Coleopterans, or beetles, are considered the largest detachment in the animal kingdom. More than one million species are known in the world, of which seven hundred thousand belong to the class of insects, three hundred thousand are winged. Every year, scientists find and describe dozens of new species.
Representatives of the order of beetles, or coleoptera, have rigid front wings, which can grow together in the middle of the back, thereby forming a special protective cover for the rear wings. Coleopterans are considered to be the only insects that use mainly hind wings for flight.
Beetle spread
They are distributed almost everywhere and are found in various places, for example, under logs, stones, in gravel near rivers, as well as in fresh water bodies. Under the bark of diseased trees or even in the remains of decaying animals, one can find larvae of representatives of beetles, or beetles.
Nutrition
For a squad of beetles, almost any animal or plant matter can become food.
Some species consume plants, the rest feed on insects, snails or other small invertebrates. In addition, there are species that like to eat decaying or dead tissues of animal or vegetable origin.
Structure and physiology
Representatives of beetles can be of various sizes. For example, the Hercules beetle, which is common in Central America, can grow up to fifteen centimeters in length, and other small beetles no longer than five millimeters.
The body of adults, as a rule, has three main parts - this is the head, chest and abdomen. Such a separation is the same for all representatives of insects. However, there are features with which you can distinguish beetles from other representatives of insects. Beetles raise elites during the flight, thereby creating lift, or they remain folded. However, in order to fly, most beetles need only to spread their wings and jump up. For this, large and heavy individuals need to crawl onto the plant and preheat under sunlight.
Head
Representatives of the Coleoptera have antennas on their heads, or they are also called antennae, as well as the oral organ, usually with horizontally moving parts of the gnawing type. The upper and lower jaws, the lower lip are included in the oral apparatus. For example, in phytophage beetles, the lower jaw looks down, and in predatory representatives it looks forward.
The organs of vision in the beetles are poorly developed, when compared with other insects, so they rely on a perfectly formed sense of smell. The exception is only predatory species. On the antennae are olfactory receptors. For example, in a dung beetle, they look like plates that are able to move apart and fold. Hearing is also poorly developed. Some representatives are able to produce different creaks due to the friction of body parts against each other. In addition, they make sounds by tapping their heads on hard objects. For example, a grinder beetle is able to tick, like a clock, tapping its head on a tree, where it makes moves.
Chest
The second part - the chest - consists of three segments. On the first is only a pair of legs. Basically, beetles have a larger prothorax than most insects. The next segment consists of leathery or strong (solid) elytra and a pair of legs. On the third segment or hind thorax there is a third pair of legs, the posterior membranous wings, capable of folding and hiding under the elytra.
Belly
Behind the chest is the body, which consists of several parts and is closed by the elytra from above. Representatives of the Coleoptera have a cuticle, which serves as the external skeleton and the cover of the body. As a rule, it is thicker and tougher than many other insects. Distinguish black, brown, shiny color. And in some beetles, it is covered with colored spots, stripes or a pattern similar to the natural environment in which it lives.
The mobility of beetles is very limited due to the fact that the covers of the body are hard, therefore, if the beetle is turned upside down on a flat surface, then in most cases it will not be able to take its original position on its own. The rigid cuticle, as well as the elytra, perfectly protect the insect from moisture loss and mechanical damage.
Internal structure
Representatives of the winged wing order have the same internal structure as the rest of the insects. Under the cuticle is the heart, and along the lower part there is a neural chain. Beetles have an open circulatory system, so the blood freely washes internal organs, and is not enclosed in arteries and veins. Coleopterans breathe air penetrating through special tubules on the sides of the body, and then it enters through the tubes to all tissues.
Some families of beetles
More than one hundred families of beetles are known. Coleoptera representatives (list):
- Swimmers. There are about 2100 representatives of this family. In adults, a smooth and streamlined body. Basically, these animals are painted black or dark brown. In males, large pads of a circular shape are located on the front legs.
- Leaf beetles. This family is recognized as one of the largest in the order of beetles. They feed mainly on plant foods. They have a spectacularly painted body with a metallic sheen, some representatives have a pattern composed of stripes. Some representatives, such as earthen fleas, jump well. The principle of the jump is the same as that of a grasshopper, due to the similar structure of the hind limbs, which have a thickening in the upper part.
- Little twigs. About four hundred species are known. They live in groups most often in the coastal zone of rivers and lakes. Insects have an oblong-oval shape. Apple seeds resemble their shiny, smooth appearance . The organ of vision is divided into lower and upper parts, which differ in the size of the facets and are adapted to see under and above the water.
- Horses There are approximately 1300 species. These are quite mobile and interesting insects that can be painted in red, blue or green with a metallic sheen on the underside. And on top is a sandy or ginger body with a pronounced pattern. Steeds are mainly found in sandy areas. They can be seen on hot sunny days. Thanks to sharp and long stings, they are able to quickly run and defend themselves from enemies.
- Ladybugs. There are more than three thousand species. They are classified as predators, although in external parameters they are completely different from them. They lack long legs, large and bulging eyes. It is likely that this is due to the fact that they prey on slowly moving prey, such as aphids, scale insects. These representatives of beetles have a round body slightly longer than a centimeter. Elytra orange or red, covered with black dots.
- Kozheedy. Representatives of this family are very small. Spotted body. They live on the remains of decaying animals, in pantries, under carpets, in furs, and skin.
In the life cycle, insect representatives of the beetles undergo a complete transformation, beginning with the stage of the egg and ending with the imago. An interesting fact: it turns out that every fifth living creature on planet Earth is a bug. An exact answer about their origin has not been found to date. The remains of ancient beetles are found in strata of 250 million years old, while it was a rare species of animal. Beetles are popular and favorite insects for collectors.