Plant–pollinator interactions and flower diversification

There is good evidence that plant–pollinator interactions and plant diversification rates are interrelated, although the actual mechanisms involved, and their relative importance, remain to be fully elucidated. In some groups, such as orchids, specialized relationships with pollinators may increase the likelihood of reproductive isolation between similar plant taxa and thus increase speciation rates. More commonly, however, effective flower–pollinator relationships may contribute to plant diversification rates by reducing the rates of extinction. Finally, in some plant lineage, the association between specialized pollination and species diversity may reflect specialization in response to selection generated by pollinator sharing with closely related, sympatric species.