Fireflies glow through this effect. The light emitted in this way is called cold light, because most of the energy is converted into light energy and only a small part is converted into heat energy. Because the conversion between luminescence and light energy is quite efficient, fireflies can glow for a long time. The firefly itself can also control whether it does this to control whether it shines.
2. The structure of the light emitter also makes the glow of fireflies brighter. The luminous organ of fireflies consists of several layers of cells. There are luminescent cells under the skin, and there are reflective cells under the luminescent cells, which can reflect the light emitted by the luminescent cells and make the light look brighter.
The fluorescence of fireflies is produced by the reaction between fluorescein and luciferase in the body. The researchers found that the isoleucine residue in luciferase can firmly grasp the luminescent substance produced by fluorescein oxidation, making fireflies emit yellow-green fluorescence. They also compared the three-dimensional structure of luciferase when fireflies emit yellow-green light and red light. The results showed that isoleucine residues were closely bound to oxidized fluorescein in yellow and green, but relatively loosely bound in red.