A naturally derived pesticide previously considered safe for insect pollinators may hamper the foraging of wild bees, researchers report.
Bumblebee larvae raised on pollen spiked with spinosad, an insecticidal mixture of chemicals made by bacteria, grow up to be slow, clumsy foragers, say Lora Morandin of Simon Fraser University in Burnaby, British Columbia, and her colleagues in the July Pest Management Science. As adults, the bees suffer from muscle tremors and take longer to penetrate complex flower structures than do bees nourished as larvae with untainted pollen, the researchers found.
Previous studies on bees hadn't focused on sublethal effects of pesticides or on larvae, says Morandin. Moreover, researchers had looked mostly at domesticated honeybee colonies, which farmers can move before spraying a field. Wild bee colonies don't relocate during spraying, and so these bees probably suffer higher exposures to pesticides.
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