Byjus Logo

Why Do Fireflies Glow?

Team StoryWeavers|November 07, 2021, 03:34 IST| 1

During summer or the monsoons, you may have seen fireflies light up the night skies. And if you have been to the Western Ghats, there is a high chance you may have seen the evening sky illuminated by them. 

There are chances that you may have missed the first one when it shows up,but as more appear in the sky, it’s certainly scenic – all those bright beetle-like fireflies flashing their unique lights. 

For those who haven’t seen fireflies, they are not flies at all. They are insects that emit light from their bodies. And we are going to tell you how they achieve this. 

Why do fireflies glow?

Fireflies are insects that belong to a group of organisms that are ‘bioluminescent.’ It means they emit light from their bodies. 

During the day, they look like just another beetle with soft wings, but at night, they emit light.

Inside their bodies, there is a chemical reaction that makes them emit light. Their bodies light up because of a special organ in their abdomen that produces light. Also, the brightness of the light depends on the oxygen supply to these light-producing organs. 

Fireflies have acquired the ability to light up because of evolution

Experts believe that their ability to light up is due to evolution. 

How exactly does a firefly emit light?

As we mentioned earlier, fireflies have light producing organs near their abdomen. 

These organs store a protein called luciferin, which is crucial for these insects to emit light. And when luciferin combines with oxygen that’s present in the air, it becomes a compound called oxyluciferin. An enzyme called luciferase helps the reaction between luciferin and oxygen happen. 

And as this conversion happens inside the body of a firefly, light is emitted and the firefly gets its characteristic, natural glow at night. All this while, you may have been wondering – if all you need is oxygen to make the insect glow, why don’t we spot them during the day?

That’s because they are nocturnal insects that hide in tall grasses during the day. They are also tiny insects that you may not spot easily, unless you drop on all fours and actively look for them. 

Fireflies are nocturnal insects

How does bioluminescence help them?

Now that you know the process behind the glow, we shall look at how the light serves the fireflies. 

Younger and older fireflies mainly glow to ward off predators. The process is interesting, actually. These fireflies produce steroids that make them unpalatable. Through the glow, the larvae (younger ones) communicate that they are not very tasty to the predators and the attackers might as well pass! 

They identify their mates through the light that they emit

Older fireflies use the lights as a signal to mate with the correct species. Apparently, each species of these beetles have a unique glow and this is used as an identification mark for their mates to join them. With around 2,000 species, an identification mark is necessary, right?

How can humans benefit from fireflies?

Fireflies are indeed really fascinating insects. The way they use light emitting capacity in their everyday lives is simply genius! But did you know that human beings are working with this very property for biotechnology research?

Experiments have tried harnessing the light from fireflies using nanotechnology to produce light without using any batteries. Scientists from Syracuse University in the USA believe that this may be very efficient.

That’s cutting edge, isn’t it? 

We hope loved learning about bioluminescence and how fireflies emit light. Did you know that there are other animals that emit light too? 

Can you think of any? Let us know in the comments below. 

About the Author

Aparna is a mom, singer and dreamer. At BYJU'S, she writes stories about learning for children. She believes in the power of music, especially ghazal, the magic of the universe and happy learners. When not writing or singing, you will find her intensely engaged in conversations about life and the power of words.

Leave a Comment




December 1, 2021



Join 100+MN Registered BYJU'S Users

Book Your Free Class Now

Thank you!

Your details have been submitted