Photo By Terry Priest / CC BY-SA 2.0

What Makes Them Glow?

On those nice spring, summer, and early fall nights, its hard to miss the glow of fireflies in the night. Fireflies are not just beautiful, but many children have fun trying to catch them, and keeping them as pets in a jar. People even travel from all over the world to come see them in the Great Smokey Mountains as they, once a year, all gather together to light up the sky together. But what makes them glow? And why do they all gather in the same spot one a year?

The reason they are able to glow is because of a chemical reaction in their abdomen. Things like oxygen, calcium, magnesium, and a naturally occurring chemical called luciferin are some of the chemicals inside that create this light. This reaction that causes light isn't just something simple however. It's very complex, and something that has baffled scientists for nearly 60 years! The main problem is the fact that the luciferin and oxygen are somehow, which most scientists have always thought was impossible. Without getting to confusing, the reason the firefly is able to defy logic is because when the oxygen enters the firefly abdomen, it gets an extra electron, making it possible to react.

So, why do they all gather in the Great Smokey Mountains every year? Well, this phenomenon is called the FireFly Shuttle, and it is part of a mating ritual. The males and females gather from all around. The males synchronize their flashing pattern, and the females synchronize their flashing pattern. This makes it obvious to each firefly which one is a male, and which one is a female so a mate can be chosen quickly.