Evolution of conditional cooperation

Social interactions are ubiquitous across the tree of life, from microbes to complex social systems of higher organisms. The evolutionary consequences of social interactions have been extensively studied theoretically and are well characterised experimentally. However, aside from a few studies in model organisms, we have limited understanding of the evolution of conditional or 'strategic' social interactions, especially cooperation. This studentship will utilize mathematical theory and the social amoeba Dictyostelium discoideum to dissect patterns of variation in contributions to cooperative social traits. D. discoideum live in soil as single-celled amoebae but upon starvation large numbers (ca. 105) aggregate to form a multicellular fruiting body composed of dead stalk cells holding aloft a ball of viable spores. Because fruiting bodies can contain mixtures of genotypes (i.e., multicellular individuals can be chimeras) this scenario can favour exploitative strategies that increase representation among the viable spores. Our previous work demonstrated that strains employ varying social strategies that determine social success. This studentship is aimed at understanding the evolution of these strategies, viewed at the level of conditional modulation of contributions towards cooperative traits.