Theirs is a world of mystery and magic. Has development snuffed out fireflies?
They looked like stars that decided to fly down to earth for the night. It took a while for my mind to register them as insects that carried light on their bodies — fireflies. They could be seen in clumps along the densely wooded path at the tiger reserve. Sprinkled like sparkles, a little here and a little there. The fireflies hovered about, talking to each other with light.
What are they telling one another? That they are ready to mate and start a family. The light flash is primarily used by male fireflies to attract a female. Naturalist ‘Poochi’ Venkat says that a female chooses one among the many males that flash to get her attention. The nightly display of fireflies, however, has other stories to tell — that of deception and mystery.
It is interesting to note the way fireflies use their lights to grab the attention of those in their community. In The Insects – An Outline of Entomology , Penny J. Gullan and Peter S. Cranston speak of how the duration, number, and the frequency of flashes are “species-specific”. A male “advertises his presence” with a flash or more and the female responds to him with a flash — she has a manner of flashing that’s unique to her species. These signals are sometimes mimicked by a carnivorous female of another species, says the book. She lures a male and eats him up!
There have not been serious studies on fireflies in India so far; as a result, their world remains vastly unexplored. This lack of information makes them more intriguing. In Fundamentals of Insect Life , C.L. Metcalf and W.P. Flint explain the mechanism behind the formation of light in these insects. The substance that produces light in fireflies is called ‘luciferin’. “It is formed in certain specialised cells of the insect body….When air is admitted under the control of the insect, the combustion of luciferin takes place in the cells that produce it and the production of light is instantaneous,” they write. This light has a special quality. For, it emits no heat rays, say the authors. The energy is entirely converted into light. In a gas flame or an incandescent bulb, for instance, most of the energy is lost as heat.
Apart from the wild, the insects can mostly be seen at the fringes of urban spaces and rural areas where the air is pure. Venkat says that their presence is an indicator that the area has “good atmospheric conditions”. For, they need a balanced eco-system where “everything is in its natural form” to survive. Fireflies are often elusive to photographers. Macro photographer K. Jayaram who has a frog and spider species named after him, says that he has never been able to capture them on lens. Their “light intensity is very low” to be photographed, he says. Perhaps the current crop of lenses will help? Karthik Muthuvali, an upcoming macro photographer says that even with cutting-edge technology, photographing fireflies is “very difficult”. For their light is visible only when they fly out at night and use of the camera flash “nullifies it”, he feels. But there are photographers such as Radim Schreiber who has shot the insects in action. “It wasn’t until new advancements of low light capabilities of the latest camera equipment were sufficient enough to photograph fireflies,” he writes in his website fireflyexperience.org.
Jayaram was witness to “billions of fireflies one night in the jungle.” It was a night he would never forget: It was around 1985 and he was high up in Top Slip. An unworldly display unfolded before him. The fireflies arranged themselves in four-tiers, each consisting of thousands. Each tier lit up one after the other, flashing with fascinating synchronisation. “They appeared to be doing sorties like aircrafts,” he remembers. It has been long since Jayaram saw something similar. “Their numbers have reduced,” he says. He attributes this to habitat destruction and population increase. Ace photographer T.N.A. Perumal too feels that there has been a “general decline” in the population of fireflies. He recalls seeing a “firefly orchestra” some 20 years ago in Nagarhole during the wet season. “They flashed on and off like lights on a Christmas tree,” he recalls. The flashes were beautifully synchronised. “How did they do it?” wonders Perumal. “It’s a mystery.”