Old male mating advantage results from sexual conflict in a butterfly

► We tested reasons for old male mating advantage in Bicyclus anynana. ► Mating with older males reduced egg hatching success. ► Females were more willing to remate, mainly with young or virgin males. ► Older males are known to be more aggressive and persistent during courtship. ► Old male mating advantage results from sexual conflict in Bicyclus anynana.