Spatial genetic structure and distribution of knockdown resistance (kdr) mutations in Aedes albopictus across different climatic zones of China

Aedes albopictus is a globally invasive mosquito and a major vector of dengue and other arboviruses in China, where effective control is increasingly constrained by environmental change and insecticide resistance. Climate zones and rising regional connectivity may reshape population structure and facilitate resistance emergence and spread, threatening the sustainability of current control programs. This study evaluated the influence of climatic factors on population differentiation, dispersal, and knockdown resistance ( kdr ) patterns in Ae. albopictus across China to inform climate-responsive vector management. Based on samples from 12 geographic populations across tropical, subtropical, and temperate regions of China, population genetic structure and dispersal patterns were analyzed using COI gene sequences, and the distribution of kdr mutation sites was detected using the VGSC gene. Twelve populations from tropical, subtropical, and temperate regions were analyzed using mitochondrial COI gene ( n = 743) and voltage-gated sodium channel ( VGSC ) gene ( n = 546) sequencing. Thirty-four COⅠ haplotypes were identified (Hd = 0.6566, π = 0.00172), with tropical populations, particularly Xishuangbanna (Yunnan), showing the highest genetic diversity and haplotype richness. STRUCTURE analysis identified K = 3 as the optimal number of genetic clusters, with tropical populations forming a distinct genetic cluster, while temperate and subtropical populations displayed admixed genetic compositions. LAMARC analyses revealed frequent gene flow between subtropical and temperate regions (166.56), indicating mosquito movement across operational control boundaries. Environmental analyses identified mean annual temperature and annual precipitation may be the significant predictors of genetic differentiation. Significant differences in kdr mutation frequencies were detected among climatic zones. Notably, mutation frequencies at codon 1532 were negatively correlated with mean annual temperature ( r = −0.766, P < 0.05). Haplotype network analyses indicated haplotypes carrying kdr mutations were scattered across different branches of the network. Our findings suggest that temperature may influence population connectivity and geographic distribution patterns of kdr mutations in Ae. albopictus . The expansion of subtropical populations into temperate regions, together with higher kdr mutation frequencies in warmer areas, highlights the potential for spatial spread of pyrethroid resistance-associated genetic markers.