An online resource based on the award-winning nature guide

Winter Fireflies Emerging

2-24-14  winter firefly 316After pupating in a rotting log, adult Winter Fireflies emerge in late summer and are often seen on the trunks of trees. When the temperature starts to drop, they crawl under tree bark for the winter. They stay there until late winter/early spring when they reappear. Considered a pest by some sugar makers, they’ve been said to “circle around sap flows on maples like cattle around a trough.” Although the adults do not possess the bioluminescence of the firefly species we see in the summer, the larval and pupal stages of Winter Fireflies do produce their own light.

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6 responses

  1. Cara Washburn

    Hmmm, interesting little organism of magic, no?

    February 24, 2014 at 12:16 pm

  2. cathq75


    How big are these critters? We have some new visitors that look similar, have hard brown shells, move very slowly, and are nearly an inch long. Any ideas?

    So nice that you could join me for Marie’s BD! Let’s make it an annual event:)

    Xoxo Charlotte

    Sent from my iPhone


    February 24, 2014 at 12:52 pm

    • Hi Charlotte,
      Winter Fireflies are roughly 1/2″ long…any chance you could send me a photograph of your insect? I am having a hard time coming up with what you might have seen, other than a western conifer seed bug ( see p. 260 in Naturally Curious). .A definite yes to M’s b’day – thank you for including me!

      February 24, 2014 at 1:52 pm

  3. dellwvt

    So . . . I’m taking it that these are a different species from “summer fireflies”? How interesting! Do they sneak back under the bark for the rest of the winter, when it gets colder? Do they have some sort of “antifreeze” in their innards, to protect them? (Is that how many insects that overwinter in trees manage?) When do theY breed? (So many questions come to mind – so many things I don’t know!)

    February 24, 2014 at 2:48 pm

  4. I also see these on warm days in late fall when little else is about. I always welcome their visit, but then I don’t tap my maple trees. 🙂

    February 24, 2014 at 2:50 pm

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