellow shiny eggs. Small, black, six-legged larvae emerge from them and immediately begin to eat aphids, just like the adults. Where the cows have settled, the aphids are completely destroyed. This picture can often be observed in gardens, berry fields and fruit nurseries. Beetles overwinter in crevices of buildings, under fallen leaves, in dead grass and other places. Early in the spring, after overwintering, they emerge from their shelters, crawl out onto trees and begin to eat pests. In favorable years, cows (also called ladybugs) multiply quickly and eat not only aphids, but also other small pests. In search of food and water, they accumulate en masse near bodies of water, on the sea coast, on rocks, and crawl along roads, where a large number of them die under the feet of passers-by. At such a time, ladybugs should be saved from death, collected in special boxes made of thick mesh and stored in refrigerators or basements in cold places so that in the spring they can be released onto plants damaged by aphids.

Two-spot ladybird (Adalia bipunctata L.). The beetle is 3-4 mm long, with red elytra, on which there are 2 black round spots. Lives and eats in the same way as the seven-spotted ladybug.

Syrphus ribesii L.K Diptera insect, black with bright yellow bands on the abdomen. In appearance, it looks more like a wasp than a fly. Body length is 11 -12 mm. The female looks for colonies of aphids and lays eggs on leaves damaged by them. From the eggs yellowish or greenish legless larvae emerge, similar to tiny leech. The larvae are very voracious: each eats up to 2000 aphids during its life.

Lacewing (Chrvsopa perla L.). A delicate bluish-green slender insect with four transparent wings, golden eyes and long antennae. Body length 12-15, wingspan 25-30 mm. Lays oblong emerald eggs on the leaves and stems of plants damaged by aphids. After a few days, grayish six-legged larvae emerge from the eggs. They run quickly and with their long sharp jaws grab aphids, suck them out, leaving only the skins that pile up on the backs of the larvae. Lacewing larvae make cocoons from aphid skins before pupating. Adult lacewings overwinter indoors. When danger approaches, the lacewing emits a persistent unpleasant odor that scares away enemies.

Ktyr (Selidopogon diadema F.). A predatory dipterous insect similar to a fly. The male is black, with brownish transparent wings; the female is brown, with a yellowish-brown pattern on the chest and abdomen, gray wings with a yellow base. Body length 18-22 mm. It feeds on insects by piercing them with a hard proboscis and sucking out lymph. Often catches pests on the fly. It is found on leaves and on the soil in gardens, fields and vegetable gardens, where it watches for prey. The larvae also feed on insects living in the soil.

Dragonfly (Leptetrum quadrimaculatum L.). A predatory insect with large compound eyes occupying most of the surface of the head, a strong gnawing mouthpart and two pairs of transparent long narrow wings with a dense network of veins. The wings of a dragonfly are always located perpendicular to the body. They fly very quickly, catching many small insects on the fly, especially mosquitoes, midges, moths and other pests, which is of great benefit to humans. The larvae live in ponds and rivers and feed on small aquatic animals. There are about 200 species of dragonflies in the USSR.

8.Insect pests of fields and gardens

Insect pests of fields and gardens are a fairly serious problem. Currently, there are a huge number of different types of insect pests that are ready to destroy our crops. They damage both young plantings and adult plants. In order to protect your crop from pests, you need to know them.

9.Types of insect pests

Insects are a large class, including more than a million different species:

Orthoptera

Homoptera

Hymenoptera

Diptera.

Insects are divided into groups that damage different parts of plants:

pests that damage the root system of plants

pests of seedlings and seedlings

aboveground pests

pests of foliage and shoots.

The greatest damage to vegetable gardens and fields is caused by mass reproduction of insect pests - locusts, aphids, butterflies, and beetles. Locusts are especially harmful; they are the most voracious. The offspring of one female can eat 300 kg of plants in its lifetime! Locusts form swarms of up to ten billion individuals, 120 km long. Such a flock can fly 2000 km without stopping!

10.Description of the most common pests

Orthoptera insects plant

The underground parts of plants - tubers, bulbs, roots and rhizomes - are damaged by mole crickets, chafer larvae, grasshoppers, some types of flies, and caterpillars of some types of butterflies.

The rudiments and seeds of plants suffer from the invasion of voracious bugs, beetles, weevils, beetle larvae and butterflies.

Ground parts of plants are damaged by Colorado potato beetles, beet weevils, and grasshopper beetles.

The Colorado potato beetle is especially dangerous for potatoes. Over the summer, two or three generations of beetles grow. Both beetles and larvae feed on potato leaves. An adult beetle and its larvae are capable of destroying 100 thousand potato bushes in a season!

The greatest damage to beets is caused by the beet weevil. From the eggs laid by the females, worm-like larvae develop that feed on beet roots.

Click beetles harm many plants. The larvae of click beetles are called wireworms. They are practically omnivorous, affecting potatoes, carrots, beets, daikon, radishes, and root parsley. They also harm melon plants - watermelons, melons, pumpkins and zucchini.

Huge damage to fields and vegetable gardens is caused by white moths and fall armyworms. White butterfly caterpillars feed on plants of the Brassica family. Caterpillars of the winter cutworm destroy seeds and emerging sprouts.

Some flies also cause damage to field and garden plants. Female onion flies attack onions and garlic. They lay eggs on the ground near these plants. The emerging larvae crawl into the bulbs, into the leaves, and eat away numerous passages in them. Soon the plants will turn yellow and dry out.

The larvae of cabbage and carrot flies cause enormous harm to radishes, celery, root parsley, carrots, and plants of the Brassica family.

Ripe fruits of wheat, rye and barley suffer from the invasion of the grain beetle. Adult beetles eat grains. One beetle destroys 9-10 ears of corn.

Bibliography

.Biology: Animals: Textbook. for 7th grade avg. school / B. E. Bykhovsky, E. V. Kozlova, A. S. Monchadsky and others; Under. ed. M. A. Kozlova. - 23rd ed. - M.: Education, 2003. - 256 p.: ill.

.. Insects in nature, Vorontsov P.T., Leningrad, “NEVA”, 1988.

.Life of insects, FabrZh.A., Moscow, “TERRA”, 1993.

.Key to insects, N.N. Plavilshchikov, 1994.

.Morals of insects, Fabre J.A., 1993.

.Secrets of the world of insects, Grebennikov V., 1990

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The importance of insects in human life

Insects have both positive and negative significance in human life and economic activity. There are more than one million insects in total, so the real pests that really need to be fought are only 1%. But other insects are either beneficial or indifferent to humans.

There are domesticated insects, for example, the honey bee and the silkworm - they are specially bred. The honeybee produces honey, wax, propolis, apilac, royal jelly, and the silkworm produces silk thread, which can be continuous and reach 1000 meters.

In addition to these insects, the caterpillars of the oak cocoon moth are very valuable - they have a coarser silk thread and it is suitable for making comb fabric, lacquer bugs - they secrete a wax-like substance with insulating properties, which is used in radio - and carmine bugs - they produce red carmine dye , blister beetles - they secrete a caustic substance called cantharidin, which is used to make blister plaster.

Insect pollinators - they represent many orders, among them Hymenoptera occupy an important place - they increase the yield of seeds, berries, fruits, flowers of many cultivated plants - fruits and berries, vegetables, fodder, flowers.

The importance of insects in nature

Insects make up 80% of all animals on Earth. By the way, according to various estimates, there are from 2 to 10 million species of insects in the modern fauna, and of these, only a little more than 1 million are known so far. Actively participating in the cycle of substances, insects play a global planetary role in nature.

For example, more than 80% of plants are pollinated only by insects. It is safe to say that a flower is an exceptional result of the joint evolution of plants and insects. The adaptations of flowering plants to attract insects are varied: pollen, nectar, essential oils, aroma, shape and color of the flower. But the adaptations of insects are the sucking proboscis of butterflies, the gnawing-licking proboscis of bees; or special pollen-collecting apparatus - bees and bumblebees have a brush and a basket on the hind legs, megachila bees have an abdominal brush, numerous hairs on the legs and body.

Insects also play a significant role in soil formation. This participation is associated not only with loosening the soil and enriching it with humus by soil insects and their larvae, but also with the decomposition of plant and animal residues - plants, corpses, animal excrement, at the same time fulfilling a sanitary role and the circulation of substances in nature.

The following types of insects perform various sanitary roles:

Coprophagous - among them dung beetles, dung flies and cow flies;

Necrophages - such as carrion beetles, gravediggers, leather beetles, meat-eating flies and carrion flies;

Insects that are destroyers of dead plant debris: be it wood, branches, leaves, needles - these are borer beetles, longhorned beetle larvae, golden beetles, horntails, long-legged mosquitoes, carpenter ants, fungus gnats and so on;

Insects-sanitizers that feed on suspended or settled rotting organic matter (detritus) - these are the larvae of mosquitoes, or bells, mayflies, caddis flies, purify water and serve as a bioindicator of its sanitary condition.

Thus, insects are the most important element of the food pyramids. Many animals feed on insects: fish, amphibians, reptiles, birds and mammals.

This is interesting!

Adult sizes of modern insects range from 0.139 mm (0.00547 inches) for fireflies to 55.5 cm (21.9 inches) for stick insects.

Scientists have discovered the longest insect on the island of Borneo - a stick insect, the length of which reaches half a meter. So far, experts have discovered only three individuals and can say practically nothing about the characteristics of this species.

Another notable find was a chameleon frog. At night, the covers of these 3.5 centimeter amphibians are bright green, and during the day their body color turns brown.

The role and importance of insects in nature is enormous. The mere fact that the number of insect species far exceeds the number of species of any other group of animals, and many forms are also capable of reproducing in countless quantities, turns insects into a powerful biological factor.

As shown by special calculations, the results of which, of course, are approximate, for every person on earth there are about 250,000,000 different representatives of this class. Moreover, this is not an indifferent mass, but organisms actively participating in a wide variety of biological processes.

Speaking about the positive or negative significance of insects, it is necessary to remember that these assessments are often very subjective and reflect only our attitude towards certain results of the life activity of insects. Sometimes a person himself, disturbing the balance in historically established biological complexes, causes a mass reproduction of some type of insect, leading to catastrophic consequences. There are no and cannot be absolutely harmful or absolutely beneficial species in nature. And insect pests are just forms that cause direct or indirect damage to humans, and in some cases the “harmful” properties of a species turn out to be truly harmful, and in others they bring great benefit to humans.

Everything that has been said can be illustrated by a huge number of examples, but we will dwell on only a few of them.

The positive activity of insects in nature is primarily expressed in their pollination of flowers of various plants. In this sense, their significance is extremely great. For example, about 30% of European flowering plants are pollinated by insects.

Bumblebee on a flower

Some plants are completely unable to reproduce without special pollinators. Clover, which gave excellent yields in New Zealand, did not produce seeds at all until bumblebees, which were absent there, were brought to New Zealand - special pollinators of clover. The main role among pollinators is played by Hymenoptera and especially bees and bumblebees; the second most important are dipterans and the third are butterflies.

Insects are of great importance in soil-forming processes, especially termites and ants. These insects, as well as the larvae of many insects living in the ground, loosen the soil with their moves, promote better ventilation and moisture, and enrich it with humus. The latter is associated with the destruction of plant and animal residues that accumulate in abundance on the soil surface. Without the activity of insects, for example, decomposition of coniferous plant litter is impossible, and where this does not occur, peat-like infertile layers accumulate. The destruction of animal corpses and excrement, carried out by representatives of a special faunal complex, is of very great sanitary importance.

The role of insects is enormous as one of the most important links in the cycle of substances in nature. Many insects are part of various food chains. In almost every class of vertebrate animals one can find specialized entomophages, that is, forms that feed exclusively on insects. This phenomenon is most developed in birds and mammals.

The negative consequences of insect activity are no less significant. Thus, many of them feed on living plant tissues, causing significant harm. Damage caused by insects is sometimes very diverse and affects a wide variety of plant organs: the root system, stems and trunks, leaves, flowers, fruits, etc. In some cases, this may be the destruction of plant tissue - gnawing, boring holes in leaves, called mines). In other cases, on the contrary, the presence of insects leads to the formation of galls, which are ugly growths of some parts of the plant - leaf blades, buds, stems. In the event of a massive attack by pests, both lead to a weakening of the plant organism, a decrease in its resistance to fungal and other diseases, a decrease in the production of fruits and seeds, and often to death.

It is in this area that the interests of humans and insects most often clash. Pests of agricultural crops and forest species cause enormous damage.

Failure to take precautions can lead to the introduction of insect pests into areas of the globe where they were not previously present. Not finding natural enemies in the new conditions, pests begin to multiply quickly. The absence of protective reactions developed over a long period of time in the plants on which the pest settles leads to the fact that the damage caused increases significantly.

The harmful properties of insects can sometimes be used by humans to their advantage. The successful experience of using insects to limit the spread of certain plants (in Australia, for example, specially acclimatized leaf beetles destroyed St. John's wort, which was growing rapidly on agricultural land) allows us to hope for the development of biological methods for controlling weeds.

Sometimes transmission occurs through simple contact with transmitting insects, for example, when they contaminate food, etc. In this way, the house fly spreads various diseases ( Musca domestica), crawling through any dirt, capturing bacteria, helminth eggs and transmitting them to humans. In total, flies carry about 70 species of different organisms, many of which are causative agents of dangerous diseases (cholera, diphtheria, etc.).

Speaking of practical significance Insecta, special attention should be paid to the forms directly used by humans. Among them there are species that have essentially become domesticated.

Honey bees provide direct benefits to humans - Apis mellifera and the silkworm - Bombyx mori; breeding them and obtaining products is the basis of two branches of the national economy - beekeeping and sericulture.

In addition to bees and silkworms, some insects are of known technical importance. They deliver medicinal substances (cantharidin from Spanish flies), coloring substances (different types of scale insects, Coccinea, especially Mexican cochineal, Coccus cacti, used for the production of carmine), tannin (in ink nuts, gallworm, Cynipidae), varnish and wax (some scales), etc.

Insects are becoming more and more important in the practice of agriculture and forestry in connection with the development and improvement of biological methods of pest and weed control. For this purpose, individual forms (hymenoptera: ichneumon wasps, hunting wasps, some predatory and herbivorous beetles, etc.) are specially acclimatized in disadvantaged areas. An example of the successful application of such control measures is the importation of the equestrian into the CIS Aphelinus mail, which completely suppressed the reproduction of a dangerous pest of the root system of apple trees - blood aphids ( Eriosoma lanigerum), which came to Europe from America. The mass reproduction of the citrus pest, the grooved bug, brought from Australia to America and then to Europe, was stopped by a ladybug Rodolia. These beetles have been successfully acclimatized in various regions of the globe, including here in the Caucasus. In recent years, artificial breeding of such insects in industrial conditions and their mass release in pest breeding areas have been widely practiced. The genetic method is also widely used to combat harmful insects. The intensification of agriculture and forestry currently does not allow us to completely abandon the use of insecticides. The future, however, undoubtedly belongs to biological methods of pest control.

These examples, like many others like them, well illustrate the thought of the French entomologist R. Chauvin: “Insects are harmful to man only until he uses them as assistants and refuses to use the power of his mind to solve the problems posed by their existence.”

Literature: A. Dogel. Zoology of invertebrates. Edition 7, revised and expanded. Moscow "Higher School", 1981

IMPORTANCE OF INSECTS

The importance of insects in nature

Insects make up about 80% of all animals on Earth; according to various estimates, there are from 2 to 10 million species of insects in the modern fauna, of which just over 1 million are known so far. Actively participating in the cycle of substances, insects play a global planetary role in nature.

More than 80% of plants are pollinated by insects, and it is safe to say that a flower is the result of the joint evolution of plants and insects. The adaptations of flowering plants to attract insects are varied: pollen, nectar, essential oils, aroma, shape and color of the flower. Adaptations of insects: sucking proboscis of butterflies, gnawing-licking proboscis of bees; special pollen-collecting apparatus - in bees and bumblebees there is a brush and a basket on the hind legs, in megachila bees - an abdominal brush, numerous hairs on the legs and body.

Insects play a huge role in soil formation. Such participation is associated not only with loosening the soil and enriching it with humus by soil insects and their larvae, but also with the decomposition of plant and animal residues - plant litter, corpses and animal excrement, while simultaneously fulfilling a sanitary role and the circulation of substances in nature.

The following types of insects perform a sanitary role:

· coprophagous - dung beetles, dung flies, cow flies;

· necrophages - carrion beetles, gravediggers, leather beetles, meat-eating flies, carrion flies;

· insects - destroyers of dead plant debris: wood, branches, leaves, pine needles - borer beetles, longhorned beetle larvae, golden beetles, horntails, long-legged mosquitoes, carpenter ants, fungus gnats, etc.;

· insects - orderlies of reservoirs feed on rotting organic substances (detritus) suspended or settled on the bottom - larvae of mosquitoes, or bells, mayflies, caddis flies, purify the water and serve as a bioindicator of its sanitary condition.

The importance of insects in human life

In human life and economic activity they have both positive and negative meanings.

Of the more than 1 million insect species, only about 1% are actual pests that need to be controlled. The bulk of insects are indifferent to humans or beneficial. Domesticated insects are the honey bee and the silkworm; beekeeping and sericulture are based on their breeding. The honey bee produces honey, wax, propolis (bee glue), apilak (bee venom), royal jelly; silkworm - a silk thread secreted by the spinning glands of a caterpillar during the construction of a cocoon; the silk thread is continuous, up to 1000 m in length. In addition to these insects, valuable products are produced by: caterpillars of the oak cocoon moth, their coarser silk thread is used to make tussock fabric; lac bugs secrete shellac, a wax-like substance with insulating properties used in radio and electrical engineering; carmine bugs (Mexican and Ararat cochineal) produce red carmine dye; Blister beetles secrete a caustic substance called cantharidin, which is used to make blister plaster.

Insect pollinators, representatives of many orders, among which Hymenoptera occupy an important place, increase the yield of seeds, berries, fruits, and flowers of many cultivated plants - fruits and berries, vegetables, fodder, and flowers.

The Drosophila fruit fly, due to its fertility and reproduction rate, is not only a classic object of genetics research, but also one of the ideal experimental animals for biological research in space. Fossil insects are used in stratigraphy to determine the age of sedimentary rocks.

Beneficial insects

Seven-spotted ladybug (Coccinella septempunc-tata L.). A small black beetle, 6-8 mm long, with red elytra, on which 7 black round spots are clearly visible, which is how the insect got its name. The beetles fly well and with amazing accuracy find colonies of aphids, which they greedily eat. Here, on leaves or branches, females lay piles of yellow shiny eggs. From them emerge small black six-legged larvae, which immediately begin to eat aphids, just like the adults. Where the cows have settled, the aphids are completely destroyed. This picture can often be observed in gardens, berry fields and fruit nurseries. Beetles overwinter in crevices of buildings, under fallen leaves, in dead grass and other places. Early in the spring, after overwintering, they emerge from their shelters, crawl out onto trees and begin to eat pests. In favorable years, cows (also called ladybugs) multiply quickly and eat not only aphids, but also other small pests. In search of food and water, they accumulate en masse near bodies of water, on the sea coast, on rocks, and crawl along roads, where a large number of them die under the feet of passers-by. At such a time, ladybugs should be saved from death, collected in special boxes made of thick mesh and stored in refrigerators or basements in cold places so that in the spring they can be released onto plants damaged by aphids.

Dragonfly(Leptetrum quadrimaculatum L.). A predatory insect with large compound eyes occupying most of the surface of the head, a strong gnawing mouthpart and two pairs of transparent long narrow wings with a dense network of veins. The wings of a dragonfly are always located perpendicular to the body. They fly very quickly, catching many small insects on the fly, especially mosquitoes, midges, moths and other pests, which is of great benefit to humans. The larvae live in ponds and rivers and feed on small aquatic animals. There are about 200 species of dragonflies in the USSR.

Insects cause enormous economic damage to humanity by eating crops, wooden buildings and other objects made from materials of plant origin. These insects include many types of butterflies: apple and plum moths, apple and cotton moths, representatives of the moth family (destroy grain crops, cotton, corn, sunflowers, beets, etc.), pine moth and Siberian silkworm (pests of coniferous forests). Bark beetles, woodcutter beetles and borers cause great damage to forests. Leaf beetles, weevils, weevils and chafers cause damage to the green parts of plants. The cockchafer is especially dangerous at the larval stage, which lasts 4–5 years. The larvae feed on the roots of herbaceous plants and trees. Devastating locust attacks have been a terrible disaster since the dawn of human civilization and affect the economies of many modern states. Termites cause great damage because, thanks to the fauna of intestinal symbionts, they perfectly absorb fiber, destroying huge amounts of wood.

The role of insects is extremely large both in human life and in natural processes. Due to the fact that insects make up a significant proportion of terrestrial fauna, they greatly influence the flora and fauna of the Earth. Insects are found in all land areas, including deserts, high mountains and polar regions.

The existence of many insects is closely related to the life of plants, as they consume living plants: roots, stems, leaves, fruits, seeds. During mass reproduction, insects destroy or damage plants over vast areas.

The role of insects in nature and human life is enormous

However, in addition to harm, insects bring great benefits to crop production as pollinators of flowering plants. In the course of evolution, remarkable mutual adaptation has developed between many species of insects and flowering plants (for example, plants have various adaptations for pollination by certain types of insects, and in insects the length and shape of the proboscis strictly correspond to the structure of the flowers of the plants that they pollinate).

Insects are destroyers of dead plant parts. Many types of insects and their larvae, living in the ground, digging tunnels and loosening the soil, accelerate the formation of humus. Many vertebrates (fish, amphibians, reptiles, birds and mammals) feed on insects at various stages of development.

In connection with human economic activities, it is important to preserve the species diversity of insects. The use of insecticides to control pests of agricultural and tree crops, plowing of land, due to which the number of some species of wild plants is sharply reduced, has threatened the existence of some species of insects.

To protect endangered insects, special reserves are being created in our country, and many (about 20 species) are already listed in the Red Book. These include two species of praying mantises - predatory insects that feed on other insects, a mollusc-eating ground beetle, an alpine longhorned beetle, a gigantic hawkmoth and several species of butterflies: the polyxena swallowtail, Apollo, the death's head hawkmoth, the Proserpina hawkmoth, the oak hawkmoth, Saturnia aglia, Saturnia minor, etc.

Biological method of pest control

To combat harmful insects, along with mechanical, chemical and agrotechnical methods, biological control methods are increasingly being used, i.e. destruction of insects at all stages of development with the help of their natural enemies. Such enemies of insects are frogs, toads, lizards, wild birds, shrews, hedgehogs, moles, bats, etc. Therefore, all these animals must be protected and, if possible, attracted to fields, vegetable gardens, and orchards. Poultry have also been increasingly used to kill pests in recent years.

Pests and insects have many natural enemies. Of great importance in the destruction of pests are riders and other insects. Ladybugs, for example, destroy aphids and other pests. Predatory beetles (ground beetles) hunt gypsy moth caterpillars.

Previously, a lot of planned work was carried out on breeding and using various types of insects to control plant pests.

In special laboratories, certain species of ladybugs, ichneumon fly, Trichogramma and other insects are bred in large numbers. They are released in areas where there is a massive outbreak of pests. Biological methods of controlling plant pests have a great future.