Complete and incomplete transformation of insects determines the difference in their development and life. This is especially true of development and adaptation to adverse conditions. Insects with full metamorphosis will be discussed in our article.
General characteristics of the class Insects
Insects are the most numerous class of the phylum Arthropoda. Their distinguishing features are the differentiation of the body into the head, chest and abdomen, as well as the presence of jointed limbs. Insects have six walking legs and one pair of antennae. Most of them have wings on their chests. They are double folds of covers.
All insects are characterized by indirect development. This means they are in the larval stage. But her metamorphosis can proceed in different ways. For example, insects with complete transformation are in the form of a chrysalis for a certain time. During this period, they do not eat, which provides them with a painless experience of adverse conditions.
Incomplete transformation
Let's consider the main phases thatmake up the complete and incomplete transformation of insects. As a result of fertilization, in both cases, a larva hatches from the egg. When developing with incomplete transformation, it generally resembles an adult, but does not have wings. Such a larva feeds and grows. Since its covers are not capable of stretching, this stage is accompanied by molting. Only under this condition is it possible to increase in size and its transformation into an adult.
Insects with full metamorphosis molt at the larval stage, but after that turn into a pupa. This does not happen with representatives of the Orthoptera and Lice orders. Their larva immediately develops into an adult. Examples of such insects are grasshoppers, grasshoppers, bears, locusts, body lice and human lice.
That is, during development with incomplete transformation, insects go through the following stages: egg, larva and adult.
Insect cycle with complete metamorphosis
Full transformation involves development from a larva to a pupa. She bears little resemblance to an adult. The pupae do not have wings or eyes. Their limbs may be shortened or absent altogether. Some insects develop temporary larval organs. For example, butterfly caterpillars develop false legs.
Insects with full metamorphosis molt several times at the larval stage. Then they pupate. During this period, there is an almost complete restructuring of the body. At this stage, insects do not feed and do not move. There is a misconception that the chrysalis forms from aboveextra cover. Actually it is not. At all stages, the insects are covered only by the cuticle. Development from larva to pupa, and then to an adult insect, is accompanied by periodic molts.
Insects with full metamorphosis: table
Insects that go through the pupal stage during development are more numerous. Since during this period the animal may not eat, it is possible to endure adverse conditions in this form. For example, this is how many butterflies hibernate. Insect squads with full transformation and their main characteristics are presented in our table.
| Squad name | Signs | Representatives |
| Beetles (Coleoptera) | Gnawing mouthparts, hard elytra | Colorado beetle, dung beetle, gravedigger, swimmer, ladybug |
| Butterflies (Lepidoptera) | Sucking mouthparts, membranous wings covered with scales | Swallowtail, hawk, lemongrass, admiral, peacock eye |
| Hymenoptera | Mouth organs of gnawing-licking type, membranous wings | Bee, bumblebee, hornet, wasp, ant |
| Diptera | Developed front pair of wings, hind wings turned into h alteres | Fly, mosquito, horsefly, hoverfly |
| Fleas | No wings, mouthparts piercing-sucking, jumping legs | Flea human, rat |
Beetles
Coleoptera are the most numerous order. In general, there are about 300 thousand species. Representatives of the detachment can be found on all areas of land and in fresh water. All of them have hard elytra, often painted in various colors. Remember how noticeable the Colorado potato beetle is against the background of green leaves. This coloration is called warning.
Beetles feed on leaves or smaller animals. So, ladybugs eat aphids, and beauties eat butterfly caterpillars. The development of insects with complete transformation, including beetles, occurs in several stages: egg, larva, pupa, adult insect - imago. Moreover, they all differ in external signs. If the larvae look like caterpillars, then the adult has all the signs of arthropods.
Lepidoptera
Insects with complete transformation, examples of which we will now consider, are one of the most beautiful representatives of the animal world. Their scientific name is associated with the structure of the wings, which are covered with scales. But everyone is used to calling them butterflies, which means "old woman, grandmother" in Orthodox. This is due to the ancient belief that these insects are inhabited by the souls of the dead.
The salivary glands of butterfly caterpillars secrete a special substance from which threads are formed. Of these, insects weave protective shells - cocoons or attach pupae to various objects. Threads of silkworm butterflies, the length of which can reach 2 km,used to obtain natural fabrics.
Hymenoptera
Squads of insects with complete metamorphosis cannot be imagined without social representatives of the Hymenoptera. First of all, these are honey bees and ants. They live in large groups, within which responsibilities are clearly distributed. Thus, a bee colony consists of a queen (womb), male drones and numerous workers.
A similar pattern is observed in anthills. These insects are real workers. By building their own dwellings, they mix the soil, increase its porosity and enrich it with organic matter. Ants are also considered unsurpassed "strongmen". These unique insects are capable of lifting up to 25 times their own weight. This is possible due to the extreme force of contraction of their muscles.
Diptera
Representatives of the order Diptera are also insects with complete metamorphosis. They are easily recognizable by their characteristic hum. This sound occurs when the modified rear pair of wings vibrates. They are called h alteres and provide balance to the insect during flight.
Contrary to popular belief, the main food of mosquitoes is the nectar of flowers. But the females of some species really feed on the blood of humans and animals. This substance is necessary for them to form eggs. At the same time, mosquitoes can carry dangerous diseases, such as malaria.
Dangerousflies are also insects. These, at first glance, harmless, the inhabitants of human dwellings eat food. Therefore, their larvae develop in accumulations of organic matter: garbage pits, waste bins, animal corpses. As a result, on the surface of their body and in the digestive tract contains a huge amount of viruses, helminth eggs, bacterial spores. They flies and contaminate food. Using them, a person can become infected with dysentery, typhoid, tuberculosis and other dangerous diseases.
Fleas
Another blood-sucking insect with complete metamorphosis is fleas. As a result of their parasitic lifestyle, they are completely devoid of wings. They have piercing-sucking mouthparts that feed on the blood of humans and mammals.
Fleas are very small. Their body, flattened from the sides, barely reaches 5 mm. It increases in size due to the growth of the abdomen as it fills with blood. But flea larvae feed on organic debris. Therefore, they can be found on the floor of residential buildings and rodent burrows.
Fleas are very dangerous. They carry a range of bacterial and viral diseases. These include salmonellosis, tularemia, hepatitis B and C, tick-borne encephalitis, typhus, plague, myxomatosis.
So, insects with complete transformation, examples of which we examined in our article, are represented by the following orders: Beetles, Butterflies, Fleas, Hymenoptera and Diptera. The larvae of these insects differ significantly from the adults. And in the course of transformation, they undergo a complete metamorphosis of the body. When developing with fulltransformation insects go through the stages of eggs, larvae, pupa and adult insects - imago.
