Are virgin male lepidopterans more successful in mate acquisition than previously mated individuals? A study of the European corn borer, Ostrinia nubilalis (Lepidoptera : Pyralidae)

Male phenotypic quality may significantly influence female reproductive suc cess. Depletion of sperm and accessory-gland secretions with successive mat ings represents a reduction in male phenotypic quality and is known to decr ease female reproductive output in several lepidopteran species, including the European corn borer (ECB), Ostrinia nubilalis. We therefore tested the hypothesis that female ECBs, given the simultaneous choice of an experience d male and a virgin male, preferentially mate with the virgin. However, con trary to prediction, females mated significantly more often with experience d males. Experienced males were significantly lighter than their virgin cou nterparts, the result of producing three spermatophores that were transferr ed during previous matings. However, differences in body mass or wing-loadi ng did not appear to play an important role, for within either the experien ced or virgin classes, heavier males obtained more matings than lighter one s. Why would females prefer to mate with sexually experienced males? Female s may not be exercising any precopulatory choice, and the greater mating su ccess of previously mated males may be related to previous experience. Beha vioral observations, however, suggest that female choice occurred. In the p rocess of selecting experienced males, the number of consecutive matings wa s correlated with low fluctuating asymmetry of the forewing (R-L). This sug gests that males who acquired 3 consecutive matings were of above-average q uality and were actively selected by females.