Fireflies or Lightning Bugs?

It’s the age-old question, isn’t it? Personally I’ve always said “firefly,” but the more I think about it the more “lightning bug” makes sense. I mean, it doesn’t look like the beetles are on fire, it looks like they have an electrical current running through their bodies that makes their abdomens glow like a lightbulb. Maybe they should be called “lightbulb beetles.”

Don’t worry, I’m not going to rename arthropods in every blog. Probably.

Fireflies are another one of my favorite childhood insects. My first memory of playing with fireflies is from back in my preschool days, when I was running around with some friends in their neighborhood at dusk. For some reason, I wanted to see how many fireflies I could catch at once, using one hand to hold my captives and the other to grab more. When I had so many beetles that I couldn’t open my hands without risking their escape, my dad made the unfortunate mistake of asking what I was holding.

As I mentioned in the roly poly blog, young me was not always gentle with tiny animals. I can only remember a handful of times when I have harmed bugs intentionally, but I probably killed at least half the arthropods I came across as a kid simply out of oblivious recklessness. Case in point, I’m surprised that Dad didn’t throw up immediately when I opened my hands. Half the fireflies were still crawling around and began to fly away, but the other half weren’t so lucky – my hands were white and gooey with beetle guts. Ugh.

Needless to say, Dad immediately whisked me away to the bathroom, where we spent the next five minutes washing and rinsing my gory hands. Since then, my experiences with lightning bugs have been much more pleasant.

I can remember many a summer night when a jar of fireflies glowed beside my bed as I fell asleep. In fact, making firefly jars was one of my favorite summer activities: I would dig a mason jar out of the pantry, poke some holes in the lid (much to my mom’s dismay), and drop in some grass and a few twigs. Then I would spend the rest of the evening chasing fireflies around the yard, often accompanied by my brother and our neighborhood friends.

My favorite firefly experience was in middle school, when a friend and I were backpacking with our families in the Blue Ridge Mountains. One night, while we were all sitting around the campfire, the dads called to us to follow them into the woods. We grabbed our flashlights and walked with them until the fire was a small glow in the distance. Then, they told us to turn the lights off.

At first it was so dark that I couldn’t see my hand in front of my face, so all of us kids huddled together and giggled nervously. Then, slowly, I began to make out soft, blue lights glowing in the distance. Soon the lights were floating all around us, like glowing feathers drifting on a silent breeze. I would later learn that these lights belonged to Blue Ghost Fireflies, a rare but fascinating summer inhabitant of the North Carolina mountains. To this day, that night remains one of the most beautiful moments of my life. 

If you’re anything like me, you’ve probably wondered how fireflies are able to glow in the first place, and why they do it – aren’t they just flashing their location to every predator in the area? Some fireflies must have thought about this too, because there are species that don’t glow at all. While glowing is often part of the fireflies’ mating rituals, the lightless beetles prefer to be a bit more discreet and rely on their sense of smell rather than sight to find their true love.

There are actually over a thousand different species of firefly, and each of the glowing species has a different sequence it follows for how often it ignites its light organ, or the “lightbulb” at the end of its abdomen. Fireflies can distinguish their own species from other fireflies by watching these sequences as if it were insect Morse code. In fact, females of a particularly deadly genus of lightning bug known as Photuris will mimic the codes of other fireflies to lure in unsuspecting males, which they promptly cannibalize. Gosh, and I always thought fireflies were so pure and innocent.

As for how fireflies glow, these beetles possess of one my favorite animal superpowers: bioluminescence. This fancy, beautiful word basically means that, like the glowing plankton you can find at some beaches or that scary angler fish in a certain clownfish movie, fireflies can emit light via chemical reactions in their bodies. Fireflies turn their light on and off by controlling how much oxygen enters their light organ. They regulate their oxygen intake via tracheoles, or little holes in their abdomen that allow air in and out of their bodies much like a trachea would in a human.

I’ll admit, even as an adult I sometimes chase fireflies around in the summer. I don’t usually put them in jars anymore, but if I’m walking my dog at night and I notice a yellow flash of light close by, I’m probably going to make a grab for it. Honestly, I’ll probably be catching fireflies, saving worms* from hot sidewalks and picking up granddaddy longlegs for the rest of my life. That’s just how ArthroBloggers roll.

*Yes, I know worms aren’t arthropods – I’m allowed to like annelids** too.

**But I don’t like leeches. Leeches creep me out.