Sexual selection may mediate or prevent lineage divergence. Understanding the mechanisms underpinning mate choice can inform the causes and consequences of phenotypic divergence that evolves among populations. The red-eyed treefrog (Agalychnis callidryas) exhibits strong population-level phenotypic divergence in many traits important in sexual selection, including male advertisement call and color pattern. Previously, we documented female preference for local over non-local males in choice experiments; yet the mechanisms of choice remain untested. We examined the relative role of visual and acoustic cues in female mate selection in red-eyed treefrogs. We first tested whether females can discriminate among populations based on a single cue (acoustic or visual signal alone). We then paired call and color stimuli to test the relative contributions of each signalling mode. We presented 158 gravid females with animated male models and/or pre-recorded advertisement calls, representing traits from both local and non-local populations.
A Χ2 goodness-of-fit test showed that females can select mates based on acoustic or visual alone. However, a single trait alone was not sufficient to elicit the local-male preference seen in previous studies. Future mate selection studies will focus on the contributions of other traits that diverge among red-eyed treefrogs, including skin peptide composition, body size, and female behaviour.