Size-dependent clonal reproduction and sex allocation in the monoecious Begonia emeiensis

Abstract

Size-dependent clonal and sexual reproduction has been studied in many species. However, very few attempts have investigated size-dependent resource allocation among clonal reproduction, female function, and male function within a species. Moreover, how clonal reproduction and sexual reproduction interact to influence size-dependent sex allocation has not been explored. In this study, we investigated the size dependency of clonal reproduction and sex allocation and how clonal reproduction and sexual reproduction interact to influence size-dependent female function, male function, and sex allocation in the monoecious Begonia emeiensis. Individuals with no reproduction, reproducing clonally through bulbils, reproducing sexually through flowers, and reproducing through both bulbils and flowers differed significantly from each other in terms of size (leaf area), suggesting a threshold size for clonal versus sexual reproduction. Bulbil number per individual increased with size regardless of flower production. In contrast, the relationship between size and female and male flower production per individual was influenced by bulbil production; both female and male flower numbers per individual increased with size at a slower rate for individuals reproducing clonally and sexually than for those reproducing only sexually. The ratio of female to male flowers per individual increased with size independent of bulbil production. Our study shows that the size dependency of clonal reproduction was unlikely to be influenced by sexual reproduction; however, the size dependency of female and male function was influenced by clonal reproduction.