Can Mushrooms Really Power a Machine? The Science Behind the Scarab

In Flight of the Scarab a clockwork beetle takes flight beside a body found in a glowing fairy ring. Later, we learn the little automaton runs on mushrooms of its own. Pure fantasy?

Not as much as you’d think. Scientists really are turning mushrooms into batteries, sensors, and even “nerves” of robots.

Can a mushroom actually make electricity?

Yes, in several ways. Portobello mushrooms are naturally full of tiny pores, and engineers at UC Riverside found that heating them creates a porous carbon material that makes a surprisingly good battery part-one that improves with use instead of wearing out. Swiss researchers built a battery that’s part fungus, fed it sugar and water to keep it running, and then let it break itself down when the job was done. And Ohio State researchers even managed to train shiitake mushrooms to act like tiny computer memory chips!

What about the mushroom’s roots-can they carry a signal?

Yes. Mycelium (which are not actual roots) are the thread-like network that grows beneath a mushroom and are capable of carrying electrical signals in much the same way as wires. Some researchers have recorded bursts of electrical spikes in species like enoki and ghost fungi that cluster into patterns statistically similar to a vocabulary of dozens of “words.” While no one is claiming fungi are carrying on any conversations (the signals might just be a byproduct of mycelium tips brushing past an electrode) it’s an open question as to what they’re doing. Coordinating growth and resource usage across the fungus, not unlike a nervous system?

Has anyone built an actual robot run by mushrooms?

They have! And it’s the closest real-world relative to my scarab. At Cornell, researchers grew mycelium right into the electronics of two robots and used its natural electrical pulses to control their movement, almost like a nervous system. They even took things a bit further and used UV light to change how the mycelia moved the robots.

So the scarab’s tiny mushrooms aren’t so far-fetched after all?

Not in spirit. The species (Mycena stylobates) powering my clockwork scarab is real, but their use as a battery is entirely fiction. However, the conceptual building blocks-mushrooms generating power, mycelium carrying signals, fungal tissue steering a machine-are all things scientists are working on right now. Close enough to real science to feel possible, fantastical enough to take flight.