Evolutionary Shifts in Life‐History Traits of <i>Culex quinquefasciatus</i> (Culicidae) Under Sustained Insecticide Pressure

ABSTRACT The growing threat of insecticide resistance in the southern house mosquito, Culex quinquefasciatus , presents a significant obstacle to effective vector control efforts worldwide. While previous research has largely focused on elucidating the genetic and biochemical mechanisms of resistance, there remains a critical gap in understanding how prolonged insecticide exposure influences mosquito physiology across generations. In this study, we investigated the effects of multigenerational insecticide exposure on key life history traits in Cx. quinquefasciatus . We hypothesized that sustained exposure would (1) increase resistance, (2) influence survival and tolerance in a sex‐specific manner, and (3) increase physiological parameters such as body size and fecundity across generations. Insecticide susceptibility bioassays were performed following standard WHO and CDC bottle bioassay protocols. The bioassay was conducted across eight generations (F 0 ‐F 8 ) to monitor temporal trends in resistance. The natural longevity of males and females was observed to assess adult survival under insecticide exposure. Wing length was used as an indicator of body size variation associated with deltamethrin exposure. Our results demonstrated that female mosquitoes subjected to repeated insecticide exposure exhibited increased survival, body size, and modified fecundity patterns over successive generations, while males showed comparatively limited changes. These findings suggest that physiological adaptations are emerging under selection pressure. This study provides insights into the evolutionary consequences of insecticide pressure on mosquito biology and underscores the need for integrated and long‐term vector management strategies tailored to resistance dynamics in endemic regions.