Effects of flowering mode and pollinator sharing on reproductive success in natural hybrid of two Epimedium (Berberidaceae) species

Abstract Natural hybridization mediated by pollen flow has been considered as an important factor to drive speciation in floral plants. The diversity of Epimedium species is centered in southwestern China, yet the potential role of interspecific pollination in natural hybridization has not been empirically examined. The flowering period and floral visitors, and conducted a series of pollination experiments to examine breeding systems and hybrid compatibility within three Epimedium which are commonly sympatric in the Jinchengshan National Foreast Park, Nanchong of Sichuan Province. Epimedium pubescens and Epimedium wushanense are morphologically clearly distinct and easily recognied by flower morphology, the putative hybrids (not been named) are morphologically between them. We found that E. pubescens and E. wushanense had 15 days of overlapping anthesis during consecutive three years of observation. Both species in research region are self-incompatible and need pollinators service for successful reproduction. Their pollinators are different in quantity and species, but Lasioglossum spp. (Hymenoptera: Halictidae) visited all of them. No breeding barrier between any of the three species were detected by artificial pollination, and the hybrids seeds were fertile. The overlapping time of flowering, common floral visitors and compatible of hybrid may be important factors to make interspecific pollination and speciation successfully for natural hybrids species of E. pubescens and E. wushanense . The role of potential interspecific pollination is essential to hybrids speciation and the evolution of Epimedium species.