Insects are the most diverse class of animals in terms of species composition, which differ from each other in various ways. One of them is the type of transformation in the process of individual development.
Types of insect development
In all representatives of this class, a newborn individual differs significantly from adults. This type of development is called indirect. But in different groups of insects, it can occur with complete and incomplete transformation. Often, the larva and the adult differ not only in appearance, but also in the ways of life. So, the butterfly larva feeds on green foliage, and the adult - on flower nectar. Insects, which are characterized by incomplete transformation, lead the same way of life at all stages of development.
The term "transformation" itself means the presence of a larval stage in the process of individual development. Only the ontogeny of insects can occur in different ways.
Full and incomplete transformation
In some insects, a larva hatches from an egg, in general terms resembling an adult - an imago. These are individuals with incomplete transformation. Themthe larvae are immediately capable of self-feeding, growth and molting, after the last of which they turn into adult insects. For example, incomplete transformation is characteristic of cockroaches. In the course of their development, they go through the following stages: egg, larva, adult.
Different types of beetles, butterflies, bees, bumblebees, ants and mosquitoes develop with complete transformation. Their larvae are largely visually distinct from adults. This primarily consists in the absence of wings, compound eyes. In addition, the larvae have shortened or missing limbs, and the mouthparts are modified. After this stage, insects with complete metamorphosis pupate. This process is very important. At the pupal stage, insects do not feed and practically do not move, which ensures the survival of adverse conditions. The duration of this period varies from 6 days to several months, depending on the species. In the photo you can see the larvae of the Colorado potato beetle, which, you see, barely resemble an adult.
Insects with incomplete metamorphosis
This group of animals includes representatives of the orders Termites, Orthoptera, Lice, Bedbugs, Praying Mantises, etc. Incomplete transformation means that the appearance and lifestyle of newly appeared larvae is no different from adults. For example, in all parasitic bugs at different stages, the body is flattened, and wings are absent. And termites have very thin, and sometimes transparent covers that persist forof life.
Orthoptera Order
Incomplete transformation is also a hallmark of all representatives of the order Orthoptera. They are quite diverse: in total in nature there are more than 20 thousand species. Orthoptera are easily distinguished from other insects by their leathery hind elytra. During the flight, they fan-shaped unfold. This device serves as a reliable protection for membranous thin wings. Also characteristic features of this detachment are the mouthparts of the gnawing type and the hind legs, capable of jumping quite high and long in relation to the size of the insect itself.
Incomplete metamorphosis is characteristic of all Orthoptera. These are well-known grasshoppers. And the owners of gardens and orchards will surely remember the bear, which is a pest of the root systems of many cultivated plants. This insect has well-developed digging legs, with which it makes long passages in the soil.
Locusts are also Orthopterous herbivorous insects with indirect development. They pose a significant threat to agriculture, as they destroy everything in their path when flying from place to place. And above all - the harvest of cultivated plants, because they are very voracious.
Lice Squad
Surely many recognized the wingless parasitic insects depicted in the photograph. It's lice. Attached to the hairs on the host's body with movable clawseach leg, they feed on his blood. To do this, lice have a characteristic mouth apparatus of a piercing-sucking type.
These insects are very dangerous. The human louse is a carrier of diseases such as relapsing fever and typhus. For a long time there were no drugs against them. During severe epidemics over the past century, about 30 million people died from typhus. To avoid infection with lice, you need to follow basic hygiene rules: do not use other people's combs, towels, clothes, hats.
Thus, incomplete transformation is one of the types of indirect development of insects, in which there is no pupal stage, and the larva is morphologically and anatomically similar to an adult - imago.
