In a weird quirk of the natural world, lots of species glow. From dormice to puffins, they are lighting up under UV light for reasons scientists still aren't sure about. While the sea has a bioluminescent glow created by dinoflagellates, known as sea sparkle, fungi are also joining the glow up, with their own bioluminescence known as foxfire.
This bioluminescence is found in fungal species that live on decaying or rotting wood and is far from a new phenomenon – in fact, according the University of Chicago Library, Aristotle even wrote about it thousands of years ago as “cold fire” light coming from the woods.
The reasons for the glow have been confusing science for hundreds of years, but a paper published in 2015 suggested the purpose of the night-time glow was to attract beetles and other potential pollinators that would spread the spores of the mushroom throughout the surrounding area.
By studying the mushroom species Neonothopanus gardneri, the researchers also found that the fungus was regulating the bioluminescence through its circadian rhythm, allowing it to peak at night and attract more insects that would otherwise be unable to find it in the dark.
The team created LED mushrooms with the exact same color of green to mimic the real mushrooms. They also set up fake mushrooms with no glowing light and found that three times as many insects visited the glowing mushies.
“Results indicate that the bioluminescence can attract animals to disperse spores. This additional dispersal mechanism might confer to this fungus some advantage, especially in dense forest,” co-author Cassius Stevani told the Guardian.
Exactly how the foxfire is created is down to the interplay of three things: luciferin, reductase, and luciferase were all found to work together to make the glow, and their levels peak at night. A team from Russia found that a precursor to luciferin was present in non-glowing fungi, but up to 100 times more prevalent in the species that glowed at night. Luciferin is present in other species, including the tiny organisms that make sea sparkle; however, the team found differences between the mushroom-based luciferin substance and those already known.
"Fungal luciferin is chemically unrelated to other known luciferins, therefore it represents a totally different mechanism of light emission. This is important from the points of view of photochemistry, biochemistry and evolution. Moreover, it gives the possibility to search for an unknown fungal luciferase,” senior author of the Russian study Ilia Yampolsky told the Guardian.
The team hoped that one day they would be able to create genetically modified trees that would emit glowing light that could act as street lights, for example. Until that becomes a reality, you’ll just have to enjoy the foxfire in the woods with the insects.