Reduced reproductive success for a conditioning mutant in experimental populations of Drosophila melanogaster

Abstract

Male Drosophila melanogaster that have courted newly-emerged males can modify their subsequent courtship behavior to avoid further courtship with immature males for up to 6 hr (previously reported). Here, it was hypothesized that such an experience-dependent modification would afford a mating advantage to normal males over males that carried a mutation that affects learning and memory. Coisogenic lines were constructed which varied at the dunce gene (dnc+ and dnc(M14) alleles) on order to test this hypothesis. Whether previously experienced with immature males or not, dnc+ and dnc(M14) males were indistinguishable in their response and mating efficiency when individually paired with virgin females. However, courtship performance of dnc+ and dnc(M14) males was different if they were first experienced with immature males and were then individually tested in an artificial population of nine immature males and one virgin female. In this situation, dnc+ males spent much less time in courtship with immture males and achieved copulation in one-third the time required for dnc(M14) males. As a control, the behavior and mating efficiency of courtship-naive dnc+ dnc(M14) males in the artificial population was indistinguishable. In competition for a single virgin female, experienced dnc(M14) males showed a slight mating advantage over experienced dnc+ males. But when competition by experienced males for a single virgin female took place in the presence of nine immature males, dnc+ males were the successful maters in three-fourths of the trials.