Population size and dispersal of Anopheles coluzzii on São Tomé and Príncipe Islands based on mark-release-recapture

Mosquito-borne diseases continue to exact a heavy toll on human health, particularly in sub-Saharan Africa. Yet in many environments, fundamental aspects of mosquito behavior and population dynamics remain poorly characterized. Here, we employ a well-established method for directly measuring mosquito dispersal and estimating population size: mark-release-recapture (MRR). We focused on the key malaria vector Anopheles coluzzii and conducted experiments in São Tomé and Príncipe, an island nation in the Gulf of Guinea under consideration as a site for the first field trial using gene drive mosquitoes for malaria elimination. Understanding mosquito dispersal, population size, and responses to environmental factors is essential for planning such releases. To assess these parameters in An. coluzzii, a total of four MRR experiments were conducted across both São Tomé and Príncipe islands during both wet and dry seasons. Population size estimates were higher during the wet season in both study areas, but seasonal fluctuation was more pronounced in São Tomé. Seasonal patterns of mosquito dispersal differed by location, with greater dispersal in São Tomé during the wet season and in Príncipe during the dry season. Mosquito flight direction was biased toward broad-scale wind direction in São Tomé, but not in Príncipe. Together, these results enhance our understanding of An. coluzzii behavior in island ecosystems and support the design of effective vector control approaches in this biogeographical context.