One June evening, while walking down a street in Bengaluru, I froze in my tracks. In an unlit green patch that was informally being used as a dump yard, I could see stars twinkling a few feet above the ground. I looked closer and realised that it was fireflies, flashing their lights. It took humans so long to invent a light bulb, but fireflies have been making their own light since creation, and more efficiently than a light bulb! I couldn’t help but marvel at these amazing creatures and wanting to know more about them.
Where’s the fire?
The name ‘fireflies’ is used to refer to over 2,000 species of beetles. Fireflies produce their own light. This process is called bio-luminescence and it can be seen not just in fireflies but also creatures of the sea and even some types of bacteria and fungi. Light is produced in these creatures because of an enzyme called luciferase that helps in a chemical reaction that creates light. Scientists have discovered medical uses for luciferase in detecting diseases in the human body and tracking their spread. Earlier, lots of fireflies used to be captured to extract luciferase, but thankfully now this practice has been replaced by synthetic, laboratory-made luciferase. In olden times, coal miners also used fireflies trapped inside a glass bottle as a kind of lamp.
Light of my life
The light in the ‘lightening bugs’ is not just to look pretty. It has different uses in different species, or at different life-stages in the same firefly. Most firefly larvae produce a glow to send a warning to predators that they taste disgusting or are toxic. This helps both the predators and the fireflies. In adults, the flashing lights may be used to select a mate, depending on the rate and intensity of the flashes. Each species has a special signature pattern of flashing. But there are some cheating female fireflies that copy flash patterns of other firefly species to attract their males, and eat them as soon as they come close.
We must also remember, that not all these light-producing bugs can fly. In many species, firefly larvae and their females are flightless and are called glow worms.
Dark nights
The numbers of fireflies are reducing all over the world. Many forests and riverbanks that used to be their homes have been taken over by humans and their usage changed, hence they are no longer available for fireflies (and other wild creatures). Additionally, artificial lighting or ‘light pollution’ of the sky makes it hard for them to detect each other’s flash patterns, thereby affecting their ability to attract mates. But all is not lost. Fireflies can still be sighted at many different locations all over India.
If you can find or create a patch of greenery around your place with plenty of leaf litter, a small water body, and no electric lights in the evening, you may witness the magic of fireflies, in late May or early June.
Conservation and Nature is a series brought to you by Kalpavriksh Environmental Action Group (www.kalpavriksh.org)
