Discovery Science • SCIENCE OF THE MONTH

Drosophila melanogaster is a fly, distributed worldwide with the exception of extremes of altitude or latitude. It is most commonly found in close association with human habitation, and is often found inside houses, especially in the fall where it is attracted by fruit and wine. D. melanogaster was suitable for experimental work and brought it to the attention of Thomas Hunt Morgan, an embryologist at Columbia University in New York who wished to make an experimental study. There are about 7,500 researchers devoted to the study of fundamental problems in biology working withDrosophila. The researchers found that Male fruit flies use a sensory system in their legs to determine whether a potential mate is from a different species. Researchers at the University of California, San Francisco (UCSF), have discovered a chemoreceptor called Gr32a on the forelegs of male fruit flies that sense whether female flies are of the same or different species. Male fruit flies (Drosophila melanogaster) approach prospective mates and repeatedly tap them on the side with their forelegs, attempting to detect unpleasant-tasting waxy chemicals on the females ’ skin. This sensory system would prevent the creation of hybrids that may not survive or cannot propagate, thereby helping the species preserve its identity. If the prospective mate is not of the same species, and Gr32a is activated, the mating ritual stops right there. Males lacking Gr32a receptors, or males with their forelegs surgically amputated, attempted to mate with fruit flies of other species, even if those flies were 2-3 times larger. The researchers found that female D. melanogaster have neurons bearing Gr32