Future climate scenarios reshape the suitability of major malaria vector taxa in South America.

Malaria remains a major health burden in South America, but the extent to which climate change will reshape vector communities is poorly understood. We modeled the distributions of 15 key Anopheles species, representing primary, secondary, and unclassified vectors, under current and future climate scenarios (SSP2-4.5, SSP5-8.5) using ensemble ecological niche models calibrated with 20 climatic and physiographic predictors. We quantified niche breadth and overlap and achieved high predictive performance. Analyses in environmental space revealed moderate overlap between primary and secondary vectors and lower overlap between primary and unclassified vectors, although ecological breadth did not differ significantly among classes. Future projections revealed divergent trajectories among Anopheles species. Climate-sensitive primary vectors such as An. darlingi is projected to undergo severe contractions and fragmentation, particularly within the Amazon Basin, whereas An. albimanus and An. aquasalis are predicted to expand southward under SSP5-8.5. Several secondary or unclassified species (An. janconnae, An. marajoara, An. argyritarsis) also showed potential for expansion. These results suggest a major reorganization of vector assemblages, with potential epidemiological implications. Understanding this reshuffling and clarifying the roles of emerging vectors will be crucial for guiding future malaria control and surveillance strategies in South America.