For more than a week, the Nilgiri Biosphere Reserve (NBR) and parts of Coimbatore are witnessing migration of Globe Skimmer (Pantala flavescens) or Globe Wanderer dragonfly, widely called as insect world’s longest traveller. Swarms of Globe Skimmer on movement were seen in Wayanad in Kerala, Mukurthi in the Nilgiris, Anaikatty in the Kerala-Tamil Nadu border and parts of Coimbatore. K. A. Subramanian, scientist with Zoological Survey of India, said that a study based on observations on the travel pattern of Globe Skimmer had pointed to its migration to Africa. “There is no marker study to prove this as done to decode migration of birds. Globe Skimmer is a circumtropical species found in all tropical parts,” says Mr. Subramanian. According to V. Prabhakar, a nature enthusiast associated with Osai NGO, other species of dragonfly normally do not travel much from their habitat, mostly water bodies, like Globe Skimmer.
Globe Skimmer make swift movements during day and rest in groups on thickets and small plants by sunset. According to M. Suhirtha Muhil, who did her research on ‘Odonates of Coimbatore’ at Salim Ali Centre for Ornithology and Natural History, the lifespan of adult Globe Skimmer is one to two months. It takes for 40-50 days for the larvae to reach adult stage. “The migration starts its peak by the middle of September and continues throughout October,” said Ms. Muhil. Meanwhile, the movement of Globe Skimmer in large numbers is in turn a grace for Coimbatore which is witnessing an upsurge of dengue. “Dragonflies are known for preying on mosquitoes. But their numbers have dwindled like anything due to pollution of freshwater bodies were they lay eggs. They are predominant predator of mosquitoes even in larvae stage as they prey on mosquito larvae. Pollution and other control measures done in fresh water bodies thus kill beneficial larvae like that of dragonflies,” said Peter Prem Chakravarthi, Biologist with Anamalai Tiger Reserve (ATR).
According to Mr. Chakravarthi, ATR is home for 70 varieties of the insect order Odonata which comprises dragonflies (30 varieties) and damselfies (40 varieties). The study done by Ms. Muhil had recorded 57 species of dragonflies in Coimbatore.
