Chasing lightning on a summer night is a rite of passage for many young people.
You know how it goes, chasing twinkling lights across the twilight sky until you clap your hands in a sphere around you. And then wait to see the little flash between your fingers before releasing it again.
In North America, there are over 170 species of Lampyridae, or light-emitting beetles, and there are over 2,000 types worldwide. And they’ve been around for millions of years.
But you may feel like you see less lightning in the night sky than when you were younger. You might be right, because there are signs that the flashy beetle that was once so common – much like the hobby of catching them – could be a thing of the past.
Lightning bugs or fireflies:What are these luminous insects called?
Short answer: fireflies suffer
The lights of the fireflies go out. At least that’s what the evidence suggests.
“If we just go by the qualitative assessment alone, they appear to be in decline,” said Sérgio Henriques, invertebrate conservation coordinator for the Indianapolis Zoo’s World Center for Species Survival.
“If you ask people on the street,” he said, “a lot of people will think fondly of a time when they saw more and now don’t see as much.”
Part of the problem, however, is that there isn’t big lightning bug data to speak of quantitatively or with specificity.
Researchers across the country, like Henriques, are trying to change that. They are working to gather more information. There has been a recent and ongoing effort to better capture populations of lightning bugs, or fireflies, across North America and assess the threat of extinction, he said.
The results of this research were fascinating, even frustrating.
The fireflies they studied fell into three main categories. The former are species that are not considered endangered, and Henriques said there are only a few like that. They are species with a wide geographic distribution and that alone makes them less of a concern at the moment.
The second group accounts for 40% and includes the fireflies that too little is known about: “They were so little seen and reported so rarely,” Henriques said. While that means they could be doing just fine, they could also be in such a small pocket that they’re about to leave or, worse, have already left.
The last set is the threatened category, which accounts for about 14% of firefly types. These are the species for which there is enough information to know that they are in decline.
These include the Bethany Beach firefly (Phothuris bethaniensis), which is found only along the Atlantic coast of Delaware, according to the Xerces Society. The Portland, Oregon-based conservation group has worked with the International Union for Conservation of Nature (IUCN) to document the plight of the fireflies.
Long answer: Habitat, light pollution and chemicals
For fireflies, “key drivers of decline include habitat loss and degradation, light pollution, and climate change,” according to the State of the United States and Canada’s Fireflies report released in January 2022. by the Xerces Society, IUCN and Albuquerque Biopark.
Fireflies do well in wetlands – they often live near ponds, streams, marshes, 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 conditions, the ecosystems and the conditions in which they survive are shrinking.
Beetles are also losing their habitat to development. As wooded areas or those with tall grass and native species continue to be lost to buildings, parking lots, and manicured lawns, lightning bugs are left without a home.
Another major reason why they suffer is light pollution.
Decades ago, there weren’t so many lights, like the lights on street corners and outside houses. Although they are good for city and road safety, not so much for fireflies.
“It comes at a cost to wildlife that ‘sings’ with the light,” Henriques said.
Firefly light is like a whisper, he says, “while our lights are really loud in comparison and drown them out.”
Fireflies have a fairly short lifespan – just a few months – and therefore a narrow window to reproduce. All the lights at night confuse them and can interfere with their ability to find a mate.
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There are a few species of lightning bugs that do better, but still not well, with light. This includes a species called the Big Dipper, which firefly watchers likely see in backyards in the eastern half of the United States. Although they avoid light whenever possible, they can tolerate it a bit longer than most.
Another major threat comes from chemicals: The use of pesticides and herbicides on lawns. Although intended for pesky mosquitoes or pesky weeds, these applications can wreak havoc on fireflies in a number of ways.
Lightning bug larvae are extremely sensitive, so these chemicals can poison and kill them while they are still in the ground before growing their wings. Pesticides can also kill their food – mainly slugs, snails and other types of insects – so they have nothing left to eat. If the chemicals don’t eliminate their dinner, they enter their system and effectively poison the fireflies as they feed.
All of these issues put fireflies at risk, and losing a family of insects that has been around for 100 million years would be a travesty, experts said.
“The fleeting wonder of watching fireflies reminds me not to take things for granted – neither the weather, nor the tiny beings that live around us, nor the healthy habitats that maintain biodiversity. Fireflies remind us that we are lucky to be alive and to share the world with them,” endangered species conservation biologist Richard Joyce wrote on the Xerces Society blog this week, noting the annual celebration of this World Firefly Day weekend July 2.
Beyond their beauty, lightning bugs perform essential environmental functions.
They loosen the soil, which allows sunlight, oxygen, and water to penetrate underneath. Beetles also maintain a balance by eating slugs and snails, keeping these critters under control. And they themselves play an important role in the food chain as food for spiders and frogs, for example.
“They are an indicator species for soil system health,” said Cliff Sadof, professor of entomology at Purdue University in West Lafayette, Indiana. “If they are declining, 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 investigate and know the extent of lightning populations across the country. Called Firefly Watch, the researchers ask citizens to follow a procedure that allows them to count the number of fireflies they see over a short period of time.
While a simple measure, citizen science efforts like this can help get the big picture of what’s going on, Sadof said. This can help provide a foundation to help initiate further studies.
“If anyone wants to contribute to our understanding of the abundance of fireflies,” he said, “this is the best way to do it.”
Henriques also said there are “small and easy” things you can do to help lightning bugs across the state. He suggests dimming the lights at night, planting native species or installing a rain garden. Another option: reduce the chemicals you use in your garden or in your home.
“Fireflies are a privilege,” he said. “It would be such a waste of a treasure if they were to decline or disappear.”
Contributor: Mike Snider, USA TODAY
Contact journalist Sarah Bowman by email at sarah.bowman@indystar.com and on Twitter: @IndyStarSarah.