Inheritance of beta-cypermethrin resistance in the housefly Musca domestica (Diptera: Muscidae)

BACKGROUND: Beta-cypermethrin, a synthetic pyrethroid insecticide, was applied frequently in the control of health pests including houseflies, Musca domestica L., in China. However, different levels of resistance to beta-cypermethrin were monitored in field strains of houseflies. A strain of M. domestica, 4420-fold resistant to beta-cypermethrin after continuous 25 generations of selection, was used in this paper to determine the mode of inheritance of. pyrethroid resistance. RESULTS: The estimated realized heritability (h(2)) of beta-cypermethrin resistance was 0.30 in this resistant strain. Results of bioassays showed no significant difference in values of LD50 and slope of log dose-probit lines between reciprocal progenies F-1 and F-1', and yielded values of -0.10 (F-1) and -0.11 (F-1') for the degree of dominance (D). Chi-square analysis from responses of self-bred and backcross progenies (F-2, BC, and BC2 respectively) indicated that the null hypothesis, a single gene responsible for resistance, was accepted. The minimum number of independent segregation genes was 0.93 for F-1 by Lande's method. CONCLUSION: It was concluded that beta-cypermethrin resistance in the housefly was inherited as a single, major, autosomal and incompletely recessive factor. These results would provide the basic information for pest management programmes. (c) 2007 Society of Chemical Industry.