Neonicotinoids are the most widely-used pesticides in world. They are also toxic to insects, birds and mammals.
“That’s where the controversy lies,” said Morrissey, an ecotoxicologist and professor with the Department of Biology and School of Environment and Sustainability. “If you look at the lab studies, they’re highly conclusive. Neonicotinoids have a range of affects on all sorts of organisms, both honey bees and wild bees included. But when you start moving out into the field, you get messier responses.”
The Canadian study, led by researchers at York University and conducted in corn fields in Ontario and Quebec, found that the pesticides can hurt the health of Canadian honey bees—leading to higher mortality rates for worker bees and queen bees.
A second European study, which examined three bee species throughout Germany, Hungary and the U.K., had more variable outcomes, largely due to the geography variance, but also tended toward negative effects for bees.
“These are both very strong papers and will certainly have an impact,” Morrissey added.