The effect of metals and alcohol on sexual isolation in Drosophila melanogaster.

Strong sexual isolation established between D. melanogaster long-term cage populations (originated from common parents and being under selection pressure since 1972) is maintained (with a tendency to increase) for twelve years after the origin of the populations. The sexual isolation is also maintained when the populations are kept in common conditions for about two years, while it dramatically decreases when the populations live on a food medium supplemented with strong chemical selective factors, such as various metals or ethanol. Seasonal or geographical studies of sexual isolation between natural and our cage populations did not reveal significant deviation from random matings. The genetic nature of sexual isolation is discussed.