By Susan Milius
What does not kill them does not in fact make them stronger when it comes to bees and pesticides. Two unusual studies with free-flying bumblebees and honeybees find that survivable exposure to certain pesticides can lead to delayed downturns in bee royalty and a subtle erosion of workforces.
Pesticides appear as a suspect in widespread declines, sometimes subtle and sometimes dramatic, of the bees and other animals that pollinate crops and wild plants. And in one of the most dramatic still unsolved mysteries in those declines — why honeybee colonies suddenly collapse — one leading hypothesis combines chronic pesticide exposure with other stressors such as disease.
Both of the new studies, appearing online March 29 in Science, test the risks of foraging on flowers treated with common insect killers from the nicotine-inspired class called neonicotinoids. These pesticides course through the whole plant, killing aphids and a range of other nibbling and sipping pests, but also work their way into the nectar and pollen that bees collect.