They conquered all habitats (except oceans and seas), adapting to the most difficult conditions of existence. They can be found everywhere: in cities, forests, steppes, swamps, deserts and taiga. Highly organized individuals form the most extensive class - insects, which in their species diversity and abundance surpass all other animals on the planet. And it is precisely the representatives of this class that are assigned the primary role in the multi-link food chain, in its subtlest elusive processes, as well as in soil formation, plant pollination and environmental sanitation.
Ancient organism
Determine the origin of the class of insects for scientists was somewhat difficult. The main problem was the lack of fossils of them so that phylogenetic relationships could be revealed. For a long time, on the basis of morphological comparisons, centipedes were considered closely related to insects. But the construction of phylogeny (the development of an organism over time) and recent morphological studies have indicated that insects are much closer to crustaceans, and not to centipedes.
Crustaceans familiar from sedimentsearly era of the Cambrian period (about 541 Ma), while insects are found in the paleontological record only in the Devonian system (about 419 Ma). The assumption of their origin from one ancestor contains a time interval of more than 100 million years, in which insects should have already existed. Recent morphological comparisons and evolutionary reconstructions based on genomic sequences confirm that insects are indeed found to be descendants of crustaceans. According to the analyzes, insects branched off from crustaceans in the early Devonian (or late Silurian). This verdict is consistent with both paleontological data and the molecular clock estimate.
Progressive Group
Modern fauna, according to various sources, ranges from 900 thousand to 2 million species of insects. Some forecasts report that the number of existing species may reach 5 million or more. There is every reason to believe that such figures may be quite real, given how intensively new discoveries of new organisms are currently taking place. On the territory of Russia, insects presumably number from 70,000 to 100,000 species.
The class of insects represents terrestrial animals, as a rule, of tiny sizes, in which the body has a clear division into the head, chest and abdomen, and the main limbs (3 pairs) used for movement are located on the thoracic region. The process of breathing is performed using the tracheal system or the entire surface of the body (skin). Representatives of this class differ in body configuration, the size and shape of the eyes, the size of the antennae, and other features. In particular, their bright diversity is shown in the mouth organs and limbs. For example, the mouthparts of May beetles are gnawing, while those of mosquitoes are piercing-sucking; or hind limbs in grasshoppers are jumping, and in swimming beetles they are swimming. All structural features of insects developed as a result of mechanisms of adaptation to certain living conditions.
From 40 orders of insects, 5 of the largest are distinguished, whose representatives also live in Russia: beetles (leaf beetle, ladybug, stag), Diptera (midges, horseflies, mosquitoes), Lepidoptera or butterflies (silkworm, meadow moth, room moth), hemipterans or bugs (leaf bug, tortoise bug, Siberian cruciferous bug) and hymenoptera (wasp, bee, bumblebee).
Squad beetles or beetles
Beetles are the largest group not only among insects, but also living beings in general. The order has more than 400 thousand species, and hundreds more newly discovered ones are added every year, so it is very difficult to give a true assessment. Beetles are common in all latitudes, with the exception of Antarctica and the highest mountain peaks. In Russia, insects of this order are represented by about 14 thousand species from 155 families.
As the name of the detachment conveys, a distinctive feature of beetles is the presence of strong leathery elytra (elytra), developed from the upper pair of wings. The original armor bearsthe protective function of the membranous lower wings during those minutes when the insect is not in flight. At the same time, its elytra are closely adjacent to each other, forming a suture line. Also, the body of the beetle, in particular the head and pronotum, has a chitinous coating.
This order has no competition in terms of diversity in shapes, sizes and colors. Their well-known representatives in Russia are: ladybugs, ground beetles, bark beetles, weevils, rhinoceros beetles, Colorado beetles, dung beetles and many others. The beetles can range in size from less than 1 mm (wingfly) to 9 cm (male stag beetle).
Diptera order
In terms of the number of species, this order of insects ranks fourth, skipping ahead of Coleoptera, Lepidoptera and Hymenoptera. The name "Diptera" speaks of the main feature of the detachment: the preservation of only one front pair of wings. The second pair was modified in the process of evolution and is now represented by club-shaped outgrowths (h alteres). At present, science has described about 200 thousand species of Diptera from 150 families. On the territory of Russia, the most famous representatives of the detachment are: flies, mosquitoes, mosquitoes, midges, horseflies and gadflies.
In the order Diptera there is a considerable variety of colors, sizes and body shapes. Moreover, the shape of the body can be either oblong and slender, or compactly short, as in some parasitic species. But despite the great diversity, Diptera have common features: adults have a sucking or licking type of oralapparatus (proboscis), developed compound eyes, thin sensitive covers and 5-segmented tarsi. Ontogeny of insects proceeds with complete transformation.
Squad Lepidoptera
Insects of this order are valued with no less passion than works of art. Even the ancient Romans believed that Lepidoptera (butterflies) were formed from the inflorescences of plants that broke away from the stems. Their wings are the most important feature: they have a dense cover of chitinous scales, the structure and arrangement of which determine the originality of the color. According to various estimates, butterflies currently number over 200 thousand species, from more than 200 families of insects. About 9 thousand species of the order live in Russia, the famous representatives among them are: urticaria, cabbage, cat's eye, dawn, meadow jaundice, wine hawk moth and others.
Another essential feature of Lepidoptera is the structure of the oral apparatus. Most butterflies have a thin and long proboscis, a highly specialized sucking organ that was formed from modified mandibles. In some species, the proboscis may be underdeveloped or absent. Some of the lower members of the order retained the gnawing (original) mouthparts.
According to systematization within the detachment, 3 suborders are noted: jawed, homoptera and heteroptera. Most of the Lepidoptera species belong to the latter. In addition, there is a conditional division of butterflies into diurnal (club-whiskered) and nocturnal (different-whiskered) butterflies.
Order of Hymenoptera
A detachment of insects with membranous wings in terms of species diversity is second only to beetles and butterflies. According to various conclusions, it has from 150 to 300 thousand species. More than 16 thousand species of Hymenoptera are noted in the fauna of Russia. These include both primitive horntails and sawflies, as well as insects with more complex biology and highly organized nervous systems - bees, wasps and ants.
In the description of the species of this order, the following distinguishing features are distinguished: 4 membranous wings have a loose network of veins, they are also found without them (wingless forms also exist); mouth apparatus of gnawing-licking (bees) and gnawing (ants, wasps) types; development with complete transformation. Many Hymenoptera insects live in communities, and some of them are characterized by polymorphism. The composition of such a family is represented by one or more queens, a small number of males and many working individuals (sterile females). These species are characterized by nervous activity with predominant instinctive actions.
Hymenoptera play an important role in nature and are also of great economic importance. Among them there are dangerous pests of plants (nutworms, seed-eaters, horntails), there are predatory forms (ants, wasps), there are also human allies (bees, bumblebees).
Hemiptera squad
Bugs or hemipterans inhabited all possible biotopes of land, penetrated into fresh waters, and such as halobates water striders have also mastered the open ocean. This one is quite varied anda large detachment, which, according to recent estimates, has more than 42 thousand species of insects. About 1.5 thousand species live in Russia, of which a significant part is concentrated in the southern regions (marble bug, perillus, tropical bug, lace bug).
Hemiptera have two pairs of wings, which are laid at rest, covering the abdomen from above. The front pair of wings (elytra) are leathery at the base and membranous in the apical part (hence the name of the detachment), the hind wings are completely membranous. The oral apparatus is represented by a piercing-sucking type, in the form of a jointed proboscis. All representatives of the group also have odorous glands, the secretions of which carry a specific smell. In an adult individual, the openings of the glands go to the metathorax, in nymphs (the larval stage of development) - on the abdominal segments. Hemiptera have development with incomplete metamorphosis.
Among the bugs, both herbivorous forms and predators (bugs-hunters) are observed. Some species are ectoparasites of mammals and humans (bed bugs).
Predatory species
The activity of predatory insects (entomophages) helps maintain and maintain balance in nature. They often turn out to be the main regulatory factor that restrains the overproduction of some herbivorous species.
Mantis. When describing an insect, the front legs are the main feature: the thigh and lower leg form a kind of grasping apparatus, acting like scissors. Adults feed on grasshoppers, flies, small butterflies, and larvaemostly aphids. Praying mantises are a classic example of "predator lurking" behavior.
Ladybug. The diet of adult insects and their larvae are: spider mites, aphids, eggs and small caterpillars of butterflies. These predators have a very good appetite. One larva absorbs up to 600-800 aphids during its development, and an adult can eat up to 40 aphids per day.
Coleopteran ground beetles. In the description of predatory species of the family, a long upper jaw similar to a sickle (mandible) is distinguished, with which they firmly hold the victim. Insects move nimbly along the soil surface, destroying snails, caterpillars, slugs, phytophages and many other pests.
Predatory insects are an important biological factor in the fight against parasites. They are successfully used in agriculture, protecting fruit and berry orchards, vegetable fields and cereal crops.
Disappearing insects of Russia
According to researchers, at the moment there is an active decline in the number of 41% of insect species, and this figure will continue to grow every year. On the territory of Russia now lives 110 species of insects that are under special protection and are included in the Red Book.
Wax bee. The range of the species is rather narrow in Russia: the south of the Far East and possibly on Sakhalin. Today, the number is critically low: no more than 40-60 families have been recorded in nature.
Clanis wavy. A butterfly from the hawk family is found in the south of Primorsky Krai. The number is very lowand is subject to significant fluctuations.
Heavenly barbel. Preserved in the Ussuriysk-Primorsky region in the forests from Partizansk to Khasan, as well as in the vicinity of the Shkotovsky, Terneysky districts and near the settlements of Kaimanovka, Kamenushki and Nikolo-Lvovskoye. The species is marked by single specimens.
Steppe bumblebee. It is considered a characteristic element of the insect fauna of forest-steppes and steppes. In Russia, the species is distributed in the southern Baikal region and the extreme south of the Far East. Numbers are low.
Repeated studies have shown that the main reason for the extinction of insects is the change or disappearance of their habitat. Pollution of the environment with pesticides and insecticides has become another important factor.
Interesting facts
- Of all the butterflies living in Russia, the largest is the peacock-eye pear. Its wingspan reaches 15 cm.
- The male earwig has 2 penises that are longer than the insect itself. These organs are very fragile, which is probably why nature has taken care of a fallback.
- Of all flying insects, the Asian giant hornet has the most painful bite. In Russia, it can be found in Primorsky Krai.
- Gflies and gadflies belong to different families of insects. Unlike the horsefly, which only bites painfully and drinks blood, the gadfly parasitizes animals and humans, laying eggs on the skin of the chosen victim.
- The famous writer Vladimir Nabokov was extremely passionate about entomology. He enriched science by making the discoveryseveral types of butterflies.
- Ladybug is ranked among the sexual giants. She is able to mate without rest for 9 hours.
- In 1479, the trial of the Maybug took place in Switzerland. The verdict ordered the beetles to leave the territory of the state, but there was no reaction from their side. The church was forced to admit that this insect was sent by God as a punishment for sins.
