Insecticide Resistance and Fitness Cost

Abstract

This review focuses on insecticide resistance fitness cost and its consequences on resistance stability. Many cases of insecticide resistance are associated with fitness cost even though sometimes, resistance is not costly. The cost may be evidenced by different methods. Thus decrease of insecticide resistance in heterogeneous populations in the absence of any insecticide treatment supposes a hypothesis that fitness cost is associated with resistance. This hypothesis can be tested by comparing biological, morphological and ecological parameters of susceptible and resistant strains. Quantitative and qualitative enzyme overproduction and mutation are major resistance fitness cost mechanisms. The cost may be explained by the energy invested to synthesize protein for enzyme overproduction. At the beginning of the resistance, the cost appears to be unstable, but with time it stabilizes. Sometimes modifier gene is selected during resistance appearance process and resistance fitness cost is deleted. When resistance is associated with fitness cost the latter can be used in insecticide rotation strategy for resistance management.