Scientists investigating the fundamental question in biology as to why individuals have evolved to cooperate rather than simply exploiting the contributions of their rivals, have found that microbes vary their contribution to maximise the return of investment.
A collaboration between the Milner Centre for Evolution and University College London has revealed that microbes act like shrewd economists when cooperating. When they find themselves in groups with mostly relatives they contribute heavily to cooperation, which benefits the group. In contrast, when they are in a group outnumbered by unrelated individuals, they exploit the contributions of the others.
The team studied the social amoeba Dictyostelium discoideum or slime mould. Slime moulds live in the soil as single-celled organisms, but come together to form a slug-like creature when they run out of food. The newly formed slug will eventually form a fruiting body composed of a stem and spores. This process requires cooperation between the individual amoebae to form a successful fruiting body.