Some Modes Of Insect Reproduction Are Too Strange To Believe
Sexual reproduction that requires the genetic input of a male and female is known by the term “amphimixis”. Many of you probably already know that most insect species reproduce through amphimixis, just like humans and many other animals. In fact, most people may not have been aware that insects, and other animals, can also reproduce through entirely different biological mechanisms. For example, some insects can reproduce individually without biological input from a male specimen. Some insects can develop from unfertilized eggs. Amazingly, some insect species can switch from sexual to asexual reproduction depending on the availability of mates and resources during particular seasons. There also exists a handful of insect species that possess both male and female reproductive systems, which is a biological phenomenon known as “hermaphroditism”. However, all insects must lay eggs, right? Actually, this is not the case as several larval species develop within the reproductive tracts of their insect mothers, similar to mammalian species.
Most insects are “oviparous”, which means that insect eggs begin to develop once they are laid by their mothers. In this case, egg development does not occur within the female's reproductive tract; instead, the egg only develops once it is exposed to natural environmental conditions in the outside world. However, the term “viviparity” is a term that is used to refer to organisms that carry developing eggs. Some viviparous insect species include cockroaches, thrips, aphids, scale insects and several fly species. These insects retain their eggs within their reproductive tracts during their offspring’s development. Once the offspring has developed to the point of hatching, these insects immediately eject their eggs at which point the offspring wastes no time breaking free from the egg. This form of reproduction differs from mammalian reproduction on several levels, but most notably the presence of a placenta is absent in viviparous insects; instead, the developing offspring are enclosed within an egg-yolk. Some viviparous insects may carry larvae that hatch from their eggs prematurely in the womb. These poorly developed larval species will then begin to feed on milk that is secreted by glands in the mother’s uterus. This type of reproduction is known as “adenotrophic viviparity”.
Have you ever seen a pregnant viviparous female insect? If you have, did the female insect appear enlarged?