The effect of group size and tutor-to-observer ratio on socially learned antipredator responses in woodfrog tadpoles

摘要

It is well established that living in a social group provides animals with considerable antipredator benefits, including the ability to socially learn the identity of unknown predators by observing the actions of others. There has been considerable interest in understanding optimal group size, but surprisingly, little work has focused on understanding how different group composition (i.e. group size and tutor-to-observer ratio) influences the acquisition of information about predators. Here, we manipulated the composition of woodfrog, Lythobates sylvaticus, tadpole groups and found that the ratio of tutors to observers, but not group size, influenced the intensity of learned predator recognition. This finding is in line with theoretical models of the spread of information in social groups but contrasts with some empirical work on information transfer in fish shoals. We suggest that such a discrepancy could arise from the degree to which different animals rely on coordinated group evasion behaviour to avoid capture. (C) 2015 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.