Fitness Cost in Laboratory Selected Strain of the Potential Mosquito Vector of West Nile Virus (Culex pipiens) Associated with Resistance to the Insecticide Temephos

The fitness cost associated with resistance genes was investigated on mosquito's viability. We studied four fitness parameters in a laboratory-selected strain of Culex pipiens associated with resistance to the insecticide temephos. S-Lab was the susceptible strain used for comparison. Two genes are involved in resistance to organophosphate (OP) insecticides: Ace-1 and Ester. After 5 generations of pressure, the temephos resistance ratio increased to 60.51 at RR95, exhibited a deficiency in the following two parameters: female fecundity (χ2=infini; dl=1; P.05) and mortality rate (P.05). Characterizations of resistance mechanisms indicate that resistance Ace-1 alleles coding for a modified acetylcholinesterase were associated with a higher mortality rate and lower fecundity. Several previous studies were used to compare and discuss our results.