Lekking males aggregate to attract females and contribute solely to egg fertilization,without any further parental care.Evolutionary theory therefore predicts them to be nonchoosy toward their mates,because any lost mating opportunities would outweigh the benefits associated with such preferences.Nevertheless,due to time costs,the production of energetically costly sexual displays,and potential sperm limitation,the mating effort of lekking males is often considerable.These factors,combined with the fact that many females of varying quality are likely to visit leks,could favor the evolution of male mate preferences.Here,we show that males of the lekking lesser wax moth,Achroia grisella,were indeed more likely to mate with heavier females in choice experiments,even at their virgin mating (i.e.,when their reproductive resources have not yet been depleted by previous matings).This differential female mating success could not be attributed to female behavior as heavy and light females showed similar motivation to mate (i.e.,latency to approach the males) and time to copulate.Males seem to benefit from mating with heavier females,as fecundity positively correlated with female mass.This new empirical evidence shows that male mate choice may have been underestimated in lekking species.