Ecological and behavioral determinants of sex-biased predation of katydid prey by a bat predator

Abstract Sexual selection theory predicts that males are more likely than females to invest in costly mate-finding behaviors. In species that use acoustic signaling and searching by walking or flight for mate-finding, predation risk constitutes an important cost imposed on signalers and searchers. We tested the relative predation costs associated with mate finding for males and females in the katydid genus Mecopoda. To achieve this, we took an integrated approach. First, we examined sex-biased predation in the wild. Second, we experimentally tested the sex-specific predation risk of different mate-finding behaviors. Third, we quantified the frequency with which risky behaviors are performed in the wild. Males experienced higher predation than females during the breeding season by their bat predator Megaderma spasma, a pattern not explained by sex ratios, indicating male-biased predation. Enclosure experiments and field observations showed that males frequently engaged in high-risk behaviors, particularly calling and flight. Although flight was equally risky for both sexes, its rarity in females reduced their exposure. These results demonstrate that male Mecopoda spp. adopt a high-risk call-and-fly mate-finding strategy, incurring greater predation costs than females.