[4] As individual females synchronize with males nearby, waves of alternating bright light and darkness seem to travel across the landscape.

Firefly displays typically occur in early June near Elkmont, Tennessee, in the Great Smoky Mountains National Park, near Gatlinburg.

Both male and female adults produce mating signals with an abdominal light organ or "lantern".

[6] P. carolinus was the first North American species found to show synchronized flashing behavior.

[9] In the southern part of its range, P. carolinus is usually found in hardwood forests that are 65 years old or older, in mountain river valleys at elevations from 1,400–6,000 feet (430–1,830 m).

Scientists use a degree day model to try to predict the onset of each year's peak display.

[13] The firefly display near Elkmont attracted more than a thousand visitors nightly in early June 2011.

A biologist who has studied the fireflies expressed concern about increased crowds at the park, saying, "The bulk of people are respectful ...