Activity Responses of Rana forreri and Rhinella horribilis Tadpoles to Predation Cues

Tadpoles must rapidly detect and respond to predation cues to survive the most vulnerable stage of anuran development. Although previous studies have examined the effects of visual or chemical cues on tadpole behavior, none have compared the effects of multiple predator-associated sensory stimuli across species. Here, we examined the responses of two neotropical tadpole species, the Forrer's leopard frog Rana forreri (non-toxic), and the cane toad Rhinella horribilis (toxic), to visual, chemical, and auditory predation cues. Tadpoles were exposed to simulated bird shadows (visual cue), belostomatid-conditioned water (chemical cue), and calls of the Green Kingfisher predator, Chloroceryle americana (auditory cue). We recorded tadpole activity for 4 min prior to, 1 min during, and 4 min following treatment exposure using portable locomotion activity monitors (pLAMs). Rana forreri exhibited increased activity in response to auditory cues, whereas chemical and visual cues did not produce significant changes in activity levels relative to the control. Conversely, R. horribilis showed no significant differences in activity level across treatments. These findings suggest that antipredation responses vary in their sensitivity to sensory modality and may be shaped by species-specific defensive strategies. In particular, chemical defense may reduce reliance on immediate behavioral responses, while non-toxic species may exhibit stronger responsiveness to specific sensory cues. Together, our results highlight the selective prioritization of sensory information in shaping antipredation behavior in larval anurans.