Individual and social information gathering are fine-tuned to the internal state of the group

It is well known that the environment a group inhabits influences the frequency at which its members use information gained from one another, that is, social information. However, the potential link between internal state (i.e. individual and social physiology) and use of social information has received little attention. This is surprising as it is known that internal state has profound effects on group behaviour in many group-living animals and especially eusocial insects. Energy reserves are a particularly important determinant of internal state and have been predicted to affect the use of social information. However, empirical studies on foraging dynamics of ants subjected to different durations of food deprivation supply conflicting evidence. We investigated how information is gained by the tandem-running ant, Temnothorax albipennis, when the colony had been fed compared to when it had been deprived of food. Our results indicate that both individual and social information gathering occurred significantly more when the colony had been deprived of food and that both were fine-tuned to internal state. We found no strong evidence that social information gathering increased more quickly with an increased perceived level of starvation. We suggest that differences between colonies in their internal state can be an explanation for the inconsistencies among previous studies regarding whether low food availability increases or decreases the benefit of acquiring social information. (C) 2013 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.