The role of insects in nature and their practical significance. The value of insects in nature Insects their meaning

Sushi. Their importance in the biogenic cycle is great.

Example 1

Insects saprophages (cockroaches, primary wingless) process plant remains. Xylophages feed on wood (bark beetles, termites, larvae of borers, barbels). In many insects, symbionts (flagellates, bacteria) live in the intestines, contributing to the digestion of fiber. Animal remains are eaten by kozheeds, mervoeds, dipteran larvae. Animal excrement is disposed of by dung beetles and dung beetles.

Remark 1

All insects saprophages and xylophages contribute to the formation of soil.

Large animals - reptiles, amphibians, birds and mammals feed on insects. Almost all songbirds feed their offspring with insects. Insects are an important factor regulation of the population of both plants and animals. Phytophages destroy mainly weakened plants, as well as species that are not characteristic of these communities.

Example 2

Ants control the number of species inhabiting meadows, forests, and deserts. Ladybugs are able to suppress the number of homoptera insects (aphids). Lizhelitsy destroy arachnids, soil-dwelling insects, mollusks.

Coevolution of insects and angiosperms led to mutual adaptations in phytophagy and pollination. Insects are the main pollinators of flowering plants and yields of berry and fruit crops depend on their activity. A large number of different species utilize dead organic material: wood, leaf litter, manure, etc.

The value of insects in human life

Man widely uses insects in order to obtain a variety of products:

1. Beekeeping. Human use in Food Industry honey, in medicine - bee venom and propolis, in the perfume industry - bee milk.
2. Sericulture. Silkworm caterpillars produce silk, which is used to make durable and fine fabrics. To obtain silk, oak silkworms and mulberry silkworms are bred.
3. Insects are a source for obtaining paints, varnishes, medicinal substances.
4. In many parts of the world, insects are used as a food or condiment.
5. Drosophila flies are an important laboratory object in genetic studies.

Example 3

Natural varnish, shellac, is obtained from the special secrets secreted by varnish insects. Cantharidin is prepared from blister beetles (“Spanish fly”). Ararat cochineal is used to obtain red carmine dye.

Insect Biotechnology

Insects also play a negative role in people's lives. All the negative impact of insects can be divided into several groups:

Insects are plant pests. The most harmful species include polyphagous insects: Asian locust, Italian locust, click beetles, lepidoptera (shovels, meadow moth), dark beetles. Each group of fruit and berry crops has its own composition of pests.

Example 4

The most important pests of the apple tree are: caterpillars of the apple moth, apple weevil, apple codling moth. Caterpillars of the gooseberry sawfly, larvae of the raspberry beetle, and phylloxera cause great harm to the berries.

Pests of forest plantations. Among these pests, primary ones are distinguished, which damage fruits, leaves, flowers, and secondary ones, which damage weakened trees, their trunks and roots. Trees suffer from ringed and gypsy moth, pine sawfly, pitcher, weevils, leaf beetles, aphids, psyllids and many others.

A huge number of species and individuals of insects, their distribution in water, in the soil and on its surface, in the air, in various parts of plants, in the body of animals determine their role in nature.

The significance of insects is extremely great and varied. Some of them cause great harm to plants, animals and humans, the activity of others is very useful.

Interestingly, the same insect is harmful at one stage of development and useful, even necessary, at another. For example, a caterpillar eats leaves and a butterfly pollinates flowers.

The positive activity of insects in nature is manifested mainly in the pollination of flowers by them. various plants. This is extremely important. Thus, about 30% of European flower plants pollinated by insects. Many typical external signs of flowers (their bright color, smell) arose to attract pollinating insects. The main role as pollinators is played by bees, bumblebees, various dipteran insects and butterflies.

Some insects are food for fish, birds and other animals. Certain types of insects are domesticated by man for the sake of their products (bees) and precious raw materials for the manufacture of silk fabrics (silkworm).

The silkworm is the main producer of raw materials for the production of natural silk. Not found in the wild. Bred for several millennia. Silkworm butterflies have lost the ability to fly. They are off-white in color with brownish stripes. The eggs of the silkworm are called grenades. In winter, it is stored at a low temperature; in spring, to activate the development of eggs, the temperature is increased to 26-27 °. The caterpillar is kept in special rooms fed with mulberry leaves. At the end of development, the caterpillar builds a cocoon from the liquid secreted from the mulberry glands and turns into a thin thread. Cocoons are used for silk production. Sericulture is well developed in the USSR. They are engaged in sericulture in Central Asia, in Ukraine, in the Caucasus and in other republics where there is raw material for growing silkworm caterpillars.

honey bee. Bees feed only on nectar and pollen of plants and make up about half of all pollinators of plants, their economic importance lies in the fact that they provide honey and wax. In medicine, poison and royal jelly are used for medicinal purposes. Bees live in families. According to the structure and duties that they perform, bees are divided into queens, males and worker bees. The queen lays fertilized eggs, from which queens and worker bees develop, and unfertilized ones, from which males (drones) emerge. The eggs are laid in the cells of the comb, where the larvae close and develop into pupae and then into adult forms.

Our Fatherland has always been famous for beekeeping. Everywhere the frame hive was invented by P.I. Prokopovnch in early XVI V.; Rollers for the manufacture of artificial foundation were invented by Kuzmenko.

Many insects are useful in that they eat rotten substances and bacteria, acting as "orderlies". Ants, living in the ground, loosen the soil with their moves and thereby contribute to its better ventilation and moisture, enrich it with humus. In some places of the USSR, there are 28,000 anthills per 1 km2, therefore, their influence on soil-forming processes is significant.

Useful insects should be protected from extermination, their reproduction should be promoted. The school can play a big role in this matter. If students know what the value of this or that insect is, they will protect the places of their distribution, prevent their destruction or destroy those that are harmful.

"The importance of insects in nature and human life"

1. Abundance of insects

Insects are the most numerous class of animals with more than a million known species. Calculations made by scientists showed that about 1017 (100000000000000000) insect specimens 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 beetles, which have rigid forewings. There are three main groups according to the nature of their diet. Firstly, these are predators that feed on various small animals, mainly insects.

Such, for example, are brightly colored ladybugs. Some ladybugs are bred in laboratories and released into greenhouses and gardens to control aphids that damage agricultural plants. Secondly, they are consumers of decaying plant and animal remains. These include, for example, dead eaters and gravediggers who use animal corpses as food. Their larvae also feed on the same food. They are among the orderlies of nature: without them, the corpses of animals would decompose and infect the surrounding area. Thirdly, these are herbivorous beetles that consume all kinds of plant parts, including wood. This includes, for example, the cockchafer and other beetles, leaf beetles. The leaf beetle 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. More than 300,000 species of beetles are known on Earth.

2. The value of insects in nature

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

An important link in the food chain.

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.

The soil-forming role of insects.

They feed on other insects, limit their numbers.

Biological suppression of insect pests.

Food for other animals: feeding on plant foods, they themselves become the prey of other animals.

Aesthetic value: beautiful shapes evoke feelings of joy and admiration.

Destroying corpses and manure, they perform a sanitary role.

Insects make up about 80% of all animals on Earth, according to various estimates, in the modern fauna there are from 2 to 10 million species of insects, of which just over 1 million are known so far. Actively participating in the circulation 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 the flower is the result of the joint evolution of plants and insects. The adaptations of flowering plants to attract insects are diverse: 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, a brush and a basket on the hind legs, in megachil bees - an abdominal brush, numerous hairs on the legs and body.

Insects play an important role in soil formation. Such participation is associated not only with the loosening of the soil and its enrichment 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 the sanitary role and the circulation of substances in nature are performed.

The following types of insects perform a sanitary role:

coprophages - dung beetles, dung beetles, cowsheds;

Necrophages - dead-eaters, gravediggers, leather-eaters, meat-eating flies, scavengers;

Insects - destroyers of dead plant residues: wood, branches, leaves, needles - drill beetles, larvae of barbels, borers, horntails, centipede mosquitoes, carpenter ants, mushroom mosquitoes, etc .;

Insects - orderlies of reservoirs feed on rotting organic matter suspended or settled to the bottom (detritus) - larvae of mosquitoes-twitchers, or bells, mayflies, caddisflies, purify water and serve as a bioindicator of its sanitary condition.

3. Soil-forming role of insects

In the course 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. 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 pollination by insects.

The most important in the formation 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 cultivated plants.

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

Butterflies play a very insignificant role in the pollination of flowers, and among the hymenoptera, short-proboscis wasps, oysters, gall wasps, riders and sawflies. Among the 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 the pollination of plants of certain species. For example, that long-proboscis bumblebees are more successful than other insects in pollinating red clover flowers. Individual representatives solitary bees are well adapted to opening flowers and pollinating alfalfa. Flower flies are most successful in pollinating carrot seed plants. However, the number of wild insects changes dramatically in different years, not to mention the fact that due to the plowing of boundary lines, empty lands and the massive introduction of chemical measures to combat pests and plant diseases, the number of wild pollinators is sharply reduced. At present, 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, the structure and lifestyle of which in the process of evolution the best way adapted to this function. They live in large families, the number of which during the flowering period of the most important honey plants reaches several tens of thousands.

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

While many species of solitary bees are monotrophic (they visit the flowers of plants of only one genus or species) or oligotrophic (they visit the flowers of a number of 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 arrays of plants of various species during their mass flowering, that is, at the time of the greatest need for pollinators. To load the honey goiter in one flight, the bee must visit, depending on the nectar productivity of plants, 80-150 flowers. The bee must visit the same number of flowers to collect pollen and form pollen. Two pollen bees weighing about 15-20 mg contain over 3 million pollen grains. Thousands of pollen grains of different quality stick to the body of the bee, covered with hair, during repeated visits to the flowers, which are transferred to the stigma of the pistils. Moreover, each flower is visited by bees during its life, usually not alone, but many times. Thus, 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 is a necessary element of the agrotechnical complex for obtaining high yields, improving product quality and reducing its cost.

5. The value of insects in human life

In the life and economic activity of a person, they have both positive and negative significance.

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

Insect pollinators, representatives of many orders, among which important place occupied by Hymenoptera, increase the yields of seeds, berries, fruits, flowers of many cultivated plants - fruit and berry, vegetable, fodder, flower.

The Drosophila fruit fly, due to its fecundity 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 age sedimentary rocks.

6. Insects causing harm to humans

Of the vast number of insect species described (about 1,000,000), only a small part, about 1%, directly or indirectly harms 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 pest - Insects that can cause death or harm to humans, their pets, food supplies, or other plant products. The term is also applied to many insects that are more of a nuisance to humans than a serious threat. Insect pests that cause serious harm to human health are of particular importance in countries with a warm climate and in the tropics, of which the most dangerous mosquitoes. 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, stingers and lice. Each type of plant used by humans has its own insect pests that eat either the whole plant or parts of it. Roots feed on beetles, wireworms (larvae of click beetles), and other insects. Among insect pests that feed on aboveground parts of plants, aphids, scale insects and locusts are of the greatest importance, but many caterpillars also cause significant harm.

An example of insects that annoy humans are mosquitoes biting in summer, midges and stinging wasps. Domestic insect pests are cockroaches, silverfish, clothes moth and bed bugs; none of them are dangerously deadly, but it is believed that almost all of them can threaten human health.

7. Beneficial insects

Ladybug seven-spotted (Coccinella septempunc-tata L.). A small black beetle, 6-8 mm long, with red elytra, on which 7 black caugle spots are clearly visible, thanks to which the insect got its name. Beetles fly well, with amazing accuracy they find colonies of aphids, which they greedily eat. Immediately on the leaves or branches, the females lay heaps of yellow shiny eggs. Small black six-legged larvae emerge from them, which immediately begin to eat aphids, like adults. Where the cows settled, aphids are completely destroyed. Such a picture can often be observed in gardens, berry fields and fruit nurseries. Beetles hibernate in crevices of buildings, under fallen leaves, in bough grass and other places. In early spring, after overwintering, they leave their shelters, crawl out onto trees and begin to eat pests. IN favorable years ladybugs (they are also called ladybugs) multiply rapidly and eat not only aphids, but also other small pests. In search of food and water, they accumulate en masse near water bodies, on the coast of the seas, on rocks, crawl along roads, where a large number of them die under the feet of passers-by. At such times, cows should be saved from death, collected in special boxes made of thick mesh and stored in refrigerators or in basements in cold places in order to release them on plants damaged by aphids in the spring.

Two-spot ladybird (Adalia bipunctata L.). Beetle 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-spot cow.

Bandaged Sirphus (Syrphus ribesii L.K. Diptera, black with bright yellow bands on the abdomen. By appearance more like a wasp than a fly. Body length 11 -12 mm. The female looks for colonies of aphids and lays eggs on the leaves damaged by them. The eggs hatch into yellowish or greenish legless larvae resembling a tiny leech. The larvae are very voracious: each eats up to 2000 aphids during their 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 fast and grab aphids with their long sharp jaws, suck them out, leaving only the skins that pile up on the backs of the larvae. From the skins of aphids, lacewing larvae make cocoons for themselves before pupation. Adult lacewings overwinter indoors. With impending danger, the lacewing emits a persistent unpleasant odor that scares off enemies.

Ktyr (Selidopogon diadema F.). A predatory two-winged insect that looks like a fly. Male 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, piercing them with a hard proboscis and sucking out the lymph. Often catches pests on the fly. It occurs on leaves and on 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.). Predatory insect, with large complex eyes occupying most of the surface of the head, strong gnawing mouthparts and two pairs of transparent long narrow wings with a dense network of veins. The wings of a dragonfly are always perpendicular to the body. They fly very fast, catching many small insects on the fly, especially mosquitoes, midges, moths and other pests, which are of great benefit to humans. The larvae live in ponds, rivers and feed on small aquatic animals. There are about 200 species of dragonflies in the USSR.

8. Insect pests of the field and garden

Insect pests of the field and garden are quite a serious problem. There are currently a huge number various kinds 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 over a million different species:

orthopterans

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

aerial pests

foliage and shoot pests.

The greatest harm to gardens and fields is caused by mass reproduction of insect pests - locusts, aphids, butterflies, beetles. Locusts are especially harmful, they are the most voracious. The offspring of one female can eat 300 kg of plants in her life! 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

orthopteran insect plant

Underground parts of plants - tubers, bulbs, roots and rhizomes - are damaged by bears, larvae may beetles, grasshoppers, some types of flies, 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 beetles, beet weevils, grasshopper beetles.

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

The beetroot weevil does the most damage to beets. From eggs laid by females, worm-like larvae develop, which 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, root parsley. They also harm melon plants - watermelons, melons, pumpkins and zucchini.

Huge damage to fields and gardens is brought by whites and winter scoops. White caterpillars feed on plants of the Cabbage family. Caterpillars of the winter scoop destroy the seeds and sprouts that have appeared.

Harm the field and garden plants and some flies. Onion fly females infect onions and garlic. They lay their eggs on the ground near these plants. The emerging larvae crawl into the bulbs, into the leaves, eat out numerous passages in them. Soon the plants will turn yellow and dry.

Larvae of cabbage and carrot flies cause great harm to radishes, celery, root parsley, carrots, plants of the Cabbage family.

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

Bibliography

.Biology: Animals: Proc. for 7 cells. 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.

.Determinant of 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 regulation of the functions of the organism of insects is carried out with the help of the nervous and humoral systems. Therefore, they are characterized complex behavior. The importance of insects in nature and human life is often due to this very reason.

central part nervous system- The brain is well developed. Especially his front section. This is manifested in the presence of a system of instincts - innate programs of behavior. Insects are characterized by hunting, sexual, building and other types of instincts.

Humoral regulation of the body occurs with the help of biologically active substances - hormones. They are secreted by specialized glands into the blood. An example of their action can be the regulation of molting processes, the transition to a state of rest, communication with individuals of the opposite sex.

social insects

Social species have especially complex behavior. The value of insects in human life is to obtain honey, bee bread and other useful substances. You, of course, guessed that we are talking about bees. They live in large families, in which each performs its irreplaceable role. The fertile queen and males are responsible for reproductive function. But working individuals build honeycombs, and in their free time they collect pollen. At the same time, they transfer it to the stigmas of the pistils, providing conditions for the fertilization of flowering plants. It is thanks to these insects that the fruits and seeds of many plants appear. These hard workers and provide a positive value of insects in human life and nature.

Ant Workers

The importance of insects in nature and human life can also be considered on the example of other creatures - ants. In making their own dwellings, they collect much building material. At the same time, the ants mix the soil, making it more porous and rich in organic matter and oxygen.

Large red species eat a large number of forest pests. However, their bites can be dangerous for humans. Formic acid, which is released during this, can cause itching, irritation, and allergic reactions.

Gluttonous Orthoptera

Representatives of the order Orthoptera are also of particular importance to insects in human life. These are grasshoppers, bears, locusts and other species. But many of them are not as safe as the famous children's song says. Locusts, which are herbivorous insects, are capable of destroying crops in the fields. This species is able to reproduce rapidly. Huge families flying in search of food look like real clouds. At the same time, they destroy all plants on their way.

But the enemy of vegetable gardens and orchards is the bear. With the help of powerful digging legs, she makes moves in the soil to search for edible underground parts of plants. This leads to their death. The activity of the bear sometimes takes on a significant scale, causing irreparable harm to the crop.

What are dangerous lice and fleas

The value of insects in human life and in nature is often negative. Lice are no exception. These wingless insects attach themselves to the hairs of the host's body with a movable claw, feeding on its blood. At the same time, lice can carry deadly diseases: relapsing fever and typhus.

To avoid infection with these dangerous insects, you need to follow the rules of personal hygiene: do not use other people's clothes, hats and combs, take water procedures change linen periodically.

Amazing beetles

The value of insects in human life and nature is positive and not very, have a representative of the order Coleoptera. Many of them are predators. At the same time, they destroy many agricultural pests. For example, ladybug eats aphids, and krasotel - caterpillars of insect pests. But, unfortunately, some species of beetles themselves cause great damage. agriculture. Weevil destroys sugar beet shoots. And the one who had to collect the larvae of the Colorado potato beetle from potatoes knows that this "handsome man" does not need a special introduction. But the most merciless insect is the ground beetle. She attacks the prey, even being full to the limit. In captivity, it is even sometimes fed with small pieces of meat.

But dung beetles, despite the unpleasant name, clean environment from the excrement they feed on. At the same time, they rightfully deserve the title of the most powerful beetles, because they are able to lift a load 90 times heavier than their own.

Diptera bites

A person who had to experience the bites of these arthropods must have long decided that the importance of insects in human life and nature is negative. When it comes to mosquitoes, it's hard to argue with that. Of course, their larvae serve as food for fish. But mosquito bites can cause serious allergic reactions. Some species are carriers of malaria and yellow fever. These diseases are often fatal.

The importance of insects in human life and in nature is also determined by the activity of flies. Do not think that they are just intrusive and harmless. On the surface of their body there are many eggs of helminths, viruses, pathogenic bacteria. However, by participating in the processing of dead organic matter, flies increase soil fertility.

It can be concluded that the value of insects in nature and human life is both negative and positive. But in the course of life, everyone will have to face them, because there are 250 million insects per person!

The role and importance of insects in nature are enormous. The number of insect species far outnumbers the species of any other group of animals, according to rough estimates, at least 108 billion insects live on our planet at the same time.

The positive activity of insects in nature is expressed in their pollination of plants, for example, about 30% of European flowering plants are pollinated by insects. Some plants are unable to reproduce without special pollinators. Clover, which gave excellent yields in New Zealand, did not produce seeds until bumblebees, which were absent there, were introduced - pollinators of clover. Hymenoptera and especially bees and bumblebees play the main role among pollinators; Diptera are second in importance and butterflies are third.

The importance of insects in soil-forming processes, especially termites and ants, is great. These insects, like the larvae of many insects living in the ground, loosen the soil with passages, promote ventilation and moisture, and enrich it with humus. Without the activity of insects, for example, the decomposition of litter is impossible. coniferous plants, and where this does not occur, peat-like infertile layers accumulate. The destruction of animal corpses and excrement by insects is of great sanitary importance.

The role of insects in the cycle of substances in nature is enormous. In almost every class of vertebrates (especially birds and mammals) there are entomophages - forms that feed exclusively on insects.

No less significant are the negative consequences of insect activity. So, many of them feed on living tissues of plants, causing significant harm. Damage caused by insects is diverse and affects various organs of plants: the root system, stems, trunks, leaves, flowers, fruits, etc. called mines). In other cases, the presence of insects leads to the formation of galls, which are growths of plant parts. 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.

Failure to comply with precautionary measures leads to the introduction of insect pests into areas of the globe where they were previously absent. Not finding natural enemies in the new conditions, pests begin to multiply rapidly. The absence of protective reactions developed over a long period of time in plants on which the pest settles leads to the fact that the damage inflicted 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 some plants (in Australia, for example, specially acclimatized leaf beetles destroyed St.

Sometimes the transfer is made by simple contact with insects - transmitters, for example, when food is contaminated by them, etc. In this way, the house fly (Musca domestica) spreads various diseases, capturing bacteria, helminth eggs and transmitting them to humans. Flies carry about 70 species of various organisms, many of which are pathogens of dangerous diseases (cholera, diphtheria, etc.).