Polyandry works as bet-hedging in the field cricket Gryllus bimaculatus, even after eliminating females in poor condition that cannot accept remating

Abstract

Any kind of unpredictability affects female reproduction. In fluctuating environments, the fittest genotype can change between generations, and mating with “unsuitable” males will result in reproductive failure due to their genetic or environmental factors. If females cannot discriminate the quality of mates, monandrous mating with “unsuitable” male may lead to reproductive failure. Bet-hedging polyandry hypothesis suggests that polyandry can spread such risks over multiple males and some empirical studies support this hypothesis. However, no studies have considered the effect of female condition on mating acceptance. Because polyandry accumulates the costs of mating, only high conditioned females could accept multiple mating. In this study, females were assigned to monandry (M), two mating polyandry (2P), or three mating polyandry (3P) treatments. All females were mated with three males. For females assigned to the M treatment, for the second and third matings, we removed spermatophores immediately after transfer. For 2P females, the final spermatophore was removed immediately after transfer. Geometric mean fitness across (pseudo) generations as a long-term fitness index (calculated from the egg fertilization rate and egg hatching rate) significantly increased with the number of undisturbed mates. Therefore, the bet-hedging polyandry hypothesis is again supported after adjusting for the female condition.