Fireflies make dazzling comeback in NYC area for this surprising reason

It turns out the gloomy spring was good for something.

The metro area’s once-dimming firefly population has made a dazzling comeback this summer thanks to the abnormal amount of rain dumped on the region in the past few months.

“They need to have moist, wet environments. They do really well when there’s a lot of rainfall,” explained Dr. Jessica Ware, an entomologist and curator at the American Museum of Natural History.

“The extra rain, that extra moisture, that is really good for the juvenile [fireflies] — the juveniles develop into adults, and those are the adults that are moving around and flashing.”

While the wet stuff may have foiled plenty of human-made plans, it made for an all-out buffet of snails and slugs for young lightning bugs to feast on before burrowing in the moist ground to transform from their wormlike state into the illuminated critters that are synonymous with summer.

Scientists have not yet been able to quantify just how much lightning bugs are surging across the five boroughs and New Jersey, but it’s clear to anyone who takes a walk at dusk that the illuminated critters are floating around in stronger numbers than in previous years.

The flood of bugs can be directly linked to the nearly double amount of rainfall that was doused on the five boroughs alone this spring, with roughly 6 inches falling in May.

More than half the month — 18 days — recorded precipitation.

But the surge in fireflies this summer is also a trick on the eyes, Ware said.

“In general, populations are declining, so it’s not necessarily that we’re seeing more. It’s that we’re not seeing as few,” Ware said.

Fireflies are not considered to be an endangered or threatened species, but their populations have been seriously dwindling in recent years.

They face a series of hazards, including from insecticides and light pollution, the latter of which is a serious issue in the Big Apple.

As with migrating birds, lightning bugs become disoriented by overwhelming lights — and if it’s too bright, the fireflies are unable to see one another’s flashing bulbs, an issue with mating.

There also were fewer inches of rain overall in the Big Apple in the past two years, meaning fireflies were a rarer sight in the city — if anyone cared enough to notice.

“That’s the Joni Mitchell song, right? ‘You don’t know what you’ve got ’til it’s gone,’ ” Ware said, quoting the classic “Big Yellow Taxi.”

Fortunately, New Yorkers can expect the lightning bugs to light up the rest of their summer, especially for the remainder of July.

The fireflies are putting on their flashy and bright “teenage dance” to find their mates this month, with most of the action lighting up the sky at dusk.

“This is a peak time for them — they’re all going crazy with their hormones, but they’re just trying to get as many copies of their genes for the next generation as possible,” explained Ware.