There is one place in the National Park System where the fireflies are almost like a well-conducted orchestra in that they all blink in unison. And if you head to Great Smoky Mountains National Park now, you just might see that performance.
Synchronous fireflies (Photinus carolinus) are one of 14 species of fireflies that live in Great Smoky Mountains National Park. 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.
This year Great Smokies officials have lined up shuttles to run June 4-12 to carry visitors to Elkmont to view the fireflies' show.
"All visitors wishing to view the fireflies during this time must ride the trolley to Elkmont. The trolley operates on a first-come, first-served basis," the officials note. "Please note that once the parking lot at Sugarlands Visitor Center fills, additional visitors have to be turned away."