I’ve noticed something missing from my backyard this summer: fireflies.
Also known as lightning bugs, the flying, flashing beetles are a magical image and a staple of summer nights in and around Chicago.
Though not yet this summer, they’re usually out in force this time of year in my North Side neighborhood.
There are no hard numbers, and insect populations can cycle year to year.
But it’s clear that around Chicago firefly populations “got off to an absolutely terrible start this year,” says Doug Taron, longtime curator of biology at the Peggy Notebaert Nature Museum in Lincoln Park.
Taron, who recently retired, says he normally sees a lot of fireflies around his Elgin home just after Memorial Day.
“Then, it was like somebody flipped a switch,” he says, and they began showing up in larger numbers in late June after some rain.
Elsewhere — based on some very unscientific surveying on social media and by phone — people in some parts of the Chicago area have been seeing plenty, but many have hardly seen any at all.
Experts say firefly populations have been under stress for reasons that include bright lights, dry weather and things we do that hurt the environment.
Artificial light interferes with mating, says May Berenbaum, who heads the entomology department at the University of Illinois Urbana-Champaign. Female fireflies flash to attract males. Bright lights can block those signals.
Drought has an effect, too. Firefly larvae remain underground as long as two years, chomping on worms and soft-bodied insects. They need rain to help ensure an ample supply of food.
And chemicals can be deadly to these charming insects. Products that rid your yard of grubs also kill firefly larvae.
There’s more than just a single type of firefly. Actually, there are about 180 firefly species in North America, says Ben Pfeiffer, who founded the Texas nonprofit Firefly Conservation & Research in 2009.
In Chicago, we often see a bug nicknamed the big dipper firefly, for its pattern of flight and flashing that often forms the shape of the letter J, Pfeiffer says. It’s also known as the eastern common firefly.
After mating, females lay eggs in moist conditions. The loss of that just-right habitat is another reason some declines might be occurring, he says.
What helps? “They love dead wood, grass, vegetation,” Pfeiffer says.
If you haven’t seen them yet, the experts say fireflies still could emerge this month. Fingers crossed.
Brett Chase’s reporting on the environment and public health is made possible by a grant from The Chicago Community Trust.
