The ground beetle is a beetle with a colorful back that lives almost everywhere. There are other names: scorers, jumpers, garden beetles. Some of them are very useful for cultivated plants, and some bring only harm. Who are the ground beetles, we will now try to figure it out.
Origin of the species and description
Ground beetles (Carabidae) are a family of beetles, class insects, such as arthropods, order Coleoptera. The name of the beetles comes from the word «buzz». Entomologists know about 40 thousand species of ground beetles, and at least 3 thousand species can be observed on the territory of Russia alone. All of them belong to the same genus, but at the same time they have some differences among themselves: in size, color and even in appearance.
Video: Ground beetle
Ground beetles are usually dark in color, sometimes with a bright steely sheen of green, blue and gold. Occasionally you can find red and red shades. If you look closely at the metallic sheen, you can see a lot of very thin stripes. The body length of different types of ground beetles varies from 1 to 10 cm.
The most interesting types of ground beetles:
- Caucasian ground beetle. It lives mainly in the north of the Caucasus, but is often found in the Krasnodar Territory. The Caucasian ground beetle has a bright bluish, sometimes purple or greenish color. The number of the species is rapidly declining, which is why it is listed in the Red Book of Russia;
- Ground beetle Crimean. The species occurs only on the territory of the Crimean Peninsula and is active mainly at night. This beetle is quite large – its body length often reaches 6 cm.
Interesting fact: In the back of the body, the Crimean ground beetle has glands with a caustic, but not poisonous liquid, with which «shoots» at your enemies up to 2 meters away.
Appearance and Features
Everyone has a head species of ground beetles are small in size and usually directed forward. It has a gnawing mouth apparatus with rather strong and sharp jaws. The shape of the jaws can be different and depends on the food preferences of a particular species.
For example, predators are characterized by long sickle-shaped mandibles, with which they grab and hold their prey tightly. Vegetarian ground beetles are characterized by large and blunt jaws, which are well suited for grinding plant fibers.
The size of the eyes of ground beetles depends on their lifestyle: in burrowing and cave species, they are very small, barely noticeable, in nocturnal species – larger, in twilight and diurnal species the eyes are large. The antennae of beetles are usually thin, consisting of eleven segments.
The body shape of most is oval, slightly elongated, but there are also varieties that have a different shape:
- round, biconvex;
- convex with constriction and large head, similar to ants;
- round, unilaterally convex;
Ground beetles, like all insects, have 6 legs, consisting of five segments. Their form, appearance and functionality depend on the mode of movement. For example, burrowing species are characterized by short and wide limbs with sharp teeth, while all other species are long and thin. It is noteworthy that on the lower leg of each foot there is a special notch, with which the beetles clean their antennae.
The wings of ground beetles can be different even among representatives of the same species: short or long, well developed or not very well developed. The elytra of beetles are rigid, can be both relatively even and covered with grooves or bulges of various shapes. In wingless species, the elytra fuse and form a single surface.
Sexual dimorphism in ground beetles is markedly pronounced. For example, females are always larger than males. Also in males, the front legs and longer antennae are expanded and noticeably pubescent. The color of ground beetles can be different, but with a predominance of darker tones, as well as with a metallic and iridescent tint. Ground beetle species living on plants and near water bodies are usually brighter: blue, green, purple.
Now you know what a ground beetle looks like. Let's see where this beetle lives.
Where does the ground beetle live?
Ground beetles are insects that are distributed almost everywhere around the globe, except for Antarctica. They can be found in Europe and Asia, Africa, Australia, North and South America, and in a variety of climatic zones. There are species that can survive at sub-zero temperatures and species that are resistant to drought.
Since the species diversity of ground beetles is quite large, they can be found in the tropics and subtropics, in temperate climates, in the taiga and tundra. Their habitats are also very different: the zone of forests and steppes, savannahs and deserts, forest-steppes and semi-deserts, humid tropical jungles and highlands.
For their livelihoods, ground beetles, as a rule, choose:
- upper layers of soil (in fields, meadows and garden plots);
- the bark of old trees and fallen leaves (in forests and parks);
- cracks, caves and crevices (in mountains).
Among the many species of ground beetles, entomologists also distinguish many diurnal and nocturnal species, but with a small caveat. Its essence lies in the fact that the most determining criterion for activity for beetles is not the presence or absence of sunlight at one time or another of the day, but increased air humidity. Indeed, in spring, when air humidity is high, nocturnal species tend to be active in the daytime.
What does the ground beetle eat?
As you know, ground beetles live in fields, forests, parks, household plots, gardens, in general, where there are many different small living creatures that run, crawl or fly. Food preferences of ground beetles: snails, slugs, larvae of other insects, caterpillars, aphids.
Thanks to this «menu» Predatory beetles are highly revered by gardeners, as they make a significant contribution to the ongoing fight against pests. The principle of hunting for ground beetles is quite simple. When the beetle sees its prey and is ready to attack it, a special paralyzing fluid appears in its jaw glands. The beetle sprays its prey with this liquid, waits for a few minutes and starts eating.
This liquid contains substances that immobilize and soften the victim, turning it into a semi-liquid slurry. The beetle absorbs this slurry and returns to the shelter for several days – to digest food and rest. After a couple of days, the beetle comes out of hiding and starts hunting again.
Among the ground beetles, there are predatory species, species with a mixed diet, as well as vegetarian species. Among the latter, the most dangerous for plants are one of the representatives of the genus Zabrus & # 8212; bread beetles. They feed mainly on semi-ripe grains of cereal plants: rye, wheat, barley, oats, corn, which cause irreparable harm to agriculture.
Ground beetle larvae generally feed in much the same way as adults, with the exception of a few species. In larvae, parasitism on the larvae of other insects is also very common.
Character and lifestyle features
Most species of ground beetles lead a terrestrial lifestyle, preferring a layer of rotted fallen leaves or a layer of dry last year's grass. However, there are also ground beetles living on plants, soil or parasitic.
Most often, beetles equip themselves with a refuge among fallen leaves, under stones, at the roots of trees, in the grass. Some species also live on the branches of trees at a height of up to three meters. The main conditions for their habitat are a stable temperature, high humidity, shading.
According to the latest scientific observations, ground beetles are considered insects living in small groups, which allows them to successfully hunt not only insects, but also larger prey, such as small lizards.
The way of life of ground beetles is mostly nocturnal, although there are exclusively diurnal species. From the onset of darkness, all members of a small family go hunting, and early in the morning, before dawn, everyone hides in the shade.
With the onset of autumn, in the middle lane it is about mid-October, when the average daily temperature is already low, ground beetles burrow into the ground to a depth of half a meter and hibernate. Approximately in the middle of March or a little later, depending on the weather, the beetles come to the surface and continue their life cycle again.
The life span of different species of ground beetles differs, and radically. For example, there are ground beetles that live only one year and give only one generation of offspring in their short life. There are also species that live 2-5 years or more.
Social structure and reproduction
Reproduction in ground beetles begins at the age of 9-12 months.
Entomologists distinguish the following types of annual rhythm of ground beetles:
- the mating season occurs in the spring (the development of the larvae occurs in the summer, and insects in the adult stage fall into hibernation);
- the mating season occurs in the summer or autumn (the larva hibernates, there is no summer hibernation);
- mating season occurs in summer or autumn (the larva hibernates, there is summer hibernation); li>Mating and development take over a year.
An interesting fact: Some species of ground beetles living in the tropics and subtropics breed twice a year.
Ground beetles are insects with complete transformation, that is, they go through 4 stages in their development: egg , larva, pupa, adult. In the middle lane, the mating season for ground beetles begins in late April or early May. After mating, the female makes a clutch at a depth of 3-5 cm. One clutch may consist of 20-80 eggs. The place of masonry should be dark, warm and humid. The soil should be rich in humus.
In species of ground beetles, which are characterized by care for offspring, there are fewer eggs in the clutch and they are larger, in other species the eggs are rather small, but there are many times more of them. In shape, the eggs can be in the form of an elongated oval or a cylinder rounded at the ends with a thin translucent yellowish or white shell, through which the larva can be seen by the end of incubation.
In most species of ground beetles, care for offspring consists in choosing the most suitable place for laying eggs, however, there are species in which it takes on more complex forms. For example, in the Pterostichini ground beetles, the female guards the eggs until the larvae hatch, protecting them from encroachment by other beetles and from mold infection. feeding them with caterpillars and earthworms. In the ground beetle Harpalini, the female lays a stock of plant seeds in the nest chamber, which are then eaten by the hatched larvae.
Ground beetle larvae have an elongated body (up to 2 cm in length) with a large head, large mouth, segmented abdomen, and short legs. They eat, as a rule, the same as adult beetles. In the process of growth, the larvae molt three times. The pupae of ground beetles are naked, without a shell, very reminiscent of adults. They lie in a depression made in the soil, some species pupate in a cocoon. The pupal stage usually lasts 7–12 days.
Beetle natural enemies
It is known that the ground beetle feeds on both adult pests of gardens and orchards and their larvae, preventing them from multiplying quickly and thereby bringing great benefits. So if there are ground beetles on the garden plot, you should not destroy them, because their benefits are invaluable. It has been estimated that, on average, one adult ground beetle per season is capable of destroying 150-300 caterpillars, pupae and larvae. Thus, most species of these beetles are orderlies of forests, orchards, fields and orchards.
Despite the fact that most species of ground beetles are carnivorous insects, beetles, their eggs and larvae are not averse to dine on many types of insects, such as ants, as well as many species of both small and large birds. Also, hedgehogs and badgers like to feast on ground beetles, and in the taiga even such large animals as bears and wild pigs do not disdain these beetles.
It is noteworthy that ants prefer to climb into the nesting chambers of ground beetles and carry away their eggs, either live or larvae, although sometimes they are not averse to dragging a dead adult beetle into the anthill. Ants do not touch living beetles, because they themselves can become its prey. After all, ground beetles spray liquid on their prey, which actually turns it alive into mush.
Population and species status
Ground beetles are a fairly large family of beetles, which, according to various estimates of entomologists, contains 25-50 thousand species. Most of them are carnivorous insects, which in turn works great as a deterrent to the spread of insect pests.
Despite the abundance and diversity of ground beetles, there are many species that are declining:
- ground beetle Shagreeneva (found throughout Europe and in the European part of Russia; beetles are listed in the Red Book of the Smolensk region, the Chuvash Republic, Lithuania, Belarus); , listed in the Red Book of Russia, Georgia);
- Crimean ground beetle (found only within the Crimean peninsula; due to its large size and spectacular appearance, it is very popular with collectors, which is why its number is decreasing, it is listed to the Red Book of Ukraine);
- ground beetle krasotel odorous (lives in the forests of most European countries, in Belarus, Moldova, Georgia, in some countries of Central Asia; the insect is listed in the Red Book of Europe and the Red Book of Russia);
- Lopatin-Yankovsky ground beetle (found on the European part of the territory of Russia; it is listed in the Red Book of Russia as an exceptionally rare species).
Numbers rare species of ground beetles are constantly declining in all their habitats.
The following factors contribute to this:
- expansion of recreational areas;
- weak ability of beetles to migrate;
- frequent treatment of forest and agricultural land with pesticides and fungicides;
- in order to preserve rare species of ground beetles and increase their numbers, it is necessary to introduce a strict ban on collecting insects, the widespread reconstruction of forest park areas in their habitats, and also start mass breeding in captivity.
Moreover, the latter has long been practiced in order to combat pests of agricultural crops. For this, special containers are equipped – cages (aquariums) with soil and a layer of moss or rotten leaves. Several pairs of ground beetles, water and their usual food are placed there. Ground beetles live there, mate and successfully lay eggs.
After hatching, the larvae are removed and placed separately. The larvae are usually fed with snails, caterpillars, slugs, earthworms. For wintering, the cage with larvae is placed in a specially equipped basement or refrigerator.
In the spring, when the larvae pupate, the containers with them are transferred to a warmer room. After a couple of weeks of days, adult beetles crawl out of the soil layer, which are then released into areas with pests. The industrial use of ground beetles is not a mass phenomenon, since it is quite difficult to breed these beetles in captivity.
Most gardeners and gardeners, when they see such an insect as a ground beetle on their site, do not even suspect and do not realize that these insects can be very helpful. Therefore, often when they see them, they immediately try to destroy them. There are actually a lot of species of ground beetles, and among them there is only one species that is a serious pest – the bread beetle (humped peun).