Walking around in the evening and suddenly you see a flicker of light flying around. Do you guess what’s that? It’s yet another firefly flying past you. On a pleasant evening, you might see dozens or even hundreds of fireflies flying, flashing their mysterious lights. Fireflies, commonly known as lightning bugs, interestingly are neither flies nor bugs. They are the parts of the Lampyridae family or they are beetles with soft wings. They often pay a visit to a backyard, park or garden as they thrive in grassy and humid climates. The starkest fact about them is that they can produce light, which is quite rare. People often get confused about why do fireflies glow at night.
How Do They Glow?
The bodies of fireflies produce a chemical reaction inside them which allows them to light up. This light production is called bioluminescence. The light produced by fireflies is the most common instance of bioluminescence. In fireflies, when the combination of calcium, oxygen, adenosine triphosphate and a chemical luciferin takes place in the presence of luciferase, a bioluminescent enzyme, light is produced.
There is a big difference between the light produced by a source like a bulb and a firefly. A bulb produces ‘hot light’ which emits a lot of heat in addition to light, whereas fireflies produce ‘cold light’ which doesn’t produce a lot of heat. This is very important for the insect as if the light would produce a lot of heat, the firefly would become hot and would not be able to survive the situation.
Most fireflies create a distinct greenish-yellow flash while some species make an orange or yellow glow. Some views say fireflies glow up in different colours for better adaption to their surroundings.
Why Do Fireflies Glow At Night?
Different species of fireflies produce light for a variety of reasons.
- The primary of them is for mating purposes. Typically, a male will light up and send signals to several females for seeking the perfect partner. They send different patterns of flash and once a female finds the male attractive, that too depending on the light and lighting patterns, then she emits her signal to the male. Studies have suggested that males with specific flash characteristics such as higher flash intensity and higher flash rates are much more attractive for females.
- Secondly, the flash also acts as a way to catch the prey. Female flies emit the light to catch the attention of males and eventually eat them up. Yes, they do eat their own species as well.
- Another reason why do fireflies glow up at night is to protect them. Whenever they sense some kind of danger, they use their glow to warn their predators and defend themselves.
- The glow also warns the predators that potentially they are not a tasty meal. Fireflies produce defensive steroids in their bodies which has an unpleasant taste. Young larvae use their glow to display their distastefulness.
Also Read : Why Are Insects Attracted To Light?
The flash of fireflies is primarily visible at night although many species emit light throughout the day. Due to the natural light, their glow is most often not visible and that’s why people think why fireflies glow at night.
Adults of few species do not emit light at all and use pheromones for communication. Emitting light in fireflies has been seen as a recent development. Some species may emit their lights for many hours a night, while some may light up just for 15-20 minutes. Some of them have several systems for signalling while few may use their light organs for other purposes.
The beauty of a dark night increases manifold when a herd of glowing fireflies passes by you and you just watch and adore them.