Firefly Species on Grandfather

Research on Grandfather Mountain has confirmed the presence of 10 species of fireflies or luminous insects:

Photinus carolinus – Synchronous Firefly
Synchronous firefly males produce a flash pattern of five to 10 single flashes, pause for approximately 10 seconds and repeat. Males will generally fly around five to six feet off the ground in search of females, who wait on the forest floor or perched on a blade of grass and respond with a flash of their own. In areas with high population densities, males will begin to flash in synchrony and produce a “light train” that resembles running Christmas lights. This species is most active toward the end of June and prefers mature cove hardwood forests, especially within the forest interior. Synchronous fireflies are relatively large, measuring about 0.4–0.6 inches long.

Phausis reticulata – Blue Ghost Firefly
Blue ghost males produce a bluish-green light (the light itself is green but appears blue to the human eye). Males fly low to the ground in search of flightless females on the forest floor. Rather than flashing, males emit a continuous glow that can last up to 15 seconds. Blue ghosts are most active from late May through mid-June. Their mating season has two distinct peaks, with the second peak less abundant than the first. This species occupies a variety of Appalachian forest types, ranging from moist and dry forests to areas along streams and high, dry ridges. At 0.2-0.4 inches long, blue ghost fireflies are quite small – approximately the size of a grain of rice.

Photinus macdermotti – Father Mac’s Firefly
Males produce a distinctive doublet flash — two flashes spaced a few seconds apart — followed by a four-second pause before repeating. They fly low to the ground in search of females, who perch on vegetation a few feet above the ground. This species is most active in late June and prefers open, moist forests, often near streams. It is a medium-sized firefly, measuring about 0.4 inches long

Photinus ardens – Northern Ablaze Flash-train Firefly
Males produce a triplet flash — three flashes in quick succession — followed by a five- to seven-second pause before repeating. Females respond with a doublet flash while perched on vegetation near the ground. This species is most active in late June and prefers open habitats such as fields or pastures. It is a medium-sized firefly, measuring about 0.4 inches long.

Photuris versicolor – Variable Triple Flash Firefly
Photuris species are predatory fireflies, often referred to as “femme fatales.” Females mimic the flash responses of other firefly species, luring unsuspecting males close enough to capture and eat them. Males produce a very rapid triple flash, followed by a pause of about five seconds before repeating. Photuris fireflies are most common in June and July and are widespread and highly adaptable, occupying a wide range of habitats. They are large fireflies, measuring approximately 0.5 inches long.

Photuris tremulans – Christmas Lights Firefly
This species produces a greenish flash approximately once every two to three seconds and is commonly found high in the treetops. When present in large numbers, their flashing creates the impression of Christmas lights strung through the trees. Females respond to males with short, single flashes. This species is most common in June and July and occurs in a variety of forest habitats, with a preference for forest edges near open areas such as fields or meadows. It is a medium-sized firefly, measuring about 0.4 inches long.

Pyractomena angulate – Candle Firefly
Males of this species produce an orange, stuttering flash that lasts about one second, followed by a two- to three-second pause before repeating. The flash is typically angled diagonally upward or downward. Males are commonly observed flying from about six feet above the ground up into the treetops. Females respond to the males’ flashes while perched on vegetation two to four feet above the ground. This species is most common from June through July and prefers interior forest habitats as well as forest edges. It is a large firefly, measuring approximately 0.5 inches long.

Ellychnia corrusca – Winter Firefly
This is a day-active (diurnal) firefly that lacks a lantern and does not produce flashes or glow. It is often observed on tree trunks in late fall and early winter, or flying within the forest interior in early spring. Mating occurs from mid-March through early May. This species prefers mature hardwood forests and forest edges. It can be medium to large in size, measuring approximately 0.3–0.7 inches long.

Lucidota atra – Woodland Lucy Firefly
This is a day-active (diurnal) firefly that lacks a lantern and does not produce flashes or glow. Its long, flattened, segmented antennae are a distinctive identifying feature. Instead of using light signals, individuals attract mates through pheromones. This species is most active in July and prefers open forest habitats. It is a medium-sized firefly, measuring approximately 0.3–0.4 inches long.

Orfelia fultoni – a glowworm
The larval form of a fungus gnat, this is the only fly species in North America with bioluminescent larvae. The larvae have blue lanterns at both the anterior (head) and posterior (tail) ends of their bodies. The blue light they emit is the purest blue of any terrestrial animal. This species is found along moist banks near streams and in forested areas. The larvae feed on tiny insects, which they trap in a web after luring them with their blue lanterns.

Read about upcoming Firefly events and their presence on Grandfather Mountain.

As a UNESCO International Biosphere Reserve, Grandfather Mountain has long been known for its natural wonders and as a haven for more than 70 rare or endangered species.

Photo at top: Blue Ghost Fireflies by Radim Schreiber