Posts tagged lightning bugs

What do lightning bugs eat / An Evening with Fireflies

     An upcoming event at the Indian Creek Nature Center prompted me to call one of our awesome entomologists at Iowa State University. The Nature Center is having a walk at 8 p.m. Friday featuring one of my favorite insects –  the lightning bug!  

Lightning bug/ David Cappaert, Michigan State University,

Lightning bug/ David Cappaert, Michigan State University,

    What’s not to love about lightning bugs? They light up dark summer nights with their intermittent flashes and unlike other nighttime bugs, they don’t bite – in fact, they kind of tickle when you catch them. Best of all, in their younger stage, they eat slugs and other pests. 

Lightning bug larva/ Gerald J. Lenhard, Louisiana State Univ.,

Lightning bug larva/ Gerald J. Lenhard, Louisiana State Univ.,

   I wrote about lightning bugs last year after attending a workshop led by ISU entomologist Donald Lewis. Until then, I had no idea that  lightning bugs, as larvae, dined on not only slugs, but other insect larvae and snails – a real beneficial beetle! But I’ve had a nagging question since then: what do adult lightning bugs eat? After all, kids catch lightning bugs all the time, put them in a jar, punch holes in the lid and throw some grass inside. So do lightning bugs eat grass??

   Probably not, was the answer.  Donald Lewis said, if anything, they might occasionally feed on nectar. Some female species of lightning bugs use the signal of a different variety of lightning bug to attract males, and then, well, the male doesn’t become their mate, but their meal!  So, that’s what that species eats, but, he said, most adult lightning bugs appear to not eat much of anything.

   As an aside, he noted that punching holes in the lid of a jar might be more harmful to lightning bugs than leaving the lid intact and not-too-tight on the jar. Lightning bugs come out at night because they need a certain level of humidity and would basically dry up in the hot summer sun. Punching holes might allow too much air into the jar and also dry out the bugs. Safest bet might be a catch and release method. Get a good look, admire their flashing lights and let them fly free.

     Here’s some info about Friday’s (June 5, 2009) walk:   An Evening with Fireflies, Indian Creek Nature Center, 6665 Otis Rd. SE, Cedar Rapids. 1 ½ mile walk on grass-surfaced trails. Members, $3; non-members, $5. Children, $1. For more details, see: or call (319) 362-0664.

    REMINDER: Remember to stop by the Gazette/KCRG tent between 9-10 a.m. Saturday (June 6, 2009) at the Downtown Farmers Market in Cedar Rapids. Sign up for the drawing (rattles, corn-made dishes and other baby items courtesy of Dandelion Earth Friendly Goods) and let me know what you’d like to see on the Homegrown blog and in The Gazette. The tent will be in Greene Square Park, along 4th Avenue, close to the corner along the railroad tracks. See you there!

Comments (2) »

Lightning bugs eat WHAT??

Who doesn’t like lightning bugs, the quintessential sign of summer? Of all that I learned at Saturday’s Winter Gardening Fair, my favorite tidbit is another reason to love this beneficial beetle. The next time my kids ask what lightning bugs eat, I’ll know, thanks to entomologist Donald Lewis, whose session, “The Good, the Bad and the Buggly,” was one of three workshops I attended at the gardening fair.

Here’s more of what Lewis, from Iowa State University’s extension, had to say.

On earwigs:

It’s a myth that earwigs crawl into a sleeping person’s ears to lay its eggs and they don’t burrow into your brain (whew!) Their name comes from a habit they had in the damp castles of Europe of crawling into the white wigs of the castle’s inhabitants and then wandering into the wig-wearer’s ears. Of more relevance to our time,  earwigs, identifiable by pincers on their tailend, are both beneficial, as they feed on decaying matter, and a pest, as they also nibble on foliage.

White grubs and Japanese beetles:

White grubs are the larval stage of various types of June bugs. Most of those in Iowa are the “masked chafer,” and more and more, the dreaded (editor’s note) Japanese beetle. The grubs live in lawns and chew the roots off grass. Secondary damage is done when raccoons and skunks scavenge for this “land shrimp” and tear the turf to get at the grubs. Moles, by the way, don’t indicate that your lawn has grubs. Their favorite meal is earthworms. There are various chemicals to rid lawns of grubs and to spray on the adult beetles, but just getting rid of the grubs won’t eradicate problems with the adults, because even if your lawn is grub-free, adult beetles – Japanese beetles, at least – can come from far away to dine on your roses, raspberry bushes and 350 other types of plants. Hand-picking the adults works best when done early in the season, as their chewing releases a scent to other Japanese beetles of where to find their next meal. Lewis said what you do with them after you pick them off is your choice: hammer, etc. Mine is to knock them into a container of soapy water. If you use plain water, they can swim around for several days and be none the worse off for your trouble.


 Aha! This is where the lightning bugs come in. Placing copper strips or pennies in your hosta – a favorite target of Iowa’s gray garden slugs – hasn’t been proven to prevent the slugs’ damage. But lightning bugs, in their larval stage, prey on slugs. Lightning bugs also eat other insect larvae and snails. What a beneficial beetle!

There was so much more I learned at the gardening fair. From Linn County Master Gardener Lu Barron – you might know her as one of our Linn County Supervisors – I found out why my peonies might not be blooming. Too much shade, too much competition from other plants, buds nipped by a late frost or too much nitrogen fertilizer are among the possible reasons. I also learned the best way to plant peonies – with eyes 1 to 2 inches below the soil line.

All of the presenters undoubtedly put quite a bit of preparation into their sessions, but I don’t know of anyone who had more work to do than Master Gardener Nancy Sutherland, who labeled and bundled dozens and dozens of tiny dried flowers so each of the attendees at her “Everlastings” workshop could leave with a whole box to take home and examine. Sutherland and other Master Gardeners can be found at the Lowe Park demonstration gardens in Marion, as soon as the weather warms.

Finally, what a great presentation by keynote speaker, Melinda Myers! Some of my previous posts (including excerpts from my interview with Melinda, if you want to hear her for yourself) address her topic of attracting butterflies and birds to your garden.  But I think my favorite quote from her speech was about how to get children interested in gardening. “Even if you don’t enjoy them, bugs get kids in the garden,” she said. “And the creepier the bugs are, sometimes, the better.”  

Comments (1) »