Offspring allocation in externally ovipositing fig wasps with varying clutch size and sex ratio

The simultaneous optimization of clutch size and sex ratio is a tricky problem. Unless parameters such as host size or fecundity exist to pin down the optimal clutch size, this problem remains elusive to analytical analysis. This is because the fitness landscape with respect to clutch size and sex ratio does not have one single evolutionarily stable peak toward which the population can evolve. To solve this problem, I used a computer simulation to optimize both clutch size and sex ratio using externally ovipositing fig wasps as a model taxon. The simulation approach allows the use of integer numbers of eggs rather than assuming that females can produce any sex ratio between 0 and 1. When females have no information about the patches on which they oviposit, they produce either large clutches with a strong female bias or clutches of a single male egg. When females have complete knowledge of their oviposition site, a set of conditional substrategies is evolutionarily stable. Again, these substrategies are either large clutches with a female bias or clutches consisting of a single male egg. This dichotomous oviposition pattern results in unrelated males sharing a fig, a condition conducive to the evolution of fatal fighting. Selection on female oviposition strategies may therefore be an important driving force behind high levels of fighting observed between male fig wasps.