A flash in the dark

“Where are the fireflies?” read a Facebook post from my friend, Jen, early this month. The question surprised me; weren’t the fireflies out already? But no. The minute I read Jen’s question, I realized that I hadn’t seen any fireflies yet myself. I commented on the post, suggesting that maybe it had been too cool recently. Then several other people asked me independently about the same phenomenon.

Finally, one evening a week ago, walking back on the French Creek Trail in East Pikeland Township, Charlie and I saw fireflies rising up out of the tall grass on the sides of the trail. Beautiful! But there weren’t many of them, and in my own yard I’ve only seen a few at a time where normally I’d expect to see easily a hundred.

What is going on? Are firefly populations in decline in our area? Over the past ten years or so, I’ve heard that this has been happening elsewhere. But as long as the little beetles continued to spark up the nights here, I didn’t think too much about it. Time to learn more!

There are upward of 2,000 species of firefly; about fifty of them occur in the United States. “Our” firefly here in Pennsylvania is Photuris pennsylvanicus. It happens to be our state insect, chosen through the efforts of elementary school students in Upper Darby. They heard that Maryland had adopted a state insect and they thought that Pennsylvania should have one, too. The firefly was formally adopted as our state insect by the Pennsylvania General Assembly on April 10, 1974. (Details at http://bit.ly/2rzlJkU)

It would be hard to find a cuter candidate for the job. Fireflies are relatively small, silent, do not bite, do not carry disease, don’t invade houses, don’t demolish crops or other plants, and only fly in the evening and at night. We probably wouldn’t even notice them at all if they didn’t look so magical, sending their flashing signals as they look for a mate. Fireflies are also fun to catch and observe; they are easily removed from the underside of a leaf or caught right out of the air with only your hands.

Living on the East Coast my entire life, I’ve been treated to the spectacle of fireflies each summer, but only once have I seen a glow worm — the larval form of the adult beetle. At first, I thought it was a cigarette butt that had been carelessly tossed from a car window and landed in the leaf litter, still burning. Lucky for the glow worm that I decided to look more carefully before grinding out the “cigarette butt.”

For years, I’ve told people that there are no fireflies in the west. Turns out that’s not exactly true. Fun firefly facts courtesy of the Smithsonian Institute reveal that the reason I never saw fireflies in my travels in the Rockies and beyond may be because western fireflies lack the ability to produce light. (http://bit.ly/2rqKdfE)

When I “Googled,” “where are the fireflies,” I discovered that every spring people flock to Elk-

mont, Tennessee, in the Great Smoky Mountains, to witness a remarkable phenomenon: the simultaneous flashing of synchronous fireflies (Photinus carolinus). That’s something I would like to see, and apparently others feel the same way. There are so many people who want to witness the event that the National Park Service requires people to apply for parking permits,

via a lottery system that awards 225 passes a day for the eight-day peak activity of the fireflies. (http://bit. ly/2rMGeyH)

In my searching I did also learn that yes, fireflies are declining. Next week I’ll share the suspected causes and what can be done to help these insects.

Note: Regarding the story of the black swallowtail caterpillar (From the Ground Up, June 1, 2017), I’ve posted a final update and photo to my Chester County Roots Facebook page. Check it out.

Pam Baxter is an avid organic vegetable gardener who lives in Kimberton. Direct e-mail to pamelacbaxter@gmail.com, or send mail to P.O. Box 80, Kimberton, PA 19442. Join the conversation at “Chester County Roots,” a Facebook page for gardeners in the Delaware Valley. Go to Facebook, search for Chester County Roots, and “like” the page. To receive notice of updates, click or hover on “Liked” to set your preferences.