Firefly Information for the Great Smoky Mountains National Park (GSMNP)

Besides the beauty and tranquility of the Great Smoky Mountains national park, there are a staggering number of plants and animals, so far 18,038 have been identified with 923 species that are brand new to mankind, and none garner as much amazement and excitement as the synchronous firefly found in limited areas of the Southern Appalachians.

Nothing in nature is more fascinating than seeing a firefly for the first time, that is until you see a mass of synchronous fireflies, also known as lightning bugs in the Smokies showing off where hundreds of not thousands of individual lights blink on and off first randomly, and then in unison. It is also most impressive when they all go dark for a few seconds.

It’s not just any firefly that has the ability to put on a synchronous flashing light show in the Great Smoky Mountains, after all, of the 19 known species that now inhabit the National Park, only 1, Photinus carolinus also known as the "synchronous firefly" is the only lightning bug which does this in the Americas. Before the Synchronous Firefly was known to exist in the Southern Appalachian Smokies, a similar firefly was known to exist in South East Asia.



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Where and When to Find Synchronous Fireflies in Great Smoky Mountains(GSMNP)

The quick answer as to where and when to find the Synchronous Fireflies in the GSMNP:

The Synchronous Firefly's peak season in the Great Smoky Mountains National Park ranges anywhere from the 3rd week in May to the 3rd week in June highly dependant on previous and current weather conditions.

The best place to be assured to see the best display of Synchronous Fireflies in the GSMNP is along the Little River Hiking Trail adjacent to the Elkmont Campgrounds during the first and second week of June.

Conclusion: The Great Smoky Mountains National Park gets at least 1,000 visitors a night during firefly season so the park provides a shuttle from the Sugarlands Visitor Center parking area to the Little River Hiking Trail trailhead and back.

Firefly Shuttle Bus Information: Shuttle Bus service is provided on City of Gatlinburg Trolleys and usually takes place for a week starting the first or second week in June. The cost of riding on the Firefly shuttle bus is $1 per person round trip. You will also require a Firefly trolley parking passes at$1.50 per standard vehicle which holds 6 persons. An additional 4 parking passes a day will be issued to larger vehicles that are up to 30 feet long and can hold up to 24 people.

2017 Firefly Season runs from Tuesday, May 30 through Tuesday, June 6th.

The Firefly Lottery will be open for applications starting Friday, April 29th at 12 noon and goes until Friday May 1st at 8:00 pm. The results of the lottery will be available on Wednesday, May 10th 2017.
(All firefly trolley tickets are sold out. All Elkmont campsites are booked.)


Trolleys start departing the Sugarlands Parking area to Elkmont at 7:00 pm and will start returning visitors back to the Sugarlands Visitor Parking Area after 9:30pm and runs until everyone is returned, which may take until after 11 pm.

Firefly Event Film Permitting Requirement:
To obtain a film permit to photograph or film the firefly event in the Great Smoky Mountains national park, please contact Molly Schroer (865)436-1209 or molly_schroer@nps.gov in order to start the process to secure a film permit access pass along with dates and times.

The filming/photography permit is only required for those individuals who want to capture the firefly event using specialized photographic/sound equipment and/or crew, which requires monitors from park staff to ensure they are not damaging firefly habitat or disturbing the visitor experience for others.

Detailed answer as to where and when to find the Synchronous Fireflies in the GSMNP:
The synchronous firefly Photinus carolinus has been found in various elevations throughout the park in Sevier, Blount and Cocke county Tennessee as well as Haywood and Swain county North Carolina. Besides the wide geographic area they inhabit, specimens have been collected in Cove Hardwood, Mixed Mesic Hardwood, Pine and treeless environments.

Synchronous fireflies can mostly often be found with a few hundred yards of slow moving bodies of water. That's not to say they cannot be around large fast moving bodies of water or large open field or forests that have water further away.

Where to Find Synchronous Fireflies in the Smokies is also very dependant and when you are looking. The reason for this is that fireflies breed in the spring and a few days later, a female firefly will lay her eggs below or on the forest floor.

The lightning bugs eggs hatch about a month later and spend the next stage of their lives as larvae called glowworms underground. Here they will remain and feed during the summer and through the fall and winter in a state of hibernation.

Sure lightning bugs in their glowworm larval state are interesting, but that's not what you are interested in. What you are waiting for is when they wake up, eat some more for a few weeks, pupate for a week or so and then emerge from the soil and in an attempt to find the best mate, the firefly will start his one light show repeated by countless others.

What triggers the synchronized firefly emergence is one simple thing, temperature. At 55 degrees the glowworms have awoken and start their feeding until it is time to metamorphosize into an adult beetle during the chrysalis stage.

Once they emerge as adults, the light show begins for the synchronous firefly Photinus carolinus as they have about 3 weeks left in their lives, and so many competing fireflies to outshine!

Since the Great Smoky Mountains national park is comprised of so many elevations, forest types and elevations, firefly emergence and maturity to adulthood does not happen all at once for the Synchronous lightning bugs, but will happen over a period of 3 or more weeks.

While the best light show in terms of population density and the lack of ambient light so that the show appears far brighter is in Elkmont, the Synchronous Firefly show can be seen in the back end of Cades Cove by the Abrams Fall Trailhead at around the same time as well as through Cataloochee Valley about 1 week or more after the Elkmont Peak.

Synchronous Fireflies can also be found in Tremont and in the Cherokee Orchard Roaring Fork area at around the same time as Elkmont. Later in the season by at least a week they are on Clingmans Dome Road and in July the place to find them in the Balsam Mountain Campgrounds.

While finding the synchronized fireflies away from the structured event by the park service can be fun and exciting, it is not as safe as in an area where there is no vehicle traffic and a smooth a walking surface as that you will find in Elkmont. If you fall and get hurt, it could be quite some time before you are found and rescued.

Even if you found the right place where the Photinus carolinus should be and you are there at the right time, you still may not be able to find them if the temperature is at or below 50 degrees.

The last weather related factors that can affect the behavior of synchronized fireflies are excessive moisture such as during or just after a rainstorm and heavy winds.

You will also find that even though the synchronized fireflies generally start producing light just after dusk, if there is a very bright moon it can delay that start of the light show for a half hour or more.

Even the best Photinus carolinus shows are generally finished with peak intensity around midnight, though some may shine hours later.


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A Fireflys Life Cycle in the Great Smoky Mountains National Park (GSMNP)

Just as their are many species of fireflies on the GSMNP, there are many flash patterns, light color, feeding habits, seasonal patterns and flight capabilities, however, the basics of their lifecycle is the same with all of these beetles.

All fireflies start as eggs on the forest floor, beneath it or on plant material such as bark. After the egg hatches the larva will feed on snails and/or small insects depending on the species. This is the only time in their lives that fireflies eat.

Fireflies in the Smokies will mature from larvae to adult in a 1 year to 2 years depending on the species. Once mature, the lightning bugs flash, to attract mates or as defence, for the last few weeks of their lives.

When fireflies can be seen at night varies upon the species and the geographic location. Some fireflies can be observed as early February, but the vast majority of the firefly flashes can be seen from mid spring through last summer.

Generally the female lightning bugs, some of which are flightless, are close to the ground and the males are usually higher up in the canopy and they start the light show and the females respond. Some species start flashing far before dusk, some start during dusk and some later.

For the males starting the light show higher up gives them a better view of the females that may be in the distance and more visibility of his manly flashes to the female firefly as well. As the males flash, they slowly make their way closer to the ground where the females are.

So what makes one male firefly more attractive to a female than another with his flashing? Studies of one species of firefly, Photinus greeni, it was found that the length of the pulses by the male created the most interest in females. It is belied that for most species of firefly that only a single aspect of the flash such as intensity, color or duration maters more than multiple characteristics of the light.

Since there are so many species of fireflies, they adapted a way to find each other at night based upon the particular flash pattern that each species has as well as the colors ranging from yellows to greens, white and a light blue tint.

Unfortunately for the fireflies, there is a predator fireflies which can mimic various flashing patterns of females from different species of fireflies and if a male come to close to the predator beetle as he is looking to mate, he is no more.

Firefly Species in the Great Smoky Mountains National Park (GSMNP)

There are no less than 19 species of fireflies which are actually beetles that are known to live throughout the Great Smoky Mountains National Park. Not all of the fireflies in the Smokies, also called lightning bugs, are active at night where you can observe their flashes. Of the 19 species of GSMNP Fireflies, 6 of them are only active during the daytime.

The remaining 13 species of fireflies produce chemicals in their bodies to create light that is visible at night to recognize each other to attract mates and in one case, mimic each other for a meal delivered right to their doorstep.

The 13 firefly species along with their common names in the Great Smoky Mountains that produce their own light at night are: Phausis reticulata (Blue ghost firefly), Pleotomus pallens (Firefly), Photinus brimleyi (Brimley's firefly), Photinus carolinus (Synchronous firefly), Photinus macdermotti (McDermott's firefly), Photinus marginellus (Marginellus firefly), Photinus pyralis (Big Dipper firefly), Photinus sp (Photinus firefly species), Pyractomena angulata (Say's firefly), Pyractomena borealis (Firefly), Photuris lucicrescens (Predator firefly), Photuris sp. 1 (Predator firefly), and Photuris sp. 2 (Predator firefly).

The 6 species that are day active that do not produce light are Ellychnia corrusca (Firefly), Lucidota atra (Black firefly), Lucidota punctata (Punctate firefly), Pyropyga decipiens (Firefly), Pyropyga minuta (Firefly) and Photinus cookii (Cook's firefly)

It is also believed that at least 3 more luminous fireflies Photinus acuminatus, Photurus quadrifulgens, and Photurus tremulans may inhabit the park but have just not been found yet. The same for the non luminous Phausis inaccensa.

How A Firefly Produces Light in the Great Smoky Mountains (GSMNP)

Of course what makes fireflies so interesting is the same thing that can be found in select marine plants and animals such as plankton, jellyfish, shrimp and fish, or in some terrestrial species such as fungus, springtails, glowworms and gnats: Bioluminescence, the ability for organisms to create "cold" light chemically.

A plant or animal with Bioluminescence can give off light continuously, because of physical stimulation, instinctively, or what appears to be at will. The "cold" light produced through Bioluminescence is not warm like a light bulb because the production of light is wasting as much as 90% of the valuable energy, but virtually 100% efficient, thus studying Bioluminescence is a valuable step toward a brighter future for the mankind and our environment.

The Bioluminescent light created by the fireflies is actually made by combining a chemical inside their abdomen with and enzyme and exposing this bioluminescent compound to air.

The organ which gives off light is called the "lantern" and it is located on the bottom of the fireflies at the tail end of the beetle. There are nerves that trigger the release of a chemical neurotransmitter called octopamine which starts the luciferin reaction that produces light.

The chemical reaction takes place in light cells in the lantern called phagocytes that have access to oxygen through cylinders. The cylinders are composed of trachea that are surround with phagocyte cells so that oxygen passed into the body can activate the most surface area of light producing cells and thus produce the most light.

The chemical reaction to make the firefly bioluminescence is done in this 3 steps technical explanation:

  1. The firefly has an enzyme luciferase which catalyzes the formation of a luciferin and ATP complex known as luciferyl adenylate.
  2. This complex is oxidized by oxygen, leading to the production of a cyclic peroxide that eventually becomes high-energy oxyluciferin which is in an excited state.
  3. By relaxing the oxyluciferin back to the ground state, energy is released as light.

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