Mate Choice by Lekking Males: Evidence from the Mediterranean Fruit Fly from Field Cage Trials (Diptera: Tephritidae)

Abstract

Abstract The Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann), exhibits a lek mating system characterized by intense female choice apparently based on male courtship performance. However, recent observations showed that receptive females are aggressive toward one another and compete for access to displaying males, suggesting that the traditional view that sexual competition in the medfly is restricted exclusively to males may not be accurate. The current study further examines the accepted view of the medfly mating system by investigating the possibility that males discriminate among potential mates on the basis of female age. In field cage trials, we scored matings for males presented with virgin females of different ages. Young females were mated more frequently than old females, and additional tests revealed that this pattern did not reflect age-dependent variation among virgin females in mating propensity or response to male signaling. Although the experimental environment was artificial in simultaneously providing males with young and old virgin females, the existence of nonrandom mating nonetheless was unexpected given the accepted view that, given limited mating opportunities, male medflies will copulate indiscriminately with available females. Fecundity, fertility, egg-to-pupal yield, and longevity were compared among females of different ages to assess the potential reproductive benefits gained by males via age discrimination among potential mates. Young females (10–15 d old) had significantly higher fecundity, fertility, and egg-to-pupal yield than old females (35–40 d old), and consequently male choice for young females appears to confer substantial fitness benefits.