For some insect societies a colony can comprise several discrete nesting units. This phenomenon of colony fractionation, or polydomy, produces nest subunits that can differ primarily in whether or not they contain a queen. Since workers and their mother queen are in conflict over how reproductive energy should be allocated polydomous colonies represent natural systems for studying conflict and cooperation within the squabbling family. Furthermore, polydomous colonies represent a tractable ecological system for studying levels of selection. Colonies of the ant species Myrmica punctiventris are seasonally polydomous: in spring a colony emerges aboveground as a unit, but then fractionates. Nest subunits are functionally autonomous during the summer months, but re-coalesce in fall for overwintering. Previous work has shown that workers can exploit this system to bias reproductive broods towards their own interests and away from the interests of their mother queen. The proposed research will characterize colony structure and reproductive allocation for three populations of this species; contextual analysis will allow us to distinguish selection on the local nesting unit versus on the entire colony. A field experiment will be carried out to assess the impact of ecological parameters for seasonal polydomy, reproductive allocation, and levels of selection in this species. The research will provide considerable insight to the evolutionary mechanics of social behavior. Furthermore this project, while primarily basic research, may have implications for control of pest ant species, which are notoriously polydomous.
