Efectos de la dieta y la temperatura en la resistencia de las hormigas a patógenos

Temperature influences biodiversity and ecosystem dynamics, as well as the behavioral responses and physiology of individuals. Variations in ecological dynamics can modify access to food and, therefore, impact health and vital functions. The ratio of proteins to carbohydrates in the diet has a clear effect on the organism: high-protein foods reduce the lifespan of organisms as phylogenetically distant as yeasts and humans, including insects. A possible mechanism behind this effect may be related to the immune system, since malnutrition compromises the ability of organisms to fight infections. To avoid the complex balance between nutrition and reproduction, in this project we used sterile worker ants of the Mediterranean ant species Crematogaster scutellaris as an experimental model. Our main hypothesis is that temperature and diet will influence their lipid reserves and compromise their response to infections. Fat bodies have a conserved role in energy supply and are also involved in immune and regenerative processes. Therefore, our first objective is to evaluate the effect of diet and temperature on the lipid and fat body content of these insects, and the second is to examine their role in survival against pathogens. To achieve this, we borrow techniques from fields such as metabolomics, medical optics, physiology, histology, nutrition, and ecology. Using artificial diets (varying in their protein and carbohydrate content) and environmental chambers at different temperatures, we analyzed physiological and histological changes in worker ants under varying conditions. To assess the effects on the immune response, we challenged their immune system with the entomopathogenic fungus Metarhizium brunneum. Furthermore, we compared these responses in laboratory workers and untreated wild workers. In this way, we can assess whether there are metabolic, physiological, and anatomical changes associated with diet and temperature variation, and how they affect a key trait such as resistance to pathogens under both controlled laboratory conditions and natural field conditions.