Prior Experience Alters the Behavioral Response of Prey to a Nonnative Predator

Abstract

Anuran larvae (tadpoles) can alter their behavior and morphology in response to predators with which they have coevolved. Furthermore, tadpoles of a few species are capable of learning, which can elicit or reinforce predator-avoidance behaviors. However, it remains unclear how widespread this capacity for learning is among anurans and whether it is biased in favor of evolutionarily familiar predators. Here, we test whether prior experiences will modify the behavioral response of Lowland Leopard Frog Lithobates (Rana) yavapaiensis tadpoles to Green Sunfish Lepomis cyanellus, a recently introduced predator. We exposed focal tadpoles for 10 days to the chemical and visual cues of one of three conditioning treatments: a cricket-fed Green Sunfish, a tadpole-fed Green Sunfish, or a control tank without predator. Subsequently, we measured the swimming activity of focal tadpoles in response to a neutral cue (water) and the chemical cues of Green Sunfish. No difference between conditioning treatments was observed in response to the water cue. In contrast, tadpoles that had previously experienced either of the sunfish conditioning treatments displayed significantly higher swimming activity than control tadpoles for 2-4 min after exposure to the sunfish chemical cues. Our results indicate that the behavior of tadpoles can be altered by prior experiences, even in the absence of alarm cues. In addition to providing another example of learning in tadpoles, our results suggest that tadpoles may have a broad learning template that can be applied to organisms with which they have recently come into contact.