The economics of tracking a changing environment: competition and social information

When food patch quality varies unpredictably over time, animals may benefit from sampling to track these changes. Previous theoretical work has shown how patch and environmental characteristics influence the optimal sampling policy, but there has been little attention to the effects of conspecifics, especially for species that do not live in groups. We used a simulation model to investigate the influence of conspecifics, as both competitors and providers of social information, on the optimal sampling behaviour of nongroup foragers. Competition reduces the range of patch characteristics for which frequent sampling provides a higher gain rate than rare or no sampling. Under conditions where sampling is beneficial, however, competition has little effect on the optimal sampling rate. Social information generally decreases the optimal sampling rate. However, the effect is small when the social information is unreliable. This will often occur when animals forage solitarily because of an inability to detect other animals at the patch or to distinguish animals that are sampling the patch from those that are exploiting it. Thus, the presence of conspecifics should reduce the sampling rate of nongroup foraging animals, but the extent of the reduction will depend on the reliability of the available social information.