Nest structure and collective behaviour in the red ant Myrmica rubra
Claire Detrain, Oscar Vaes , Claire Detrain
Unit of Social Ecology, Universite Libre de Bruxelles, Brussels, Belgium; Unit of Social Ecology, Universite Libre de Bruxelles, Brussels, Belgium ; Unit of Social Ecology, Universite Libre de Bruxelles, Brussels, Belgium
Nests provide a shelter to insect societies but also offer a space for food exchanges and information transfer between nestmates. Despite the obvious influence of spatial proximity on interactions and on communication, the impact of nest structure is rarely considered in studies on social organization and collective behavior in ant societies. Therefore, we compared, in the red ant Myrmica rubra, three nest topologies that differed by the network properties of galleries connecting nest chambers and that showed variable connectivity, centrality and meshedness. We found that a central and highly connected chamber acting as a hub, promotes a homogeneous occupancy of all nest chambers. By contrast, a serial configuration of successive chambers makes more variable their level of occupancy, namely depending on their distance to nest entrance. Regardless of nest topology, both the workers and the queen are mainly located in the entrance chamber, with a marked preference shown by the queen for the most crowded chambers. Finally, we investigated how nest topology influences two important collective behavior, which are the management of waste items and the exploitation of food resources. This namely confirms that ant density in entrance chamber strongly influences the dynamics of food exploitation. Our study is a first step to uncover general principles on how the structure of a living space can shape the collective behavior of its inhabitants.