Here come real stars to fill the upper skies,
And here on earth come emulating flies,
That though they never equal stars in size,
(And they were never really stars at heart)
Achieve at times a very star-like start.
Only, of course, they can’t sustain the part.
–Robert Frost, “Fireflies in the Garden”
The warm glow of fireflies—also called lightning bugs—may seem magical as it fills the summer evening skies. However, that’s not magic behind their blinking yellow lights. It’s a fascinating chemical reaction that scientists have been able to use to study important events that take place in the cells of many living things.
Fireflies use their flashing lights to ward off predators, attract a mate and identify themselves to others of their own species. Their glow is what scientists call bioluminescence, a fancy term to describe the biochemical production of light by living things. In the case of fireflies, these little bugs make a chemical called luciferin and a protein called luciferase. These lightning bugs control the light flashes by releasing oxygen which, when combined with other chemicals, causes their bodies to glow.
Scientists also have multiple uses for the very same luciferase reaction. They can artificially manufacture the ingredients that make up the chemical reaction to study how genes are activated in living cells. Using the luciferase reaction, scientists can also watch biological processes in living beings in real time. They can even use the chemical reaction to test food safety.
Recreating the glow of lightning bugs is an excellent example of how the study of one small organism can lead to potentially huge advances in human health. Without the “magic” of the firefly luciferase reaction, we might still be in the dark about so much that happens in our cells.
Interested in fireflies and science? Become part of the Firefly Watch Citizen Science Project to help scientists study changes in firefly populations.
Audrey A. Vasauskas, PhD, is an associate professor of physiology at the Alabama College of Osteopathic Medicine. She is a former volunteer editor for the I Spy Physiology blog.