Today’s Wonder of the Day was inspired by Patrick from Grand Rapids, MI. Patrick Wonders, “How do fireflies glow?” Thanks for WONDERing with us, Patrick!
In the summer, have you seen lights in the night sky? We’re not talking about stars, or even the Northern Lights. Instead, we’re talking about fireflies.
Fireflies are sometimes called lightning bugs. They are known for their glow power, but they’re not alone. There are also deep-water fish and even bacteria that produce their own light. The fancy word for this is “bioluminescence.”
Fireflies never need to worry about changing a light bulb or paying the electric bill. Their light source comes from inside! A chemical change makes each blip of light. The reaction occurs between a protein called luciferase, a pigment called luciferin, and oxygen. When they combine, the firefly glows!
Most bioluminescent creatures glow all the time, like a light bulb with no off switch. What makes fireflies unique is how they turn their lights on and off. Researchers believe fireflies turn on their lights by sending signals from their brains to special light organs in their abdomens. Their abdomen is where the light-producing chemical reaction takes place.
So why do fireflies spend so much time flipping the lights on and off? Fireflies are born knowing how to glow as larvae. Some people call them “glow worms.”
Science believes bioluminescence serves a different purpose for larvae than it does for adult fireflies. The larvae contain chemicals that are yucky or even toxic to other creatures. As little worms, the light is more of a warning that alerts anything on the hunt for a snack that they should stay away.
For adult fireflies, science believes bioluminescence serves two purposes: to find a mate and to lure prey. Lightning bug blips happen in the blink of an eye. While we can’t tell the difference, female lightning bugs know what they’re looking for.
Research has found that female lightning bugs prefer “flashy” males. Some females prefer to mate with males that have the longest flash, while others prefer males that flash the fastest.
Scientists study the lightning bug’s glow-power. They have found ways to use luciferase. By putting this light-making gene into the cells of other animals, they can watch what happens.
This is an exciting discovery for the world of medicine. With more research, we might be able to make cancer cells glow so researchers can easily track and kill them.
Forensic science also uses luciferase. Investigators sometimes use a weak solution that has this firefly enzyme. When used at a crime scene, it can reveal tiny bits of blood the human eye might not see. That means fireflies can help solve a mystery!