Effects of Temperature and Bacillus velezensis on the Development, Longevity, and Reproduction of Culex quinquefasciatus

Temperature is a key environmental factor that influences mosquito phenotypic traits and the effectiveness of vector control strategies. <i>Bacillus velezensis</i> (<i>Bv</i>) has shown promise as a microbial biocontrol agent due to its insecticidal properties; however, its effects on mosquitoes under different environmental conditions are still unexplored. This study investigated the effects of <i>Bv</i> (strain WHk23) exposure on the life history traits of <i>Culex quinquefasciatus</i> at two temperature conditions (20 °C and 30 °C), focusing on development, longevity, and reproductive fitness. Results showed that temperature significantly affected mosquito development and longevity, with faster development and shorter adult longevity observed at 30 °C compared to 20 °C. Exposure to <i>Bv</i> further accelerated larval development and reduced adult emergence, with the effects being more pronounced at 30 °C than at 20 °C. Exposure to <i>Bv</i> reduced adult longevity regardless of temperature. In addition, <i>Bv</i>-exposed females had larger body sizes but lower fecundity and fertility, suggesting that <i>Bv</i> exposure may cause physiological stress that disrupts reproductive processes. These findings highlight the importance of considering environmental factors in mosquito control programs while reinforcing the efficacy of <i>Bv</i> as a sustainable biocontrol agent under a variety of environmental conditions.