Angiosperms show remarkable floral diversity. However, the ecological
processes involved in flower diversification remain poorly understood.
In this article I propose that different plant species abundance drives
adaptation to different pollinators and promotes different degrees of
specialization. In this view, interspecific variation in species
abundance can foster floral diversification. 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. To assess if and
how floral abundance can generate floral diversity, I use the model to
assemble plant-pollinator networks from simulated plant and pollinator
communities. The model shows that evolution of flowers towards highly
specialized pollinators and pollinators with high pollen carryover
capacity is favoured at low floral abundance, while evolution on more
abundant pollinators is favoured at higher abundance. Furthermore,
floral specialization is favoured at low floral abundance, while
generalization is favoured at high abundance. In simulated plant
communities of variable floral abundance, different pollinator systems
evolve among the different plant species. The model demonstrates a new
mechanism by which floral diversity can be generated, contributing to
our understanding of floral evolution and diversification.