Worker reproduction and social hierarchies in Leptothorax ants

Kin selection theory predicts the existence of potential conflict between queen and workers and among workers concerning the production of males in insect societies with a single, once-mated queen. We investigated the occurrence of reproductive conflict and worker reproduction in both single- and multi-queen colonies of 10 species of the ant genus LeptothoraxIn contrast to previous observations in related species, workers only infrequently engaged in aggressive interactions and did not lay large numbers of eggs in colonies containing queens. Allozyme analyses of queens, workers and males suggest that the contribution of workers to the males produced in colonies with queens is indeed minimal, at least in L. unifasciatusWhen the queens died or were experimentally removed from the colonies, in most species dominance interactions among workers became significantly more frequent and one or several high-ranking workers started to lay eggs. Workers with an increased number of ovarioles per ovary apparently had a reproductive advantage over workers with normal ovaries.Copyright 1997 The Association for the Study of Animal Behaviour1997The Association for the Study of Animal Behaviour