Individual experience-based foraging can generate community territorial structure for competing ant species

Abstract

To gain additional territory while defending existing territory, animals must acquire and use information regarding resource characteristics and competitive pressure. For social organisms like ants, individual workers have experiences to acquire information, but territory establishment is a colony level behavior. Colony behavior, in turn, affects community structure. Here, I investigate how an individual ant’s previous experience affects its future foraging behavior and how individual behaviors can scale up to community territorial structure for two coexisting Formica species. To do this, I combine a field survey, a multi-agent computer simulation, and a manipulation experiment. The field survey shows that workers of both species co-occur on many trees early in the season, but ants on trees become segregated by species as the season progresses. The simulation demonstrates how this segregated spatial distribution can result from ants using a foraging strategy in which individuals show a preference for foraging sites based on previous experience. The experiment suggests that these ants are indeed capable of experience-based foraging behavior; ants preferentially return to sites where they have had positive experiences and avoid sites where they have had negative experiences. Results from this study suggest that spatially explicit information can be collected and stored by individuals to facilitate colony territorial structure, and that future investigations of community territory formation should include effects of individual previous experience.