Many species of plants depend on insects for pollination, including most of the fruits and vegetables that humans eat. However, for pollen to fertilize a flower, it must generally come from the same species of plant. A critical attribute of insect pollinators is thus their fidelity, how likely they are to carry pollen from one flower to another flower of the same species. One reason that bees are especially valued as pollinators is their high fidelity, but recent research has shown that the fidelity of bees can vary. This project will test which specific factors enhance or diminish fidelity in bees. Besides increasing scientific understanding of an important ecosystem service, the project will add a new component to a doctoral dissertation and provide intensive field research experience for two undergraduate students. To communicate results to the general public, researchers will help create an outreach program on the importance of pollinators at the Desert Museum in Tucson, Arizona.
Previous work on pollination by bumblebees in meadows in the Rocky Mountains of Colorado shows that competition between bumblebees for flowers promotes fidelity. However, this depends on the mean length of the tongue of a species: when other species of bumblebees are removed, shorter tongued species tend to lose fidelity more and plant reproduction decreases more. This project will test whether variation between individuals within a species has the same effect. Researchers will remove all but one species of bumblebee from areas in meadows and follow the flights and measure the tongue lengths of individual bees. Results will advance knowledge of the ecology of fidelity in pollination. More broadly, research will show how differences between individual animals cause them to respond differently to competition, with consequences for ecosystem function.
