Descripción del proyecto
Cooperation represents an evolutionary puzzle because natural sCooperation poses an evolutionary problem because natural selection is thought to favour cheaters over co-operators. However, theory and studies in humans show us that co-operators are preferred over cheaters as social and sexual partners. Partner choice may therefore provide a powerful explanation for the evolution and stability of cooperation, alongside kin selection and self-serving benefits, but we lack an understanding of its importance in natural systems. Recent studies showing that animals have a preference for associating with more cooperative individuals are promising but were mostly conducted in artificial captive conditions, making the evolutionary implications of partner choice hard to assess. Manipulating cooperation in the wild to test the fitness consequences of partner choice is the leap that is required to understand whether or not partner choice provides an evolutionary explanation for cooperation. I will pursue this goal using a long-term study that I established on a highly cooperative wild bird, the sociable weaver Philetairus socius. New methodological developments now allow us to conduct large-scale experiments in the wild, and detailed tracking of individual for several years will allow us to quantify the fitness consequences of choice. Specifically, here I will: i) use a new conceptual framework to test whether cooperation is repeatable (a pre-requirement for partner choice); ii) use state-of-the-art technology to manipulate cooperative behaviour and measure the resulting patterns of social and sexual partner choice; iii) use physiological measures and lifetime reproductive success to examine the fitness benefits arising from partner choice and the underlying mechanisms for both co-operators and the individuals that associate with them. Ultimately, the project will provide a novel and robust evaluation of the roles of social and sexual selection for the evolution of cooperation.