Differentiation in breeding system and pollination of three sympatric Corydalis species

To illustrate the adaptive significance of breeding system differentiation to pollination environments, we studied the floral traits, distribution patterns, flowering phenology, mating system, and pollination system of three sympatric Corydalis species (Corydalis edulis Maxim., C. shearer S. Moore., and C. racemosa (Thunb.) Pers.) in Hubei Province, China. Results showed that the three species usually co-occurred in plant communities and the flowering phase overlapped to some extent. Their floral traits diverged in color and size of corolla, as well as nectar production. Corydalis shearer was self-incompatible, depending on cross-pollination by pollinators, whereas C. edulis and C. racemose were self-compatible and had mixed mating systems, reproducing through both autogamy and cross-pollination. All three species shared their main pollinators (bumblebees, honeybees, and leafcutter bees) and the floral sexual organs contacted the same body parts of the pollinators, but the visitation frequency differed significantly. In the mixed plant community, the pollinators constantly visited flowers of the same species, probably due to differences in floral morphology. In conclusion, the divergence in floral traits and mating systems might contribute to the avoidance of pollination interference among related species. The mating systems might be associated with the pollination environment, and those species with mixed mating systems showed advantages at adapting to different habitats and climates.