A recent study uncovers serious dangers that pesticides present to ground-nesting bees, which play a vital role in pollinating crops and ensuring food production. As the agricultural sector increasingly depends on pesticides to safeguard crops, the adverse effects on these important pollinators are becoming more evident.
A recent study uncovers serious dangers that pesticides present to ground-nesting bees, which play a vital role in pollinating crops and ensuring food production. As the agricultural sector increasingly depends on pesticides to safeguard crops, the adverse effects on these important pollinators are becoming more evident.
Conducted by Sabrina Rondeau, an NSERC Postdoctoral Fellow in the Department of Biology at the University of Ottawa, the study emphasizes the pressing need to reevaluate pesticide safety regulations in order to protect these key pollinators.
The findings indicate that existing pesticide risk assessments, which mainly utilize honeybees for testing, do not take into consideration the specific risks faced by wild bees that nest in the ground. “Our results reveal that more than 70% of wild bee species, essential for pollinating our food crops, are subjected to serious threats from pesticide residues in soil — a danger which current regulations ignore,” Dr. Rondeau explains.
Key insights from the study include:
- Bumble bee queens may be drawn to soil contaminated with pesticides, increasing their exposure during critical hibernation periods.
- Exposure to certain pesticides in the soil, especially cyantraniliprole, diminishes survival rates and reproductive success for bumble bee queens, potentially affecting future generations.
- For squash bees, exposure to combinations of insecticides and fungicides disrupts their behavior and reduces the number of offspring, which may indicate possible declines in population.
“We discovered that larger bumble bee queens, which are generally more likely to survive the winter and successfully create colonies, were unexpectedly more at risk from pesticide exposure,” explains Dr. Rondeau. “This could lead to significant impacts on bumble bee populations.”
The research utilized both field and laboratory studies, beginning with measuring pesticide residues at appropriate hibernation sites for bumble bee queens on Ontario farms. These field data were used to inform further studies on how such exposure affects the hibernating bumble bee queens and the hoary squash bee, a solitary species that nests in the ground.
“Our research highlights the need for a fundamental reevaluation of how we judge pesticide safety to effectively protect wild pollinators,” Dr. Rondeau concludes. “This is essential for both the security of our food systems and the conservation of biodiversity.”
This study emphasizes the urgent need for significant changes in pesticide regulations to ensure the safety of all pollinator species, particularly those that nest in agricultural soils.
