Mosquito Ecoclimatic Regions Reveal Variability in Community Composition and Habitat Suitability of West Nile Virus Vectors (Diptera: Culicidae) in Germany under Climate Change

Background: Climate change is a major driver of increasing mosquito populations and mosquito-borne disease (MBD) risks across Europe. In Germany, rising temperatures and shifting precipitation regimes are creating more favourable environmental conditions for mosquito establishment and pathogen transmission. However, the extent to which regional climate variability shape spatial patterns of mosquito community composition remain insufficiently understood. Methods: Mosquito specimens were trapped using Biogents CO2-baited traps at several locations in Germany between 2016 and 2025. Using k-means cluster analysis applied to a set of mosquito-relevant bioclimatic indicators, we developed a data-driven ecoclimatic regionalisation to identify seven mosquito ecoclimatic regions (MERs). To validate the regionalisation, we conducted community analysis on nationwide mosquito surveillance dataset. Mosquito richness and diversity metrics were estimated per MER. Non-metric multidimensional scaling (NMDS) and Permutational Multivariate Analysis of Variance (PERMANOVA) were used to visualise and test differences in community composition between MERs. The robustness of the regionalisation was further evaluated by comparing within- and between-region Bray-Curtis beta diversity. Results: A total of 288,689 mosquito specimens were collected using 5,840 trap deployments. Results revealed varying mosquito habitat suitability and community composition across MERs in Germany. Pronounced regional differences in mosquito richness (S) and Simpson diversity (D) were observed among MERs. The identified MERs include: Alpine (S=1.00, D=1.16), Low Mountains (S=7.99, D=2.04), Northwest Cool (S=21.67, D=1.99), Continental-Dry (S=31.99, D=2.39), Warm Continental (S=32.49, D=2.55), Southeast Foothill (S=24.39, D=2.77) and Coastal Maritime (S=24.00, D=4.39) regions. Future MER projections reveal expansion in the spatial distribution of dry and warm conditions in Germany under the RCP8.5 scenario. Community composition differed significantly among MERs (NMDS: stress=0.133; PERMANOVA: p < 0.05, F=6.68, R2=0.16, d.f.=4). Beta-diversity analyses showed that mosquito communities were more similar within than between MERs (Mann-Whitney-Wilcoxon test: p < 0.0001; Z=23.26). Across regions, Culex pipiens s.l. was the dominant native vector while Aedes albopictus and Aedes japonicus were observed in several MERs. Conclusions: Identifying ecoclimatic regions that explain spatial variability in mosquito habitat suitability and community composition is essential for targeted vector surveillance and to improved early warning of climate-sensitive MBDs.