An ecotron located on the Commune of Caumont in Ariège (France), dedicated to the study of ecological and evolutionary processes inside semi-controlled environments. It comprises 48 mesocosms, each with a surface of 100-m2; and a height of 2-m, each acting as a small ecosystem, with natural and diverse vegetation and insect communities and a relatively wide variety of thermal microhabitats (shaded, dense vegetation, sun-battered rocks and logs, and ponds). In each mesocom, we can monitor and manipulate climatic conditions (temperature, humidity or solar radiation) with automatic motor-driven shutters and sprinklers. Species movements among units can further be manipulated with corridors between mesocoms which can be opened or not to allow species to freely disperse from one unit to another. This apparatus is used to study the effects of climate and fragmentation on the eco-evolutionary dynamics of ecological systems.