Why we don't see lightning bugs in the suburbs

Our suburban night skies give us dazzling light shows. Public fireworks grow more spectacular each July 4. Illegal backyard explosives also seem more plentiful and grander. Even Mother Nature has chimed in with impressive lightning displays.

But one light show can be difficult to find in our suburban skies this summer. During holiday weekend evenings at outside parties and backyard gatherings, I didn't spot a lightning bug.

Suburban homeowners might be part of the reason why.

"Chemicals put on the ground kill the lightning bug larvae living in the ground, and also kill the grubs and a lot of the things the lightning bugs eat," says Jim Louderman, collections assistant for Chicago's Field Museum's insect collection. "People who have been using chemicals for years haven't seen lightning bugs for years."

When Louderman was working on a project a few weeks ago in a Hanover prairie in the northwest corner of the state, "it was just ablaze with lightning bugs," he says. "Lightning bugs are very local. Some yards have lots of them, and some have none."

Our harshly cold winter and torrential spring rains probably killed off some lightning bug larvae, says Phil Nixon, a statewide entomologist with the University of Illinois extension office. Flooding along our rivers "would have drowned a large number of larvae," Nixon says. "Normally, it's dry soils that eliminate large numbers of larvae."

That's what happened during the dry, hot spring two years ago, says Pam Otto, nature programs manager at Hickory Knolls Discovery Center, a facility of the St. Charles Park District.

"In 2012, the drought year, the lightning bugs really took a hit," Otto remembers. "They basically cooked."

A member of the beetle family, lightning bug larvae live underground through the winter, pupate in the spring and emerge as adults in the summer. "They just live long enough to mate and lay their eggs," Louderman says.

A Hickory Knolls children's presentation about lightning bugs on a night in late June gave kids a chance to see "a fair number," Otto says. But it was nothing like the scene a few summers ago when "it looked like a Milky Way of flashes," Otto remembers.

While the lightning bug season seems to have peaked a little early this year, Otto expects the glowing insects to make an appearance at the more educational "Night Flights: Hanging out with Fireflies" presentation from 8 to 10 p.m. Friday at the Hickory Knolls Discovery Center, 3795 Campton Hills Road, St. Charles. To register for the $15 event or get more information, phone (630) 444-3190 or visit kaneforest.com.

The suburbs are home to several species of lightning bugs, which often are called fireflies. "Some years, we see three distinct species, including a small one. We didn't find any small ones this year," Otto says.

In addition to cold, floods and chemicals, lightning bugs do fall prey to spiders, praying mantises and other insects.

"A lot of things do eat them. Birds, not so much, because they taste bad," says Louderman. One species of lightning bug even mimics the mating flashings of another species, just so it can lure them close and eat them.

They can live in the grass of a suburban yard, but lightning bugs prefer moist prairies with a diverse offering of plants, such as the land often found along railroad tracks.

"Those would be areas with fireflies," Nixon says. "Your typical suburban yard is not quite a botanical desert, but it's almost one."

Efforts to corral nature do hurt lightning bugs.

"Pesticides are a big concern," Louderman says. "But I'm not worried about lightning bugs so far. I don't think we are in danger of losing them. But it would be a shame if we did."

Kids love lightning bugs, but so do adults.

"It's an insect everybody has a good experience with," Otto says. "There's even a downside to butterflies with people complaining about the caterpillars eating their plants. But fireflies, everybody loves."

What do you call them?

Across the United States, 39.8 percent of people use terms “lightning bug and firefly interchangeably;” 30.4 percent call them "firefly” and 29.1 percent picked “lightning bug.” The term “peenie wallie” is used by 0.02 percent of Americans, according to a study by NC State University.

But whatever your preference, don't call them bugs or flies. They are actually beetles.