Fireflies: Jewels of the night

Two fireflies

Photo credit: Whitney Cranshaw, Colorado State University, Bugwood.org

Spotting a firefly on a warm summer night is a magical sight. While they’re only the size of a paperclip, their small flashing bodies quickly catch your eye – a reason why they’re also called lightning bugs.

Fireflies aren’t actually flies, but a type of beetle. If you’ve ever wondered how to tell if an insect with the word fly in its name is actually a fly, use this tip. When the word fly and the descriptive word are stuck together such as firefly, mayfly and dragonfly, these insects are not actually flies. When there’s a space between the descriptive word and the word fly such as hover fly, horse fly and house fly, the insects are true flies.

Photo credit: Jon Yuschock of Forestry Images

Firefly populations are declining in North America. This decline is believed to be largely due to wetland habitat loss and light pollution. Most firefly larvae depend on moist habitats near wetlands, streams, and ponds. It’s in these areas where fireflies find their food, including slugs, snails and other soft-bodied invertebrates. Light pollution affects a firefly’s ability to find mates. Their characteristic flashing light patterns are easily disrupted by manmade light at night.

Unfortunately, fireflies in Canada are not very well studied. They’re hard to identify and not commonly collected or reported on, so we don’t know enough about any of the 23 species of fireflies in Ontario to determine their populations trends. As a result, we’re unable to identify which species may be of conservation concern.

You can help collect data on fireflies with Firefly Watch. This citizen science project aims to fill the gaps in firefly data in North America. Participants look for fireflies for 10 minutes each week during firefly season. You don’t need to be able to say what species you’re seeing to submit your data to Firefly Watch, but they do ask you to identify how many different flash patterns you’re seeing.

Photo credit: Jessica Louque of Forestry Images

The Xerces Society for Insect Conservation also recently launched a firefly conservation campaign, called Conserving the Jewels of the Night. Their website has great resources on fireflies, including information on their biology, threats they face, conservation efforts and how you can help.

Have you ever spent a summer night watching fireflies? If not, now’s the time. Firefly season peaks in July in Ontario. Don’t forget to take pictures and share them with us on Instagram, Twitter and Facebook.

Learn more about insects in the Credit River Watershed here.

By CVC’s Kimberley Laird, Subject Expert: Laura Timms

Comments (5)

  1. Delightful! When living in Chile in the late 70’s, I witnessed miniature ‘waterfalls’ of fireflies in nightime gardens. I’ll never forget the sight.

  2. We have been seeing more than normal amounts of fireflies in our yard this year so are very happy they are making a comeback. Will check out your links for Firefly watch and more information on how they create their glow.

  3. Last night I spotted a little blinking light between my open window and the screen. A firefly!! I am on a ravine near a branch of the Credit and have seen them in years past, not so much recently. When I went to bed I am pretty sure there was a little blinking light floating around that side of my house. Thank you for the timely article – now I know what that blinking light is attached to!

  4. I’ve never seen so many fireflies as in this summer. We have a pond that may be attracting them. Some nights our mugo pine looks like it is lit up with twinkling Christmas lights! I also see them amongst our maple tree. Some are very bright too.

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