How insects breed: a description of the main ways and interesting facts

Anonim

In the world there are a huge number of insects, which can be found both in forests and fields, and in the house of man. Consider how insects breed.

Breeding features

For insects, sexual dimorphism is characteristic, that is, by appearance, it is quite easy to distinguish the male and the female. They have different sizes (with many species of females many times larger than males), differing in color, length of antennae. In some species of butterflies, females do not have wings.

Communication between representatives of the same sex species occurs in various ways:

  • With the help of features of behavior.
  • Sound and color cues.
  • Chemically - the release of pheromones.

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In certain species for fertilization, the contact of the male and the female is not required, these are the lower insects, whose habitat is rotten wood or soil. How do insects reproduce in this case? Males leave sperm droplets on the ground, and females capture them with special organs (sex appendages) located near the sex openings. This method is inherent in the representatives of the class with incomplete transformation:

  • Mantis
  • Cockroaches.
  • Bedbugs.

Other insects breed by mating individuals of different sexes, this phenomenon is called copulation.

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Most of the representatives of the class is inherent reproduction with the participation of individuals of both sexes, but in nature there are exceptions.

Ways

There are five main ways in which insects breed. Information about them is presented in the form of a table.

Description of insect breeding methods

The way

His brief description

Examples

Live birth

An embryo develops in the body of the maternal individual, and a larva or predoll is born.

Some types of flies and gadflies

Hamogenetic

Individuals of both sexes take part in the process, mating and laying eggs take place. In this way, a large number of insects breed.

Butterflies

Pedogenesis

Breeding at the stage of the larvae, the larvae develop in her body, which are eaten away by the mother's body to come out. The method is characteristic of coleoptera or hemiptera, often alternating with gamogenesis.

Some species of mosquito-gall midges

Parthenogenesis

Virgin reproduction, without fertilization.

Honeybee, some Hymenoptera

Polyembryony

Otherwise, this method is called multi-seed multiplication, it occurs at the egg stage. This method is characteristic of hymenoptera parasites: the egg of the parasite is deposited in the embryo of the host egg.

Riders

These are the main ways of breeding insects found in nature.

Parthenogenesis

Consider which insects are capable of breeding parthenogenetic. These are stick insects, some species of beetles, scale insects, aphids, many species of wasps, ants and bees.

This breeding can:

  • Males, in this case, the phenomenon is called arrenotoky.
  • Females, we are talking about telitoquii.
  • And those and others, this is amphithoquia.

It is accepted to distinguish several types of parthenogenesis, the differences of which are presented in the table.

Varieties of parthenogenesis

View

Short description

Optional

It has a partial character, it occurs only under the influence of external factors or with a special state of the female.

Cyclical

A vivid example is reproduction of aphids. There is an alternation of generations: virgin and bisexual, in this case, the offspring of the female, which did not receive fertilization, for a long time consists of females, however, the vegetation period always ends with amphitocia or arrhenotokya.

Constant

Most often observed in conditions of closed ground, under optimal external conditions, in the absence of the need to move to reproduction with the participation of both sexes.

This method of reproduction has an adaptive value, an individual of only one sex is engaged in the process, this helps insects survive even in adverse environmental conditions.

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Stages of development

Consider how insects multiply and develop. If the breeding process can take place with or without fertilization, then the development goes through several stages:

  • In the case of an incomplete transformation cycle, it includes three stages: the egg - the larva - is an adult individual (in science adults are called). In this case, the features of the structure of the larva practically do not distinguish it from the imago.
  • The complete cycle of transformation implies four stages: egg - larva - pupa - imago. The larvae are significantly different from adult insects.

These are the phases of insect development. The larva may molt several times, gradually increasing in size.

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Egg features

We looked at how insects breed. Now we will find out what is the peculiarity of their development at each of the phases.

The eggs of the representatives of the class are covered with two shells, have a very different shape, color and size. Most often in nature there are such forms:

  • ball;
  • oval;
  • hemisphere;
  • barrel.

For example, eggs of butterflies and flies are most often oval, and in bedbugs they are in the shape of an almost regular ball. Most often they are deposited in small groups - egg-laying, but in some species they can be deposited alone.

Larvae classification

By the type of larvae are:

  • Imago-like (nymphs) - in insects with incomplete transformation. As previously mentioned, they are not much different from adults, hence the name. Most often lead a way of life, similar to adults and eat the same.
  • Not imagoobraznye there are representatives of the class with full transformation. Have a simpler structure of the eyes and limbs than adults, there may be a completely different structure of the mouth.

Non-animal, in turn, are divided into three types:

  • Campoids - reminiscent of adults, quite active, are often predators.
  • Worm-like. These larvae are large, their body is almost not divided into departments, legs are short or may be completely absent.
  • Caterpillars are distinguished by the presence of several pairs of accessory legs.

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These are the main species of insect class larvae.

Pupa stage

Most often, the transformation of the larvae into a pupa occurs in the soil, less often - inside the plants or on them. The insect itself remains stationary, but inside it an intensive process of formation of adult tissues takes place. By the end of its development, the pupa becomes very similar to the adult, however, it is still possible to distinguish the pupa from the imago: the latter lack an additional protective shell.

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Curious facts

Having learned how insects breed, we will get acquainted with a selection of interesting facts:

  • Bees mate only once in a lifetime.
  • In mosquitoes, mating occurs in the fall, but the females lay eggs only in spring, that is, a rather long time elapses between copulation and fertilization.
  • Under certain circumstances, almost all insects are capable of breeding parthenogenetic, with the exception of dragonflies and bedbugs.
  • The process of mating ladybirds can take more than 10 hours.
  • After mating, the female mantis often eats the male to compensate for the lack of nutrients in the body.

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We reviewed briefly how insects breed. There are a lot of ways; they help populations to survive and spread, despite adverse environmental conditions.

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