Visual cues elicit courtship signals in a nocturnal anuran

In lekking species, the allocation of effort into mate attraction signals is not uniform over time, and signalers may expend the greatest effort when potential mates are nearby. Close-range courtship interactions are critical determinants of male fitness and the study of these interactions can therefore answer important questions in sexual selection. In anurans, attention has largely focused on long-range mate attraction mediated by acoustic signaling. However, many species also engage in courtship behaviors at close range, and the cues that elicit these behaviors are unknown but likely to be non-acoustic. I performed an experiment in which I assessed the role of female visual cues in eliciting courtship calls by males of the nocturnal treefrog Hyla versicolor. Males that could see an approaching female were more likely to give courtship calls than those that could not. These results provide some of the first evidence for an effect of vision on calling behavior in a nocturnal anuran and demonstrate that multiple sensory modalities are involved in the final stages of mate attraction.