Scientists find how fireflies get their glow

London: Scientists have for the first time unravelled the firefly's intricate light-producing system.

Fireflies emit light when a compound called luciferin breaks down. It is known that this reaction needs oxygen, but what remained unknown was how fireflies actually supply oxygen to their light-emitting cells.

Using state-of-the-art imaging techniques, scientists from Switzerland and Taiwan have determined how fireflies control oxygen distribution to light up their cells.

The firefly's light-producing organ is called the 'lantern', and it is located in the insect's abdomen.

It looks like a series of tubes progressing into smaller ones and so on, like a tree's branches growing into twigs.

The function of these tubes is to supply oxygen to the cells of the lantern, which contain luciferase and can produce light.

However, the complexity of the firefly's lantern has made it difficult to study this mechanism in depth, and reproduce it for technological applications.

Giorgio Margaritondo at Swiss Federal Institute of Technology Lausanne (EPFL), Yeukuang Hwu at the Academia Sinica and their colleagues at the National Tsing Hua University in Taiwan have successfully used two sophisticated imaging techniques to overcome the complexity of the firefly lantern and map out how oxygen is supplied to light-emitting cells.

The techniques are called synchrotron phase contrast microtomography and transmission x-ray microscopy. They can scan down to the level of a single cell, even allowing researchers to look inside it.

By applying these techniques on live fireflies, the scientists were able to see the entire structure of the lantern for the first time, and to also make quantitative evaluations of oxygen distribution.

The imaging showed that the firefly diverts oxygen from other cellular functions and puts it into the reaction that breaks up luciferin.

Specifically, the researchers found that oxygen consumption in the cell decreased, slowing down energy production. At the same time, oxygen supply switched to light emission.

The study is the first to ever show the firefly's lantern in such detail, while also providing clear evidence that it is optimised for light emission, said scientists.

The research is published in Physical Review Letters.