Sex-Specific Survival and Morphological Adaptations in Culex quinquefasciatus (Diptera: Culidae) Mosquitoes Under Multi-Generational Insecticide Selection in North-East Guwahati, Assam, India

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—particularly in a sex-specific manner. In this study, we investigated the effects of multigenerational insecticide exposure on key life history traits, including adult survival, body size, and reproductive output in Cx. quinquefasciatus . We hypothesized that sustained exposure would (1) increase resistance, (2) influence survival and tolerance, and (3) impact physiological parameters such as body size and fecundity across generations. Our results demonstrate that female mosquitoes subjected to repeated insecticide exposure exhibit increased survival, larger 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, potentially enhancing the vectorial capacity of resistant mosquito populations. This study provides novel insights into the evolutionary consequences of insecticide pressure on mosquito biology and underscores the urgent need for integrated, long-term vector management strategies tailored to resistance dynamics in endemic regions.