Consequences of floral variation for male and female reproduction in experimental populations of wild radish, Raphanus sativus L.

Abstract

Documented effects of floral variation on seed paternity and maternal fecundity in small experimental populations. Each population was composed of 2 competing pollen donor groups with contrasting floral morphologies and several designated maternal plants. A wide range of pollinator taxa visited the populations, and patterns of discrimination appear to vary among them. Visits of small native bees significantly increased paternal success while those of honey bees Apis mellifera reduced male fitness. Only visits by large native bees had discernible effects on recipient fecundity and, overall, fecundity was not limited by visitation. Maternal plants bearing large-petalled flowers produced fewer flowers during the experiment, reducing their total seed production. In these small populations, postpollination processes (at least in part, compatibility) significantly influenced male and female reproductive success. Variation in pollinator pools occurring on both spatial and temporal scales may act to preserve genetic variation for floral traits in this species. -from Authors