A study published in Nature (2012) 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 similar to those found in the field reduces foraging efficiency, increases worker mortality, and leads to significant reductions in brood development and colony success. Worker foraging performance, particularly pollen collection efficiency, was significantly reduced, with knock-on effects on forager recruitment, worker losses, and overall productivity. Combinatorial pesticide exposure also increased the likelihood of colony failure. The study used 40 bumblebee colonies (Bombus terrestris) exposed to different pesticide treatments: Control (no pesticide), Imidacloprid (I), λ-cyhalothrin (LC), and a combination (M). Imidacloprid, a systemic pesticide found in plant tissues, was administered at a concentration found in crop nectar and pollen. λ- cyhalothrin, a sprayed pesticide, was applied according to label guidelines. Foraging bees were simultaneously exposed to both chemicals, making them ideal for studying combinatorial effects. The study found that Imidacloprid-treated colonies had significantly lower worker production compared to Control colonies, with a 27% reduction in I colonies and 9% in M colonies. Worker mortality was also significantly higher in LC and M colonies, with 36-39% of workers dying in these groups compared to 9% in Control colonies. Additionally, a higher proportion of workers in LC and M colonies died within four days of eclosion, indicating a waste of resources. The study also found that Imidacloprid-exposed foragers collected significantly less pollen per foraging bout and had lower success rates in collecting pollen compared to Control foragers. The duration of successful foraging bouts was longer for Imidacloprid-exposed foragers, but their overall efficiency was lower. These findings suggest that Imidacloprid impairs pollen foraging efficiency, leading to increased colony demand for food and reduced brood development. The study highlights the importance of considering the combined effects of pesticides on bee colonies, as exposure to multiple pesticides can have severe consequences for colony survival. The findings emphasize the need for longer-term toxicity testing and separate risk assessments for different bee species, particularly in areas of agricultural intensification. The study also underscores the limitations of current pesticide safety guidelines, which do not account for the risks of multiple pesticide exposure.A study published in Nature (2012) 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 similar to those found in the field reduces foraging efficiency, increases worker mortality, and leads to significant reductions in brood development and colony success. Worker foraging performance, particularly pollen collection efficiency, was significantly reduced, with knock-on effects on forager recruitment, worker losses, and overall productivity. Combinatorial pesticide exposure also increased the likelihood of colony failure. The study used 40 bumblebee colonies (Bombus terrestris) exposed to different pesticide treatments: Control (no pesticide), Imidacloprid (I), λ-cyhalothrin (LC), and a combination (M). Imidacloprid, a systemic pesticide found in plant tissues, was administered at a concentration found in crop nectar and pollen. λ- cyhalothrin, a sprayed pesticide, was applied according to label guidelines. Foraging bees were simultaneously exposed to both chemicals, making them ideal for studying combinatorial effects. The study found that Imidacloprid-treated colonies had significantly lower worker production compared to Control colonies, with a 27% reduction in I colonies and 9% in M colonies. Worker mortality was also significantly higher in LC and M colonies, with 36-39% of workers dying in these groups compared to 9% in Control colonies. Additionally, a higher proportion of workers in LC and M colonies died within four days of eclosion, indicating a waste of resources. The study also found that Imidacloprid-exposed foragers collected significantly less pollen per foraging bout and had lower success rates in collecting pollen compared to Control foragers. The duration of successful foraging bouts was longer for Imidacloprid-exposed foragers, but their overall efficiency was lower. These findings suggest that Imidacloprid impairs pollen foraging efficiency, leading to increased colony demand for food and reduced brood development. The study highlights the importance of considering the combined effects of pesticides on bee colonies, as exposure to multiple pesticides can have severe consequences for colony survival. The findings emphasize the need for longer-term toxicity testing and separate risk assessments for different bee species, particularly in areas of agricultural intensification. The study also underscores the limitations of current pesticide safety guidelines, which do not account for the risks of multiple pesticide exposure.