Résumé
Understanding how vector richness influences malaria transmission remains a critical challenge in disease ecology and public health. We develop a mathematical model that integrates both interspecific and intraspecific phenotypic diversity within mosquito populations, structured by chronological age and continuous phenotypic traits. Our framework couples these diverse mosquito populations with a human host population to analyze the eco-epidemiological dynamics of malaria transmission. We conduct a detailed analysis of the mosquito population's asymptotic behavior and invasibility analysis. Additionally, we identify an eco-epidemiological threshold parameter that synthesizes mosquito vectorial capacity, intrinsic fitness differences, and ecological competition to predict whether the addition of a new mosquito species amplifies or dilutes epidemic risk. Through this approach, we show that vector species abundance alone is insufficient to determine malaria transmission potential; rather, the interplay between phenotypic variation and ecological interactions governs epidemic outcomes. Our results generalize and extend previous theoretical studies by incorporating structured population dynamics and continuous trait variation, providing a mechanistic basis for anticipating how changes in mosquito community composition may impact malaria transmission risk.