Effects of the pyrethroid insecticide deltamethrin on the hemocytes of Galleria mellonella

In the present study, the effects of deltamethrin on cell-mediated immune response and genotoxic damage of Galleria mellonella (Lepidoptera: Pyralidae) were investigated. Different concentrations of deltamethrin (5, 20, 50, 100, and 150 μg) were administered to G. mellonella at 24, 48, 72, and 96 h. Five types of hemocytes were identified in G. mellonella: prohemocytes, plasmatocytes, granulocytes, spherulocytes, and oenocytes. Total hemocyte counts (THCs) were significantly affected by deltamethrin. At 72 h, THCs of the treated group had significantly decreased compared with the control groups at high deltamethrin concentrations (50, 100, and 150 μg); however, at 96 h, THCs had significantly increased at deltamethrin concentrations of 100 and 150 μg. Micronucleus formation was significantly affected by deltamethrin; in particular, high concentrations of deltamethrin (100 and 150 μg) caused an increase in micronucleus formation at all time points. We conclude that deltamethrin affected THCs and caused the induction of micronucleus formation via genotoxic damage in G. mellonella.