MOTHER-OFFSPRING DATA IN A STUDY OF THE MATING SYSTEM IN A NATURAL-POPULATION OF BULINUS-GLOBOSUS (GASTROPODA, PLANORBIDAE) IN ZIMBABWE

The mating system of a natural population of Bulinus globosus from the Chiweshe area, Zimbabwe, was studied with mother-offspring data using isozyme genetic markers. The study was done in response to work on th e genetic structure of this population which suggested a limited exten t of cross-fertilization. Of the 24 adults whose progenies were analys ed, at least 15 showed evidence of outcrossing and 9 had results consi stent with selfing. These results show that the two modes of reproduct ion are important under natural conditions and the mating system of th is population is considered to be 'partially-selfing'.