Investigation of genetic factors influencing duration of copulation in "eastern" and "western" Drosophila athabasca.

Observations of mating behaviour were made on "eastern" and "western" Drosophila athabasca and on flies of mixed genetic background. Duration of copulation in mixed combinations of D. athabasca is determined by the male. In F1 males the source of X-chromosome, whether eastern or western, partly determined suration of copulation. However, durations of copulation of backcross males suggest autosomal influence, in that males derived from an eastern backcross demonstrate significantly shorter durations than males derived from a western backcross. In addition, durations of copulation from F2 combinations exhibit greater variance than the F1 and thereby represent evidence of F2 segregation.