Biology of beetles

Beetles are a well-defined group of insects. Their main common feature is the hard front wings, or elytra, covering the abdomen on top and the hind membranous wings folded on it (and under the elytra). The second pair of wings either retains the membranous structure usual for flying insects, or is reduced; rarely both pairs are absent. The line of contact between the elytra is called a suture in beetles; The outer edges of the elytra are usually delimited by narrow longitudinal stripes - epipleurae. At the posterior edge of the pronotum, a scutum is often visible - a portion of the mesotunum not covered by the elytra. The prothorax is movably articulated with the head and mesothorax; the metathorax is motionlessly fused to the mesothorax and abdomen. The mouthparts are gnawing. In some groups of beetles, the elytra are sometimes greatly shortened and almost do not cover the abdomen. Then the membranous wings either fold even more strongly and still hide under the elytra, or lie open on the surface of the abdomen. Some beetles, on the contrary, lose their second pair of wings and are unable to fly. These beetles are often called wingless, although they always retain the first pair of wings - the elytra. The elytra of wingless species are sometimes fused.

In general, all beetles are similar to each other, but the difference in growth is very large: from 0.25 millimeters to 18 centimeters. The largest beetles are hundreds of thousands of times heavier than the smallest mammals, such as some bats and shrews.

Beetles have been known since the Permian period (280–230 million years ago). The number of described species is approaching 300 thousand. Consequently, there are approximately 6 times more different types of beetles on Earth than vertebrates.

So, on Earth there are about 300 thousand (more precisely, 272) species of Coleoptera known to science. But this number does not exhaust the diversity of the beetle tribe: every year, researchers around the world discover and describe thousands of new species and subspecies of beetles. How many are there really? As some entomologists suggest, at least half a million species. According to literary sources, from 270 thousand to 1 million are known. There are about 20 thousand species of beetles in Russia. And we will limit ourselves only to those who are interesting in behavior, lifestyle, significance (harmful or useful) in a person’s economy, or simply some other qualities, say, unusually large growth.

Beetles, or Coleoptera. These insects are called Coleoptera because they have dense, hard wings of the front pair - the so-called elytra, which cover, like a lid, the thin, transparent wings of the rear pair and the abdomen. Another common feature shared by all beetles is their gnawing mouthparts. The antennae of representatives of different families are very diverse: thread-like, lamellar, club-shaped, comb-shaped - beetles are often identified by them.

Based on the nature of their diet, there are three main groups of beetles: carnivorous, feeding on various invertebrates, mainly insects; consumers of decomposing plant and animal residues; herbivores and animal remains;

Family of Ground Beetles

Ground beetles are usually small or medium-sized; Relatively few species are large (up to 50mm). The whiskers are thread-like or bristle-like; gnawing mouth parts are well developed; legs walking or running. Typical terrestrial inhabitants whose life activity is associated with the forest litter or upper layers of soil. Mainly predators; They feed on all kinds of invertebrates - insects, mollusks, earthworms. Some species consume not only animal, but also plant food; Purely herbivorous forms are also known, among which there are dangerous agricultural pests. There are more than 2,300 species.

Ground beetle. Black, usually with a bronze tint; base of pronotum densely punctured; elytra with longitudinal rows of deep punctures. Body length 14 – 16mm. Adults and larvae are dangerous pests of many agricultural herbaceous plants, especially cereals. The beetles feed on their seeds. The larvae eat the young leaves of the seedlings, leaving only veins. They often drag leaves into burrows and feed on them. In places where larvae accumulate, plants die and bare spots appear on the crops. The greatest damage is caused to winter wheat. The ground beetle is part of the genus Zabrus.

Ground beetle granular. Elytra with a notch on the lateral margin in front of the apex, flat above with three longitudinal rows of large elongated tubercles and barely visible pits; on the pronotum there are evenly and densely located points; body length 17-23 mm. Common near water and in damp places.

Forest ground beetle. Black ground beetle with a bronze sheen, 20–26 mm in size. The edges of the thorax and elytra are purple, and there are three rows of small dots on the elytra. Common in forests, as well as in city gardens and parks.

Field horse. Brightly colored: grass-green above, blue-violet below, elytra on the sides and in the middle with white spots. Body length 12-15 mm.

Found along forest roads, on the slopes of sandy hills, along sandy river banks. Distributed in the taiga zone, except for the extreme northern regions.