XVI International Botanical Congess

Theoretical work has shown that reproductive assurance(RA) mechanisms are selected for when pollen becomes limiting or when environmental variation compromises the ability of pollinators to visit flowers, however the importance of this theory remains untested. To quantify selection of RA attributable to lack of pollinators in natural populations, we conducted a series of integrated experiments in the field. We documented significant variance in pollinator visitation rates, indicating selection for the retention of RA floral traits. Controlled-environment experiments revealed significant genetic variation in floral traits associated with RA and thus suggest a potential for these traits to respond to selection. The role of RA in mixed mating systems will be discussed.