All together now – flash
Around 2 a.m. the other morning I was walking Maddie, my seven-month-old, around the house trying to convince her that it was still bedtime. We passed by our wall of windows in the living area and our yard was ablaze with fireflies. There were so many it even got Maddie’s attention, and she watched intently for a couple of minutes.
My bioluminescent yard jarred my gray matter and I remembered it was around time for the annual firefly pilgrimage in the Great Smoky Mountains National Park. Alas, my timing was as good as always. I searched the Internet and found that the park’s 2006 firefly programs had concluded on June 8. The illuminating insect, however, will continue displaying through the end of the month. Elkmont, Cades Cove, Greenbriar and Townsend are all good spots to find this synchronistic beetle.
This flashy insect is Photinus carolinus. It is one of about 20 species of fireflies in the park. Biologists divide the fireflies in the park into two groups. In one group are about eight species; the adult beetles don’t flash but the larvae (“glowworms”) do.
Photo carolinus is in the second group comprised of about 12 species; the adult beetles produce flashes. Each species has a unique pattern of flashing which allows for species recognition – primarily for mating.
Synchronous fireflies were once thought endemic to Asia. However in the early 1990s naturalist Lynn Faust noticed a definite pattern to the nighttime flashes outside her Elkmont cabin. Faust contacted Jonathan Copeland of Georgia Southern University and he came to take a look. In 1994 Copeland documented the first species of synchronous firefly outside of Asia.
Photinus carolinus emits a series of 5-8 flashes with a 5-8 second pause between each series. In large clearings like Cades Cove and Elmont there may be thousands of these synchronistic lightning bugs. P. carolinus generally starts displaying as soon as it’s completely dark (9:30 p.m.) They will display until around midnight.
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The adult life of a firefly is short (2-4 weeks), its purpose is to procreate. The adults mate, the females lay their eggs and they pass on to firefly heaven. The larvae hatch and live in the soil for about two years. Then in late May or early June, they pupate and emerge as fireflies.
Photinus carolinus is known from every watershed in the park and is likely found in other openings around Western North Carolina. To date, the Southern Appalachians and Southeastern Asia are the only known locales for synchronistic fireflies.
There are, of course, other species of non-synchronous fireflies for your night time viewing. One of my favorites is Photinus pyralis. This species only flashes for an hour or so every evening during mating season – usually from around 9 p.m. to 10 p.m. But the flash has a distinctive wiggle or “J” pattern to it.
A good resource for fireflies in the park is Discover Life in America’s website – check out http://www.discoverlifeinamerica.org/atbi/species/animals/invertebrates/
arthropods/insects/beetles/lampyridae.shtml.
After you visit the site get out and see if you can identify any of these cold fusion phenomena. Make it a weekend so the kids can join you.
