Biochemical Genetics of House Fly Resistance to Carbamate Insecticide Chemicals12

Abstract

One resistant strain (R_Hokota) and 2 susceptible multi-chromosomal marker strains (S₂₃₅₆and S₂₄₅₀) of house flies, Musca domestica L., were used for genetic analyses with the F₁ male backcross experimental design for determining linkage groups. Genetic analyses were made as follows: (1) resistance to Baygon® (O-isopropoxyphenyl methylcarbamate) in the presence and in the absence of the synergist piperonyl butoxide; (2) Baygon metabolism in living flies; (3) Baygon metabolism by the fly abdomen enzyme-reduced nicotinamide-adenine dinucleotide phosphate (NADPH2) system; (4) resistance to Matacil® [4-(dimethylamino)-m-tolyl methylcarbamate]; (5) Matacil metabolism by the fly abdomen enzyme-NADPH₂ system. Each of these comparisons showed the importance of the 5th chromosomal effect in conferring both high carbamate resistance and high activity for microsomal oxidizes involved in metabolism by ring hydroxylation and attack on N-methyl and O-alkyl groups. The 3rd chromosome is secondary in importance to the 5th chromosome in each of the above comparisons, while the 2nd chromosome is also involved in the resistance but not in the enzyme activity. Piperonyl butoxide minimizes the importance of the 5th chromosome in conferring Baygon resistance. Differences in penetration rates do not contribute materially either to the resistance or synergistic effects. Detoxification reactions involving the microsome-NADPH ₂ system, which are controlled by the 5th chromosomal gene (s), are important in the mechanism of resistance to carbamate insecticide chemicals; they may also be important with other types of insecticide chemicals which are metabolized by this system and to which resistance is conferred by 5th chromosomal factors.