Mycorrhizal Biological Market: Partner Choice

Underground, a single fungal network can link the root systems of many plants at once — a common mycorrhizal network. This simulation models the trade that keeps that partnership honest: each round every root pays a carbon ration into the network, and the fungus allocates its shared phosphorus pool back in proportion to what each root paid. Drag any root's carbon slider down to simulate a shaded "free-rider" plant, tune how strongly the fungus discriminates between generous and stingy partners, and switch reciprocal rewards off entirely to see why real mycorrhizal fungi practising partner choice — first demonstrated with isotope tracing by Kiers et al. (2011) — outcompete symbioses that don't.