Molecular Population Genetics of Social Insects

Abstract

The life of social insects centers around sedentary colonies that can include individuals belonging to different patrilines or matrilines, with a turnover of reproductives. The colony is a scene for both cooperation and conflicts, and the conceptual framework for the evolution of social life and colony organization is provided by the kin selection theory. Variable molecular markers make it possible to dissect kinship within colonies, identifying patrilines and matrilines and estimating genetic relatednesses. Such markers have been used to test hypotheses on social conflicts between queens and workers (split sex ratio hypothesis), among workers (worker policing hypothesis), and among reproductive females (skew hypothesis). The data from several species of ants, bees, and wasps indicate that workers can obtain information on the genetic heterogeneity of their colonies and use that information to manipulate reproductive decisions. The social structure of colonies and the mode of colony founding affect the population-wide dispersal of sexuals. Populations with multi-queen colonial networks have limited dispersal; females stay in their natal colonies, and mating flights can be restricted. As a result, coexisting queens tend to be related to each other, maintaining the genetic integrity of colonies, and populations become spatially differentiated to an extent that can lead even to socially driven speciation.