Inside Hazard Cave at Pickett State Park, you’ll find something that you can almost never find anywhere else: glow worms.
Located just a little more than a tenth of a mile along a footpath off S.R. 154 along the southern edge of Pickett State Forest, Hazard Cave isn’t actually a cave at all; it’s a sandstone rock shelter. Nor is it hazardous; it was named for former Pickett State Park manager James Hazzard. But it does contain a little magic.
In the early 1970s, Richard Hilten — an eccentric state park naturalist — discovered something glowing inside Hazard Cave: little blue lights, the color of blue jeans.
The glowing lights were actually insects — glow worms, to be exact. And they’re found almost nowhere else in the world.
The glow worms at Hazard Cave are the larvae of the Ofelia fultoni, a species of fungus gnat that is found only in the Appalachian Mountains and Cumberland Plateau — mainly in Tennessee, western North Carolina and northern Alabama, along with parts of Virginia. This isn’t your typical fruit fly. This gnat grows to the size of a mosquito and is known for its manic behavior.
You can actually find the gnats along the trail near Hazard Cave, but they don’t live long. Their primary purpose is to find a mate, then die; their typical lifespan is two days. But the larvae are long-lived, spending as much as a year in that form before maturing. And if you want to find them, Hazard Cave is the place to look.
In the dark confines of the cave, or rock shelter, the blue, glowing worms are nearing the end of their “glowing season.” They can be seen throughout the year, but are at their best in the summer months, particularly in June.
There is still much about the glow worms that is unknown. It was only recently discovered, for example, that they are actually cannibalistic — willing to feed on their own. But what is known is that they use their luminescence to attract prey; flying insects that are guided by the stars mistake the glowing blue lights for stars and fly straight to their death.
That’s because the glow worms build silk webs that cover their den in the dark places they inhabit. The worms not only use the webs to catch their prey, but also as a defense mechanism and as a means of retreating into their den. They’re surprisingly quick when they need be, gliding on the silky webs. And because their bodies are covered by a film of liquid, they have been described as a sort of aquatic insect that carries its own pond.
The glow worms found here were first discovered by BB Fulton, who studied them behind his summer home in North Carolina. Later, University of Florida graduate student John Sivinski was looking for firefly larvae when he stumbled across a stream bank that was literally speckled with blue lights. He said, “That color attracted me, it was like a starry night against the road bank.” He began his own study of the worms and carried on the work of Fulton.
It was Sivinski who actually proved that glow worms attract prey — like midges and tiny flies — with their luminescence. So, in a sense, the glow worms inside Hazard Cave are literally mimicking the starry night sky.
While the glow worms are rarely found in North America, similar insects are rarely found anywhere in the world. The only other species like the glow worms that inhabit Hazard Cave are found at Waitomo Cave in New Zealand.
Hazard Cave is also notable because the rock overhang that borders it is a habitat for Cumberland Sandwort. Sometimes called the Cumberland stitchwort, the flowering sandwort is endemic to the northern Cumberland Plateau, near the Big South Fork River. It grows in the cool, shaded sandstone rock shelters like this one, and is federally-listed as an endangered species. It is known to grow in only 28 places along the northern Cumberland Plateau.
To get to Hazard Cave, take S.R. 297 east to its terminus at S.R. 154 in Fentress County. Turn north on S.R. 154 and continue into Pickett State Park. The trailhead for Hazard Cave is located on the left side of the highway just beyond the park entrance, about three miles north of S.R. 297. The cave is located less than one-fourth of a mile from the highway. (See related story, page B4.)
Footnote: Much of the information for this article was provided by Dustin Burke, a former ranger at PIckett State Park.
This article is the July 2017 installment of Our Back Yard, presented by First National Bank on the first week of each month as part of the Independent Herald's Back Page Features series.