64.3 Jan. 7 The attractiveness of courtship signals increases with predation risk KIM, T. W.*; CHRISTY, J. H.; CHOE, J. C. ; Ewha Womans University; Smithsonian Tropical Research Institute; Ewha Womans University email@example.com
Although the sensory trap model for sexually selected signals has been suggested over 2 decades, there has not yet been direct evidence how the sensory-trap response functions in the context of mate choice. In some species of fiddler crabs (genus Uca), courting males build ornamental structures at their burrows using mud or sand. There has been considerable suggestion that structures attract females because they elicit landmark orientation, a behavior that has evolved for predator escape not for mate choice. Here we tested if mate-searching female Uca beebei and U. terpsichores change their preference on structure building wavers depending on predation risk, by manipulating the predator visit frequency. We found that mate-searching females of both species more often oriented to the male building ornament when predation risk increased. Our finding suggests that, by orienting to the structures, females reduce their risk when searching for mates and then the relative attractiveness of males with structures should increase with an increase in the level of disturbance by predators. This study provided the first evidence that a female preference based on a sensory-trap response benefits the female when made in the mate-choice context.