Abstract

Supercolonies of ants are perhaps the largest non-human animal societies, at their largest spanning several millions of individuals and thousands of nests and in invasive species even crossing oceans. Supercolonies have convergently evolved in several ant groups, and they all share a syndrome of key features. First, their colonies spread by budding, which leads to extensive polydomy and inter-nest movement of individuals. Second, local mating and recruitment of queens lead to extensive polygyny. Their ecological dominance is clear, but their evolutionary maintenance is enigmatic due to low relatedness among cooperating individuals and the lack of clear functional organization above local polydomous units. This review takes a multi-level look at the social evolution of supercolonies in an inclusive fitness perspective, outlining key behavioural, ecological, and genetic processes as well as open questions. Such consideration of cooperation and competition from the gene level to the level of populations of supercolonies is necessary for understanding the history and future of supercolonies.