Bumblebees exposed to pesticides take longer to learn how to collect pollen and seek different flowers, according to a new study.
“Bees rely on learning to locate flowers, track their profitability, and work out how best to efficiently extract nectar and pollen,” Nigel Raine, an environmental sciences professor at the
University of Guelph in Canada and senior author of the study, said in a statement. “If exposure to low levels of pesticide affects their ability to learn, bees may struggle to collect food and impair the essential pollination services they provide to both crops and wild plants.”
The study,
published this week in the journal Functional Ecology, found that bees exposed to neonicotinoid insecticide collected more pollen but took longer to do so. Previous studies of honeybees found that exposure to the pesticides caused changes in their brains, the statement said.
Lead author Dara Stanley, of Royal Holloway University of London, said control bees may be investing more time and energy in learning, figuring out how to gather pollen from wildflowers with different shapes.
“Our results suggest that the foraging behavior of bumblebees on real flowers can be altered by sublethal exposure to field-realistic levels of pesticide,” the study said. “This has implications for the foraging success and persistence of bumblebee colonies, but perhaps more importantly for the interactions between wild plants and flower-visiting insects and ability of bees to deliver the crucial pollination services to plants necessary for ecosystem functioning.”
The Ontario government was the first in North America to impose limits on
neonicotinoid insecticides, The Canadian Press reported. The law, passed last year, restricts farmers from using the pesticide-treated seeds on half their land this year, and on any of it in 2017. It also requires vendors to be licensed to sell seeds treated with neonicotinoids, which have been banned in Europe.
Twitter users expressed concern about the effects of the pesticides on bees.