Evolution of male workers in the hymenoptera

Abstract

Deterministic computer simulations were used to find the conditions under which eusociality with male (haploid) workers can evolve in haplodiploid populations. Workers were completely sterile, and non-workers mated once only. Parental manipulation by mothers and kin selection acting on males themselves were compared as mechanisms for this evolution. Parental manipulation alleles were selected if workers raised more than half as many siblings as their potential mate would have raised offspring (that is, if K > 1 2 ). Under kin selection, male workers are favoured if K > 1. This is because males are equally related to their siblings and to their mates' offspring. These conditions for the evolution of male workers by parental manipulation or kin selection are essentially the same as for female workers. It is concluded that the absence of male workers in Hymenoptera is not a consequence of haplodiploidy and kin selection, but is a result of the biology of Hymenopteran males, and as such favours neither mechanism over the other.