The pristine forests around Top Slip in the Anamalai Tiger Reserve (ATR) resembled James Cameron’s fictional bioluminescent universe Pandora in the movie Avatar, for a few nights recently.
Officials of ATR were awestruck as several lakhs of fireflies perched on every plant and tree and illuminated the forests, turning them into a magical world of yellowish green light. The insects emitted light synchronously, starting from one tree, and the relay was carried across the forest. The cyclic phenomenon continued throughout the night for a few days.
Though the mass congregation of fireflies has been recorded a few times in ATR, synchronised lighting by several lakhs of fireflies was reported this year. S. Ramasubramanian, ATR Field Director, witnessed the phenomenon with M.G. Ganesan, ATR Deputy Director, and Sriram Murali, a software engineer and an expert in light pollution and fireflies. “It will not be an exaggeration if I call the phenomenon a world wonder. The insects emitted light in a synchronised pattern, the reasons for which are beyond our understanding,” he said.
According to Mr. Murali, male fireflies normally emit light to attract females. “Researchers have observed that males emit light together in trees to attract females. When a mating pair was observed in ATR, we found that only the male was flashing. There are around 2,000 species of fireflies, and there can be differences in the lighting pattern,” he said.
Through communications with firefly scientists in the U.S., Mr. Murali found that a visiting researcher had noted the synchronous behaviour in ATR in 1999, but no research paper was published. A team of researchers from the Institute of Forest Genetics and Tree Breeding, who visited ATR in 2012, had also chanced upon the phenomenon.
Mr. Ganesan said the ATR team, scientists and conservationists were working towards understanding the ecology and life cycle of fireflies, their selection of trees and their relationship with other forms of wildlife. The mass congregation of fireflies in ATR could be an indicator of a pristine ecosystem, he said.
Lack of lights, night tourism, habitation and vehicle movement could be reasons for the large population of fireflies in ATR, Mr. Murali said, adding that synchronous flashing of fireflies had been observed in neighbouring Parambikulam and Nelliyampathy, and in Maharashtra, too.
Mr. Murali said fireflies spend most of their lives as larvae - about a year or more living in soil and feeding on soft-bodied insects. The adults, as beetles, live for two to four weeks, and feed on nectar and pollen.