In this study, the efects of dietary CuO nanoparticles (NPs) on metabolic enzyme activity, biochemical parameters, and total
(THC) and diferential hemocyte counts (DHC) were determined in Galleria mellonella larvae. Using concentrations of 10,
100, 1000 mg/L and the LC10 and LC30 levels of CuO NPs, we determined that the NPs negatively impacted metabolic
enzyme activity and biochemical parameters in larval hemolymph. Compared with the control, the greatest increase in THC
was observed in larvae fed on diets with 100 mg L−1 of CuO NPs. Plasmatocytes and granulocytes were among the most
numerous hemocytes in all treatments. These results suggest that dietary CuO NPs efects the metabolic metabolism and
immune system of G. mellonella and provide indirect information regarding the toxic efects of CuO NPs in mammalian
immune system given similarities between mammalian blood cells and insect hemocytes.