A temporal analysis of sexual activity in a natural population of Drosophila willistoni.

We have analyzed the mating activity of F1 flies in mating chamber from five samples of wild Drosophila willistoni females. The files were collected from an area (in south Brazil) that has well-defined seasons and considerable variation in temperature and in the abundance of drosophilids. We estimated copulation frequency at first five minutes of observation, copulation frequency at ninety minutes of observation and copulation latency. We did not observe differences in the total copulation frequency throughout seasons, as opposed to copulation frequency in the beginning of the observation period and to copulation latency which varied significantly. The results show that mating activity in a natural population can vary along with the seasons and that this variation can be correlated to some environmental factor. Mating activity tended to be higher during high warm temperature periods, when the flies were abundant.