Arthropods are Attracted to Luminous Fungi
Luminescence in some fungi may be present in mycelia or in both mycelia and fruiting bodies. Lights have been described as blue, white, or green depending on the species, and emission intensities vary considerably.
In the forests of Borneo, Mycena (= Poromycena) manipularis are visible at ca. 40 meters, and an Australian species pours forth its emerald green light with sufficient intensity to read. Some North American forms tend to be dimmer. The eye often requires several minutes of dark adaptation before their glows become visible.
The receiver(s) toward which fungi direct their luminous signals are unknown. Lights have been supposed to lure spore dispersing insects. There has apparently been no conjecture on the benefits mycelia accrue by glowing. The different environments of mycelia and fruiting bodies make it questionable whether their lights are directed at identical receivers or even serve similar functions.
A study with North America bioluminescent fungus (Mycena sp. and Dictyopanus pusillus), published by John Sivinski (1981), evidence that certain arthropods are more likely to be captured in traps baited with light- emitting mycelia and fruiting bodies than in controls containing fungus-free substrate or dead and dark specimens of luminous species. Several possible interactions between fungi and attracted arthropods are possible.
Attraction of insects to fungal lights does not demonstrate that luring arthropods is the function of the bioluminescence. With this caveat in mind, note that an acceleration in the rate of certain fungus/insect interactions even as an effect of a bioluminescent signal is apt to influence the evolution of luminous fungi.
Photo: Mycena (= Poromycena) manipularis, a species of bioluminescent fungus in the family Mycenaceae, that can be found in Australasia, Malaysia, and the Pacific islands. Credit: ©James Winder & Michael Pilkington