Direct and indirect estimates of the selfing rate in small and large individuals of the bumblebee pollinated Cynoglossum officinale L (Boraginaceae)

We measured the relationship between selfing rates and flower number in an experimental population of bumblebee pollinated Cynoglossum officinale, wit h plants differing in flower number. Results were compared with the predict ion of a model based on pollen dynamics and pollinator behaviour. The selfi ng rate, as measured by multilocus oligonucleotide DNA fingerprinting, incr eased with flower number and ranged from 0% to 70%. Flowers on large plants received an equal number of visits from bumblebees as flowers an small pla nts. On large plants more flowers in a row were visited, inducing geitonoga my. The overall relationship between selfing rate and number of flowers can be explained by pollen dynamics and pollinator behaviour without invoking postpollination processes such as differential pollen tube growth and abort ion.