SAN FRANCISCO For years the news has been the same: Honey bees are being hammered by some mysterious environmental plague that has a name -- colony collapse disorder – but no established cause. A two-year study now provides evidence indicting one likely group of suspects: pesticides. It found “unprecedented levels” of mite-killing chemicals and crop pesticides in hives across the United States and parts of Canada.
The worker bee goes out, picks up pollen containing residual chemicals and brings it back to the hive where it goes into the wax. This goes on until prolonged exposure causes her to either drop dead en route or forget how to get back home.
The researchers have several suspicions why the bees looked cleaner than their dwellings. In some cases, detoxifying systems within the bees might have broken down the chemicals, fostering their excretion. But an even likelier explanation: The sampling focused primarily on live bees extracted from the hives. These tended to be the queens, brood nurses and adolescents – hive residents that aren’t on the chemical frontlines, foraging in pesticide treated fields. Indeed, the fact that researchers found so few healthy worker bees in many of the hives from which they received samples suggests that sickened foragers probably die before they get home.