Increased male mating success in the presence of prey and rivals in a sexually cannibalistic mantis

Pre-copulatory sexual cannibalism--or cannibalism without mating--is expected to promote the evolution of male strategies that enhance mating success and reduce the risk of cannibalism, such as preferential mating with feeding females. However, sexual selection on male competitiveness may alter male courtship decisions in the face of cannibalism risk. We investigated the effect of prey availability and rival presence on male mating decisions in the highly cannibalistic Springbok mantis, Miomantis caffra. We found that males approached females more rapidly and mated more often in the presence of prey, suggesting that females distracted with foraging may be less of a threat. The presence of a rival also hastened the onset of copulation and led to higher mating success, with very large effects occurring in the presence of both prey and rivals, indicating that intrasexual competition may intensify attraction to foraging females. Taken together, our results suggest that pre-copulatory cannibalism has selected for male preference for foraging females, and that males adjust their mating strategy to both the risk of competition and the threat of cannibalism. LAY SUMMARYDeciding when to approach a mate is critical for male mantises at risk of being cannibalised. A male might do well to pounce when a female is distracted with prey, but what if a nearby male has the same intention? In the Springbok mantis, we show that males mate faster and with greater success when both prey and a rival are present, suggesting that mating decisions depend on the dual threats of cannibalism and competition.