Effect of group size on producer-scrounger strategies of Wistar rats

In a collective foraging situation, we assessed the distribution of search responses of Wistar rats relative to the size of the group. For both, small and large groups, the number of production opportunities per capita was equal. Foraging strategies were classified as either production (opening gates with food) or scrounging (following conspecifics). Small groups showed a higher proportion of producers than large groups and required less time to deplete the food. The proportion of producing and scrounging responses yields to equilibrium between their payoffs. Producing and scrounging were highly correlated with different prior responses. Also, the relative frequency of producing and scrounging associated activities correlated with the time spent consuming food procured by each activity. It is possible that a simple outcome-strategy feedback mechanism mediates the choice of prior activities and procurement responses.

Automated summary

In a collective foraging situation, it was found that smaller groups of Wistar rats tend to have a higher proportion of producers and deplete food faster than larger groups. The balance between producing and scrounging responses is influenced by different prior activities, and the frequency of associated activities correlates with the time spent consuming food. A feedback mechanism may mediate the choice of prior activities and procurement responses.