Why we’re seeing more fireflies light up Quebec skies – and how to find them

Julia Mlynarek, entomologist with the Insectarium, explains why we might be seeing more fireflies in Quebec right now.

Fireflies are lighting up the night sky, a sure sign that summer is in full swing.

If you think you’ve seen more of them in Quebec lately, you’re not wrong.

There’s been an especially strong showing of the glow-in-the-dark beauties this season, explained Julia Mlynarek, an entomologist with the Insectarium in Montreal.

“This year seems to be a particularly good year for fireflies, especially because of the rains we’ve been having, and they need to develop in wet habitats,” she said. “But we’re having a hard time knowing whether it’s a trend… there’s a lot of variation in the populations.”

Fireflies, Mlynarek explained, are beetles about two to four centimetres long.

Their evening glow is thanks to a chemical reaction involving luciferase and luciferin in their abdomen.

Luciferin is a light-emitting compound, and luciferase is the enzyme that catalyzes the reaction, making the light.

“It lights them up, but it doesn’t heat them up,” she said. “And so, that’s what creates that light that you see in the night.”

While their glow is a welcome sight on a warm evening, fireflies face environmental threats, said Mlynarek.

“There’s a lot of risks [for] them,” Mlynarek said. “There’s been some decline in the number of species and so, it’s really kind of hopeful to see them this numerous this year. At the same time, we have to be quite cautious about their presence... Light pollution, herbicides and pesticides actually can harm the populations of these beetles.”

Climate change may also play a role in firefly fluctuations, she added.

“I think especially in the insect world, we don’t have enough data to be able to really kind of determine how they’re affected,” she said. “But huge variations in droughts or... in rain can actually have big impacts on these beetles.”

Beyond their beauty, fireflies are also beneficial for gardens and the ecosystem.

“They’re predators as larvae, so they eat other insects in the leaf litter and the soil,” Mlynarek said. “Even as adults, they are predators, so they do eat. They can eat mosquitoes that are flying around in your backyard and other types of insects as well. So, they are beneficial in our backyards and in the environment overall.”

For anyone wanting to catch a glimpse of them, you can increase your chances by seeking out wet areas.

“The females lay eggs in wet habitats,” she said. “Wet meadows, big fields, around lakes… even in parks and city parks as well, you can actually see them, especially when there’s a lot of little bodies of water here and there.”

With files from CTV News’ Matt Grillo.