- November 3, 2021 - Insectarium : Insect diversity
Did you know that insects were capable of cloning themselves, meaning having offspring without needing to breed with a partner? That’s called parthenogenesis.
What is parthenogenesis?
Unlike sexual reproduction, where fertilization is carried out through the fusion of two gametes, one from a male and one from a female, parthenogenesis is a form of asexual reproduction. It enables a female to reproduce even in the absence of a male. Thus, females in certain species have the ability to develop new embryos using genetic material that is wholly their own. The new individual is therefore generally identical to the mother.
Are all insects capable of cloning themselves?
Not all insect species are capable of cloning themselves. Parthenogenesis has evolved primarily in species where the males are not readily available in nature or in species living in adverse environments. This type of reproduction, therefore, is most frequently observed on islands or in deserts.
Among the insects able to clone themselves may be mentioned wasps, bees, ants, aphids, weevils, cockroaches, stick insects, leaf insects...
How do insects use parthenogenesis?
Most species use sexual reproduction and parthenogenesis alternately during their lifetimes. At the Insectarium de Montréal, my colleague Mario Bonneau, an entomology technician, is raising a number of stick and leaf insect species, and all of them are capable of reproducing both these ways. In other words, they have a choice! That’s the case, for example, with the stick insect Heteropteryx dilatata. When a female lays her eggs, we collect them and set them to incubate in little boxes where the humidity is controlled so that they have every possible opportunity of success. One of the most interesting facts is that the development of an egg resulting from parthenogenesis doesn’t follow the same development as that of an egg resulting from fertilization. Mario Bonneau has gathered a lot of data on this species and observed that a fertilized egg took an average of 11 months to hatch, whereas a parthenogenetic one took about two years to do the same!
Certain species use parthenogenesis almost exclusively: the leaf insect Phyllium giganteum, for instance. This species is represented for the most part by females; males are extremely rare in nature and have never been observed in captivity. Meaning that every rearing of Phyllium giganteum around the world is made up solely of females – just like the one at the Insectarium!
What are the advantages?
Parthenogenesis allows a female to reproduce even when she encounters no males in her environment. This also makes it possible for her to have offspring at the precisely desired period, which is an advantage in environments where living conditions are difficult. However, since each individual is genetically identical to the mother, parthenogenetic populations are more sensitive to disease and more likely to die out quickly as they evolve.
Are insects the only ones that are able to clone themselves?
Many animals can reproduce by parthenogenesis, and the list of scientific discoveries in that regard is steadily growing. Examples of those animals include certain species of reptiles (pythons, Komodo dragons), fish (zebra sharks), crustaceans (marbled crayfish), amphibians (salamanders), birds (turkeys)...
A few years ago, the discovery of a soil mite, Oppiella nova, surprised quite a number of scientists because that species has never created males and has reproduced exclusively by parthenogenesis for millions of years!
Before your very eyes!
If you want to learn more about parthenogenesis, visit the new Insectarium de Montréal and come marvel at insects with this fascinating ability!
Bibliography
- Marguerite Narbel-Hofstetter. 1961. L’origine de la parthénogenèse, Bulletin de la Société vaudoise des Sciences naturelles, No. 303, Vol. 67.
- Eva D’Agoste. July 2021. “La parthénogenèse: définition et exemples.”
- Corryn Wetzel, August 25, 2020. “How some animals have ‘virgin births’: Parthenogenesis explained.” National Geographic.
- Brandt Alexander, Tran Van Patrick, Bluhm Christian, et al. 2021. “Haplotype divergence supports long-term asexuality in the oribatid mite Oppiella nova.” Proceedings of the National Academy of Sciences USA, 118(38). DOI: 10.1073/pnas.2101485118
