Insect-mediated pollination is a critical, and often limiting, step in the reproductive cycle of many wild plants and crops. Thus, understanding the effects of losing pollinator species is a question of central importance for the long-term persistence of healthy, functioning ecosystems and for the security and productivity of our agricultural enterprise. This project focuses on pollinator floral fidelity, or how closely a single pollinator species interacts with a single plant species over the short term. Such fidelity is of key importance to plants, because pollinators with low fidelity visit many different plant species in a single foraging trip, thus transferring the wrong kind of pollen between individual plants and reducing the number of seeds they produce. This project will investigate the hypothesis that competition between pollinator species is positively related to pollinator floral fidelity. If this hypothesis is true, as is suggested by theory and pilot data, loss of pollinator species or populations could reduce floral fidelity in the pollinators that remain, thereby leading to unanticipated reductions in plant reproduction. To test this, manipulative experiments will be conducted in subalpine meadows in the Colorado Rockies where we selectively - but temporarily and non-lethally - remove an abundant pollinator species from a plot, and assess the floral fidelity of other pollinators both before and after the manipulation. The effects of these pollinator removals on plant reproduction will also be preliminarily assessed. In addition, this project investigates flower fidelity in experimental foraging trials in the lab, where pollinator and plant diversity and abundance can be controlled. This work may have implications for the effects of pollinator losses on plant reproduction, especially given ongoing pollinator declines around the world.
Beyond the research results, the broader impacts of this project include its conservation implications; the training of a post-doctoral research fellow; improvements to the pollen and bee reference collections at the Rocky Mountain Biological Laboratory; and development of a pollination classroom module for fourth graders that will be implemented in under-resourced schools in Atlanta and widely disseminated.