Floral and inflorescence effects on variation in pollen removal and seed production among six legume species

Abstract

Summary Most flowering plants display multiple flowers, so that the interaction with pollinators that determines their mating success can vary with both the characteristics of individual flowers and aggregate properties of the entire floral display, especially the number of open flowers (floral display size). These effects are seldom examined in concert and their collective consequences for interspecific differences in reproductive performance have not been considered previously. In this paper, we characterize the relation of pollen removal and seed production to differences in floral and inflorescence characteristics among six species of herbaceous legumes (Fabaceae). Several aspects of reproductive performance varied significantly among species with either plant traits or aspects of pollinator behaviour that depend on plant traits. Pollinator visitation, as measured by the ratio of pollen removal during 24 h to first‐visit removal, varied positively with both nectar production per flower and floral display size. Bumble‐bees visited more flowers per inflorescence on species with large floral displays, with no increase in the proportion of flowers visited. Pollen removal during a flower's first visit varied negatively among species with the mean number of flowers visited by bees per inflorescence. These results indicate that floral and inflorescence traits act together to influence both pollinator energetics, which affects a plant species’ attractiveness, and the rate of pollen removal, which should affect pollen export. In contrast, neither pollen removal during 24 h, nor female fecundity varied significantly with floral or display characteristics.