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 LD(50) 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(1) and BC(2) 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.


CONCLUSIONS
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.
Zhang
Lan
L
Department of Entomology, China Agricultural University, Beijing 100094, People's Republic of China.
Shi
Jing
J
Gao
Xiwu
X
D000818:Animals; D006793:Houseflies / Q000187:drug effects* / Q000235:genetics*; D007305:Insecticide Resistance / Q000235:genetics*; D007306:Insecticides / Q000494:pharmacology*; D011722:Pyrethrins / Q000494:pharmacology*
D007306:Insecticides; D011722:Pyrethrins; C017160:cypermethrin