Wild bees provide insurance against ongoing honey bee losses

In many parts of the world, crop pollination is perceived to rely on a single domesticated pollinator species, the honey bee (Apis mellifera). Honey bees are currently (2006-2007) undergoing extensive die-offs in North America and Europe in a syndrome termed Colony Collapse Disorder. We studied watermelon pollination by honey bees and wild bees in New Jersey and Pennsylvania, USA, in 2005, before Colony Collapse Disorder occurred. We collected data on bee visits to watermelon flowers (N = 6187 visits) and pollen deposition per visit (N= 271 pollen counts). We used these data in a simulation to estimate total pollination by different bee taxa, and found that ~50 wild, native bee species provide sufficient pollination to watermelon at >90% of the farms we studied. We therefore predict that in 2007 wild bees will buffer this system against pollination deficits and declines in agricultural production, despite honey bee losses. In July 2007, we will repeat our field work at a subset of farms in order to compare watermelon pollination before and after Colony Collapse Disorder. Both the before and after data will be presented. If wild bees are still fully pollinating the watermelon crop in 2007, our work will provide a compelling example of the insurance value of biodiversity. If they are not, it will suggest that wild bees may be susceptible to whatever agent(s) causes Colony Collapse Disorder.