Synchronous fireflies (Photinus carolinus) are the only species in America whose individuals can synchronize their flashing light patterns.  Fireflies (lightning bugs) are beetles.  You know, we are all guilty of going out and catching them when we were kids, putting them in glass jars to watch them glow.  They take from one to two years to mature from larvae, but will live as adults for only about 21 days.  While in the larval stage, they feed on snails and smaller insects.  Once they transform into their adult form, they do not eat.

Synchronizing Fireflies

Their light patterns are part of the mating ritual.  Each species of firefly has a characteristic or flash pattern that helps it's male and female individuals recognize each other.  The males fly and flash and the usually stationary females respond with a flash.  The production of light by living organisms is called bioluminescence.  This process involves highly efficient chemical reactions that result in the release of particles of light with little or no emission of heat.  Fireflies combine the chemical luciferin and oxygen with the enzyme luciferase in their lanterns (part of their abdomens) to make light.  The light produced is referred to as "cold" light, with nearly 100% of the energy given off as light.

Synchronizing Fireflies

Enough of the scientific stuff.  I arrived at the parking lot around 6:30 pm and waited to board the shuttle for a six mile ride to the Elkmont area in the Great Smoky Mountain National Park.  Departing the first shuttle of the day afforded me the opportunity to scope out locations for the best viewing possibilities.  After settling down in a hallow with small swaths cut into the woods in three different directions, all I had to do now was wait.  And wait I did, for the next two hours.

Synchronizing Fireflies

I saw my first flash of greenish yellow light around 9:30pm and the flashes continued multiplying until I realized there were hundreds of flashes and they were all synchronized.  What an incredible sight!  Hearing the blaring horn from the shuttle bus told me it was time to start heading back to the staging area for the return trip.  I was on the last returning bus.

Synchronizing Fireflies

No one is sure why the fireflies flash synchronously.  Competition between males may be one reason: they all want to be first to flash.  Or perhaps if the males all flash together they have a better chance of being noticed, and the females Canaletto better comparisons.

Here's a composite I did from multiple frames.

Synchronizing Fireflies