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

摘要

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 (h2) 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 F1 and F'1,and yielded values of -0.10 (F1) and -0.11 (F'1) for the degree of dominance (D).Chi-square analysis from responses of self-bred and backcross progenies (F2,BC1 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 F1 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.