Sources of variability in copula duration of Mediterranean Fruit Flies

Previous studies have reported considerable variation in copula duration in the Mediterranean Fruit Fly (medfly), Ceratitis capitata Weidemann (Diptera: Tephritidae). Presently, however, this variation is largely unexplained. In this study we measure copula duration in two medfly strains used in applied research in Israel and examine how much of the variation in copula duration is due to the strain, age, the time of day the mating begins and the relative size of the mating pair. We found the following: flies of a strain reared in the laboratory since 1976 (Vienna) copulated for longer than flies of a strain collected in 1969 and periodically refreshed with wild males (Sade); older flies copulated for longer than young flies; and pairs in which males were smaller than females copulated for longer than pairs in which males were larger or the sexes were more evenly size-matched. The time of day the mating commenced (morning vs afternoon) had no effect. We discuss potential mechanisms underlying these variations in medfly copula duration.