May 10, 2024

When was the last time you saw a firefly?

For many of us, that answer is “back when I was a kid.”

Over the decades, I have seen a few here and there but nothing like when we hunted lightning bugs in our Arlington backyard in the 1960s and 70s.

Sam Kieschnick, DFW-based urban biologist for the Texas Parks and Wildlife Department, says fireflies conjure up nostalgia for him too.

“I played with them as a kiddo, and I still feel like a kid when I see them flashing.”

Fireflies are becoming more scarce in Texas, especially in metropolitan areas where suburban sprawl is rampant.

Ben Pfeiffer, a New Braunfels-based biologist, wants to ensure new generations don't miss out on seeing them. That’s why he launched his nonprofit Firefly Conservation and Research in 2009.

Since then, Pfeiffer has become the leading advocate for fireflies in Texas.

TEXAS ROOTS

Pfeiffer, a sixth generation Texan, spent a lot of time outdoors exploring the Texas Hill Country and South Texas, where he frequently saw fireflies.

Ben Pfeiffer founded Firefly Conservation and Research in 2009.​ Courtesy of Firefly.org.

“They were kind of ubiquitous with the environment,” said Pfeiffer. “I just always had an appreciation for them and an interest in why they light up and what were those mechanisms that created that.” 

Once, on a trip to Puerto Rico, he swam in a bioluminescent lagoon, which further piqued his interest in bioluminescent life.

“It's such a rare thing in the animal kingdom. I really wanted to understand it in a deeper way,” he said. “In the process of doing that, I discovered fireflies were in decline.”

While earning degrees in biology and business at Texas State University, he had purchased the domain firefly.org. Years later, he found a purpose for it — to educate people about fireflies.

“Then I went on this kind of great adventure, all around Texas.” 

He met with other entomologists and explored university collections from East Texas to Texas A&M, learning about the state’s fireflies.

Pfeiffer’s familiarity with the Texas landscape gave him an advantage over firefly researchers from out of state.

"I can hunt them out a little easier," he said.

FIREFLY FACTS

Today, on Pfeiffer’s website Firefly.org you can find a plethora of facts about fireflies.

Male fireflies have two light organs and females have one. Courtesy of Firefly.org.

Fireflies are beetles. They spend most of their lives as larvae, only living about three weeks in their adult stage as flying beetles. Just enough time to mate and lay eggs.

They spend one to two years as larvae, munching on snails and worms. 

“They act as nature's pest control,” said Pfeiffer.

Researchers aren’t sure what adult fireflies eat, or if they eat at all in their short lives.

LIGHT SHOW

Of course, fireflies are famous for their glowing lights. The flashing lights serve as signals, primarily to attract mates. The lights are also used to defend territory and warn predators.  

Their light is created when the firefly breaths in oxygen, a catalyst for the process, which involves two chemicals luciferin, which glows under certain conditions, and luciferase, which triggers light emission.

The females typically have one light organ on their abdomen and the males have two.

When cruising for mates, the males turn their flashers on to attract females. The females then give them the "green light" with their own luminescent response.

“She's looking for faster flash rates, or longer flashes. So she's looking for the most robust male in order to sire her offspring with essentially.”

A firefly larvae emits a glow. Courtesy of Firefly.org.

Their flashing light patterns are also identifiers, with each species flashing at signature speeds, intervals and colors.

“So it can run the gamut from red light all the way to kind of a yellow, greenish light. And you get orange in between and so on,” said Pfeiffer.

According to Pfeiffer, firefly lights are the most efficient lights in the world — 100 percent of their energy is emitted as light. Compare that to an incandescent bulb, which emits only 10 percent of its energy as light and the rest as heat, and a fluorescent bulb, which emits 90 percent of its energy as light. 

In some firefly species, the larvae and even the eggs glow.

WHERE TO FIND FIREFLIES

Fireflies have been spotted on every continent except Antarctica, according to Pfeiffer.

“Fireflies occur all along the eastern seaboard in the Mid Atlantic, all the way down to Florida, in the South and to Texas. And there's even species that occur within New Mexico and Arizona and Colorado and Utah,” he said.

Texas is rich in firefly diversity, with about 45 species of fireflies observed, a fifth of the 240 species in the U.S. 

According to Pfeiffer, fireflies can be found all over Texas — roughly 80 to 85 percent of the state — with East Texas being one of the prime spots for firefly habitat.

“Probably the only places in Texas that it's gonna be a little harder to see them is the Panhandle region or the Trans Pecos area [West Texas],” he said.

Fireflies can be found in most counties of Texas. Courtesy of Firefly.org.

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Fireflies in Texas may predate those on the East Coast.

“So for the longest time, the common knowledge was that fireflies in Texas migrated from the Mid-Atlantic because they have such robust populations of fireflies there. But researchers have found that the fireflies that occur in the Mid-Atlantic and down the East Coast, and some in the South where there are abundant populations, actually came from Texas. And that they likely migrated since the last glaciation, out of Mexico, into Texas and into other parts of the country. And so really, what we have here in Texas is kind of like the relic populations that occurred here historically, thousands and thousands of years ago." - Ben Pfeiffer

Fireflies love warm, humid areas. They thrive in forests, fields and marshes near lakes, rivers, ponds, streams and vernal pools. They spend most of their lives living low to the ground in leaf litter and under rotting logs and rocks.

“You can find them in riparian corridors,” said Pfeiffer. “We've also got species here that like it a little drier and they like to live, let's say, at the base of a cedar tree. 

Pfeiffer recommends looking for them in state parks, natural areas and nature preserves and even city parks.

Kieschnick of Texas Parks and Wildlife agrees.

“Wherever I see a lot of vertical diversity of plants (plants of all sizes mixed together), I usually will find some fireflies,” said Kieschnick. "They are also indicators of a good healthy habitat — an area that’s not been overly 'pesticided' or 'herbicided.'”

Pfeiffer said start watching for them about 15 to 30 minutes before dusk, as they typically come out before it gets dark.

Their flight time usually lasts an hour. However, in the summer, you can see fireflies from about 8:30 p.m. to 10:30 p.m. because different species come out at different times.

“And occasionally, there'll be stragglers,” said Pfeiffer. “I saw fireflies last night actually until midnight.”

Each firefly species has its own signature light pattern and color. Courtesy of Firefly.org.

GLOWING GONE

The main driving force for firefly decline is habitat loss.

“In some places in Texas, they're doing just fine in areas that are protected, and that historically had really robust fireflies — your preserves, your parks, and your natural areas,” said Pfeiffer.

But in metropolitan areas, previous ranges are turning into concrete and asphalt, he said.

“Once those populations are gone, it's very hard for fireflies to recover. They will migrate slowly. But that takes a really, really long time,” Pfeiffer said.

“And so there's just a really big loss of habitat that's occurring. And it's very unfortunate, especially along river systems that previously supported them. You can go to any major river, near like a metropolitan area and see the effect that development has on the landscape there.”

He said firefly scientists are particularly concerned about the loss of unique, locally adapted species. 

“And so there's just a really big loss of habitat that's occurring. And it's very unfortunate, especially along river systems that previously supported them. You can go to any major river, near like a metropolitan area and see the effect that development has on the landscape there.”

“So these are species that are endemic to Texas and not necessarily the common type of firefly. And so when you get the loss of those species that occurred just in let's say five counties within Texas, that’s a big loss of species diversity.”

Another cause of firefly decline is pollution — both contamination in watersheds from run-off as well as something not always recognized for its harmful effects — light pollution.

“Rarely will you ever see a firefly flash underneath a street lamp,” said Pfeiffer. “They prefer darkness to maximize their ability to flash.”

Pesticide use is another factor causing firefly decline as it can kill their food sources as well as the fireflies themselves.

“So if you're spraying anything to kill beetles, you're killing fireflies, because fireflies are beetles essentially.”

WATCH PARTY

A Firefly Watch Party will be held in Schertz, Texas, outside of San Antonio, on May 18. Courtesy of Firefly.org.

For the last 15 years, Pfeiffer has traveled around giving talks on fireflies. Every year, he hosts an annual firefly watch party at Crescent Bend Nature Park in Schertz, outside of San Antonio. This year the Dark Skies and Fireflies event will be held on May 18 at 7:30 p.m..

“This is a really great opportunity to bring out large groups of kids that have never experienced fireflies and adults as well,” he said.

Pfeiffer will talk then lead a walk through the preserve, where attendees can catch and ID fireflies.

“I do encourage people to catch fireflies. It's the only way that you can tactfully understand what they are. It's really good, especially for kids, to interact with fireflies — catch them, see them flash, put them in a jar and then at the end of the night, let them go.”

FIREFLY HABITAT CERTIFICATION

Last year Pfeiffer stepped up his firefly conservation campaign with the launch of the Firefly Certification program. On his site, he sells Firefly Habitat signs to put in your yard or other property.

The metal signs cost $45 and come with instructions on how to set up and maintain firefly habitat.

Make your firefly habitat official with a sign from Firefly.org.

Pfeiffer says it provides another tool to bring attention to the issue. He hopes the firefly habitats will catch on the way that pollinator gardens have.

So far they’ve certified around 350 firefly habitats across the nation. They’ve even been contacted by an organization called Natuurpunt, based in Belgium.

“They want to protect habitats in France, Belgium and Sweden. And so we're gonna to be working on that jointly with them.”

CREATING FIREFLY HABITAT

Pfeiffer offers tips for creating a firefly habitat in your yard.

He recommends the following: 

Plant native plants. “Native grasses are really good at retaining soil moisture, because their roots are so deep.” 

Restrict pesticides. Pesticides and herbicides can harm not only fireflies but their larvae’s food sources, snails and worms.

Leave leaf litter. The noncompacted material provides shelter and helps keep the soil moisture intact.

Reduce light pollution. Outdoor lighting can affect and disrupt successful firefly mating. Turn off lights, use security lights with motion sensors or switch to yellow or amber lights, which aren’t as disruptive to insects. Close curtains and shutters to reduce light leakage.

For more information go to Firefly.org.

Fireflies live in leaf litter, rotting logs and under rocks and require darkness to successfully find mates. Courtesy of Firefly.org.

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