A new study of fireflies suggests a new model of how these beetles glow.Image credit: Emmanuelm, Wikimedia CommonsAs fireflies are delighting children across the country with their nighttime displays, scientists are closing in on a better understanding of how the insects produce their enchanting glow. They report in the Journal of the American Chemical Society new evidence of how the beetles' chemistry works. Their findings could apply to the bioluminescence of other organisms, too.

About 60 years ago, scientists figured out in broad strokes the cascade of reactions that allows fireflies to produce light. It starts with a chemical called luciferin, which interacts with the energy-transporting molecule adenosine triphosphate, or ATP. The product of that reaction then combines with oxygen, and this in turn releases light. Intermediate steps, however, have not been fully fleshed out. Bruce R. Branchini and colleagues wanted to explore potential mechanisms.

The researchers experimented with the enzyme luciferase, which boosts the initial reaction between luciferin and ATP, under varying conditions. In contrast to the commonly accepted model, the resulting data suggest that the transfer of a single electron to oxygen occurs during one of the final steps to spur light production. Other studies of bioluminescence have pointed to the same mechanism, raising the possibility that it could be a unifying feature of the natural phenomenon.   

The authors acknowledge funding from the U.S. Air Force, the National Science Foundation, the Hans & Ella McCollum '21 Vahlteich Endowment and the U.S. Department of Energy.

To see the scientists re-create the firefly glow in the lab, click here.