Hunting lightning bugs on a summer night is a rite of passage for many young Indiana residents.
You know how it goes, chasing the flickering lights across the dim sky until you clap your hands in an orb around it. And then wait to catch a glimpse of the little flash between your fingers before releasing it again.
In fact, the Indiana state bug is a lightning bug.
In 2018, after years of campaigning by Hoosier elementary school students, the Indiana Legislature and Governor Eric Holcomb declared the Say’s Firefly the state bug. This species of firefly is not only native to Indiana, it is also named after a Hoosier who discovered it: Thomas Say.
There are about 40 species of the so-called Lampyridae, or luminescent beetles, in Indiana. North America is home to as many as 170 different species and there are more than 1,900 species worldwide. And they have been around for millions of years.
But the flashy bug — and the pastime of catching them — that was once so common may be a thing of the past.
Many Hoosiers say it feels like they see fewer flashes in the night sky compared to when they were younger. That’s what our readers want to know, including our executive editor Bro Krift. He asked: Do lightning bugs disappear from Indiana?
For this edition of the Scrub Hub, we’ll look at the status of the luminescent beetles in the state and what may threaten them. We spoke to a few bug experts to answer these questions and educate (too much?) our readers.
Here’s what you need to know.
Short answer: fireflies hurt
The lights of fireflies are extinguished. At least that’s what the evidence suggests.
“If we only rely on qualitative assessments, they seem to be decreasing,” says Sérgio Henriques. He serves as the Invertebrate Conservation Coordinator for the Indianapolis Zoo’s Global Center for Species Survival.
“If you ask people on the street,” he added, “a lot of people will fondly remember a time when they used to see more and not so much now.”
Part of the problem, though, is that there isn’t great data on lightning bugs — both state and region — to speak quantitatively or specifically.
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Researchers across the country, such as Henriques, are trying to change that. They are in the process of collecting more information. There has been a recent and ongoing effort to better understand populations of lightning bugs or fireflies in North America and estimate the threat of extinction, he said.
The results of that study were fascinating—if not frustrating.
The fireflies they examined fell into three main categories. The first are species that are not considered endangered, and Henriques said there are only a few of them. These are species with a wide geographic range and that alone makes them less of a concern at this point.
The second group makes up 40% and includes those fireflies that too little is known about: “They’re so little seen and so rarely reported,” Henriques said. While that means they could do well, they could also be in such a small bag that they’re on their way out or worse, already gone.
The last set is the endangered category. These are the species that there is enough information to know that they are declining.
The Say’s Firefly, the state insect, falls into the second group, Henriques said. The Cypress firefly, a species recently discovered in Indiana, falls into this third category.
“It’s complicated and it depends on the species,” he said. “But overall they’re not doing great.”
Long answer: Habitat, light pollution and chemicals
There are several reasons fireflies are at risk, and all of them are equally inconvenient for the charismatic creature.
The first, and one problem that plagues many struggling species, is habitat loss.
Fireflies do well in areas with some moisture and humidity – they often live near ponds, streams, swamps, rivers and lakes or in the margins where these areas meet fields and forests. However, as the climate continues to change and we have more drought-like conditions, the ecosystems and the conditions in which they survive shrink.
The beetles are also losing their habitat to development. Because wooded areas or areas of tall grass and native species continue to be lost to buildings, parking lots and perfectly manicured lawns, lightning bugs don’t have a home.
Another major reason why they suffer is because of light pollution.
Decades ago there weren’t so many lights; lights on street corners, house exteriors, etc. While they are good for city and road safety, not so much for the fireflies.
“That comes at the expense of wildlife that ‘sing’ with light,” Henriques said.
The firefly’s light is like a whisper, he said, “while our lights are really loud by comparison and drown them out.”
Fireflies have a fairly short lifespan – just a few months – and thus a narrow window in which to reproduce. Any lights at night disorient them and can interfere with their ability to find a mate.
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There are a few types of lightning bugs that do better, but still not well, with light. That includes a species called the Big Dipper, which most Hoosiers probably see in their backyard. While they will avoid light whenever possible, they can tolerate it for a little longer than most others.
One of the other major threats comes from chemicals: the use of pesticides and herbicides on lawns. While intended for pesky mosquitoes or pesky weeds, these uses can wreak havoc on fireflies in multiple ways
Lightning bug larvae are extremely sensitive, so those chemicals can poison and kill them while they’re still in the ground before they get wings. The pesticides can also kill their food — largely slugs and snails and other types of insects — leaving them with nothing to eat. If the chemicals don’t wipe out their dinner, it gets into their system and effectively poisons the fireflies when they feed.
All of these problems endanger fireflies, and to lose them would be a travesty, the experts said.
“What many Hoosiers may not have realized is that when they witnessed the beauty and magic of this fantastic phenomenon as children, they weren’t the first,” Henriques said.
Research estimates that Lampyridae have been around for 100 million years.
“We are today the keepers of that beauty and it is our moral role to pass on this legacy to our future generations so that we can enjoy it the way we have enjoyed it.”
Even beyond that beauty, lightning bugs have critical environmental functions.
They loosen the soil, allowing sunlight, oxygen and water to penetrate downwards. The beetles also maintain their balance by eating slugs and snails and controlling those critters. And they themselves play an important role in the food chain as caterpillars for, for example, spiders and frogs.
Fireflies are a good indicator of environmental health, said Cliff Sadof, a professor of entomology at Purdue University.
“They are an indicator species for the health of the soil system,” he said. “As they decline, we need to pay more attention to the health of our soils and the species that depend on them.”
There is an ongoing initiative to better research and understand the magnitude of lightning populations in both Indiana, the region and the country. Called the Firefly Watch, researchers are asking citizens to follow a procedure that allows them to count the number of fireflies they see in a short period of time.
While this is a simple measure, citizen science efforts like this one could help build a broad picture of what’s going on, Sadof said. It can help provide a foundation for launching more in-depth investigations.
“If someone wants to contribute to our understanding of the abundance of fireflies,” he said, “that’s the best way to do it.”
Henriques also said there are “little and easy” things Hoosiers can do to help lightning bugs in the state. He suggests reducing lighting at night, planting native species or creating a rain garden. Another option: reducing the chemicals you use on your yard or in your home.
“Glowworms are a privilege,” he said. “It would be such a waste of a treasure if they refused or were gone.”
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Call IndyStar reporter Sarah Bowman at 317-444-6129 or email at email@example.com. follow her Twitter and Facebook: @IndyStarSarah. Connect with IndyStar’s environmental reporters: Join The Scrub on Facebook.
IndyStar’s environmental reporting project is made possible through the generous support of the non-profit Nina Mason Pulliam Charitable Trust.