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

## TL;DR

This study shows how temperature and a bacterium affect mosquito development and reproduction, suggesting a natural way to control mosquitoes.

## Contribution

The study reveals how Bacillus velezensis impacts mosquitoes differently at varying temperatures, offering insights for biocontrol strategies.

## Key findings

- Mosquitoes developed faster and lived shorter at 30 °C compared to 20 °C.
- Bacillus velezensis exposure reduced adult mosquito numbers and reproductive success, especially at higher temperatures.
- Bv-exposed mosquitoes had larger body sizes but lower fecundity and fertility.

## Abstract

Human diseases transmitted by mosquito vectors are a major public health concern. Controlling mosquito populations is challenging, especially when some species become resistant to common chemical insecticides. This study explored the effects of the naturally occurring bacterium Bacillus velezensis (Bv) under two different temperatures (20 °C and 30 °C), on the development, longevity, and reproduction of Culex quinquefasciatus. The results showed that mosquitoes developed faster and had shorter lifespans at higher temperatures. Exposure to the bacterium further accelerated mosquito development and reduced the number of adult mosquitoes, with the effect being more pronounced at higher temperatures. Despite being larger, Bv-exposed mosquitoes laid fewer eggs and had lower reproductive success. This study highlights the importance of considering environmental variations when evaluating potential biocontrol agents for mosquito control and support efforts to develop safer alternatives to chemical insecticides.

Temperature is a key environmental factor that influences mosquito phenotypic traits and the effectiveness of vector control strategies. Bacillus velezensis (Bv) 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 Bv (strain WHk23) exposure on the life history traits of Culex quinquefasciatus 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 Bv further accelerated larval development and reduced adult emergence, with the effects being more pronounced at 30 °C than at 20 °C. Exposure to Bv reduced adult longevity regardless of temperature. In addition, Bv-exposed females had larger body sizes but lower fecundity and fertility, suggesting that Bv 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 Bv as a sustainable biocontrol agent under a variety of environmental conditions.