INTERSEXUAL SELECTION IN THE MEDITERRANEAN FRUIT FLY: DOES FEMALE CHOICE ENHANCE FITNESS?

Adaptive hypotheses of female choice predict that females use male courtship displays as an indicator of male quality. A test of whether female choice is adaptive measuring direct and indirect effects of mate choice on females was made using a laboratory population of a lek-mating species, the Mediterranean fruit fly. The nonrandom mating observed in this species is thought to be strongly influenced by female choice. Whether female choice acts to increase fecundity or offspring quality was assessed using two different statistical tests. Multiple regression showed that females generally do not receive direct benefits as a result of mating with males which are successful in copulating with many females. However, in one trial the relationship between male quality and female benefit was nonlinear. Females which mate with males that obtain few matings (<2), and females which mate with males that obtain many matings (>6) enjoy increased fecundity. Mate choice does not, however, appear to enhance offspring quality as father/son correlation and sibling analysis showed no heritable component to male copulatory success.