You Can't Take the Sky From Me

How Are Houston's Fireflies Faring?

Houston doesn't make it easy for them to thrive.

By Gwendolyn Knapp July 20, 2018 Published in the August 2018 issue of Houstonia Magazine

Image: Amy Kinkead

On a recent Saturday night, 20 people, toting babies and dogs and coolers of drinks, convened to catch a glimpse of a quintessential, yet declining, summer marvel.

Fireflies. Lightning bugs. Two thousand species of these winged bioluminescent wonders inhabit the earth, dozens of them here in Texas. But they’re actually beetles. And scientists believe they’re declining because of our planet’s urban development.

Fireflies thrive in tall grass, woods, and open spaces and near pooling water—in darkness, of course—which makes Houston, like many cities, less than ideal, considering our light pollution, pesticides, mosquito sprays, and concrete. Still, they are here.

Chris Garza, an applied ecologist on the Houston Arboretum’s Conservation Team, is hoping the park’s new savannah and prairie restoration will attract the Photinus pyralis, or common Eastern firefly. But for the past two years, he’s been pointing people to the stretch of overgrown wooded area behind Lawrence Park near the Heights Hike & Bike Trail.

It was here that, shortly after nightfall, as the bats stopped flittering overhead, the group, led by Garza, experienced a bit of magic: the J-shaped blinking of Photinus pyralis coming from the bushes, shrubs, and vines. “I’m hoping that maybe someday, it can be like the Waugh Bat Bridge,” Garza says. But for now, it’s one of Houston’s best-kept secrets.

The Tic Tac–sized Photinus pyralis uses the chemical compound luciferin (yes, like Lucifer, the bringer of light) and the enzyme luciferase to create light without heat, shining it through its abdomen to warn predators away and, most important, help attract a mate.

The males fly about blinking, and when a female sees one she likes, she blinks back. You can watch this great romance unfold in the Heights. But because the universe loves horror, too, there are also females in the firefly genus Photuris, perhaps even hiding out here in Houston, that will blink back at the male Photinus pyralis before luring them in and devouring them. Sigh. 

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