“Fireflies and Environment”

Dark can be silent and may not be everyone's preferred habitat, but a little firefly can illuminate the dark with its lighting luminescence and perfectly glow up the environment. I grew up in rural part of Chennai surrounded by a sacred grove, two lakes, 7-8 small ponds, 40-45 round wells, , and a copious 100 acres of agricultural land in my neighbourhood. Since my childhood (the early 2000s), the two lakes in our vicinity catered to the needs of our people in several ways like a playground during summer, a fishing ground during monsoon, a source of water for domestic use and agriculture, an open swimming pool for the kids and a place of recreation for elders in the evenings. My first acquaintance with fireflies goes back to my childhood days when there were much darker places, fewer street lights with sodium bulbs, and remnant vegetation near my home. Our lakes and barren agricultural land are their prime habitat; we see fireflies slowly moving, emitting light, glittering like gold after sunset in the post-monsoon months of Margazhi and Thai (Dec-Feb) in Chennai. Me and my friends used to collect them, strangle their bellies, and cage them in the Horlicks glass bottle with multiple small holes on the lid. We used to call them hide-and-seek insects; if we touch them, they stop emitting light and hide somewhere in the bushes. We played with those magnificent flies without realizing their ecological significance, eventually leading to their death after few days, instilling remorse in me.

Fireflies are known to be photophobic, soft-bodied, light-emitting nocturnal species demanding a clean and healthy environment (including water, land, atmosphere, and air). They require clear land (soil) to produce eggs and larvae, and a clear sky to attract the females. The life cycle of fireflies shows an intricate relationship with its external environment. Fireflies are unison species, meaning they synchronize their flashing patterns. Rain plays a significant role in their lifecycle, influencing each stage from egg to adult. The emergence of adult, light-emitting fireflies from the larval stage mainly depends on rain. Any shift in rain patterns can affect their emergence, potentially delaying it until the next rainfall.

As a part of the Fireflies ecology project at the Advanced Institute of Wildlife Conservation, Chennai, I had an opportunity to visit the Anamalai Tiger Reserve from April 15 to May 22, 2024. This period is called the season of synchronized firefly movement. I heard about the stories on synchronization of fireflies from a forest officer Mr. M.G. Ganesan and the award-winning photo of synchronized fireflies in Anamalai Tiger Reserve by Mr. Sriram. During the initial phase of the survey, I keenly waited for the rain to come. Every year, after the pre-monsoon rain and mango shower rain between April to May, the larvae of the fireflies emerge into adult fireflies. The adult fireflies live for 14 – 20 days in their life cycle (copulate/mate,  lay eggs, and die off). I was fascinated that even the eggs and larva can glow (two yellow lights on the lower side). These nocturnal flies glow like brilliant golden fire minuscules which the locals agree too. These glow worms set flashing lights in the obscure nights while residing beneath the leaves during day time. 

The firefly larvae are predators that feed extensively on snails, worms, slugs, and other insects. They are usually seen in the water channel and wet areas, crawling slowly with two indicator lights on their back. Our field trackers mockingly call the firefly larva  as “ravva” while seeing the animal glow with excitement. We have witnessed a huge firefly larva (4 - 5 cm in length) being hit by a vehicle.  

 

According to local Malasars and Muduvans (Tribe communities) beliefs, a large congregation of fireflies predicts a bountiful honey harvest for that year. The current year witnesses smaller congregations of fireflies due to the unusual rain patterns in 2024. With minimal light intensity and pollution, Anamalai Tiger Reserve offers an ambient abode for these unique beetles. On the other hand, Chennai is witnessing rapid urbanization, diminishing the habitats for fireflies. Recently, it has been disheartening to know that children in our area haven’t sighted or know about the fireflies and their environment. The exploration of the fireflies and environment is in our situation to protect or witness their extinction in urban landscapes. This calls for urgent conservation attention to protect the existing scattered population of fireflies in Chennai. 

 

 

Review by Chitra P and Karthy S.