The Phenomenal Firefly - The Mysterious Blinking Butts

Ahh, the firefly. Or for you country folk, the lighnin' bug. If we took a poll on who as a kid remembers catching fireflies on a summer night, the poll would undoubtedly release over 80% of readers' inner child. I remember being about 8 years old. My grandpa owned a farm and when I'd visit, it was one of my favorite things to do. I would grab a jar and go hunting. It always seemed like the best places were farther away from the house - until I got farther away from the house. Then, all the fireflies would seem to be around the back door! Yes, I was a country girl. There weren't many creepy crawling things that bothered me. Today, however, just the thought of a bug crawling on me gives me the heebie-jeebies. For a child, I knew the science of a firefly was quite a phenomenon. "How does his butt glow like that?" Yes, that was the extent of my scientific questioning. I was amazed when I realized those little butts could be robbed and turned into a really cool glow-in-the-dark ring for my little finger. Today, though, mortified is the correct term, when my son wanted to rip its tiny blinking butt off and stick it on his finger. With a sour face and clenching teeth I watched as my son did what so many children before him (including me) had done. I couldn't resist teasing him, though, with things like "Ew, you have a bug butt on you!"

All was well until my son, who's eight years old, turned to me and asked, "What makes it glow and blink like that?" Aren't we supposed to be able to answer each and every question our children bring up? I was supposed to know how these little butts blinked! So, I did what any mother of a bright (and now glowing) young boy would do. I got online to read about blinking butts of little bugs.

The more I read, the more confused I became. There are so many words to explain the traditional firefly that I could not even think about pronouncing all of them. But, I did find out that these brown, soft-bodied little bugs are actually beetles. One species of the firefly is Lampyrid. Females can often be distinguished from the larvae only because they have compound eyes. The most commonly known fireflies are nocturnal. After mating, the female firefly will lay her fertilized eggs on or just below the surface of the ground. Three to four weeks later, the eggs hatch and the larva feed until the end of the summer. Enter the glowworms! That's right The larvae are commonly called glowworms, though, do not confuse them with the distinct beetle family. Also, lampyrid larvae have simple eyes.

During the larval stage, fireflies will hide out during the winter months to avoid the cold weather. This is called "overwinter." Not so technical, right? That one was pretty self-explanatory (Thank Goodness!). Some do this by burrowing underground, while others find places on or under the bark of trees. They finally emerge in the spring, hence why spring and early summer are the best times for firefly hunting!

Now that it's spring, the fireflies pupate for one to two and a half weeks and emerge as adults. This is when we see the green and yellow flashes all around the yard at night. But, how? Light production in fireflies is due to a chemical reaction that occurs in specialized light-emitting organs, usually on the lower abdomen. To not make me look like a complete idiot, we'll call this the butt. The enzyme luciferase acts on luciferin in this organ to stimulate light emission. Luciferase is a generic name for enzymes used for bioluminescence while luciferins are a class of light-emitting biological pigments. Luciferase is also used in forensics!

Now that we know (somewhat) how a firefly's butt blinks, we must ask why. Adult beetles use their tiny blinking butts to locate other fireflies for reproduction. So, the next time you're at the bar, forget the pick-up lines! It's the blinking butts that gets all the girls. Yes, I said girls. This is because the flash patterns emitted by the species Photinus flying males are very unique when they're searching for female companions. Photinus females generally do not fly, but give a flash response to males of their own species.

Bioluminescense is a very efficient process. Some 90% of the energy a firefly uses to create light is actually converted into visible light. By comparison, an incandenscent electric bulb can convert only 10 percent of total energy used into visible light, and the remainder is emitted as heat.

Female Photuris fireflies are known for mimicking the mating flashes of other fireflies for the sole purpose of predation. Target males are attracted to what appears to be a suitable mate, and are then eaten. For this reason the Photuris female is sometimes referred to as "femme fatale."

In a nutshell, there are many different kinds of species when discussing fireflies. But, now, I have something to tell my son when he asks how their tiny butts blink!