POLLINATOR BEHAVIOR AND DECEPTIVE POLLINATION - LEARNING-PROCESS AND FLORAL EVOLUTION

Some species of flowering plants engage in nonmodel deceptive pollinat ion, attracting pollinators by large nonmimetic floral displays and pr oviding no reward. Pollinators can learn to avoid deceptive plants and to favor nectariferous species. The reproductive success of these spe cies is expected to be density dependent for two opposite reasons: the commoner cheating flowers are, the easier they are to avoid and the l ower the quality of the patch, making it more difficult to recognize t hat unrewarding flowers are not profitable. When a deceptive species i s made up of multiple floral variants, pollinators' learning could dec rease the reproductive success of any particularly common floral varia nt. Within a population of deceptive plants, mean reproductive success could, therefore, vary with the number of floral variants. We investi gate these three hypotheses by modeling the behavior of pollinators fo raging in communities of deceptive and rewarding flowers. Simulations revealed that the reproductive success of deceptive flowers varies in a density-dependent manner and that floral variants can be submitted t o negative frequency-dependent selection. We compare density dependenc e in nonmodel deceptive species to what is expected in Batesian mimics and discuss possible selection of morphological variants. Finally, we survey how pollinators' learning capacities can make mean reproductiv e success depend on morphological variability within a population.