Predation risk shapes among- and within-individual variation in behavior in poison frog tadpoles.

Environmental conditions during early development can considerably shape individual behavior, and laboratory studies suggest that predator presence is an important factor influencing both within- and among-individual behavioral variation. To test this under natural conditions, we studied neotropical poison frog (Allobates femoralis) tadpoles from pools with and without dragonfly larvae (tadpole predators) under naturally varying environmental conditions. We measured 2 behavioral traits, distance moved in a novel environment and time to emerge from a shelter, across 4 repeated trials in predator-exposed (n = 48) and predator-naïve (n = 169) tadpoles. Predator-exposed tadpoles moved less, emerged later in their first trial and were more unpredictable in emergence time than predator-naïve individuals. Moreover, among-individual variation in both behaviors was higher in predator-exposed tadpoles, although behavioral repeatability did not differ significantly between predator-exposed and predator-naïve groups. Predator-naïve individuals exhibited behavioral and predictability syndromes, individuals that moved more also emerged sooner, and individuals more predictable in 1 behavior were more predictable in the other. Despite only being significant in predator-naïve individuals, these correlations did not differ between predator-exposed and predator-naïve groups. A personality-plasticity association occurred only in predator-exposed tadpoles: individuals that initially moved less showed less behavioral change across trials. These findings demonstrate that even in naturally variable environments, predation risk shapes behavioral variation at multiple levels, thereby contributing to the emergence and maintenance of "animal personality".