Patterns of reproduction in southern versus northern populations of Leptothorax ants (Hymenoptera: Formicidae)

Populations of 2 Leptothorax ant species were sampled near the edge of their ranges. The southern population of L. curvispinosus Mayr showed no significant demographic shifts from northern populations, but the southern population of L. longispinosus Roger was almost exclusively monogynous, in contrast to northern counterparts. In both species, we found clear evidence of queen-worker conflict over allocation to males and also over allocation to growth versus reproduction in the southern populations. Geographic variation between populations can prove very useful for investigating evolutionary dynamics in social insects.