For 60 years scientists failed to decipher the mysterious chemical reaction that produces light in fireflies’ body.

However, the mystery has now been unravelled with the discovery of extra oxygen electron by the Connecticut College scientist Bruce Branchini and his colleagues at Yale University, a National Geographic report stated.

The extra oxygen electron is responsible for the fireflies’ natural light emission, the study found.

The experiments conducted by Branchini revealed that the oxygen involved in giving off the light comes in a distinct form called superoxide anion.

"Superoxide anion is a form of molecular oxygen that contains an extra electron," said Branchini.

The report also said that superoxide anion could also be the reason for the wonders of bioluminescence across nature– from plankton to deep-sea fish.

The findings were published in the Journal of the American Chemical Society and provides a comprehensive overview of biochemical processes occurring in the light illuminating insects.

"The way enzymes and proteins can convert chemical energy into light is a very basic phenomenon and we wanted to know how that biochemical process worked,” said Branchini.

In depth studies on fireflies would pave the way for more discoveries and is believed to open new exciting applications in medicine.