The neonicotinoids thiacloprid, imidacloprid, and clothianidin affect the immunocompetence of honey bees (Apis mellifera L.)

Building on existing research associating pesticide use with a reduction in honey bee immune system function, this study measured the impact of three neonicotinoids, clothianidin, imidacloprid and thiacloprid, on three distinct immune defense mechanisms. The study found that both imidacloprid and thiacloprid weakened individual bee’s immune responses at field realistic doses of 1 ug/L and 200 ug/L respectively. Clothianidin only impacted the immune parameters at levels higher than the researchers considered to be field relevant (50–200 ug/L). The results of this study suggest that field-realistic sublethal exposures levels of imidacloprid and thiacloprid can affect the immunocompetence of individual honey bees. These effects could reduce the capacity of honey bees to resist disease and survive attacks from parasites.