Dual reproductive cost of aging in male medflies: Dramatic decrease in mating competitiveness and gradual reduction in mating performance

► Aging dramatically reduces the mating competitiveness of males. ► In absence of competition older males acquire a substantial proportion of copulas. ► Younger males copulate for longer than older ones. ► Females appear less eager to mate with older males. ► Number of sperm cells increases with age in the testes of mated and nonmated males.