Fade into the night: Fireflies facing threats from climate change and light pollution

Research associate at the University of Guelph fears that threats such as climate change and light pollution could snuff out these luminescent insects, depriving future generations of the "magic" they experienced as a child.

Aaron Fairweather remembers seeing fireflies as a child for the first time, a swarm of twinkles flashing across the surface of a lake near Saint John, N.B., illuminating a summer's night.

Fairweather, who uses they/them pronouns, was fly-fishing with their father at the time. Now, the research associate at the University of Guelph fears that threats such as climate change and light pollution could snuff out these luminescent insects, depriving future generations of the "magic" they experienced as a child.

"It's really sad to see that one of these childhood marvels -- these insects that make us say, 'Isn't the world incredible? These organisms can produce their own light and see how beautiful the natural world is' -- we're losing them."

While the number of fireflies has remained steady this summer compared with last year, overall numbers of these bugs have decreased by about 35 per cent over the last five decades, Fairweather said.

There are 173 species of fireflies in North America that have been identified by scientists, and 29 are found in Canada, said Candace Fallon, a senior biologist with the American conservation group Xerces Society, which is lobbying the United States government to extend endangered status to fireflies.

Fallon is the lead author of a study published in 2021 in the journal PLOS One, suggesting that up to one in three firefly species may be threatened with extinction and that some species might disappear before they are even discovered.

Wingless firefly females -- and sometimes larvae -- are known as glow worms, while the flying beetles -- usually male -- are known as fireflies.