One of the many steps people have taken to control their environment is to conquer the darkness by providing light. Lanterns, torches, candles, flashlights, campfires, and many electric sources of light are produced by chemical reactions. There are plants and animals that produce their own light by chemical reactions, too. This light is produced without heat. A common luminescent animal is the firefly, or otherwise known as the lightning bug. They belong to the order Coleoptera (beetles) and the family Lampyridae. There are over 2000 species in the world, and over 125 in the U.S. and Canada. The larvae of most species of firefly also glow. The light produced by fireflies is produced by a reaction between the chemical luciferin and the enzyme luciferinase in the presence of oxygen, ATP, and magnesium ions. These beetles can control the flashes of light by controlling the supply of oxygen to the light-producing organs.

Fireflies use their lights to attract mates. Every firefly species has its own flash pattern. The male Photinus pyralis, the most common species, flashes his yellowish light for a half a second while ascending and repeats about every seven seconds. The flightless females respond to these flashes from the ground or vegetation. The male knows a female of his species by the response time of her flash. The male then has to reach the female before another male that saw the flash, does. Then they can mate!

This may seem like a bunch of friendly courting going on, but one species, the Photuris versicolor, initiates a type of predation called 'agressive mimicry'. The female, 3 days after mating, takes a station near the ground, stands erect with her jaws open and begins to mimic the flash responses of other species of firefly. She is now a predator! Apparently, there is some type of chemical transfer within the sperm that initiates this transformation. When the female's flash is successful and she attracts a male of another species, she devours him! So much for friendly courting!

Another form of luminescence is the 'foxfire'. If you have ever trampled around the woods after dark, you may have noticed an erie glowing substance on the forest floor. This is the light from luminescent fungi. The most common fungi responsible for foxfire are the Clitocybe illudens, Panus stypticus, and Armillaria mellea. These fungi are usually found in rich soil or on decaying logs. Foxfire appears as a stain on the wood- not actually a mushroom. It is the mycellium (one mass of branching, threadlike filaments that form the mushroom's main growing structure) that glows- not the full-blown mushroom.This light is the result of a chemical reaction within the fungi pigment molecules. Scientists have not made a case for why foxfire glows. Fireflys do it for mating purposes, but why would a mushroom glow?

It has to be pitch-dark to really see the foxfire glowing. If you start digging around a decaying log, with the proper conditions and the correct fungi present, you will see a 'city of lights'! In Ireland and Scotland, foxfire was called 'fairy fire'. In Irish fairy tales and folklore, foxfire is usually called the 'fairy fire' or 'will-o-the-wisp'.

There is another common glowing fungus- the Jack-O-Lantern mushroom, Omphalotus olerius. The fresh gills of this fungus give off an erie green glow. It grows in clusters on the base of stumps and on buried roots of oak and other deciduous wood in July through November. Other fungi glow as well, such as the Luminescent Panellus, Panellus stipticus. Like the Jack-O-Lantern, the gills give off a greenish light. It grows on logs and stumps in May - December.

There are other mushrooms that are luminescent, and the color of light varies somewhat with the species of mushroom. The colors range from greenish-white, white, yellowish, greenish, and even blue! The light, whatever its color, is continuous through both day and night.

So when your out strolling about the forest at night, calling in owls and watching for bats, keep your eyes out for the flora and fauna that light up the night!