Mechanisms and Evaluation of Insecticide Resistance.

Insecticide resistance is a major concern in controlling mosquito populations, as it can lead to the failure of insecticide-based interventions.

There are four major mechanisms of insecticide resistance: cuticle modification, increased metabolism, target site alterations, and behavior change. Cuticle modification is the modification of the physical barrier to slow down the penetration of insecticide molecules within the mosquito’s body. Increased metabolism involves the over-expression of genes that lead to increased metabolic detoxification of insecticides. Target site alterations involve changes in the location where the insecticide binds, which can affect nerve impulse or chemical transmission. Behavior change involves the mosquito’s ability to recognize and avoid danger.

To evaluate insecticide resistance, bioassays can be conducted in the field or laboratory to estimate the mortality rate under different exposure conditions, timings, and concentrations.

Review questions:

• What are the four major mechanisms of insecticide resistance?
• How does cuticle modification help mosquitoes resist insecticides?
• What is the role of G-protein-coupled receptors in the development of insecticide resistance?
• What are the two examples of target-site alterations mentioned in the lecture?
• How can bioassays be used to evaluate insecticide resistance?