Modelling current and future distributions of Aedes aegypti and Aedes albopictus in China under climate change.

Climate change is reshaping the distribution of Aedes aegypti and Ae. albopictus, the primary vectors of dengue, potentially expanding their habitats and increasing the risk of disease transmission. Given its climatic heterogeneity and dense population, China is particularly vulnerable to mosquito-borne diseases. However, comprehensive studies of the potential distribution of these species under varied environmental scenarios remain limited. To understand the distribution of suitable habitats for Ae. aegypti and Ae. albopictus in China under current and future climate scenarios, we built Maximum Entropy (MaxEnt) models based on observed occurrence points of the two species. We then projected their potential distribution across mainland China for the present and the future (2041-2100) using climate data from the Coupled Model Intercomparison Project Phase 6 (CMIP6). The results indicated that annual mean temperature, temperature seasonality, and precipitation of the wettest quarter were the most influential climatic variables shaping the distribution of Ae. aegypti and Ae. albopictus. Under future climate scenarios, the existing suitable habitats for Ae. aegypti and Ae. albopictus are projected to remain stable, whereas the total extent of suitable habitat is projected to increase. Aedes aegypti suitability is projected to expand in Guangxi and Guangdong provinces. Under the SSP5-8.5 (SSP585) scenario for the years 2081-2100, new suitable habitats may emerge in the southern parts of regions such as Sichuan, Guizhou, Jiangxi, and Fujian. Aedes albopictus is projected to expand its habitat, with Yunnan, Guangdong, and Guangxi gradually becoming its most suitable habitats. The northernmost extension is projected to reach small suitable areas, such as the southern part of Qiqihar and the western part of Daqing, in Heilongjiang province. However, the projected expansion is minimal along China's western and northern borders, remaining largely within the species' current range. Climate change is projected to expand the habitats of Ae. aegypti and Ae. albopictus in China, particularly southward and northward for Ae. albopictus. These findings highlight the urgent need to prioritize dengue surveillance and vector control in the projected expansion zones, particularly the southward frontiers in Guangxi, Guangdong, and Yunnan, and the northernmost foci in Heilongjiang, to mitigate future transmission risk in China.