Biotic characteristics in the deltamethrin-susceptible and resistant strains of Culex pipiens pallens (Diptera: Culicidae) in China.

Culex pipiens pallens was selected with deltamethrin for 12 generations, and the LC 50 value rose steadily from 0.040 mg/l to 24.660 mg/l (617 times).The biotic parameters were observed for the deltamethrin-susceptible (SS) and resistant (RR) strains of C. pipiens pallens in the laboratory.In the RR strain, the fecundity, percentage of pupation and emergence decreased by 44.8%, 17.6% and 8.9% respectively; the percentage of scattered eggs increased by 22.5%; the time from hatching to emergence was prolonged by 1.32 days; the weight of female and male adults increased by 0.202 mg and 0.231 mg, respectively; and the life-span of the female and male adults was reduced by 4.13 days and 4.74 days, respectively.The results indicated that deltamethrin resistance of the mosquito was correlated with disadvantages during reproduction.