A41: Carman, G.M. and L. Packer 1996. A cryptic species allied to Halictus ligatus Say (Hymenoptera: Halictidae) detected by allozyme electrophoresis. G.C. Eickwort Memorial Volume. Journal of the Kansas Entomological Society. 69:168-176.
Abstract: The social biology of Halictus ligatus has been investigated in many localities from Southern Canada to the Caribbean. In southern Florida it seems to be multivoltine and continuously brooded unlike the situation in more northerly areas where it has a more typical annual colony cycle with a moderately well established reproductive division of labor. In order to investigate the possibility of genetic differentiation between southern and northern behavioral types, samples of this species were collected along a transect from Toronto, Ontario in the north, to the Florida Keys in the South; additional samples were available from New Mexico and California. Two distinct species were found but surprisingly, their geographical ranges about far to the north of the behavioral disjunction. The two species are differentiated by no fewer than 7 fixed differences out of 34 loci surveyed using standard gel electrophoretic techniques. It is probable that true H. ligatus is the northern form and that the Southeastern species should be called either H. poeyi Lepeletier or H. capitosus Smith. The two species are sympatric along a narrow stretch around the southern end of the Appalachian Mountains. Several biogeographic hypotheses are suggested which may account for the distribution of these two taxa. Further samples are required from the Southern USA, Central America and the Caribbean to differentiate these hypotheses. Comparisons of the social biology of these two species in an area of sympatry should be performed.