Hyphal connection increases net resource utilization of saprotrophic fungal mycelia by improving local performance

To identify the functional advantages of hyphal connections in the fungal mycelial networks, we compared the wood decay abilities of the mycelia of a saprotrophic basidiomycete, Phanerochaete velutina , in a soil dish with two or three wood baits. The dishes were surrounded by water, allowing the mycelia to access water if they grew out of the dish. Dishes with two or three baits were attached to or distant from each other, respectively, and representing the ease of creating hyphal bridges between the two dishes. After 8 months of incubation, the weight loss of the wood bait was significantly reduced in the distant pair of dishes compared to the attached pair of dishes. Hyphal outgrowth onto water was observed more frequently in the three bait dishes than the two bait dishes, and water accessibility was positively associated with the water content of the bait, which improved the rate of wood decay. These results suggest that hyphal bridges increase the decay abilities of whole mycelia by improving local performance through the active transfer of water.