Fireflies: Glowing, Snail-sucking, Poisonous Hedonists

By Matt Stansberry, Illustrations by David Wilson

Thunderheads had been building, scudding across the northern plains for weeks, dumping rain into basements, swelling the rivers. Over eight and a half inches of rain fell in the month of June, the third wettest in Cleveland’s history.

I wondered if the fireflies had drowned. I’d been watching, scanning the dark edges of lawns around suburban Cleveland at sundown. And then one warm night near the summer solstice, hundreds of fireflies flew out of the yard and twinkled, ghostly green flares in the darkening suburban understory.

I snuck my six-year-old son out of bed, clambering under a half moon in pajamas.

A few bats swooped overhead. Junebugs bumped clumsily against our screen door. We found moths flitting in the porch lights. We listened to the green frogs chortling in the slough behind the house.

The boy and I ran through the night to gather the first lightning bugs of the summer.

We brought a few specimens into the kitchen for closer examination. These insects had straw-colored carapaces with brown stripes down the middle, and huge black liquid eyes. They looked very different from the red and black fireflies I’d found as a kid.

We didn’t know at the time we’d captured Photuris pennsylvanica, a predacious trickster. The female of this species mimics the flash patterns of other firefly species. When suitor males come to investigate, these females eat them.

This betrayal represents just one tiny example of the sordid behaviors of our beloved fireflies. Of which most of us know nothing about.

Those fireflies in your kids jar? They are snail-sucking, slime-trail-following, poisonous little hedonists with nothing to lose.

* * *

Common animals in our midst live unexamined, surprising and complex lives.

I’ve been in close contact with fireflies since I was a toddler, and knew nothing about them. I didn’t even realize there was anything to know.

[blocktext align=”right”]“People know three things about fireflies. They come out at night, they flash, and people like them. That’s about it.”[/blocktext]It’s like learning your sweet grandparents had run a brothel, or finding out years after the fact that your mother held the world record for most times going over Niagara Falls in a barrel. We know relatively nothing about our familiar and constant companions, beyond their physical presence.

“People know three things about fireflies,” says Don Salvatore, Firefly Watch Coordinator at the Museum of Science in Boston. “They come out at night, they flash, and people like them. That’s about it.”

Salvatore runs the museum’s citizen science project, studying North American firefly populations. “When we started the project, there was nowhere to learn about fireflies other than children’s books or scientific research,” Salvatore says. “Have you’ve ever tried to read research papers? They’re terrible.”

The Firefly Watch website is probably the best source of firefly information currently available.

Fireflies are not flies but beetles, and there are over 150 species in North America. There are fireflies all over the U.S., but west of Kansas, for some unknown reason, they do not flash as adults.

They have two pairs of wings. The outer wings are actually the shell of the beetle. They hold these outright during flight like the wings of an airplane. The softer inner pair beat to power and control the beetle’s flight. This typical beetle wing design doesn’t tend toward speed, which explains why little kids can snap them out of the air.

According to George Keeney, a research associate in the department of entomology at Ohio State University, we have 43 species of fireflies in Ohio, 30 of which can flash.

Fireflies exist on every continent except Antarctica, explains Keeney. There are over 2,000 described species worldwide, and perhaps three times that number yet to be discovered and given a scientific name.

“Over half of the described firefly species are in the tropical Americas, but we’re still discovering new species right here,” Keeney said. “We recently found a new diurnal species on our West Campus wood lot.”

The most common species in our area, the ones you likely see on your lawns in June and July, are called the Big Dipper fireflies, Photinus pyralis, Keeney explained.

They dip midflight in a J-shaped motion as they flash.

The other common species in Ohio include the Pennsylvanian firefly, the predacious mimic species that prefers wooded areas, and the Angled Candle firefly, which flickers with an orange flame-like glow.

[blocktext align=”left”]It’s like raising your kids in an aquarium on a diet of algae and rotten leaves so they’ll stay the hell out of your way and not eat everything in the fridge.[/blocktext]All of these species follow the holometabolus lifecycle – egg, larva, pupa, and adult – transforming from one form into another, with totally different behaviors and bodily features. This biological adaptation (common to beetles, butterflies, moths, flies, and wasps) allows species to maximize success by programming different forms of the insect to utilize different parts of the habitat and resources.

It’s like raising your kids in an aquarium on a diet of algae and rotten leaves so they’ll stay the hell out of your way and not eat everything in the fridge. Given the fact that I have three young boys, I probably should have looked into this sooner.

* * *

Valerie Fetzer, Rocky River Reservation’s Nature Center manager and naturalist for Cleveland Metroparks, leads an annual adults-only firefly program.

When parents ignore the guidance, she tries to send the kids home.

“The program focuses on stalking, lust, and betrayal,” Fetzer says. “Most of us have had this magical firefly experience as a kid. But they’re not what we think, not what they seem. I would hate to break a child’s heart.”

[blocktext align=”right”]“The larvae are carnivores. This is where the stalking comes into play. They eat worms, snails, and slugs. They stalk the slimy mollusk trail. They inject a toxin through their mouths and digest prey alive.”[/blocktext]The adult firefly lays her eggs in moist plant material at the end of summer. After about four weeks, the eggs hatch into larva that live in the damp areas under bark and yard debris for one to two years.

The juvenile or larva phase of the firefly looks and acts like something out of Ridley Scott’s Alien movies.

“The larvae are carnivores,” Fetzer says. “This is where the stalking comes into play. They eat worms, snails, and slugs. They stalk the slimy mollusk trail. They inject a toxin through their mouths and digest prey alive.”

Fetzer pulled out an 8 x 10 photo she’d printed of the jagged tail end of a firefly larva hanging out of the shell of a snail it was eating. It had climbed up inside the snail. Something about it made my stomach lurch.

I thought about one of my favorite lines by Annie Dillard in A Pilgrim at Tinker Creek: Fish gotta swim and birds gotta fly; insects, it seems, gotta do one horrible thing after another.

Fireflies creep around eating other animals, but few animals eat them aside from other fireflies. They seem like obvious targets, slow and highly visible. But the flash is a warning of their foul-tasting and even poisonous nature.

“Researchers have conducted tests on birds and jumping spiders, they don’t like them,” Keeney says. “People reported feeding fireflies to their Bearded Dragons. They killed the lizards.”

Fireflies can poison would-be predators without being eaten, even if they’re not punctured. “It’s called reflex bleeding,” Fetzer says. “They ooze a toxic substance, and in some cases the substance has the ability to glue the attackers mouth shut.”

[blocktext align=”right”]The meek and poisonous shall inherit the earth.[/blocktext]Many fireflies use a protein called luciferin to produce light. The word “luciferin” is based off the word Lucifer, Latin meaning light-bringing or morning star.

Apparently Lucifer, commonly regarded as the Devil, doesn’t create the light. He brings the light, created by God.

The light of the world is all life, a single organism interconnected as a continuous sprawling system. The firefly larva digesting the snail alive inside its own shell is ineffably a part of that light. To claim comprehension of the mystery might have been the root of evil.

My mind wobbles and warps considering bioluminescent proteins named after a fallen angel, the purpose of suffering and interconnectedness.

This is God’s light. Eat me and sicken and die. The meek and poisonous shall inherit the earth.

* * *

The purpose of the firefly’s glow is sexual communication. Each species has its own flash pattern, with varying color, length, number of flashes, interval of time between flashes, time of night, and flight pattern.

“There are more males out there than females,” Fetzer explains. “The females sit and wait while the males fly around and flash. If the female likes what she sees, she lights her own light until they are able to find each other.”

From Firefly Watch: During mating, the female firefly receives a “nuptial gift” from the male, which contains sperm to fertilize her eggs and food to help nourish them. Research suggests that the female is swayed by the brightness and duration of a male’s flash. The more robust male firefly can produce a brighter flash and offer a larger nuptial gift, thus making him the preferred choice.

“A female picks the male is going to give her the best package,” Fetzer says. “They say the mating process takes over eight hours.”

[blocktext align=”left”]“The primary purpose of an adult firefly’s life is mating. That’s what they’re here to do. They mate and then die.”[/blocktext]Goddamn tantric bugs are making me look bad.

“The primary purpose of an adult firefly’s life is mating. That’s what they’re here to do,” Fetzer explains. “They mate and then die.”

This pattern applies to many animal species. Salmon run up their natal creeks to spawn and their bodies begin to irreparably change and decay as soon as they reach the freshwater. Their carcasses provide nutrients for their subsequent generation. Mayflies spend up to two years crawling along the bottoms of lakes and streams, but once they mature and transform into their adult mating forms, they only live 24 hours.

In biological terms, this is called semelparity: a propagation strategy that puts all available resources into maximizing reproduction, at the expense of future life.

After six years of fatherhood, I feel as if I’ve begun some irreversible transformation. It’s all downhill from here, as they say. A recent study links early fatherhood with premature death in humans. There is a biological cost to sleepless nights, finishing half-eaten plates of chicken nuggets, and fighting with your spouse.

It sounds simpler to fly into the arms of some attractive impostor, be eaten alive, and recycle yourself back into the universal nutrient pool. The grass really is always greener.

* * *

In late July, my wife and I piled the three little boys into the minivan and drove to Secrest Arboretum in Wooster where Ohio State University’s entomology graduate students were hosting a bug-themed party.

There was a firefly catching contest for kids at 9 pm. My six-year-old ran around the brushy edges of the park lawn, always a few seconds behind the flash. As more beetles began to flash, he caught the rhythm and began swiping them out of the air and popping them into his plastic carrying case. My two-year-old joined in, not fast enough to catch them, but still excited to swing his hand out at the glowing bugs. As it got darker, it became harder to catch them after their lights faded. My son captured 25 fireflies in the 20 minute time period, over one per minute, and brought his haul of beetles to the judging panel.

The winning kid had captured 42.

As we started the late-night drive home from Wooster to Cleveland I felt something flutter against my exposed knee, on my forehead. I saw insects flitting against the oncoming headlights, attempting to mate with the dashboard. My six-year-old had fallen asleep and tipped open the top of his firefly container and about a dozen had escaped into the van. They landed on my face in the dark, drinking in the salt on my skin.

He kept the remaining fireflies overnight in his room, blinking on his bedside table. About half of the captives died, bled out from injuries during their capture, or dehydrated in the wee hours of dawn. He let the survivors go. Just one stayed in the case.

My son asked what adult fireflies ate, and I said I didn’t know, so he piled the bottom of the cage with grass and millipedes, covering the bases. He hoped to not lose another.

[blocktext align=”left”]“So what have we learned about firefly populations? It’s too soon to say … as crazy as that sounds.”[/blocktext]There’s a general worry among firefly enthusiasts about possibly declining numbers of fireflies. It’s more of a gut feeling than something substantiated, or really even knowable.

“There’s variation in the populations from year to year based on weather conditions and how cold the winter was,” Keeney says. “Certain species may be vulnerable due to habitat loss and fragmentation, urbanization. Certain agriculture practices, usage of pesticides and tillage affect the numbers on a local scale.”

There’s a concern that light pollution is affecting their mating. There’s the weary notion that where wildlife is involved, things are always getting worse.

“People ask ‘What’s happening with fireflies?’ Without data, it’s just hearsay,” Salvatore says, describing why his organization started the Firefly Watch program, which asks folks to submit records of the fireflies in their backyards.

“In the seven summers of Firefly Watch, we have had an average of 1,000 people participating each year,” Salvatore says. “Altogether, over 6,000 people have participated. Each person is encouraged to collect and enter data once a week during firefly season. So far we have over 30,000 entries.”

And even with all of this data, there’s really no clear picture of what’s going on.

“There is no hard and fast information. Firefly numbers vary greatly from year to year. They fluctuate. It’s like watching temperature data. You have to watch for a long period of time,” Salvatore says.

Identifying species is very difficult, and he can’t rely on volunteers’ accuracy.

“So what have we learned about firefly populations?” Salvatore asks. “It’s too soon to say … as crazy as that sounds.”

Even if getting baseline population data is difficult, Salvatore is happy to see more people interested in fireflies, and understanding the more complex aspects of their lives. He hopes it encourages people to do more to keep them around.

“One of our goals is to make people interested in their own back yard,” Salvatore says. “Let some areas go natural. If you cut down all the vegetation there’s nowhere for the females to sit and watch the males. So many people in suburban developments have pesticides in their lawns. Are pesticides killing firefly larvae underground? Seems likely, but nobody’s tested it.

“People need to realize what they do affects their local environment.”

___
Matt Stansberry was born in Akron, Ohio. He is a dad, nature writer, and fly fisherman. Find him on Twitter @LakeErieFlyFish. More of David Wilson’s illustration work can be found at dwillustration.com.

Matt and David’s monthly column, “North Coast Biodiversity,” is collected here. Order copies of the first edition of Redhorse — a print collection of the first six “North Coast Biodiversity” columns — here, and signed prints of David Wilson’s original art for the column here. 

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