The genus Mycena includes about 500 known species of gilled mushrooms. Six new species – all of which emit light – were found in old-growth forest in the state of São Paulo, Brazil, by scientists from San Francisco State University and the Instituto de Botânica and Instituto de Química in São Paulo, bringing the number of bioluminescent species to more than 30. All six were discovered in Atlantic Forest, one of the most threatened ecosystems on Earth, with less than 10% of its original land cover remaining. The forests continue to prove a gold mine for new species of plants, animals and fungi.
The authors believe the numbers of bioluminescent species of Mycena have been grossly underestimated: most have only been observed by day and nearly all luminescence in fungi has been detected only by the human eye, whereas scientists studying other organisms have used photometers to detect low levels of light production. Molecular phylogenetic studies, which look at evolutionary relationships, show that luminescence crops up in many sub-branches of the genus. The light production of white rot mycelia, for example, may be a biochemical byproduct or adaptation that affords antioxidant protection to the fungus as it degrades lignin in wood.
Mycologists have also speculated that luminescence might either attract fungivores that assist in spore dispersal or warn them off.
This discovery gives us more questions than answers, from the reasons for bioluminescence to the species diversity of the Atlantic Forest. Beyond science, these amazing mushrooms add to the wondrous beauty of the night.
Quentin Wheeler is director of the International Institute for Species Exploration, Arizona State University
