Emma Oldehoeft, “Among-Female Assessment Variation and Male-Male Spacing in Eastern Gray Treefrogs (Hyla versicolor)”
Mentor: Gerlinde Höebel, Biological Sciences
Female preferences have been widely researched as a source of sexual selection on male mating signals. The complexity of mate choice in an anuran chorus entails 1) female call assessment, 2) acoustic variation in male displays, and 3) male-male spatial dynamics. While calls and preferences are well characterized in Eastern Gray Treefrogs, assessment and localization of closely perched males is not. We explored female response to isolated and clustered artificial calls in a four-speaker playback design. Using a repeated-measure design that forces females to select a mate based on the attractiveness of a call and its proximity to other males of varying attractiveness, we examined among-female variation in dense-chorus choice scenarios. We found very strong preference against the lone call in all scenarios, while choices made among clustered calls differed between females. This preference against the lone call weakened as clustered calls dispersed. Many individuals were repeatably able to localize an attractive stimulus centered within a meter of multiple other inferior calls. Interestingly, these females expressed choice significantly faster. Lengthier choice times of less discriminant individuals seems to indicate that “confusion” can be observed in the expression of active preference. We also present unexpected evidence of spatial habituation; females appeared to remember the orientation of the cluster across trials. This study provides greater insight into the real-world mate choice dynamics of multi-signal assessment in a treefrog chorus.