My research focuses on the study of Paramecium caudatum populations, either infected or not with the endosymbiotic bacterium Holospora undulata, as well as on conducting eco-evolutionary experiments. We analyze various life-history traits, such as dispersal, virulence, and resistance, within experimental landscapes of different structures (linear, modular, regular). The aim is to assess the impact of selection and infection on these specific traits in paramecia.