I’m so happy to be home, especially because the first firefly of the summer was out last night!

Fireflies create their glow with the help of a protein with the awesome name of luciferin.

Why do they glow? SEX. If you watch for a while, you’ll notice many different patterns of flashing.The photo on that webpage shows the results of time lapse photography from some classic research. Different species have different flash patterns (except for a sneaky predatory mimic, who can lure unsuspecting males to their death). The flash is the firefly way of saying “Yo, Baby! Check out my shiny elytra!”

The female replies with a flash, usually from a safer perch in the grass or a tree. I won’t tell you what she says for modesty’s sake :)

You definitely want these fellows in your garden, since the larvae (and some adult species) are predatory.

There’s been some concern about a decline in fireflies from past years–general consensus is that there does seem to be a decline, and that habitat loss is probably to blame. Work is ongoing to quantify the numbers, and to verify the decline.

This article does an awesome job of explaining everything firefly, and also discussing the type of habitat they like best–dampish to swampy.

Enjoy the magic!

Posted by Gwen Pearson

Writer. Nerd. Insect Evangelist. Have you heard the good news? BUGS!


  1. I really like fireflies. I doubt I’ll make it out to Iowa in time to see them this year, though. Here in Colorado, we sometimes get a couple, but I’ve seen exactly two in the last 10 years.

  2. Thanks for the link… I had a very fun time trying to picture them at night (pix are at Pittsburgh, in 2006).

    As far as I know, I think their populations are fluctuating a lot, there are a lot more then last year in here (Pymatuning, PA): at least five times more if not better…

  3. That’s great news!

    This year is clearly better than last year–we had a lot of rain early in the season, although it’s very dry right now.

  4. I’ll tell you what I do have this year in the way of bugs, though: Aphids, Locusts and Earwigs.

    Good times.

  5. We have had fireflies out for about a week and a half now. The numbers seem a bit down from recent years, but nothing too alarming. It’s being a great year here for butterflies.

  6. […] of DDT.  (See my post of May 24 and the item titled “The War on Rachel Carson.”)  See also this post on fireflies and links from the cool “Bug […]

  7. hi. by any chance, do you know if there are any guides to breeding fireflies? =)

  8. Since you appear to be from outside the United States–nope. I suspect it would be difficult, since they are typically predaceous and need high humidity.

  9. can you point me to any directions that could help? it may be difficult but i might be able to find some ways.

    thank you.

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