(CN) – A team of biologists and entomologists are buzzing with excitement after discovering the enzymes that determine how sensitive honeybees and bumblebees are to a certain pesticide, opening the potential to create pest-control substances that aren’t deadly to bees.
The joint study by researchers at the University of Exeter, agricultural research center Rothamsted Research and agrichemical giant Bayer compared the effects of two neonicotinoids, a class of pesticide found to be deadly to bees.
On Thursday, the researchers said they found bee pollinators are equipped with biochemical defense systems comprised of specific enzymes that determine their sensitivity to insecticides.
The differences in sensitivities to the neonicotinoid insecticides vary greatly between honeybees and bumblebees. Previous studies have focused on the way bees process chemicals. The specific genes that metabolize pesticides were unknown until now, according to the researchers.
Neonicotinoid pesticides affect the central nervous systems of insects and are suspected of being a leading cause of colony-collapse disorder in honeybees as well as the rapid levels of decline in wild pollinator species, according to bee conservation organization Xerces Society. Bees pollinate about 30 percent of all plants that produce foods and beverages consumed by humanity.
Discovery of why “two of the most economically important bee species” are immune to one neonicotinoid pesticide but not to others could lead to production of chemical treatments that protect crops from pests without harming these essential pollinators, the researchers said.
Dr Ralf Nauen, insect toxicologist and lead investigator of the study at Bayer – which manufactures pesticides containing neonicotinoids – said knowing the why some bees are inherently tolerant helps researchers and regulators better understand why certain pesticides are more safely used around bees.
"The knowledge from our study can also be used to predict and prevent potential harmful effects that result from inadvertently blocking these key defense systems,” said Nauen, who suggested applying pesticides in combination with other chemicals could reduce effects on bees.
Neonicotinoids are a relatively new class of pesticide. Lin Field, who led the group at Rothamsted, said not all neonicotinoids are highly toxic to bees, but all get painted in the same light.
"Each insecticide needs to be considered on its own risks and merits, not just its name," she said.
The pesticides dissolve in water, and end up into waterways via agricultural runoff, according to researchers. Flowers miles away from a farm treated with neonicotinoids can absorb the chemicals, which then is absorbed into the stems, leaves, pollen and nectar.
"Identifying these key enzymes provides valuable tools to screen new pesticides early in their development to see if bees can break them down," said Professor Chris Bass, who led the team at the University of Exeter.
"It can take a decade and $260 million to develop a single pesticide,” Bass said. The knowledge from the study can help manufacturers avoid wasting time and money on pesticides that will end up being highly toxic to bees, he said.
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