BLUE GHOST FIREFLIES
On early–summer nights in pristine southern Appalachian woodlands, tiny male blue ghost fireflies–each about the size of a grain of rice–emerge en masse to beckon to wingless females in the leaf litter below. Unlike the common lightning bug, blue ghosts don't flash; instead, they emit a steady blue or green glow for 30 to 40 seconds at a time. When swarms of the flies drift together above the forest floor, nearby hikers might imagine they're standing calf–deep in an airy, luminous sea. Top spot: DuPont State Forest, NC; dfr.state.nc.us.
The rare but dazzling fungus gnat resembles a miniature crane fly as an adult, but as a larva, it behaves more like a spider with a built–in LED. On summer days, colonies of hundreds of the half–inch–long glowworms spin sticky, quarter–size webs across depressions in streambanks, cave entrances, and rocky seeps. By night, they lurk behind their snares, glowing a vivid blue to lure flies and midges that they quickly subdue with a paralyzing, venomous mucous. Top spot: Cumberland Trail, Black Mountain, TN; cumberlandtrail.org
Also known as fairy fire and will–o–the–wisp, these forest fungi lend their ghostly glow to the rotting trees and stumps on which they thrive. Mycologists theorize that the light is a reproductive strategy, attracting insects that spread the fungus's spores. In some species, such as the honey mushroom, the threadlike mycelia (or "roots") are the most luminous parts; in others, like the bright orange Jack O' Lantern, the mushroom's gills cast a dim green light. Top spot: Larch Mountain Trail, Columbia River Gorge, OR; fs.fed.us/r6/columbia.