Walrasian equilibrium behavior in nature

Significance Mutualisms are commonly observed ecological interactions, often involving the exchange of resources across species. Such exchanges can be thought of as biological markets. Biologists modeling these markets often employ an informal mix of economics and game-theoretic concepts. A fundamental question is whether exchange in biological markets is consistent with general economic equilibrium theory (GET), the main paradigm used to study exchange in economics. This paper uses data from biological experiments to demonstrate that the trading behavior of mycorrhizal fungi is consistent with the predictions of GET. The large volume of knowledge in GET might result in new insights about biological exchange. In turn, experimental findings in biology can lead to a new field of application for GET.