Keywords: CES; carboxylesterases; ChE; cholinesterase; CI50; concentration that produce 50% of inhibition; DTNB; 5,5´-dithio-2-bis-nitrobenzoate; G; gonads; GST; glutation S-transferase; OP; organophosphate insecticide; p-NPA; p-nitrophenyl acetate; p-NPB; p-nitro