Biomass Recycling: A Key to Efficient Foraging by Fungal Colonies

Using an existing fungal growth model that captures the physiological processes of vegetative growth and development of a fungal colony, and in particular incorporates, for the first time, a recycling of biomass mechanism, we explore the effects of recycling in various environmental contexts. Here we test whether resource density thresholds exist, below which finite colony expansion occurs, in three dimensions based on the number of randomly removed resource sites. We then test the effect of recycling on resource density thresholds. Modelled soil structure, derived from experiments, is combined with the fungal growth model. The effect of recycling on foraging efficiency is investigated for resource distributed homogeneously and heterogeneously throughout the modelled soil structure. The simulated results show that resource density thresholds do exist in three dimensions and that the recycling mechanism decreases the threshold value. Our results indicate that recycling promotes persistence and a recycling mechanism is crucial for those fungi that reside in a resource patchy and limited environment.