This summer felt different than past ones. All of a sudden, I had something new to look forward to every night. Early in June the first faint flashes of lightning bugs appeared in the garden, and suddenly I was a kid again staring in wonder as they lit up across the sky. How could I have missed them all these years?
I’ve always liked them, and I even knew a bit about their life cycle, but this year something shifted. Each evening I’d quietly watch this little spectacle take place. I observed the movements, the length and color of flashes, and then I’d come inside and look up everything I could from what I saw. I’d tell my wife everything I learned—until she surprised me with tickets to an evening lightning bug walk at Tyler Arboretum.
It was an incredible event. The guide equipped us with red gels for our flashlights, gave us a quick scientific overview, and then said: “just call them out when you see them.” I spotted the first one— “southeast!”, I said, pointing toward the woods just off the path. One tiny spark. And then—a dozen or more.
As the night went on, we saw hundreds, maybe thousands, filling the woods with the intermittent light and sparkle of their mating ritual. All night I was struck with wonder. Surrounded by the oaks and beeches and other native plants that have long captivated me, it was like a new little spot opened in my brain and I finally understood what a gift these little lightning bugs are—these beetles that lure us into curiosity and wonder.
I’ve been joking that lightning bugs are a “gateway beetle.” They invite us in with their magic and once we start reading, observing, and learning about them, a whole other world of beetles opens.
The Science
Here’s what I’ve discovered. Lightning bugs belong to the family Lampyridae. There are over 30 different species in the Mid-Atlantic region, and somehow there are nearly 60 species in Florida, though I don’t remember ever seeing them in the coastal city I grew up in. Their bioluminescence comes from a specialized organ on the underside of the abdomen, where oxygen reacts with a pigment called luciferin. With the addition of the enzyme luciferase, this reaction releases tiny bursts of visible light.
They go through a complete four-stage metamorphosis: egg, larva, pupa, and adult. As larvae, lightning bugs live underground for as long as two years, preying on soft-bodied invertebrates like slugs, snails, and worms. After pupating, they emerge from the soil as adults but only live for a few weeks—just long enough to reproduce and fill our evenings with light. And different species signal in different ways. Photuris pennsylvanica — the state insect of Pennsylvania — is one of the most recognizable lightning bugs in the Mid-Atlantic region. It has a bright green-yellow “dot-dash” flash pattern that consists of a quick and short flash followed by a longer, hovering flash that lasts for a few seconds.
How to Support Them
Globally, insects are under immense pressure. An article from the Xerces Society states: “In addition to the data supporting the decline of insect populations, patterns are emerging that point to the primary drivers of insect declines. The most influential factors are habitat loss and degradation, pesticides, and climate change, although other factors include disease, invasive species, and light pollution.”
If you want to create habitat that supports lightning bugs — and countless other insects — plant native. I can’t stress this enough. Plant native keystone plants. Remove invasives on your property and limit the amount of non-native ornamentals. Put lights on timers or motion sensors to support insects at night. Make clean water available. If you do those things, you really will see an abundance of wildlife and biodiversity. And next summer, if you’re lucky, you’ll be rewarded with the nightly glow of summer’s most magical insect.
