Since its first detection in 2010, Aedes albopictus has spread across northern Algeria, where vector control relies on the use of chemical insecticides. This study aimed to evaluate the susceptibility of Ae. albopictus populations from Algiers to commonly used larvicides and adulticides, as well as to characterize the underlying resistance mechanisms. Eggs were collected from three sites in Algiers. The susceptibility of larvae to temephos and Bacillus thuringiensis israelensis (Bti), as well as that of adults to permethrin, deltamethrin, malathion, and bendiocarb was evaluated using WHO bioassays. Genotyping of knockdown resistance (kdr) mutations was performed via PCR and sequencing. Metabolic resistance mechanisms were investigated using CDC bottle bioassays. The larvae were found to be susceptible to temephos and Bti. Bioassays on adults demonstrated susceptibility to deltamethrin, suspected resistance to permethrin, and resistance to malathion and bendiocarb. Genotyping revealed low frequencies of heterozygous kdr mutations (V1016G, I1532T, F1534C/S). Synergist assays highlighted the key role of esterases in malathion resistance, a minimal involvement of glutathione S-transferases and an unexpected antagonistic effect of cytochrome P450 monooxygenases. Although larvicides remain effective, resistance to organophosphates, carbamates, as well as suspected resistance to permethrin, has been detected. Esterase-mediated metabolic resistance and kdr mutations may contribute to this profile. These findings highlight the need for resistance monitoring and integrated vector control to ensure sustainable control of Ae. albopictus.

Control of vector mosquitoes (Diptera: Culicidae), particularly species belonging to the genera Aedes, Anopheles, and Culex, remains essential to limit the transmission of vector-borne diseases, but is made more difficult by the increasing level of resistance to insecticides. Among the mechanisms involved, the role of the mosquito’s cuticle is receiving increasing attention. A systematic literature review was conducted in PubMed and reported in accordance with the PRISMA 2020 guidelines, resulting in the inclusion of 56 studies specifically addressing cuticle-associated insecticide resistance in mosquitoes. Available data indicate that cuticular resistance is not based on a single mechanism, but rather on various structural and biochemical modifications that can alter insecticide penetration and interact with other resistance pathways. Although several cuticle-related characteristics have been proposed as potential markers of resistance, their relevance depends on mosquito species, developmental stages, populations, and insecticides, underscoring the need for integrated approaches that combine structural, molecular, chemical, and functional analyses. Beyond resistance, the cuticle and its exuviae also provide valuable biological information that can facilitate mosquito identification and vector surveillance. Overall, a better understanding of the properties of the mosquito cuticle could improve the characterization of the resistance while expanding the use of cuticle-derived information in medical entomology.