Using allozymes as the genetic probe, data are presented which show that wild Drosophila buzzatii females and males engaged in copulation mate at random. Hence, putative inbreeding due to local mating of genetically related flies emerging from the patchy distributed substrates, was not detected. We conclude that individuals raised from a niche disperse and mate at random with other members of the population, so only one round of drift due to the colonization of suitable and ephemeral breeding sites is taking place.