# Screening the Resistance of Male Aedes aegypti and Anopheles coluzzii to Insecticides in the Context of Using Genetic Control Tools in Burkina Faso

## TL;DR

This study examines whether male mosquitoes are as resistant to insecticides as females in Burkina Faso, which is important for the success of genetic control methods to fight diseases like dengue and malaria.

## Contribution

The study provides new insights into sex-specific insecticide resistance and body size differences in mosquitoes relevant to genetic control strategies.

## Key findings

- Male and female An. coluzzii and Ae. aegypti from Bobo showed similar resistance to deltamethrin.
- Females were generally larger than males, and larger females had higher survival rates after insecticide exposure.
- Ae. aegypti Borabora mosquitoes were fully susceptible to deltamethrin in both sexes.

## Abstract

This study explored if laboratory male mosquitoes are as resistant to insecticides as females and how this could impact efforts to control diseases like dengue and malaria. Innovative methods, such as releasing sterilized or genetically modified male mosquitoes, depend on releasing males that can compete effectively with wild mosquitoes. Ensuring these males are not more resistant to insecticides than their wild counterparts is critical. Using WHO guidelines, we tested the resistance to deltamethrin in male and female Aedes aegypti mosquitoes from Bobo-Dioulasso and Borabora and Anopheles coluzzii mosquitoes from Vallée du Kou. We also measured their wing size to see if their body size affected their survival after insecticide exposure. The results showed that male and female An. coluzzii and Ae. aegypti from Bobo had similar levels of resistance. Females were generally larger than males, and in the Bobo strain, surviving females were larger than those that died. These findings highlight the importance of considering size and sex differences to ensure the success and sustainability of techniques like releasing sterilized or genetically modified mosquitoes for controlling mosquito-borne diseases.

Background: Genetic control tools, such as the sterile insect technique (SIT) and genetically modified mosquitoes (GMMs), require releasing males comparable to their wild counterparts. Ensuring that released males do not exhibit higher insecticide resistance is critical. This study assessed the phenotypic characteristics and insecticide susceptibility of key dengue and malaria vector species. Methods: Phenotypic resistance to deltamethrin (0.05%) was tested in two-to-five-day-old male and female Aedes aegypti (Linnaeus, 1762) (Borabora and Bobo strains) and Anopheles coluzzii (Coetzee & Wilkerson, 2013) (Vallee du Kou strain) using WHO susceptibility guidelines. Wing measurements of live and dead mosquitoes were used to assess body size. Results: Mortality rates were similar between male and female Ae. aegypti (Bobo strain) and An. coluzzii, while Ae. aegypti Borabora was fully susceptible in both sexes. Females were consistently larger than males, with significantly larger live females than dead ones in the Ae. aegypti Bobo strain. Conclusion: This study highlights sex-specific differences in body size and insecticide susceptibility. Integrating these analyses into vector management programs is essential for the success and sustainability of SIT- and GMM-based interventions targeting malaria and dengue vectors. Implications for integrating genetic control strategies are discussed.