Experimental assessment of the functional morphology of inflorescences of Daucus carota (Apiaceae): testing the ‘fly catcher effect’

1. The functional significance of inflorescence morphology of Daucus carota L. (Apiaceae) was tested using an inflorescence manipulation experiment. Specifically, we sought to explain the role (if any) in pollination of the dark central floret of this species. 2. In central England, D. carota was found to be pollinated by a taxonomically wide range of insects that varied in their inflorescence visitation rates and in their pollen loads. There was also variation in abundance of some taxa between the 2 years of this study. 3. By removing the dark central floret and adding false florets we sought to affect pollinator visitation rates and seed set in a manner consistent with the ‘fly catcher effect’ hypothesis of Eisikowitch (1980). Taxa responded to these manipulations but not in ways that shed light on the adaptive role of the dark central floret. Seed set was likewise unaffected in any consistent way. 4. The role of the dark central floret remains an enigma. We speculate, following Darwin (1888), that the dark central floret may now be functionless and possibly represents a trait that has persisted long after its original function has been lost.