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firefly on orange flowers

Firefly Adjustments

By: Meredith Harman

I’m new to the Pittsburgh area and came here from the sunny coast of California. So, I’m personally experiencing a few of the differences between the East and West coasts of our country. Foremost among them is the amount of humidity and rainfall. Is there ever not some kind of moisture in the air here?

One thing that doesn’t take much adjustment, though, is the way East Coast lawns come to life with fireflies at twilight. I like to sit outside at night and watch those little pinpricks of light bloom in my yard. It’s bewitching, and their twinkling gives a whole new meaning to Christmas in July.

Apparently, fireflies produce the most efficient light of any creature, humans included. It’s called “cold light,” and 100% of its energy is released as light. (Incandescent lights emit 10% light and the rest as heat, and even fluorescent lights emit 90% light and 10% heat.) Researchers have used the design of a firefly’s light-producing organ to create LEDs that shine 55% brighter than they would otherwise. ( In other words, fireflies are cool. As usual with nature, they marry beauty with efficiency to produce something humans can benefit from mimicking.

There is one kind of firefly that does something completely unique. It is called Photinus carolinus, and members of this species have been mystifying scientists for years with their instinct for flashing in unison. Firefly researcher Sara Lewis calls them “silent synchronous symphonies,” referencing the way groups of these fireflies blink on and off at the same time. It is probably a part of their mating behavior, but the effect by all accounts is astonishing. It’s rare, too. This species is only found in small areas in Tennessee, the Great Smoky Mountains, and was discovered more recently in Pennsylvania.

firefly on orange flowers

You can observe these synchronous fireflies as well as over a dozen other species at the Pennsylvania Firefly Festival in Allegheny National Forest. The festival celebrated its sixth anniversary in June. This is an event dedicated specifically to the viewing of these remarkable glowing critters, with family-friendly activities that begin at noon and culminate in a supervised night walk through the forest to watch the fireflies shine. (

Someday I hope to attend this festival. Summer lawns tend to look barren to me without fireflies, probably because my early childhood years were spent in Pennsylvania. And so I’m glad to be back here again where I can go outside any evening and watch what look like stars come out across the grass, one by one, shining their heroic little light out into the dark.

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