Conflict in single-queen hymenopteran societies: the structure of conflict and processes that reduce conflict in advanced eusocial species

Abstract

Social insect workers can increase their inclusive fitness by increasing colony production of reproductives, by manipulating the identity of colony reproductives in favor of individuals with greater kin-value (e.g. relatedness) to themselves, or both. The manipulative option results from the non-clonal genetic structure of insect societies and necessarily introduces conflict into insect societies. This paper examines conflict over male production, queen-rearing, and sex allocation for monogynous hymenopteran societies. The structure of conflict is shown to vary according to the particular conflict, queen mating frequency, and other factors. Importantly, there are conditions under which the actual conflict (i.e. the actual manipulation of reproduction) is predicted to be markedly less than the potential conflict (i.e. all the manipulations potentially beneficial to individual workers given the kin-value asymmetries within the colony). For example, when manipulation is costly (i.e. reduces colony productivity), or relatively ineffective (i.e. because of limitations to kin recognition ability, or counter manipulations such as worker policing) it may be selectively disfavored. Furthermore, low actual conflict may be characteristic of certain sub-sets of workers (e.g. foragers) or certain phases of colony growth (e.g. the ergonomic phase). As a result, a pluralistic rather than a typological perspective on conflict in insect societies is suggested. Low actual conflict may facilitate the evolution of colony- or group-level adaptations (i.e. attributes of individuals which have evolved to enable them to function synergistically as a colony or group, such as social foraging in honey bees and army ants), despite the non-clonal genetic structure of most insect societies. However, low levels of actual conflict between individuals need not result in group-level adaptations. The term community of interest is suggested to describe groups within which there is little or no actual conflict, whether or not group-level adaptations occur. The recently revived term superorganism is problematic, because it is often used in a categorical way, to describe whole societies. This difficulty is partly overcome by the pluralistic outlook, which would favor statements such as “foraging in the honey bee shows superorganismic properties” (i.e. group-level adaptations), rather than typological thinking such as “the honey bee colony is a superorganism”.