04.05.2018 change 04.05.2018

Expert: Curious behaviour of insects during courtship and mating

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To persuade females to mate, males of some species of insects bring them gifts; others put "chastity belts" on their mates, preventing copulation with other partners. Curious mating behaviour of insects allows them to quickly colonize new spaces.

Insects undoubtedly amaze in terms of the complexity of their breeding behaviours as well as sophisticated techniques, says Dr. Radomir Jaskuła from the Department of Invertebrate Zoology and Hydrobiology, University of Lodz.

Insects live all over the world, inhabiting very different habitats. The fact that there are about a million known species of insects is the result of sex selection, including mating behaviours that can be very complex.

For example, some species of damselflies, found also in Poland, are able to persuade their chosen ones to mate with them by very complex mating dances performed in flight.

Other insects bring gifts to gain the favour of their chosen ones. This behaviour is typical for scorpionflies. "They steal insects from spider`s nets. For a female it is a message that if a male is able to steal a victim from a spider`s web, it must have very good genes, because he not only stole it, he also did not get caught" - says the expert.

In the case of some orthopterans, males put something that can be compared to "chastity belts" on females after mating. "It is a special protein secretion that hardens in contact with air. Thus, it prevents copulation with another male" - adds Dr. Jaskuła.

In turn, some species of moths, including those found in Poland, leave physical "obstacles" in the form of chitinic spines in addition to semen in the reproductive tracts of females. For another male, copulation attempt with such a female can end in a lot of pain.

In some cases, mating may involve high risk for the male. This is especially true for some species of mantis - after mating, the male can be simply eaten by the female. "It is a deep evolutionary conditioning. By becoming the first meal of the female, the male provides her with energy for the eggs. This is a good start for his offspring" - explains the biologist.

Sometimes insects "lose their heads" during mating and try to copulate with flowers that remind them of females. "There are a number of species of Hymenoptera that are so stunned by the compounds secreted by orchids and so convinced that it is a female, that they try to mate with flowers of these plants" - says Dr. Jaskuła.

Sometimes the concentration of pheromones in the air causes males to try to mate with other males, which can be perceived as a kind of homosexual behaviour among insects. Such homosexual behaviour has been observed in over 60 percent of the tested insects - from the fruit flies to butterflies, the scientist says.

In the case of some species of insects, males are unnecessary or unknown at all, and the females reproduce parthenogenetically, without needing to mate with males. Such groups include stick insects, as well as most species of aphids. In these cases there is no mating and copulation, and the young are faithful copies of their mothers.

According to the scientist, another interesting fact is that in the case of aphids the female that "gives birth to her daughter" is often also a grandmother, because her daughter already has another generation developing in her body.

"Such adaptations allow insects to quickly colonize new spaces and new habitats, thus increasing the range of their occurrence" - concludes Dr. Radomir Jaskuła.

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