Fireflies talk to each other with light.
Fireflies emit light mostly to attract mates, although they also communicate for other reasons as well, such as to defend territory and warn predators away. In some firefly species, only one sex lights up. In most, however, both sexes glow; often the male will fly, while females will wait in trees, shrubs and grasses to spot an attractive male. If she finds one, she’ll signal it with a flash of her own.
Fireflies produce “cold light.”
Firefly lights are the most efficient lights in the world—100% of the energy is emitted as light. Compare that to an incandescent bulb, which emits 10% of its energy as light and the rest as heat, or a fluorescent bulb, which emits 90% of its energy as light. Because it produces no heat, scientists refer to firefly lights as “cold lights.”
In a firefly’s tail, you’ll find two chemicals: luciferase and luciferin. Luciferin is heat resistant, and it glows under the right conditions. Luciferase is an enzyme that triggers light emission. ATP, a chemical within the firefly’s body, converts to energy and initiates the glow. All living things, not just fireflies, contain ATP.
Adult fireflies aren’t the only ones that glow. In some species, the larvae and even the eggs emit light. Firefly eggs have been observed to flash in response to stimulus such as gentle tapping or vibrations.
The glow from fireflies or lightning bugs comes from photic organs, or organs that produce light.
Fireflies combine three special substances in their photic organs to make light. The three substances are:
luciferin (a pigment),
luciferase (an enzymatic catalyst),
and ATP (nucleotide that provides energy to cells).
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