MATING SPEED CONTROL BY GENE ARRANGEMENTS IN DROSOPHILA PSEUDOOBSCURA HOMOKARYOTYPES

Abstract

Homokaryotypes of Drosophila pseudoobscura were tested for mating speed. These homokaryotypes carried different gene arrangements in their 3rd chromosomes; all descended from wild progenitors collected at Mather, California. The gene arrangements which occur most frequently in the ancestral population (ST and AR) make their carriers mate most rapidly (80% within 1 hr.). The gene arrangements which are less common in nature (CH and TL) give an intermediate mating speed (45% in 1 hr.). The relatively rare gene arrangement (PP) gives the lowest mating speed (20% in 1 hr.). These results suggest that differences in mating speed may be important in the maintenance of the balanced chromosomal polymorphism in natural populations.