Currently, over 300,000 species of beetles inhabit planet Earth. These insects can be found anywhere except the polar snow caps: in hot deserts, humid jungles, dry steppes, and in salt or fresh water. They come in a wide range of sizes: from 1 mm to 30 cm or more! They can move exclusively on land, have one or two pairs of wings, or swim in the water.
These amazing animals occupy a very important place Beetles play a role in many ecological chains: they provide food for birds, insectivores, and other beetles. Beetles themselves can be predators and control populations of other, smaller beetles or insects. Some beetles feed on plants, thereby controlling the growth of producers.
General information
The structure of all beetles is certainly It varies, but in generalIt can always be described. Most beetles have a distinct head, which likely contains antennae, eyes, and mouthparts. Behind the head is the next body section—the thorax. Relative to the head, it is less mobile. The first and second pairs of legs are located on the thorax. The last body segment is the abdomen. It contains the last pair of legs, the openings of excretory glands and secretions, which the beetle uses to mark territory or leave a trail for communication with other beetles, and the spiracles.
Between the abdominal and thoracic sections are located the wings. Both wings are hidden under hard elytra, which serves as protection against external damage. These wings often develop in beetles during the pupal stage, forming from initial tissues. Many people often wonder: "How many wings does a beetle have?" Beetles can have no more than two wings, that is, no more than one pair.
The entire body of the beetle is covered hard chitinous cover, which functions as an exoskeleton. This covering also protects the beetle's internal organs from mechanical damage. The same material is also used to make the hard elytra, which cover the beetle's wings when at rest and protect them from damage.
The structure of the mouth apparatus of beetles
The beetle's head, and in particular the mouth apparatus, consists of several components:
- Upper lip;
- Lower lip;
- Gnawing organs;
- Feelers;
The upper lip is called the labrum and is a fold of skin, which covers the mouthparts when at rest. It contains numerous sensitive taste and tactile receptors. These help the insect determine whether objects are edible. The chewing organs—the mandibles and maxillae (upper and lower jaws, respectively)—rest beneath it.
Their number is equal, meaning the beetle has as many maxillae as it has mandibles. These maxillae have serrated appendages that help the jaws grasp prey, tear off small pieces, and grind them for as long as necessary to produce manageable pieces. The food is then ground and, with the help of the maxillae and labium, carried deeper into the oral cavity, as close to the esophagus as possible.
Various types of palps (labial, maxillary, and others) located on the head provide the beetle with essential information about the world around it, as most insects have relatively poor vision. The palps can detect the scents of potential mates or danger, air vibrations, and temperature changes. They can also act as a tactile organ, examining unfamiliar substrates or food.
Gnawing functions
The gnawing mouth apparatus serves its owner not only as an effective organ of nutrition, but also as a means of defense against predators and intruders: the opposing muscles that spread the mandibles horizontally possess remarkable strength, allowing ants to hold objects several thousand times heavier than themselves. Such a bite is not dangerous (unless the beetle has venom glands), but it is quite painful and can distract the attacker for a short time, allowing the beetle to escape unharmed.
The food of beetles with a gnawing type of structure is often beetles become smaller(Examples of such predators include ground beetles and ladybugs), parts of plants, or entire plants (many species of caterpillars, grasshoppers, and locusts). Paper wasps use their mandibles to tear off small sections of bark and old wood from dry stumps, then "chew" them, thoroughly mixing them with sticky saliva and turning them into a sticky pulp that is quite strong and hard after drying. This is what they will later use to build their nest.
The structure of the mouthparts varies greatly among beetles, depending on their dietary preferences, habitat, size, and ecological niche. However, the general outline above applies to any beetle.
Other types of oral appliances
The mouthparts of beetles belongs to the gnawing typeIt is believed that the other types evolved from the gnawing mouth apparatus:
- Sucking;
- Licking;
- Piercing-sucking;
- Gnawing and licking;
These types are also widely found among insects around usLepidoptera, such as butterflies and moths, possess the sucking type. These insects feed on flower nectar, and their long, hollow proboscis helps them extract nutrients from deep within the flowers. Flies possess the licking type. The main structure of this type is a hypertrophied lower lip, modified into a proboscis, which the fly uses to capture particles of liquid food (jam or honey) and deliver them to the esophagus.
Everyone knows mosquitoes have a piercing-sucking mouth apparatus, formed from the labrum and two pairs of jaws. The hollow tube is adapted for piercing the upper layer of tissue and extracting the contents. All Hymenoptera possess the gnawing-licking type. This type is formed from modified labrum and maxillae.
In fact there are many types of oral apparatus, but they all evolved from gnawing beetles. However, it is often very difficult to determine how certain parts of a new type evolved. Therefore, the study of beetles and their mutations continues to this day, and the number of species increases daily.
