Hot firefly summer: Why NYC may see more lightning bugs this year

Firefly populations in North America may be declining due to climate change, but New York City could experience more light shows than usual this summer.

The SUNY College of Environmental Science and Forestry's New York Natural Heritage Program is in the midst of a three-year survey to identify firefly species in New York state parks and provide guidance for maximizing firefly diversity. Katie Hietala-Henschell, a zoologist with the group, says that while the firefly population is facing threats from climate change, favorable weather conditions last year may be producing a bumper crop around the region this year.

“The wet summer that we had last year probably created good conditions for high survival rates,” she said in an interview. “The larvae need wet conditions and fireflies in general rely on moisture.”

As firefly season approaches its peak, Gothamist checked in with experts to assess conditions.

First, it’s helpful to clarify terms: Whether you call them fireflies or lightning bugs – they’re neither bugs nor flies. They’re beetles, and New York state is home to about 40 different species of them.

And Photinus pyralis, the firefly species most commonly found in New York City, seems to be thriving this summer, according to Hietala-Henschell.

“They are kind of slow, they fly kind of low and they have a lingering glow,” she said. Its nickname "the big dipper" comes from its J-shaped flight pattern.

Fireflies spend most of their lives underground in the larval stage. They eat snails, worms and slugs as they grow, Hietala-Henschell said.

Zoologists say they don't have enough data to confirm if there are more local fireflies this year or why that might be, though last year’s precipitation always helps.

Overall, researchers estimate that roughly 14% of species from Canada and the United States are threatened with extinction — a trend fueled by various pressures, including climate change, habitat loss and light pollution.

Hietala-Henschell says that while firefly populations are under threat, many species are not in danger of extinction, so she encourages kids – or even adults – to keep catching them. Just do it gently.

”They are like the squishiest of the beetles though, so do handle with care,” she said.

You can tell if you caught a male or female firefly by the size of its lantern. Male fireflies have a lantern in two segments of their abdomens, while female fireflies have a somewhat dimmer lantern in the center of their abdomens.

Hietala-Henschell says their light shows are best spotted at dusk, when the sun is at its lowest and the street lights have not come on yet.

And if the spectacle leaves you feeling inspired to help the insects, the U.S. Fish and Wildlife Service recommends keeping outdoor lights off, limiting pesticides and planting native flora in the yard. They also said you can help avoid displacing firefly larvae by keeping rotting logs where they are and leaving piles of leaves on the ground after you rake them this fall.

“The fact that people are seeing how impressive this light show can be, I'm hoping people get really excited and don't want to lose this natural phenomenon,” Hietala-Henschell said.

Correction: A previous version of this story mischaracterized the level of threat to the firefly population.