Factors Influencing Pollen Flow in Bumblebee-Pollinated Delphinium virescens

Pollen flow in a population of Delphinium virescens was examined by experimentally investigating the foraging behavior of the pollinators, Bombus americanorum. When bumblebees visited inflorescences with copious nectar they picked up more pollen and flew a shorter distance than when they visited infloresences with little nectar. Thus, short flights were more effective pollen dispersal flights and pollen flow was thereby reduced. These results and other factors are discussed as to their potential effects on gene flow within the plant population.