Enforced monogamy in female Queensland fruit flies, do remating decisions influence reproductive success?

Multiple mating by females is common in many insects. However, there is still considerable debate as to the potential benefits of additional matings for females. Males may sire additional offspring with every mating, whereas females could potentially fertilize all her gamets in a single mating. Furthermore, females may incur lifespan costs with every mating. Thus, it is still not clear whether females benefit by mating with more than one male. Here, we explored the consequences of enforced monandry in Queensland fruit fly females, Bactrocera tryoni (Diptera: Tephritidae) by measuring their lifetime fecudity, fertility and longevity, Females where virgin or allowed to mate once or twice with either a normal or a sham male (ablated aedeagus). Sham males could mate but were unable to transfer sperm or accessory gland products (AGPs). To further explore the consequences of female mating decisions, we also included females that rejected either the initial or second male. Contrary to other studies, we found no evidence that enforcing monandry on females effected lifetime fecundity, fertility or egg laying rate. However, females that mated once or twice with normal males were more likely to lay eggs, and laid more eggs than virgin females or females mated to sham males. This suggests that female postcopulatory decisions such as oviposition are mediated in part by substances transferred during mating or by the act of mating per se.