These small insects with belly glowing in the dark have been familiar to us since childhood. Personally, I was always curious: "So how do they glow?" Let's figure it out together ...
It turns out that this type of glow is called bioluminescence, and in fireflies it occurs as a result of the combination of intracellular oxygen with calcium, adenosine triphosphate (ATP) molecule and the pigment luciferin in the presence of the enzyme louciferase. This is scientific, and if simple, then in the body of fireflies, certain substances are produced, which, when interacting with oxygen, begin to glow. It is noteworthy that fireflies breathe, just not with lungs, like you and me, but with special tubes - tracheas, through which oxygen is supplied to the photogenic cells, which is so necessary for the oxidative processes taking place here. Sometimes the ability to glow is possessed not only by the beetles themselves, but also by their larvae and eggs.
The light emitted by fireflies is cold. Unlike a conventional electric lamp, where most of the energy turns into useless heat, and the efficiency is 5% - 10%, fireflies convert 87% - 98% of the energy expended into light.
The luminescence of these insects belongs to the visible yellow-green part of the spectrum, corresponding to wavelengths from 500 to 600 nm.
Many types of fireflies are able to dim and increase the intensity of the glow or emit intermittent light at will. When the nervous system of the beetle gives a signal to “turn on” the light, oxygen begins to flow intensively into the photophore (the organ of luminescence), and to “turn off” it is enough to stop the supply.
For fireflies, bioluminescence is a means of inter-sex communication. Insects not only signal their location, but also distinguish their partner by a special frequency of blinking. Tropical and North American species of fireflies sometimes perform whole choral serenades for their partners, flashing and fading at the same time with the whole flock. A flock of females responds to them with the same light and music.
Interesting fact: It is correct to call these insects fireflies, not fireflies as we used to!