Full and partial transformation of insect determines the difference in their development and functioning. This is especially true for development and adaptation to adverse conditions. Insects with complete transformation will be considered in our article.
General characteristics of the class Insects
Insects are the most numerous class of type Arthropods. 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. On the chest of most of them are wings. They are double folds of integument.
All insects are characterized by indirect development. This means that they have a larval stage. But its metamorphosis can proceed in different ways. For example, insects with complete transformation for a certain time are in the form of a pupa. During this period they do not eat, which provides them with a painless experience of adverse conditions.
Incomplete transformation
Consider the main phases that make up the complete and incomplete transformation of insects. As a result of fertilization, in both cases, the larva hatch from the egg. When developed with incomplete transformation, it generally resembles an adult, but does not have wings. Such a larva feeds and grows. Since its integument is 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 complete transformation molt at the larval stage, but after that they turn into a pupa. Representatives of the Orthoptera and Lice groups do not. Their larva immediately develops into an adult. Examples of such insects are grasshoppers, rears, bears, locusts, body lice and human lice.
That is, during development with incomplete transformation, insects go through the following stages: an egg, a larva, and an adult.
Full Insect Cycle
Complete transformation involves the development of a pupal larva. It does not look much like an adult. Pupae have no wings or eyes. Their limbs may be shortened or completely absent. Some insects form temporary larval organs. For example, moth caterpillars form false legs.
Insects with complete conversion molt several times at the larval stage. Then they pupate. During this period, an almost complete restructuring of the body occurs. At this stage, insects do not feed and do not move. There is a misconception that the chrysalis forms an additional cover on top. This is actually not the case. At all stages, insects are covered only with cuticles. Development from a larva to a pupa, and then to an adult insect is accompanied by periodic molting.
Fully Transformed Insects: Table
Insects that go through the pupal stage during development are more numerous. Since the animal may not eat during this period, it is possible to tolerate adverse conditions in this form. For example, many butterflies hibernate this way . Squads of insects with complete conversion and their main characteristics are presented in our table.
| Squad name | Signs | Representatives |
Beetles (Coleoptera) | Gnawing oral apparatus, hard elytra | Colorado potato beetle, dung beetle, grave digger, swimmer, ladybug |
| Butterflies (Lepidoptera) | Sucking mouthparts, webbed wings covered with scales | Swallowtail, hawthorn, lemongrass, admiral, peacock eye |
| Hymenoptera | Mouth organs of gnawing-licking type, membranous wings | Bee, Bumblebee, Hornet, Wasp, Ant |
| Two winged | Developed anterior pair of wings, hind wings transformed into ground beetles | Fly, mosquito, horsefly, gorse |
| Fleas | Wings are absent, mouth organs are piercing-sucking, legs are hopping | Human flea, rat |
Beetles
Coleopterans are the most numerous detachment. In total, there are about 300 thousand species. Representatives of the detachment can be found on all land and in fresh water. All of them have hard elytra, often painted in various colors. Remember how the Colorado potato beetle is visible against the background of green leaves. This color is called cautionary.
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: an egg, a larva, a pupa, an adult insect - an adult. Moreover, they all differ in appearance. If the larvae look like caterpillars, the imago 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 in translation from the Orthodox means "old woman, grandmother." This is due to the ancient belief that the souls of the dead infiltrate these insects.
The salivary glands of the butterfly caterpillars secrete a special substance from which the threads form. Of these, insects weave protective shells - cocoons or attach pupae to various objects. The threads of silkworm butterflies, the length of which can reach 2 km, are used to obtain natural fabrics.
Hymenoptera
It is impossible to imagine detachments of insects with complete transformation without public representatives of Hymenoptera. First of all, these are honey bees and ants. They live in large groups within which responsibilities are clearly distributed. So, the bee family consists of a queen (uterus), males - drones and numerous working individuals.
A similar pattern is observed in anthills. These insects are real workers. Building houses for themselves, they mix the soil, increase its porosity and enrich it with organic substances. Ants are also considered unsurpassed "strong men". These unique insects are able to lift weight, exceeding their own by about 25 times. This is possible due to the extreme force of their muscle contraction.
Two winged
Representatives of the order Two-winged are also insects with complete transformation. They are easy to recognize by the characteristic buzz. This sound occurs when the modified rear pair of wings oscillates. They are called buzzers and provide balance to the insect during flight.
Contrary to popular belief, the main food for mosquitoes is flower nectar. But females of some species really feed on the blood of humans and animals. This substance is necessary for them to form eggs. However, mosquitoes can carry dangerous diseases, such as malaria.
Flies are also dangerous insects. These seemingly harmless inhabitants of human dwelling eat food. Therefore, their larvae develop in accumulations of organic matter: garbage pits, trash 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 a complete transformation is fleas. As a result of the parasitic lifestyle, they are completely devoid of wings. They have a piercing-sucking mouth apparatus with which they feed on the blood of humans and mammals.
Fleas are very small. Their body, flattened laterally, barely reaches 5 mm. It increases in size due to the growth of the abdomen as it is filled 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 number of bacterial and viral diseases. These include salmonellosis, tularemia, hepatitis B and C, tick-borne encephalitis, typhus, plague, plague, myxomatosis.
So, insects with complete transformation, examples of which we examined in our article, are represented by the following orders: Beetles, Butterflies, Fleas, Webbed and Diptera. The larvae of these insects are significantly different from adults. And during the transformation they have a complete metamorphosis of the body. When developed with complete transformation, insects go through the stages of an egg, larva, pupa, and adult insect - imago.