Characterization of a Field Strain of the Mosquito Culex Quinquefasciatus for the Distribution of Esterase Activity Variants Associated with Insecticide Resistance

Event Center A & B

In the mosquito Culex quinquefasciatus Say, the mechanism of resistance to organophosphate and carbamate insecticides is a type of metabolic resistance, which results from an increase in esterase activity that sequesters the insecticide. The esterases responsible for this elevated activity are associated with two closely linked esterase loci, Est alpha and Est beta, which code for several forms of esterase enzymes. Elevated esterase activity is due to the gene amplification of one or both of these genes. Research on insecticide resistance is an important topic to be studied in order to insure that insect pests can continue to be controlled to prevent the outbreak of disease and to control agricultural pests, and also because it provides a great way to study the mechanisms of evolution. This work characterizes a field strain of Culex quinquefasciatus for esterase activity and electromorph identity by conducting esterase and protein assays, as well as polyacrylamide gel electrophoresis on a sample of individual mosquitoes from the strain. The characterization of this field strain provides a better understanding of which esterases are present in the population that was collected and that is now being raised for future work. This characterization is necessary before any further work on this strain can be conducted to provide a baseline for esterase activity.