**5. Metabolic detoxication of pesticides**

Plant–insect coevolutionary interactions drive species diversification and the set of genetic traits that allow pest species to survive exposure to a wide variety of secondary metabolites produced by plants. Such genetic traits evolved through evolutionary history, involving several highly specialized multigene families that are responsible for detoxication mechanisms of biotic and xenobiotic compounds. Examples of these multigene families include the glutathione transferases, mixed function oxidases, and carboxilesterases superfamilies [26]. These supergene families are capable of metabolizing a large amount of chemicals, some of which are currently used as pesticides.

Some mechanisms of resistance have been identified for several important arthropod vectors. Increased esterase activity is a major component of organophosphates resistance in *Culex* mosquitoes [27]. The enhancement of mix function oxidases also plays an important role in OP and pyrethroid resistance mechanisms [28], and the combination of mixed function oxidases and esterases in high concentrations has been detected in permethrin-resistant mosquitoes [29]. Resistance mechanisms in cockroaches include metabolic detoxication and *Kdr*-type resistance. However, detoxication mechanisms mediated by esterases and oxidases have been identified as the most frequent mechanisms of resistance [30].
