Michael Minnick

Biology Graduate Student

Amur honeysuckle (Lonicera maackii) is an invasive shrub of the eastern United States and found in great densities throughout the Miami University Natural Areas. When amur honeysuckle is blooming, edges of woodlands turn white and aromatic with the appearance of flowers in the spring. This attracts bees of all sizes, colors, and shapes. But which bees are pollinating the honeysuckle and which are simply enjoying the high quantities of nectar deep in the flower? We are answering this question by taking advantage of the size differences between honeysuckle-visiting bees. Size differences range from small sweat bees that are only a few millimeters in size, to large bumblebees with queens over 20 millimeters big (some over an inch!). But larger bees are stronger fliers, and have been observed visiting flowers at the top of the honeysuckle shrubs, flying from the top of one shrub to the next instead of visiting flowers near the ground. To account for this behavior, and any inherent differences between young (small) and old (large) honeysuckle shrubs, we placed four mesh bag treatments (no-see-um mesh, 4 mm holes, 7 mm holes, no bag) on the end of branches near the top and bottom of small and large isolated shrubs while honeysuckle was flowering. So, if bumblebees are the primary pollinator of honeysuckle, then we expect to see a large increase in fruit development between branches with 7 mm mesh and branches without bags, since most bumblebees will not fit through a 7 mm hole. We also included a treatment of no-see-um mesh to establish a baseline of self-fertilization. In July, when the fruits have begun to develop, the bags will be removed and replaced with small markers that will remain until the fruit turns red. Once fruits are ripe, each marked branch will be harvested and seeds counted. This will represent the total number of potential amur honeysuckle individuals that bees of different sizes can effectively produce. We can then infer which bees are not responsible for pollinating honeysuckle, and which species are most likely candidates for pollinating this invasive shrub that is changing the landscape.