Prevalence of commercially reared bumble bees foraging near an industrial greenhouse.

Relative abundance (% total catch of bumble bees, all species) of Bombus impatiens workers collected near a greenhouse in southern Ontario during June 2005. Solid line indicates the exponential fit, y = 53.77e^−0.01x. Most, if not all, of these B. impatiens workers were from commercial colonies in the greenhouse (see text).