The proposed fellowship is designed to provide to a promising post-doctoral specialization in the microbial evolutionary ecology field by pursuing a period of training in Centre for Ecology and Conservation, College of Life and Environmental Sciences at University of Exeter in the UK. Under the supervision of a world’s leading expert in this field, and with further theoretical training, the Fellow would employ this 2 year period to develop and expand upon her highly commended PhD research into how the evolution of Pseudomonas aeruginosa mutation rates is affected by natural microbial communities.This goal will be carry out by taking two different approaches: i) to study what is the impact of natural competitors in the evolution and adaptation of mutator bacteria in a soil community context by using a direct experimental evolution system; ii) to investigate what is the role of community complexity in the selection of P. aeruginosa mutators in cystic fibrosis (CF) chronic airways infections by exploring the correlation between community diversity and prevalence of P. aeruginosa mutators in artificial and natural CF communities. The project will be interdisciplinary; bridging the gap between microbial ecology and clinical microbiology fields and having broad ecological and medical consequences. In addition, with the inclusion of a return phase, this proposal will foster long-term collaborations between Exeter University, UK and Universidad Nacional de Cordoba, Argentina; favoring the transference of knowledge and enhancing EU scientific excellence in research related to microbiology, evolutionary ecology and infectious diseases in order to extend the current state-of-the-art of mutator bacteria evolutionarydynamics.