Combined pesticide exposure severely affects individual- and colony-level traits in bees

Combined pesticide exposure severely affects individual- and colony-level traits in bees

2012 November 1; 491(7422): 105–108. doi:10.1038/nature11585. | Richard J. Gill, Oscar Ramos-Rodriguez, and Nigel E. Raine
A study by Richard J. Gill, Oscar Ramos-Rodriguez, and Nigel E. Raine reveals that combined exposure to neonicotinoid (Imidacloprid) and pyrethroid (λ-cyhalothrin) pesticides severely impacts both individual and colony-level traits in bumblebees. The research shows that exposure to these pesticides, at concentrations resembling field-level exposure, impairs foraging behavior, increases worker mortality, and reduces brood development and colony success. Worker foraging performance, particularly pollen collecting efficiency, was significantly reduced, leading to knock-on effects on forager recruitment, worker losses, and overall productivity. Combinatorial pesticide exposure also increased the likelihood of colony failure. The study used a split block design to test the effects of Imidacloprid, λ-cyhalothrin, and their combination on 40 bumblebee colonies. Colonies were exposed to these pesticides for four weeks, and foraging behavior was monitored using RFID technology. The results showed that Imidacloprid-treated colonies had significantly lower worker production compared to control colonies, while colonies exposed to both pesticides had the highest worker mortality and failure rates. The study also found that pesticide-exposed colonies had higher worker mortality and more foragers leaving the colony, leading to increased losses. The findings highlight the importance of considering the combined effects of pesticides on bee populations, as current pesticide regulations do not account for such interactions. The study underscores the need for longer-term toxicity testing and separate risk assessments for different bee species. The results have significant implications for the conservation of pollinators in areas of agricultural intensification, emphasizing the need for more comprehensive risk assessments and regulatory changes to protect bee populations from the harmful effects of pesticide exposure.A study by Richard J. Gill, Oscar Ramos-Rodriguez, and Nigel E. Raine reveals that combined exposure to neonicotinoid (Imidacloprid) and pyrethroid (λ-cyhalothrin) pesticides severely impacts both individual and colony-level traits in bumblebees. The research shows that exposure to these pesticides, at concentrations resembling field-level exposure, impairs foraging behavior, increases worker mortality, and reduces brood development and colony success. Worker foraging performance, particularly pollen collecting efficiency, was significantly reduced, leading to knock-on effects on forager recruitment, worker losses, and overall productivity. Combinatorial pesticide exposure also increased the likelihood of colony failure. The study used a split block design to test the effects of Imidacloprid, λ-cyhalothrin, and their combination on 40 bumblebee colonies. Colonies were exposed to these pesticides for four weeks, and foraging behavior was monitored using RFID technology. The results showed that Imidacloprid-treated colonies had significantly lower worker production compared to control colonies, while colonies exposed to both pesticides had the highest worker mortality and failure rates. The study also found that pesticide-exposed colonies had higher worker mortality and more foragers leaving the colony, leading to increased losses. The findings highlight the importance of considering the combined effects of pesticides on bee populations, as current pesticide regulations do not account for such interactions. The study underscores the need for longer-term toxicity testing and separate risk assessments for different bee species. The results have significant implications for the conservation of pollinators in areas of agricultural intensification, emphasizing the need for more comprehensive risk assessments and regulatory changes to protect bee populations from the harmful effects of pesticide exposure.
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