Phylogeography of social polymorphism in a boreo-montane ant.

Background: The disjunct distribution of several Palearctic species has been widely shaped by the changes in climatic conditions during the Quaternary. The observed genetic differentiation or reproductive isolation between extant populations may be the outcome of their contemporary geographic separation or reproductive incompatibility due to differences in phenotypic traits which have evolved in isolated refugia. In the boreal ant Leptothorax acervorum, colonies from central and peripheral populations differ in social structure: colonies from Central and Northern Europe may contain several equally reproductive queens (facultative polygyny), while in colonies from peripheral populations in Spain only one the most dominant of several queens lays eggs (functional monogyny).

Queen dominance and worker policing control reproduction in a threatened ant.

Background: Efficient division of reproductive labor is a crucial characteristic of social insects and underlies their ecological and evolutionary success. Despite of the harmonious appearance of insect societies, nestmates may have different interests concerning the partitioning of reproduction among group members. This may lead to conflict about reproductive rights.