Day Active Species
We typically think of fireflies as tiny twinkling lights of summer nights. While there are fireflies that certainly do match this description, not all fireflies flash! A species must glow at some point in their lives to be considered in the firefly family, Lampyridae. This means that if they glow in another life stage, such as when they are larvae, they are still considered fireflies. Day active species typically glow as larvae but do not exhibit glowing or flashing as adults. We have 5 of such species in WV.
Woodland Lucy (Lucidota atra)
Woodland lucys (AKA “black fireflies on iNaturalist”) are common to see flying midday in late spring to mid-summer, typically in forested areas. These beetles fly slowly and at human eye level. The key physical characteristic of woodland lucys are their long antennae, which are larger than that of other firefly species in WV. They use these antennae to send and detect pheromones for mating; an important feature, since they can’t rely on flashing or glowing for mating like the nocturnal species can! Other physical characteristics of Woodland Lucys include all black elytra (compared to nocturnal species which have light-colored edging around their elytra) and pale terminal abdominal segments where lanterns would be located on a nocturnal firefly. Interestingly, we have observed glowing from woodland lucys in WV before. However, this was a lucky find on our part and can be observed if the individual has just recently eclosed (i.e., became an adult). Compared to tiny lucys (Lucidota punctata), woodland lucys are nearly twice as large. This is the main difference between the two species, as both share habitat and active times during the year and during the day.
Tiny Lucy (Lucidota punctata)
Tiny lucys are similar to woodland lucys (Lucidota atra), differing primarily by size. Tiny lucys are generally half the size of woodland lucys and have characteristic red “triangles” on their headshield. However, this physical feature can be small. Sometimes, it is quite difficult to see any red coloration on their headshield at all, though the amount of this coloration can vary by individual. Like woodland lucys, tiny lucys can be found in forested areas around midday in May-June, flying slowly. They too have large antennae and vestigial light colored terminal segments on their abdomen where lanterns would be.
Sneaky Elf (Pyropyga decipiens) and Flower Elf (Pyropyga minuta)
Both species of Pyropyga are small and have black elytra. Like other day active fireflies, they do not have lanterns. They can be discovered in many different habitats and are active during the summer. They are similar in size and general appearance to tiny lucys (Lucidota punctata) and firefly mimics. However, Pyropyga have shorter antennae than tiny lucys. We have both sneaky elf (Pyropyga decipiens) and flower elf (Pyropyga minuta) in West Virginia, although, Pyropyga is challenging to identify to species without close examination under a microscope.
Winter Firefly (Photinus corruscus)
Yes, there are fireflies in the winter! While you may see them as early as the fall, you are more likely to observe them in spring, particularly on a sunny afternoon as they bask on the south-face of a tree. They are large, have black elytra, and are wider than other fireflies in West Virginia. They have thin lines of pink and yellow which sandwich a large black splotch in the center of their headshield. Winter fireflies have been seen until mid-May in WV and are found nearly everywhere. The scientific name of these fireflies was very recently changed from Ellychnia corrusca, so you may still see this name when referring to winter fireflies!
Photo by K. Noe
Winter firefly basking in the midday sun in February 2023 in Morgantown, WV.
Glowing Fireflies
PHAUSIS
This type of firefly is less commonly found in WV. The glowing fireflies of WV belong to one genus of firefly called Phausis. Instead of emitting a sequence of flashes, these fireflies emit a steady glow of light, either while flying or stationary. Physically, these fireflies are not as marked as colorfully as some others, but still have the same general firefly body form.
Shadow Ghost (Phausis inaccensa)
Shadow ghost are one of two species of Phausis we have in West Virginia. Males are small black fireflies which do not glow, but instead fly around in search of a glowing female shadow ghost. Males are very elusive and for that reason have yet to be observed in the state (but we know they are here, since we have found females here!). Females are larva-like and roughly the size of a grain of rice. Stationary, she glows from two spots on her body (opposed to the 4+ glow spots on female blue ghosts, Phausis reticulata) as true darkness falls, usually lasting for 1–2 hours, though may continue longer than this. In West Virginia, we have seen them in June and July.
Shadow ghost females emitting a steady glow close to the ground when it is over 50°F. Glowing begins during late dusk and lasts for 1-2 hours.
Blue Ghost (Phausis reticulata)
Phausis reticulata is known by its common name “blue ghost.” They were officially confirmed in West Virginia in 2023. Like shadow ghost (Phausis inaccensa), its headshield is not brightly colored like that of other fireflies and has dark wings with no elytral striping or pale edging. While shadow ghost and blue ghost males look morphologically similar, you will likely not see shadow ghost males since they do not glow and are elusive. Meanwhile, blue ghost males have a fascinating glow! They will emit a green glow as they fly low over the ground through the forest while searching for females. This continuous glow begins after dark and may last until midnight. Females shadow ghosts and female blue ghosts look similar too! Both appear as small and larviform, but shadow ghost female glow from only 2 spots
A blue ghost male holding his light during flight while in search of females. Display takes place when it is over 50°F and begins just after dark, lasting 1-2 hours.
on their abdomen, while blue ghost females glow from several spots on their abdomen. Blue ghosts are expected to appear twice in a season; one during April–May and one in June–July (Faust 2017). However, because we have no certain observations of this species in West Virginia, their seasonality may be later than this. (It is often the case that displays begin earlier in the year the farther south they are; because blue ghosts are a southern Appalachian species with primary observations south of here, we may expect a later time of emergence in the season if the species is here in West Virginia.) Be on the lookout for blue ghosts!
PHENGODES
Rail-road Worm (Phengodes spp.)
The rail-road worm is not a true firefly, but instead belongs to the family Phengodidae (as opposed to fireflies Lampyridae) and is closely related to fireflies. Rail-road worm males have distinctive antennae resembling feathers, and like shadow ghost (Phausis inaccensa) males, do not glow. Females, however, glow from all over their bodies. There are two main species of railroad worm: P. plumosa and P. laticolis; both have historically been found in WV.
Flashing Fireflies
It is this group of fireflies that we associate with wild and wonderful West Virginia summer nights. They dazzle us with their diverse performances in several colors and patterns. There are 3 genera of flashing fireflies in WV: Photinus, Photuris, and Pyractomena. A general rule of thumb to tell the different groups apart is by flash color. Many are surprised to learn that there are three main colors of firefly flashes: yellow, green, and orange. Yellow flashes are typically associated Photinus fireflies and are usually dusk active. There are a couple of species in Photuris and Pyractomena that have a yellow flash as well, but by and large Photinus fireflies make up most of the yellow-flashers we see. Photuris species in West Virginia can generally be distinguished by a beginner fireflyer by their green flashes. Be warned, though, that this is not a hard and fast rule as not all Photuris flash green and some can appear more yellowish-green, making things more tricky! These fireflies are normally larger than Photinus and come out as darkness falls, with flashing persisting far into the night for some species. Photuris appear morphologically distinct from the other fireflies we have listed here; they typically have elytral stripes, longer legs, an arrow pattern on their headshield, and are generally larger than most fireflies we have in WV. Other WV flashers you may see belong to the Pyractomena genus. Members of this genus tend to have orange flashes and are not as common to see as Photinus and Photuris.
PHOTINUS
Mr. Mac (Photinus macdermotti)
This flashing species is named after Frank McDermott, an early firefly researcher. Known as Mr. Mac, this species is active from mid-June to early July and flashes low/eye level in the woods around sunset/dusk. You’ll probably know when you see a Mr. Mac because they have a fairly recognizable flash pattern! They’ll flash twice with roughly two seconds in between, and will have a dark period of roughly 4 seconds before repeating the double flash again. Like many Photinus, their flash is yellow. Males will flash this classic Photinus macdermotti pattern and female Mr. Macs will answer from the ground with their own response flash. Although the flashes of Mr. Macs are fairly unique in comparison to the other fireflies we usually see in WV, the double cousin firefly (Photinus consanguineous) has a similar flash consisting of two quick flashes followed by a dark period and then another quick two flashes. However, we are not certain of whether double cousin is in WV.
Mr. Mac flashing classic pattern (every 2 seconds, with 4 second dark period) at 70°F around sunset. Flash timing based on temperature obtained from on Fireflies, Glowworms, and Lightning Bugs by Lynn Faust.
Little Gray (Photinus marginellus)
Little grays are a dusk-active species that you may see around late June-early July. This is when they are most active, but they are also active in lower numbers before and after this timeframe. Their flash pattern consists of single yellow flashes separated by ~2 seconds as they fly low to the ground. You may find them along forested trails or in open fields. Generally, their display lasts from around sunset until it grows dark.
Their flash pattern and habitat is similar to the creekside tree blinker (Photinus sabulosis), and both species are usually found in the same locations. Flash-wise, little grays have slightly more time between flashes than creekside tree blinkers. Physically speaking, some little grays have pale gray elytra, making them clearly unique from creekside tree blinker. However, this distinguishing feature can't be relied upon, as not all little grays have this! Little grays also generally fly lower to
Little gray flashing every 4 seconds at 71°F around sunset. Flash timing based on temperature obtained from on Fireflies, Glowworms, and Lightning Bugs by Lynn Faust.
the ground, while creekside tree blinkers generally flash at head level or higher; again, this isn't true for every case! To be more certain, a microscope is needed.
Yellow Bellied Firefly (Photinus scintillans)
The yellow bellied firefly may go by several different common names including pale firefly, low pink winker, or pine barrens firefly. The name “yellow bellied firefly” makes sense for some populations of the species, which have pale yellow abdomen segments; however, don’t let this fool you, as not all populations have this coloration and the populations we have found in WV do not have this feature. Morphology aside, the yellow bellied firefly emits a pale yellow flash every ~2 seconds at 70°F while flying low to the ground. This species is active at early dusk, usually ending their display for the night at the end of dusk. They can be found from early June to mid-July in the northern part of the state. Although they have been found in a variety of habitats in other states, we have only seen them in woodlands in WV. Flashing may appear similar to creekside tree blinkers (Photinus sabulosis) or little grays (Photinus
Yellow-bellied firefly flashing every 2 seconds at 78°F approximately 15 minutes after sunset. Flash timing based on temperature obtained from on Fireflies, Glowworms, and Lightning Bugs by Lynn Faust.
marginellus). If you are so inclined, you could search for a female on vegetation close to the ground or a log; the female of this species is different from those confusingly similarly-flashing species, as this female has brachypterous wings. This means she will appear larva-like but possess some small wings that aren’t capable of flight.
Cattail Flash Train Firefly (Photinus consimilis)
The cattail flash train firefly is a wetland-associated firefly whose flash pattern closely resembles that of the synchronous firefly. Both have a rapid 6-blink succession of yellow flashes. However, the cattail flash train firefly comes out earlier in the night (just after dark, lasting about an hour), while the synchronous firefly comes out later at ~10:30PM-12AM. The cattail flash train firefly is active in WV from June to mid-July.
Common eastern firefly (Photinus pyralis)
The common eastern firefly (AKA big dipper fireflies) is the most abundant and commonly observed species of firefly in WV. They can thrive in a wide variety of habitats and are the species that are commonly seen in yards and lawns. They emit a yellow flash while making a slight dip then upwards motion (hence the name “big dipper”). There is typically a dark period of ~5-6 seconds in between flashes. This firefly appears in mid-June and continues into August, displaying from sunset until around midnight. By the time common eastern firefly is out in great numbers, many other firefly species are already done with their displays for the year.
Common eastern firefly flashing its classic swooping flash every ~6 seconds at 73°F during dusk. Flash timing based on temperature obtained from on Fireflies, Glowworms, and Lightning Bugs by Lynn Faust.
Synchronous firefly (Photinus carolinus)
The synchronous firefly is well-known for its coordinated display. In fact, every year during the peak display season in the Great Smoky Mountain National Park, people will gather from all over to witness this magical experience. As a testament to its name, this firefly synchronizes with other members of its species! This display is intended to impress mates. So what does this display entail? First there is a flash train consisting of about 6 quick flashes (lasting for about 3 seconds), then a subsequent dark period of 6-8 seconds before the 6-flash pattern begins again. It is easier to recognize a synchronous firefly display when many are flashing! Although the flashes of each individual may be slightly off beat with each other, the dark period is pretty consistent. (I liken this staggered delay of flashing to round singing; one firefly will start flashing, triggering another firefly to begin flashing and so on and so forth.) You may see the synchronous firefly in the
Synchronous fireflies emitting a flash train of ~6 flashes with a dark period of ~ 7 seconds at 72°F at around 11:00 PM. Flash timing based on temperature obtained from on Fireflies, Glowworms, and Lightning Bugs by Lynn Faust.
woods along trails, or in low trafficked roads from mid to late June. While many Photinus fireflies in WV are dusk active, the synchronous firefly does not begin its display until later in the night. Earliest displays typically begin around 10:30 PM and can last until around or after midnight.
Creekside tree blinker (Photinus sabulosus)
The creekside tree blinker is a dusk active species that can be seen in WV from June to July. They will typically appear in trees or shrubs near openings from late dusk lasting ~45 minutes. Little grays (Photinus marginellus) can sometimes be confused with creekside tree blinkers, as they both have similar flash patterns, are often found in the same habitat, flash at the same time of night and time of year, and are similar in size. While this can be pretty confusing, there are some characteristics we can look for in the field and under a microscope. One thing we can look for in the field is if the firefly has gray elytra (wings). Creekside tree blinkers will always have black wings but some little grays can have gray wings (hence their name). Additionally, little grays usually fly lower to the ground, while creekside tree blinkers may be found flashing higher up in shrubs or trees. Though, this isn’t a hard and fast rule. Sometimes to be sure of ID, we need to take a look under the
Creekside tree blinker flashing every ~2.5 seconds at 80°F at late dusk. Flash timing based on temperature obtained from on Fireflies, Glowworms, and Lightning Bugs by Lynn Faust.
microscope at its adegus (male firefly reproductive organs), as the two species have different structures of adagai.
Murky Flash-Train (Photinus obscurellus)
The murky flash-train firefly is (surprise) a train-flashing firefly which can be found flashing at dusk in wetlands. Its flash will appear as a quick succession of three flashes every ~5 seconds and is active around May to early June. This firefly is not very common in WV and there have been very few records of the species here. Consider yourself lucky if you find one!
VIDEO: Murky flash-train emitting a flash train of 2-3 flashes every 5 seconds at 65°F after dusk. Flash timing based on temperature obtained from on Fireflies, Glowworms, and Lightning Bugs by Lynn Faust.
Double Cousin (Photinus consanguineous)
Double cousin may or may not be in WV. Members of this species will emit two quick flashes (~2 per second) every ~6 seconds at dusk. They are active around late June and can be found in shrubby and forested areas.
VIDEO: Double cousin firefly emitting its quick double-flash every ~6 seconds at 70°F at dusk. Flash timing based on temperature obtained from on Fireflies, Glowworms, and Lightning Bugs by Lynn Faust.
PHOTURIS
Spring 4-flasher (Photuris quadrifulgens)
The spring 4-flasher comes out earlier in the season, right about when the spring treetop flasher (Pyractomena borealis) is finishing up at the end of May. You may find this firefly 1-2 hours after sunset in open areas. Displays by the spring 4-flasher generally end sometime around early June.
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Like some other Photuris, this species has two flash patterns! They will complete a more common 3 or 4 flashes (roughly twice per second) with a dark period of ~4 seconds before flashing again. Less commonly, they switch to another flash pattern; this pattern consists of a wavering/flickering flash every ~4 seconds. Christmas lights (Photuris tremulans) are similar in that they too display 2 flash patterns, one of which also being a flicker flash. However, the spring 4-flasher will always revert back to its classic 4-flash pattern, while Christmas lights may be found doing either pattern.
VIDEO: One of two flash patterns of the spring 4-flasher is demonstrated in this video. It is emitting a flash train of four flashes followed by a ~5-second dark period at 68°F after dark. Flash timing based on temperature obtained from on Fireflies, Glowworms, and Lightning Bugs by Lynn Faust.
Christmas Lights (Photuris tremulans)
Christmas lights begin appearing towards the end of the spring 4-flasher season (Photuris quadrifulgens), the early days of May, and last until mid-May. Like the spring 4-flasher, they too have two flash patterns, one of which being a flicker flash. When the flicker flash is seen, the flicker lasts for about 1 second followed by 4-5 seconds of darkness in the low 60s (°F). The other flash pattern for the species is a single flash, separated by ~3 seconds of darkness. In large numbers, this single-flash display looks very similar to a Christmas light display. They can be found in open areas after dark.
VIDEO: One of two flash patterns of the Christmas lights firefly is demonstrated in this video. It is emitting a single flash every ~3 seconds at 66°F after dark. Flash timing based on temperature obtained from on Fireflies, Glowworms, and Lightning Bugs by Lynn Faust.
Potomac Firefly (Photuris potomaca)
The Potomac firefly was recently rediscovered in the state and is known to the eastern panhandle, specifically along the Potomac river and its tributaries. Displays will begin at dusk and last well past dark from early June to early July. These displays consist of green flashes of more than 60 consecutive flashes! At 70°F, males flash approximately twice per second. The Potomac firefly is associated with cobble-shores that have lots of saplings and driftwood along major rivers.
VIDEO: Potomac fireflies flashing every 0.55 seconds at 70°F at dusk.
Snappy Single Sync (Photuris frontalis)
The snappy single sync was recently discovered in West Virginia! This species deviates from the Photuris norm in that it has a yellow flash in color. It will flash less than once per second continuously at 70°F. Why is this species so cool? Synchronous fireflies (Photinus carolinus) get all the credit for their coordinated display, but they are not the only flashers that attempt to synchronize in the night sky! Much like synchronous fireflies, snappy single syncs will coordinate their displays to win the approval of mates. They have been observed in the eastern panhandle of West Virginia and are associated with forested wetlands. We have little to go on to make a WV-specific best time of year, but it is likely they are active in late June to July, and begin flashing at late dusk lasting for an hour or two.
VIDEO: A snappy single sync flashing every ~0.65 seconds at 72°F at late dusk. Flash timing based on temperature obtained from on Fireflies, Glowworms, and Lightning Bugs by Lynn Faust.
Slow Glows (Photuris “slow glow”)
If you are in a location with many of these individuals displaying, it can feel truly magical. Slow glows will emit a slow flash, lasting for about 1-1.5 seconds, with about 4 seconds of darkness in between at 70°F. You may start seeing them in the beginning of June, but their peak numbers will be in the middle of June. Their displays will be mostly over by the fourth of July, maybe with few individuals still displaying. They begin their displays at late dusk and are active for a few hours after they begin. They may appear to move downwards during their 1-2 second glow.
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(These may be my favorite, but don’t tell the other fireflies!)
VIDEO: Slow glow firefly emitting its prolonged flash of ~1.5 seconds with a ~4.5-second dark period at 73°F after dark. Flash timing based on temperature obtained from on Fireflies, Glowworms, and Lightning Bugs by Lynn Faust.
Variable Triple Flash (Photuris versicolor)
The variable triple flash can be seen in West Virginia in June and July. They are first active at late dusk and can continue their displays for hours. They emit a green, rapid fire of 3-4 quick succinct flashes. Between these flashes may be a period of about 5 seconds at 70°F. The variable triple flash is fairly common and can be found in many places including forests, fields, and near water. If you are a user of iNaturalist, this species is also referred to as “changeable fireflies.”
VIDEO: Variable triple flash emitting quick 3 flashes with a dark period of ~5 seconds at 70°F at dusk. Flash timing based on temperature obtained from on Fireflies, Glowworms, and Lightning Bugs by Lynn Faust.
Heebie-Jeebies (Photuris hebes)
Heebie-jeebies are not creepy, despite their name! Heebie-jeebies will flash yellow about once per second at 70°F. (Remember, Photuris are usually green-flashing, but this species is one of the few that have a yellow flash!) In WV, they are found flashing higher in trees and shrubs, beginning around dusk and lasting for 1-2 hours. They are active in late June. While heebie-jeebies may seem to flash similarly to the Potomac firefly (Photuris potomaca) or the snappy single sync (Photuris frontalis), they are smaller in size than the aforementioned. Their yellow flash will distinguish them from the Potomac firefly. While heebie-jeebies and the snappy single sync are similar in flash, heebie-jeebies have a slightly slower flash rate.
VIDEO: Heebie-jeebies flashing once per second at 71°F at dusk. Flash timing based on temperature obtained from on Fireflies, Glowworms, and Lightning Bugs by Lynn Faust.
Dot dashing species (Photuris pensylvanica-like species)
The true, currently recognized dot dash firefly (P. pensylvanica) is restricted to freshwater tidal areas surrounding the Delaware and Chesapeake bays estuaries, but the name P. pensylvanica has a long history and is commonly erroneously applied. Although the designated P. pensylvanica may only be found by the marshes of Delaware and adjacent areas, there are other species that may appear P. pensylvanica-like. These species are deemed “dot dashers” because their flash pattern is a short and bright flash (a dot), followed immediately by a longer flash that slowly fades (a dash). There is a dark period of about 5 seconds (in the high 60°F) between this dot dash flash. The dot dasher has a strong association with wetland and wetland-adjacent areas. Although not much is known about seasonality of dot dashers in WV, they are likely to be active in June and July, from late dusk until midnight.
VIDEO: A dot dasher flashing every few seconds. Animation created by Vincent Spaid.
PYRACTOMENA
Spring Treetop Flasher (Pyractomena borealis)
Seeing this species is a sure sign that firefly season is upon us! The spring treetop flasher may begin displaying as early as the beginning of May in WV, lasting until late May. However, we can find spring treetop flasher larvae on trees in March and April, leading up to when flashing begins. Unlike other Pyractomena species, this species has more of a yellow flash than the typical orange. It will emit a single yellow flash every few seconds when the temperature is in the high 60s (°F) during late dusk and as darkness falls. They can be found in forested areas.
Photo by K. Noe
VIDEO: A spring treetop flasher emitting one flash every ~3 seconds at 65°F at dusk. Flash timing based on temperature obtained from on Fireflies, Glowworms, and Lightning Bugs by Lynn Faust.
Photo by K. Noe
A spring treetop flasher as larva, seen on a sunny afternoon in March 2023.
Larval spring treetop flashers can be difficult to spot sometimes!
Marsh Flicker (Pyractomena dispersa)
The name marsh flicker perfectly encapsulates this species, as it is usually found flying over wetland areas and emits a flash that could certainly be described as a flicker. It has been seen in West Virginia in mid to late May and in the earliest days of June. You may see displays after dark until as late as midnight. The marsh flicker will emit an orange “flicker-flash” every ~5 seconds when temperatures are in the high 60s (°F). Morphologically, this species differs from other Pyractomena because of its lack of black coloring on the sides of its pronotum.
VIDEO: A marsh flicker emitting one flickering flash every few seconds. Animation created by Vincent Spaid.
Candle Firefly (Pyractomena angulata)
Candle fireflies (AKA angled fireflies) emit an orange flickering flash typically in an upwards or downwards movement, hence their name. In West Virginia, they have been seen in mid-June after dark until midnight. Their flashes may come every ~3 seconds in the high 60s (°F). They can be found in forested areas and their margins.