Bryant is the author of today's entry. He writes:
In honour of Halloween (a day late, thanks to Daniel's schedule) and the end of the series on fungi, I thought I would use this striking and eerie image for today's post. This image is of Panellus stipticus and it was sourced from Wikimedia Commons where it has been released into the public domain. The photographer sharing the image is Benjamin Derge (aka Ylem @Wikimedia Commons). Benjamin used a 517 second exposure to capture the bioluminescence, or light produced and emitted by this fungus. Panellus stipticus has a wide distribution and can be found in Asia, Australasia, Europe, South America and North America. It is one of more than 70 species of bioluminescent fungi known to exist.
Bioluminescence in fungi is generated from within living cells; depending on the species, it can appear in the mycelium, the fruiting body, the spores, or all three. Panellus stipticus is mainly luminescent on its gills and the periphery of the cap, as well as the mycelium, with a high level of variance between individuals. The light emitted is caused by the oxidation of a pigment named luciferin (refers to Lucifer, the "light bringer", in Latin). The oxidation of luciferin is catalyzed by a class of enzymes known as luciferase, and it is a common reaction found in many other bioluminescent species. Interestingly, not all populations of Panellus stipticus are bioluminescent. Populations in western North America, Europe, New Zealand, Russia and Japan have not yet been observed displaying luminescence. Lingle et al. in a 1992 paper, Preliminary Analysis of Genetic Complementation of Bioluminescence in Panellus stypticus Isolated from Pine and Hardwood observed that bioluminescence is an inherited trait determined by a single pair of alleles, where luminosity was dominant over non-luminosity. The variation between the levels of luminescence in different individuals is thought to be related to metabolic activity and/or environmental conditions.
The ecological function of bioluminescence in fungi is still vaguely understood. There are theories that bioluminescence in fruiting bodies helps to attract insects at night, which may aid in spore dispersal. Mycologist Larry Evans reports that bioluminescent fungi attracts insects like a "bug disco".