Mechanisms and extent of information transfer in socially foraging guppies, <em>Poecilia reticulata</em>

Many species in social groups make use of readily available, socially provided information for behaviours including predator avoidance, mate choice and foraging. Not only are actions imitated, but they may also be reapplied in variable future situations, suggesting an explicit knowledge of the purpose of the behaviours. Social learning thus enables animals to learn about their complex environments rapidly and efficiently, aiding survival. However, little is known of the processes underlying information transmission and the complexity of information that can be exchanged. We used shoals of guppies to investigate how animals decide which individual to copy, and the extent of information that can be transferred. Naïve guppies followed the first fish to move. However, although the speed and accuracy of foraging increased significantly during training, the first fish to move was not always the trained (knowledgeable) guppy. No significant difference was found between the number of guppies entering areas of varying food quality, supporting the hypothesis that these fish learn foraging locations by following and suggesting that leaders forage without considering the reduced personal reward arising from sharing a low-quality patch with followers. Animals that learn by copying thus appear limited in the amount of information they can receive, highlighting a selection pressure for more extensive means of transmitting information in complex environments.