Effect of predator diet on life history shifts of red-legged frogs, Rana aurora.

Abstract

Larval red-legged frogs (Rana aurora) are known to exhibit antipredator behavior in response to both chemical alarm cues released from injured conspecifics and chemical cues of predators. In some cases, the response to predators is dependent on the predator's diet. In this experiment, we tested whether long-term exposure to predator chemical cues and alarm cues resulted in alteration of life history characteristics of red-legged frogs. We raised groups of tadpoles in the presence of chemical cues of predators that were either fed conspecifics or heterospecific caddis-fly larvae, chemical cues of injured conspecifics, or a no-cue control. Tadpoles raised in the presence of either a predator fed conspecifics or cues of injured conspecifics metamorphosed earlier and at a smaller size than those exposed to predators fed heterospecifics or the no-cue control. The result suggests that red-legged frogs exhibit a life history shift in response to predatory cues and that this response is dependent on the diet of predators.