SOCIAL EVOLUTION IN THE GENUS HALICTUS - A PHYLOGENETIC APPROACH

Halictine bees exhibit an enormous diversity of solitary and social co lony structures. To investigate social evolution in the genus Halictus , phylogenies of 15 species of the subgenera H. (Halictus) and H. (Sel adonia) were constructed based on protein electrophoretic data. Solita ry, social, and socially polymorphic species were included. Halictus ( Seladonia) apparently renders H. (Halictus) paraphyletic. The common a ncestor of H. (Halictus) and H. (Seladonia) was probably social or soc ially polymorphic. This implies that some solitary and socially polymo rphic species, such as H. confusus and H. tumulorum, represent evoluti onary reversals from a completely eusocial condition to the solitary c ondition that is thought to be primitive for the subfamily as a whole.