Mushrooms in the Brazilian forest have developed a clever way to ensure their reproductive survival. According to new research, they emit light to attract insects.
This process of light emission, known as bioluminescence, in fungi was observed as early as 382 BC by Aristotle, but until now its role remained a mystery. In other organisms, including bacteria and fireflies, bioluminescence can have a variety of roles, from prey attraction to defence, or can simply be a byproduct of their metabolism.
Here, researchers from Brazil and the USA saw that the Brazilian forest-dwelling fungus (Latin name Neonothopanus gardneri) makes itself more noticeable to insects that will then go on to spread its spores and allow it to colonize new territory.
Using fake, plastic mushrooms and light traps placed in the fungus’ native habitat, researchers from Brazil and the USA saw that mushrooms lit up with LED lights attract more insects than ‘dark’ mushrooms. This indicates that the emitted light is used by the fungi to attract insects; much like plants use bright, scented flowers to attract pollinators, these fungi seem to be using bright light to attract insects such as beetles, flies, wasps and ants, all of which can be effective at spreading fungal spores.
Bioluminescence and the enzymes that regulate it, is actually controlled by the fungus’ biological night/day rhythm, or circadian, clock. This ensures that the fungi only emit light at night. As bioluminescence is not bright enough to be perceived by animals during the day, circadian regulation ensures that the fungus does not unnecessarily waste resources. It was this circadian regulation that hinted that bioluminescence had to be more than just a byproduct of metabolism in this fungus.
According to Cassius Stevani, one of the senior authors of the work, the results of this study are likely to apply to other fungi and ecosystems as well, and the group are currently trying to expand their findings.
Moreover, the team is currently filming the fungi using infrared cameras to capture images of their interaction with insects at night. They have been joined by the BBC, which, according to Stevani, “is currently filming N. gardneri and the animals that are associated with it for the BBC Natural History Unit’s One Planet show, due to be broadcast in 2016.”
Images: courtesy of Cassius V. Stevani, IQ-USP, Brazil. From the top: Small mushroom of N. gardneri growing for 3 days in the lab; Spider near a mushroom in the forest; Petri dishes with cultures of N. gardneri; Mycelium of N. gardneri glowing.
Citation: Oliveira, A.G., Stevani, C.V., Waldenmaier, H.E., Viviani, V., Emerson, J.M., Loros, J.J. and Dunlap, J.C. (2015) Circadian Control Sheds Light on Fungal Bioluminescence. Current Biology 25, 964–968.