Drosophila melanogaster

Sperm competition[edit]
The following section is based on the following Drosophila species: Drosophila melanogaster, Drosophila simulans, and Drosophila mauritiana. Sperm competition is a process that polyandrous Drosophila females use to increase the fitness of their offspring.^{[34][35][36][37][38]} The female Drosophila has two sperm storage organs, the spermathecae and seminal receptacle, that allows her to choose the sperm that will be used to inseminate her eggs.^[38] However, some species of Drosophila have evolved to only use one or the other.^[39] Females have little control when it comes to cryptic female choice.^[37][35] Female Drosophila through cryptic choice, one of several post-copulatory mechanisms, which allows for the detection and expelling of sperm that reduces inbreeding possibilities.^[36][35] Manier et al. 2013 has categorized the post copulatory sexual selection of Drosophila melanogaster, Drosophila simulans, and Drosophila mauritiana into the following three stages: insemination, sperm storage, and fertilizable sperm.^[37] Among the preceding species there are variations at each stage that play a role in the natural selection process.^[37] This sperm competition has been found to be a driving force in the establishment of reproductive isolation during speciation.^[40][41]
Parthenogenesis and gynogenesis[edit]
Parthenogenesis does not occur in D. melanogaster, but in the gyn-f9 mutant, gynogenesis occurs at low frequency. The natural populations of D. mangebeirai are entirely female, making it the only obligate parthenogenetic species of Drosophila. Parthenogenesis is facultative in parthenogenetica and mercatorum.^[42][43]
Laboratory-cultured animals[edit]
D. melanogaster is a popular experimental animal because it is easily cultured en masse out of the wild, has a short generation time, and mutant animals are readily obtainable. In 1906, Thomas Hunt Morgan began his work on D. melanogaster and reported his first finding of a white eyed mutant in 1910 to the academic community. He was in search of a model organism to study genetic heredity and required a species that could randomly acquire genetic mutation that would visibly manifest as morphological changes in the adult animal. His work on Drosophila earned him the 1933 Nobel Prize in Medicine for identifying chromosomes as the vector of inheritance for genes. This and other Drosophila species are widely used in studies of genetics, embryogenesis, chronobiology, speciation, neurobiology, and other areas.^{[citation needed]}
However, some species of Drosophila are difficult to culture in the laboratory, often because they breed on a single specific host in the wild. For some, it can be done with particular recipes for rearing media, or by introducing chemicals such as sterols that are found in the natural host; for others, it is (so far) impossible. In some cases, the larvae can develop on normal Drosophila lab medium, but the female will not lay eggs; for these it is often simply a matter of putting in a small piece of the natural host to receive the eggs.^[44]
The Drosophila Species Stock Center located at Cornell University in Ithaca, New York, maintains cultures of hundreds of species for researchers.^[45]