A CRYPTIC SPECIES ALLIED TO HALICTUS-LIGATUS SAY (HYMENOPTERA, HALICTIDAE) DETECTED BY ALLOZYME ELECTROPHORESIS

The social biology of Halictus ligatus has been investigated in many l ocalities from Southern Canada to the Caribbean. In southern Florida i t seems to be multivoltine and continuously brooded unlike the situati on in more northerly areas where it has a more typical annual colony c ycle with a moderately well established reproductive division of labor . In order to investigate the possibility of genetic differentiation b etween southern and northern behavioral types, samples of this species were collected along a transect from Toronto, Ontario in the north, t o the Florida Keys in the South; additional samples were available fro m New Mexico and California. Two distinct species were found but surpr isingly, their geographical ranges abut far to the north of the behavi oral disjunction. The two species are differentiated by no fewer than 7 fixed differences out of 34 loci surveyed using standard gel electro phoretic techniques. It is probable that true H. ligatus is the northe rn form and that the Southeastern species should be called either H. p oeyi Lepeletier or H. capitosus Smith. The two species are sympatric a long a narrow stretch around the southern end of the Appalachian Mount ains. 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 differenti ate these hypotheses. Comparisons of the social biology of these two s pecies in an area of sympatry should be performed.