Great Smoky Mountains National Park
Synchronous Fireflies in Elkmont, June 4-12, 2011

Firefly Info | Light Show Etiquette | Trolley to Elkmont | Recommendations and Rules

Synchronous Firefly Information

Every June for about two weeks during the mating season, the fireflies in Great Smoky Mountains National Park begin to flash in unison. Great Smoky Mountains have 14 species of firefly in the park and this phenomenon involves all the male individuals of this one species. They are the only species in America whose individuals can synchronize their flashing light patterns.

Fireflies (also called lightning bugs) are beetles. They take from one to two years to mature from larvae, but will live as adults for only about 21 days. Their light patterns are part of the adulthood mating display. Each species of firefly has characteristic flash pattern that helps its male and female individuals recognize each other. Most species produce a greenish-yellow light; one species has a bluish light. The males fly and flash and the usually stationary females respond with a flash. Peak flashing for synchronous fireflies in the park is normally within a two-week period in mid-June.

The production of light by living organisms is called bioluminescence. Many species of insects and marine creatures are capable of it. Fireflies combine the chemical luciferin and oxygen with the enzyme luciferase in their lanterns (part of their abdomens) to make light. The chemical reaction is very efficient and produces little or no heat.

No one is sure why the fireflies flash synchronously. Competition between males may be one reason: they all want to be the first to flash. Or perhaps if the males all flash together they have a better chance of being noticed, and the females can make better comparisons. The fireflies do not always flash in unison. They may flash in waves across hillsides, and at other times will flash randomly. Synchrony occurs in short bursts that end with abrupt periods of darkness.

Light Show Etiquette

Flashlights disrupt the fireflies and impair people's night vision. The light show is best when you:

1. Cover your flashlight with red or blue cellophane.

2. Use your flashlight only when walking to your viewing spot.

3. Point your flashlight at the ground.

4. Turn off your flashlight when you find your viewing spot.

Parking and Trolley Information

Great Smoky Mountains National Park officials have announced that the Elkmont entrance road will be closed to motor vehicles and pedestrian use every night starting at 5:00 p.m. until midnight, June 4-12, 2011 except to registered campers staying at the Elkmont Campground. The closure is to accommodate transportation service for visitors planning to spend the evening viewing the natural-occurring, synchronous firefly beetles at Elkmont.

The City of Gatlinburg, in partnership with the Park, will provide the trolleys for this activity. The trolley service, coinciding with the expected peak flashing period, will be the sole transportation mode for visitor access during this period; no private vehicles will be allowed to enter Elkmont. This year also new restrictions will be in place to prohibit motor vehicles from parking along roadsides, pullouts, or any other areas besides at the Sugarlands Visitor Center parking area for the purposes of viewing fireflies at Elkmont. Only those visitors parking at the visitor center will be allowed to ride the trolleys.

Chief Park Ranger Bill Wright said that “There is a growing concern over the number of people parking in undesignated areas, along roadsides with narrow grassy shoulders that do not have adequate space for getting in and out of vehicles. Walking along the roadsides, along blind curves and, in some instances in traffic, are high risk factors, especially in the dark after coming back from Elkmont. This also means that visitors will not be allowed to park their vehicles along Little River Road and walk to Elkmont. Park Rangers will be at the closed gate at the Little River Road/Elkmont Entrance Road intersection to enforce the closure.”

The trolleys will begin picking up visitors from the Sugarlands Visitor Center RV/bus parking area at 7:00 p.m. The trolleys will continually run until the Sugarlands Visitor Center parking area is full or until 9:00 p.m., whichever comes first. The last trolley to return visitors from Elkmont to the Sugarlands Visitor Center is scheduled at 11 p.m. The cost will be $1 round trip per person as in previous years. 

The annual appearance of the synchronous firefly beetles, which occurs during their mating behavior, has become so popular that Park officials began managing the number of visitors to the trailhead several years ago. The Elkmont area has very limited parking spaces that were designed to accommodate day use for several trails. The dates that the mating behavior begins can vary each year due to weather and other natural factors, but generally starts around the second week in June.

“Our main objectives,” Ditmanson said, “are to improve the experience by minimizing crowded conditions thereby reducing safety and traffic concerns and curtailing potential resource damage. These changes will also help to preserve a good experience for campers at Elkmont by diminishing the traffic in the campground and disruption of passing vehicles from the noise and headlight glare.”

Recommendations and Rules

For those riding the trolleys, it is recommended that visitors bring flashlights with red cellophane covers to reduce white light. Visitors can bring lawn chairs, and carry food and water in backpacks which can fit on their laps in the trolleys; there are no services available at the site. In order to help prevent any disruption to the firefly show, or destruction to the National Park, visitors are prohibited from bringing coolers, alcoholic beverages, or their pets.