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19 Mar 2020
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Every year in June here in the Smokies we are treated to an awesome display by Photinus Carolinus or as they are more commonly knows – Synchronized Fireflies. The Great Smoky Mountains National Park was the first location in North America where this behavior was noticed.  There are 19 different species of fireflies found in the park, but only the Photinus Carolinus exhibits this synchronized display.

Thought to be an important part of their mating cycle.  These fireflies, both male and female, flash only during their winged stage from their abdominal light organ.  The males will flash for about 2 – 4 seconds and then stay dark for 8 – 12 seconds.  The females will then answer during the males darkened stage with a flash not quite as bright as the males.  Their flashing patterns is not in sync at all times, they often will flash in waves or even randomly.

Many environmental conditions affect their behavior. On nights after a rain or when the air is full of moisture they will often stop flashing.  They also tend to stop when the temperature falls below 50 degrees.

First observed in the Smokies at Elkmont campground the interest in this phenomenon grew to the point that the National Park had to institute a system of handling the crowds.  This has been accomplished by establishing a lottery system to obtain passes for a shuttle that will take you to the viewing area.  You can no longer drive your personal vehicle to Elkmont and that is strictly enforced during the firefly 2 week mating period.

Important Dates

  • Lottery opens: April 24, 2020
  • Lottery closes: April 28, 2020
  • Results announced: TBA for 2020
  • Event dates: TBA for 2020 (dates announced on April 22, 2020)
  • Synchronous Fireflies web page

Should you be one of the lucky ones here are some ways to help preserve the habitat and the species that provides this marvelous display.

  1. Use a flashlight only when getting from the shuttle to the viewing area
  2. Point your flashlight only at the ground
  3. Cover your flashlight lens with red or blue cellophane
  4. Don’t try to catch any fireflies or allow children to do so
  5. Stay on the trail at all times
  6. Pack out any garbage