Appalachian Glow Worms Chasing the Southeast’s Hidden Lightshow Christian F. Shushok   © Copyright 2022 by Christian F. Shushok

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With little hesitation, myself and two fellow cavers raised our rainhoods, ignited the lights on our headlamps, and headed into the forest. At this point, the rain was coming down in a flurry of chaos, obscuring our eyes and providing only the small tunnel of vision that was illuminated by the LEDs on our headlamps. As the light cut through the air, it reflected off of the water and presented a sea of luminescence that appeared more similar to the lights of the Milky Way above our heads than to the dark forest dissolving beneath our feet. As we walked, rogue water paths, broken off from the springs and streams of the hollers above us, wove around our feet, forming tight braids that forced us to skip, hop, and jump first from mud patch to mud patch and later, as the water rose, from rock to rock. In about an hour, as we drew nearer to our destination, a dull roar began to intrude into the ever constant cacophony of raindrops colliding with the canopy of the oak-hickory forest overhead. As we began to descend into the valley, the grade of the hill forced the heels of my boots to cut deep into the soil, slicing through the brown organic matter on the surface and revealing bright red clay to the night air. I was completely focused on the dirt beneath my feet as I tried to ensure I did not slip down the mountainside, when suddenly, the hill levelled out. As my headlamp light cut upwards through the silk of fog, I stood in awe at the massive cliffside cave ahead of me. We had made it to the cave entrance.

Entering cave chambers such as this one through water typically requires wading that I always find reminiscent of the spring fed swimming holes I grew up with in Virginia. In Virginia, as in caves such as this, the water is cold enough to leave your legs numb, but your senses heightened. As I looked down and the roaring stream and imagined stepping in, initially, I refused.

As a young teenager, I had been swept away by rogue floodwaters in a stream much smaller than this. Peering into the dark waters below, I could only imagine that if I lost my footing again, I may not be as lucky as I was at 14. I levied my concerns onto my friends, but after the strenuous hike we had already been through, youthful desire was prioritized over safety. We were going to do what we came to do. We were going to enter the cave.

As our headlamps danced across its surface we all strained to see if we could discern the depth. Massive amounts of sediment had been kicked up by the raging storm, and as a result, we had little success finding the bottom. In an act of faith in our abilities and the folly of our youth, the first of our party eased her way into the roaring current. I followed shortly after.

Slowly, I moved along, following in her footsteps exactly. As we moved, my palms searched frantically for handholds on the limestone wall to my left, while my boots probed the floor of the stream bed, cautiously searching for pot-holes or large rocks that could cause me to lose my footing in the swift water. The darkness enveloped us and I developed complete tunnel vision, focusing only on following the light of my friend ahead, and that I maintained solid footing. After only a few short minutes, my headlight illuminated a small limestone shelf up ahead. While small, it signalled safety, and as quickly as I could, I scrambled to it. After climbing over the ledge and emptying the water out of my boots, I had the presence of mind to look up. The ceiling vaulted above me. We were in the middle of the cave’s main chamber. To our left and right, cave speleothems traced veins up the walls, pooling into stone puddles of serene reflective water that stood in stark contrast to the torrent we had just escaped.

Once we had all found comfortable seating in the main chamber, the group's members unanimously decided to switch off our headlamps. I found a large limestone slab situated beneath a deep vertical crevasse that cut through the calcite ribbons above me. As quickly as the light had been with us, it vanished. Slowly, I felt the silhouette that was burned into my vision by the headlamps fade, and the sound of the cave grow around me. To my left, and right, a consistent tick and tack of mineral rich water splashed against the floor, and the sound of the drops reverberated around the cavern. The darkness was total, and my mind began to drift into a dreamspace between sleep and consciousness. Then suddenly, out of the corner of my eyes, the ceiling began to glow. In the cracks and crevices of the cave, cobalt blue light shot out, pulsating as if laser mounted into the calcite walls. As soon as I focused on one light, I began to see more and more until the ceiling was ablaze. Their appearance was once again reminiscent of my home in the Blue Ridge Mountains, where at night, you can see fires cutting through the dark folds of the hills. With this same intensity, the blue lights above me began to define my spacial awareness--the one point of focus in an otherwise inky existence.

I called out to my partners to confirm that these lights existed physically and were not merely a trick of the rods and cones in my eyes struggling to make sense of an environment foreign to them. To my surprise, they responded that they too were mesmerized by the strange show appearing before us. My thoughts wondered fantastically--could these be a variation of the will-o'-wisps found in Scottish bogs, glowing paint left behind by travellers, or perhaps even an extension of the famous Brown Mountain ghost lights of North Carolina? As we waited, our clocks did not, and as midnight neared and the entrance of the cave was illuminated by a newly visible moon, we knew that it was time to leave behind the fantastic light, and return to the dull mundanity of the rainy night air.

As it would turn out, the explanation for the lights I witnessed that night was not supernatural, but ecological in nature. Appalachia is home to many unique and endemic species, and that night in the cave, I witnessed the performance of perhaps the most spectacular: Orfelia fultoni-- a species commonly known as glowworms.

When glowing, Orfelia fultoni is in its larval stage of life . As larvae, the worm-like creatures inhabit caves and streambanks in the Appalachian Mountains of the Southeast. The insects emit light from both the head and tail portions of their body, the purpose of which is to attract prey insects into the sticky webs woven by the larvae. Orfelia fultoni As adults, the larvae become a subtype of fly that belong to the family Mycetophilidae. This family is popularly referred to as fungus gnats.

As I looked up in the cave that evening, I had no idea how lucky I was to be witnessing such a fantastic lightshow. In 1998, it was estimated that there were around 3000 species of fungus gnat on earth. Of this massive number of organisms, only around a dozen produce bioluminescence during their lifetime. Initially, some research reported that the manner of light production in Orfelia fultoni was identical to fireflies, but recent analysis of Orfelia fultoni pathways have found that their pathways are distinct from lightning bugs. The larvae use an enzyme called Luciferase which initiates a chemical reaction that generates their characteristic glow. This reaction, combined with their sticky webs allow Orfelia fultoni to successfully lure prey.

Outside of the small portion of the Southern Appalachians in which I am fortunate to live, a glowworm enthusiast would be hard pressed to find any other bioluminescent Mycetophilidae. The species I observed, Orfelia fultoni, is the only known species of bioluminescent fungus gnat in all of North America, and are endemic only to the Appalachian mountains. Outside of North America, some of the closest relatives to Orfelia fultoni are endemic only to Australia and New Zealand.) However, in the last five years, a new species of glowing fungus gnat was discovered in the Atlantic forest of Brazil, suggesting that there may still be bioluminescent Mycetophilidae yet to be discovered within the Americas.

I grew up surrounded by the brilliant light shows of fireflies, railroad worms, and foxfire mushrooms. However, in Buggytop, the glow worm lights didn’t so much as glow ambiently, but rather cut through the darkness with stabs of neon so intense that they hardly seemed natural. As it turns out, this inhibition was somewhat correct. In recent years, entomologists have estimated that there are probably about 5.5 million insect species on Earth. However, less conservative estimates of insect species sometimes exceed more than 30 million. Out of all of these millions of lifeforms--a truly inconceivable number of critters that fly, hop, swim, and dig, the bluest light of all is emitted by an unassuming larva in the foothills of the Southeast: Orfelia fultoni. Witnessing their glow is a chance that is quite literally, rarer than one in a million.

The galaxy of lights drawn by Orfelia fultoni is a performance not soon forgotten. The steeps, hills, hollers, and valleys of the South are often assumed to be mundane, and unassuming. But too often, would-be-explorers limit themselves only to the day, naively assuming that all that there is to be seen in the forest can be witnessed in the light of day. However, in the darkest of holes on the darkest of nights, when headlamps shut off and the haze of the moon is obstructed, Orfelia fultoni sits diligently, waiting for the next traveller willing to sit with the dark long enough to finally see their light.

Christian Shushok is an Appalachian writer and storyteller from Southwest Virginia. They are interested in mountain life, Southern lineage, and identity in the Mountain South. They have never published a work of fiction.