Interspecific variation in plant abundance can contribute to the diversity and evolutionary assembly of floral communities

Abstract

Angiosperms show remarkable floral diversity in pollinator use. However, how this diversity evolves in a community context remains poorly understood. In this article I propose that different plant species abundances promote adaptation to different pollinators and different degrees of specialization. In this view, interspecific variation in species abundance can foster floral diversity. I develop a mathematical model of pollen transfer considering the interaction of several pollination processes – pollen removal and carryover, intra- and interspecific competition for pollinator visitation, and interspecific pollen transfer – that are linked to floral abundance. I integrate the model to an adaptive dynamic framework to simulate the evolutionary assembly of pollination networks. The model demonstrates that different pollinator attributes and degrees of generalization are favored at different plant relative abundances. Within communities, interspecific variation in plant abundance increased diversity in pollinator use and degree of generalization while also promoting the evolution of pollination networks with higher nestedness and lower connectance, leading to networks more consistent with natural pollination networks. The model helps understand the evolutionary assembly of flower communities and suggests a new mechanism by which floral diversity can be generated, contributing to our understanding of floral evolution and diversification.