Fireflies can be found in Southern Arizona, but flashers are few

The first flashes appeared as the sky grew dark behind a thick stand of cottonwood trees at Las Cienegas National Conservation Area.

They started at ground level, in a marshy area where the tall grass had been flattened by a recent monsoon flood — faint, yellow flares like embers, never more than one or two at a time.

Gradually, the tiny blinking lights rose a few feet into the air to patrol the young night in search of ground-dwelling females to flash them back.

It's a summertime magic show that Midwesterners take for granted and some lifelong desert dwellers never get to see. But there are some small, isolated populations of fireflies lighting up the night right now in Southern Arizona. And even the experts are trying to sort out what kinds they are and where to find them.

“As soon as you say fireflies in Arizona, people say, ‘I didn’t know we had any fireflies in Arizona,’” said Cheryl Mollohan, a wildlife biologist who is tracking the insects in the southeastern part of the state as part of a larger, international effort.

Mollohan has spent the past six weeks checking for tiny flashes of light at eight or nine sites where the insects have been reported in the past. Most are south and east of Tucson, within about a two-hour drive of the city.

Mollohan’s specialty is mammals, so she said she is relying on more bona-fide bug people to guide her in her search.

What's in a name

On Wednesday night, she was joined in the field by Joe Cicero, the leading expert — and maybe the only expert — on fireflies in Arizona.

Many of the sites Mollohan has been visiting were first documented by Cicero in the early 1980s. The two species known to flash and fly in Arizona were both named and described by him.

One is Bicellonycha wickershamorum, which Cicero said he named after a family — the Wickershams — that hosted him on their property near Sierra Vista while he was studying the insect.

The other is Photinus knulli, which is mostly found near Peña Blanca Lake and along the Santa Cruz River in Santa Cruz County. The males of that species gather in competitive arenas known as leks and flash in sync with each other, Cicero said.

“It’s fabulous beyond belief. We’ve got to get that on video. That would be a major, major breakthrough in insect behavior to see them congregate and synchronize their flashes the way they do,” he said.

The ones they were looking for Wednesday were the Wickersham variety, but they only spotted a few of them — no surprise at the tail end of the insect’s summertime mating season after one of the driest years on record.

“We’re a little too late, and we’re lucky that these came out in the first place because it’s been so bad here,” Cicero said.

Flash forward

Even in a good year, what you might see at Las Cienegas is a far cry from the stunning light show put on by synchronous fireflies in the Great Smoky Mountains of Tennessee and North Carolina, where clouds of the glittering bugs draw so many visitors each year that the National Park Service has to hold a lottery for reservations.

What makes Arizona’s modest firefly displays special is how rare and unexpected they are.

Though the state is home to about two dozen different species of fireflies, the two Cicero discovered are the only ones that flash. He said there’s a lot still to be learned about them, including how long they can live underground before they emerge to blink and mate and die.

But their signature behavior is universal and easy enough to understand.

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“All the flashing is to attract the female,” Mollohan said. “She sits in a protected spot in the vegetation and flashes very subtly, and these guys are doing all of their acrobatics. Then she picks which male she’s going to breed with.”

This is Mollohan’s second summer tracking fireflies. She said her first summer was “the pits” because of the drought.

“We saw both species last year, but in low numbers. We literally found three in a place where there should have been many, many,” said Mollohan, whose “day job” is tracking bobcats with radio collars for a study she’s leading in the Tucson Mountains.

Flies under fire

She reports her insect observations to Anna Walker, a species survival officer for invertebrate pollinators with the New Mexico BioPark Society, which is the support organization for Albuquerque’s zoo, aquarium and botanical garden.

Walker is coordinating efforts in New Mexico and Arizona to identify firefly populations and assess their conditions as part of a broader effort to understand the ongoing decline of the insects across North America.

So far, Walker said, researchers with the Xerces Society, Albuquerque BioPark, Tufts University and the International Union for Conservation of Nature have completed so-called “red list assessments” for 132 of the continent’s 167 known firefly species.

“Our results show at least 14% of these species (including both in Southern Arizona) are threatened with extinction, though we expect this number may be higher because we did not have sufficient data for more than half of the species assessed,” Walker said in an email.

Cicero said fireflies occur almost everywhere on Earth, outside of the polar ice caps, but they are under threat from habitat loss and manmade light pollution, which is disrupting behaviors that evolved in darkness over countless generations.

Other nocturnal animals like bats, moths and nighthawks are also struggling, he said. “It’s sad. It’s one of those ecological disasters that people just don’t see.”

Show must go on 

Arizona may have been home to a lot more fireflies at one time, but roughly 90% of the marshy, riparian areas where they live have been lost to water diversion and other human development. Climate change now threatens what’s left.

Cicero said there used to be fireflies in Sabino Canyon and along the Salt River, but those populations are gone.

That’s why Mollohan and others are reluctant to publicize exactly where to find Southern Arizona’s two known varieties of flying flashers.

Kerry Baldwin is a retired biologist and education chief for the Arizona Game and Fish Department who is helping Mollohan with her firefly work and her Tucson bobcat study.

He said some of the fireflies’ remaining habitat is just too fragile to support hundreds of people suddenly showing up to look for the bugs.

“These are vulnerable species, and we have to be careful that we don’t love them to death,” Baldwin said. “They’re here, and it is an opportunity to look for them, but people need to just approach it appropriately.”

Cicero isn’t worried. He doesn’t think his fireflies are flashy enough to attract much of a crowd anyway.

“The idea of 50 or 60 people coming here is very unlikely, because it’s not a grand show like it is in the Smokies,” he said while swatting away mosquitoes Wednesday night.

As far as Cicero is concerned, Arizona’s fireflies could use a little more attention. He thinks one way to save them is to show them off to the right people — the ones most likely to be fascinated by them and take an interest in their protection.

“The fireflies are for the children to see and handle,” Cicero said. “It’s important, because they’re going to be the last hope for conservation.”