Effect of expanded variation in anther position on pollinator visitation to wild radish, Raphanus raphanistrum

Background and Aims: Plant-pollinator interactions shape the evolution of flowers. Floral attraction and reward traits have often been shown to affect pollinator behavior, but the possible effect of efficiency traits on visitation behavior has rarely been addressed. Here we tested for the effect of anther position, usually considered a trait that influences efficiency of pollen deposition on pollinators, on pollinator visitation rates and visit duration in flowers of wild radish, Raphanus raphanistrum. Methods: We used artificial selection lines from two experiments that expanded the naturally-occurring phenotypic variation in anther position. In one experiment, plant lines were selected to either increase or decrease anther exsertion. The other experiment decreased anther dimorphism, which resulted in increased short stamen exsertion. We hypothesized that increased exsertion will increase visitation of pollen foragers due to increased visual attraction. We also hypothesized that exsert...