Does urbanization affect heavy metal exposure in bumble bees?

Heavy metals entering the environmnet is of high concern in urban areas due to their high production rates in manufacturing. High concentrations of these metals are known to bioaccumulate and cause disease and mortality in animals, but their possibility of exposure in insects is widely unknown. We were interested in detrmining if the common eastern bumblebee (Bombus impatiens) is exposed to higher concentrations of heavy metals in a city than in surrounding suburbs and rural areas. Bumblebee nests were commercially purchased and placed in residential backyards along a landscape gradient from Cleveland, OH to Wooster, OH. After being allowed to forage in the landscape for 3 weeks, all nests were collected and tested for presence of heavy metals. So far, we have discovered the presence of 7 heavy metals in bumblebee workers and larvae, including cadmium, mercury, lead, and arsenic. We will further be testing pupae, honey, and wax. We will also be analyzing any correlations between landscape (urbanization) and local (nearby resources) level factors and heavy metal exposure. As bumblebees are important pollinators and in global decline, understanding their risks of exposure will help in conservation of pollination services.