Ellen Roder, “Phonotaxis Plasticity & Approach Medium: Speed & Directionality in Female Frogs when Swimming vs Walking”
Mentor: Gerlinde Höbel, Biological Sciences
Poster #

During the breeding season, male Eastern Gray Treefrogs (Hyla versicolor) form large choruses in woodland ponds to advertise for mates. Females select mates by listening for the male’s call and moving towards the chosen male guided by his call, a behavior called phonotaxis. Climate change may dry up parts of their habitat, which may affect mate choice and reproductive success of the frogs. We tested the hypothesis that the approach medium (land/water) affects phonotaxis behaviors. Because frogs ultimately lay eggs in water, we predicted that phonotaxis is more accurate/faster when females approach the male in water compared to on land. To test the effects of approach medium on phonotaxis behaviors, we conducted acoustic playback experiments in the lab, taking advantage of the fact that female frogs approach a speaker playing an attractive call like they would approach an attractive male at the pond. Females were tested in a “water” treatment (testing arena was a six-foot diameter pool filled with water), and in a “land” treatment (arena was dry pool). We filmed the trials and recorded the following data: (1) distance of first jump towards the speaker, (2) angle of first jump relative to speaker location, and (3) time it took females to reach speaker. Females took wider first jumps when starting their approach in water, but approached the speaker with similar accuracy and speed in both environments. This suggests that frogs can adjust their mate choice behavior to environmental change altering the relative proportions of land and water in their breeding habitat.