Effects of Novel Pesticides on Bumble Bee (Hymenoptera: Apidae) Colony Health and Foraging Ability

Two experiments were conducted testing for lethal and sublethal effects of the transgenicproteinsCry1Acandchitinase, and thechemical seedand soil treatment imidaclopridonbumble bees (Bombus occidentalis Greene and B. impatiens Cresson, Hymenoptera: Apidae). In the Þrst experiment, B. occidentalis colonies were exposed to realistic residue levels of Cry1Ac, chitinase, and imidacloprid found in pollen. There were no effects on pollen consumption, bumble bee worker weights, colony size, amount of brood, or the number of queens and males produced. In the second experiment, usingB. impatiens, we tested the effects of Cry1Ac and two levels of imidacloprid. Similar colony health measures were collected as in the Þrst experiment, but in addition foraging ability of individual bees was tested on complex artiÞcial ßowers. There were no differences in colony characteristics among treatments. However, bees in the high-imidacloprid treatment had longer handling times on the complex ßowers than bees in the other treatments. No lethal, sublethal colony, or individual foraging effects of these novel pesticides were found at residue levels found in the Þeld, suggesting that bumble bee colonies will not be harmed by proper use of these pesticides. Use of an artiÞcial ßower foraging array proved to be a sensitivemethod for detecting sublethal response of bees to pesticides.