From anthesis to diaspore dispersal: reproductive mechanisms of rare herbaceous Moraceae species endemic to Brazil

Abstract

Studies on the reproductive biology of Dorstenia species are scarce. We analyzed the sexuality, floral biology, and diaspore dispersal of Dorstenia arifolia and D. bonijesu, including their breeding systems and pollinators, in natural populations from Minas Gerais state, southeastern Brazil. We report here, for the first time, the occurrence of both unisexual (male) and bisexual coenanthia on the same individuals of Dorstenia arifolia, while only bisexual coenanthia were observed in D. bonijesu. In both species all coenanthia were long-lived and bisexual coenanthia were protogynous. We observed the occurrence of self-compatibility and myophily in Dorstenia arifolia, a species which was pollinated by small Lauxaniidae flies. Those insects not only used pollen as food resource but they also used coenanthia as oviposition sites, which is the first report to the studied species. Dorstenia bonijesu produced seeds, even having no floral visitors, suggesting an apomictic mechanism, which is a new breeding system reported to the genus. Both studied species are autochorous, but D. bonijesu also exhibited a peculiar type of hydrochory. The novelties reported herein indicate the need of additional studies to improve the understanding of the reproductive attributes of Dorstenia species.