beetle It is a small invertebrate of small size. It is an incredibly versatile animal, available in different shapes and sizes.

They attract attention in a number of ways: economic importance, size, abundance, appearance, and remarkable habits. Several groups, such as the Lampyridae, are the few terrestrial animals capable of producing light and others (Cerambycidae family) are capable of producing sound (stridulation). Large species produce a loud noise during flight and small species are attracted to light, both natural and artificial. Other groups attract attention for their strange habits, such as the undertakers of the Silphidae family and the Gyrinidae family.

Species

There are about 350.000 recognized species of beetles, which make up 40% of the total insects. Even so, biologists estimate that the total number of beetles is between 4 - 8 million species.

The ladybug is the best known beetle species
The ladybug is the best known beetle species

Features

The beetle varies greatly in size, some measuring millimeters and others reaching more than 200 mm in length like the rhinoceros beetle (Xyloryctes satyrus). Others choose to be wider like the goliath beetle (Goliathus goliathus) up to 75 mm wide.

Structure

The body is divided into three sections covered with a hardened outer shell: head, thorax, and abdomen. They also have antennas that are used to understand the environment around them and are made up of about 10 different sections. This structure varies among all species.

  • Carabidae Family: They are ground beetles that have the most primitive shape: the body is flattened and oval with a flat surface, with regular ridges or grooves; the antennae and legs are of moderate length and thin.
  • Hydrophilidae family: The body is oval, smooth and flattened; the antennae are short or very thin, and the front hind legs are short and the hind legs are long and surrounded by hairs that are used as shovels.
  • Staphylinidae family: They have very short corneal sheaths and a thin abdomen. The soldiers (Cantharidae), fireflies (Lampyridae) and net-winged beetles (Lycidae) have a soft corneal sheath.
  • Family Elateridae: It has a hinge-shaped joint in the thorax that allows it to break its body and jump into the air; their relatives, the Buprestidae they lack the ability to jump, but can fly very quickly.
  • Family Cleridae: They are oblong or cylindrical, active and of a bright color.
  • Family Nitidulidae: They are short and flattened, and have slightly shortened corneal sheaths.
  • Family CoccinellidaeKnown as ladybugs, they have a smooth, raised top surface and a flat bottom.
  • Family Endomychidae: They often have an enlarged, rounded corneal sheath.
  • Family Scarabaeoidea: They have a number of very strange shapes. Beetles (Dynastinae) have one or more horns on the head and sometimes even on the thorax. The so-called true beetles (Scarabaeinae) and other groups also have horns.
  • Family Lucanidae: They have very enlarged jaws; some are as long as the rest of the body.
  • Family Chrysomelidae: They can vary quite a bit in shape, from simple egg-like shapes to slender, flat or wedge-shaped shapes, with wide elytra, with spines or tubercles in the case of (Cassinadiane).
  • Family Bruchinae: They are short and stocky, with short, stout legs. The head, slightly elongated in front, is similar to that of some curculionid weevils.
  • Family Cerambycidae: Different shape and structure, they usually have antennae longer than the body. Cermbycids can be thin and medium to large in size or very small.
  • Family Tenebrionidae: They are not always recognized as members of the same family. Most of the arboreal (arboreal) forms in the tropics or subtropics are slender and long-legged. Some thin, egg-shaped shapes have a metallic sheen; Most of the forms of the house on the ground are black and robust.
    • Subfamily Lagriinae: They have a characteristic shape, generally flared back, and sometimes a metallic sheen.
  • Family Trictenotomidae: They resemble some cermbicides (Prioninae) but are not related to them. Aleculins (honeycomb beetles) resemble some of the slender tenebrionids, but are generally more active.

Behavior

The beetle is solitary, but some species form groups. For example, ground beetles (Carabidae) and the longhorn beetles (Cerambycidae) are usually solitary, while many other species such as the ladybugs (coccinellidae), The leaf beetles (Chrysomelidae), The fungus beetles (Erotylidae), The dark beetles (Tenebrionidae), The checkered beetles (Cleridae), The bee beetles (Passalidae), The sap beetles (Nitidulidae) and some species of beetles of the family (Scarabaeoidea) are prone to form groups of a single or several species, such as:

Group of beetles
Group of beetles

Habitat

Beetles inhabit the entire planet except for the polar regions and high altitudes. Many species are concentrated in temperate environments, but the number is higher in the tropics, generally the individuals are more abundant in temperate zones.

Many of them live underground, in water, or as commensals in the nests of social insects such as ants and termites.

Distribution

Beetles are found all over the planet except for the polar regions and high altitudes. They can be found on subantarctic islands, near the northern ends of the Arctic, and on many mountain tops.

Food

The beetle is an omnivorous animal; many are predators; some are scavengers; many are plant eaters (phytophagous); others eat fungi; and a few are parasites of other organisms.

Plant-eating species can eat foliage, pierce wood or fruit, and attack roots or flowers.

Some species feed on small birds and mammals. Others eat wood dust and therefore enjoy digging in trees.

Predators

The beetle is prey to numerous predators, from golds insects but also reptiles, birds, fish y mammals. The exact predators of the beetle are difficult to determine since they vary enormously between species and the area in which they inhabit.

Some species can be very well armed, and therefore very well protected against predators. Most suffer from parasitism; the shorthand fly lays its eggs in adults, and then its larvae feed from within their bodies. The larvae also have the same problem, for example, longhorn beetle (Cerambycidae) larvae are parasitized by wasps that inject their eggs into their bodies.

Some beetle predators particularly feed on beetle larvae, although many beetle larvae that feed on plants and on the ground are probably unpleasant to birds and other predators.

Reproduction

The beetle has a bisexual reproduction, although some species reproduce without fertilization (parthenogenetic) and are composed only of females.

The male reproductive organ is a hardened tubular structure called edema. The edeoagus enters a structure at the tip of the female's abdomen (bursa copulatrix) and the sperm are stored in a sac-like structure inside the female until they are needed to fertilize the eggs.

Beetles go through four different stages, before completing metamorphosis. The four stages are: egg, larva, pupa and adult. The length of each stage of the life cycle depends on the climate, habitat, and available food.

Almost all species of females lay eggs. Eggs vary in shape and can be laid singly or in groups. Usually they are placed in a place that allows full development of the larvae, such as on a leaf, bark, or tree trunks. This location will depend on the species, so they can also be placed near roots, inside flowers or fruits, in tree wounds, on aquatic plants, or under rocks.

Once the larva has hatched, it feeds until the skin becomes too small and breaks open; It is then that the larva crawls out of it and a new one begins to form that hardens. This process is called molting and is repeated three to five times (depending on the species) until the larva reaches maturity.

During the non-feeding period, it enters the pupal stage. The pupa forms under the final skin of the larva and emerges when split, resembling the adult with the exception that it is soft and pale. Furthermore the appendages are rolled to the body, and the wings are folded into flat bags.

When the pulp skin is shed, the wings are extended to full size, and the new exoskeleton hardens and takes on color. There is no increase in size in the exoskeleton.

State of conservation

Relationship with humans

The beetle performs a fundamental role in the ecosystem in which they inhabit. They are consumers of plant and animal waste, including fallen petals and animal manure. By ingesting decomposing material, thus cleaning the soil of carbon dioxide and nitrogen. If it were not cleaned by them, the soil would absolve them (being harmful to the surface).

As predators

Ground beetles (Carabidae) and rodent beetles (Staphylinidae) help control populations of many insects by being predators of caterpillars, larvae, insect eggs, and other adult soft-bodied insects.

The coccinellids (ladybugs and fireflies) are very beneficial for humans, avoiding large agricultural pests. Both in larval or adult stage they feed on plant sucking insects (Homoptera) such as aphids and scale insects.

As plant predators

Most phytophagous (plant-eating) beetles are harmful to humans, especially the (Chrysomelidae). The larvae feed on the leaves, stems or roots of plants and the adults chew them.

The (Scolytinae) both in larval and adult form are classified as serious pests. For example, him Asian longhorn beetle (Anoplophora glabripennis) feed under the bark of trees, damaged vital areas of living trees, alongside long-horned beetles (Cerambycidae) that pierce stems, trunks, roots, and cones of live and dead trees and large semi-woody grasses.

Those belonging to the Buprestidae (wood borers) family behave similarly to cermbicides and many kill trees or pierce branches. Scarabaeidae form pests on crop plants, lawns, and grasses. Hercules beetles form pests on palm trees, killing them by destroying growing points.

Sometimes articles made of wood can be seriously damaged by some species of beetles that bore dry wood, such as those belonging to the Lyetinae family, Anobiidae and Bostrichidae.

As scavengers

Some beetles are corroding. They decompose materials such as dead logs, wood used in houses (becoming pests), plant matter, dead animals and excrement.

Among the scavengers we can include families Scarabaeidae, Tenebrionidae, Silphidae y Dermestidae. Many of these species cause serious damage by feeding on dried animal materials. The larvae damage carpets, upholstery and clothing. However, some are valuable as scavengers. Zoologists use them to clean the skeletons of animals.

Disease transmission

I do not know the role of beetles in transmitting diseases to plants. By not sucking juices, as if other insects do, there should be lower percentages of transmitting diseases, however they sometimes manage to transmit it. It is thought that it may be because they carry certain fungal spores in the body, for example, the fungus that causes Dutch elm disease is transmitted by the beetle scolytus multistriatus.

Popular culture

In ancient Egypt some species of beetles were revered. There is the hieroglyphic image of the scarab that could have an existential, fictitious or ontological meaning. Scarabs are mentioned as a symbol of the sun, as in ancient Egypt, in the XNUMXst century of Plutarch, in Moralia. The Greek Magical Papyri from the XNUMXnd century BC to the XNUMXth century AD describe beetles as an ingredient in a spell.

In Asian countries beetle fights are organized. In this sport the territorial behavior and the competition for the mating of certain large species are exploited. In Thailand, beetles of the Xylotrupes species are taken from the wild for training. The female is kept inside a trunk to stimulate it with her pheromones. These fights can be competitive and involve both money and property bets. In south korea, the species Dytiscidae Cybister tripunctatus it is used in a game of roulette.

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