Fungal communication networks are surprisingly intricate—and it turns out, animal urine may hold a key to understanding them
Mushrooms are remarkably social organisms. What appear to be isolated fungal communities separated by hundreds of feet are often interconnected through sprawling underground systems called mycelial networks. These hidden webs allow fungi to exchange critical information about their environment and local conditions, yet scientists still have much to learn about how these networks actually operate.
As explained here, a group of mycologists in Japan has now shed new light on one type of fungus with a particularly dynamic and responsive communication style — one that can be significantly altered by a substance every animal produces: urine. Their research was published in the journal Scientific Reports.
Ectomycorrhizal fungi belong to a broader category called ammonia fungi. As the name suggests, they rely heavily on ammonia levels in the soil to fuel their growth and spread. Urine is rich in urea, a chemical precursor to ammonia, making it a natural candidate for influencing these organisms. With that connection in mind, a research team led by Yu Fukasawa at Tohoku University in Sendai attached electrodes to 37 ectomycorrhizal mushrooms growing on the floor of an oak forest. They then exposed the fungi to varying amounts of water and urine under different conditions, recording electrical activity every second over the course of 3.5 days.
The results revealed a surprisingly complex spectrum of fungal communication. When water was applied to a single mushroom, electrical activity spiked in response. But when water was distributed across multiple mushrooms simultaneously, that activity dropped.
“It’s fascinating to think about why the mushrooms communicate the way they do,” Fukasawa said in a statement. “For example, applying water to all the mushrooms may mean that there’s no need to share information since the whole network already knows what’s going on, which could be why the flow of information decreased in this situation.”
Curiously, exposure to urine also dampened communication between the fungi—though the reasons behind this remain unclear. Even so, the experiments offer a detailed window into how certain mushrooms modulate their electrical signaling in response to external stimuli. Going forward, Fukasawa’s team aims to map specific electrical signals to particular behaviors within these underground whisper networks.