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The hovering allure of Iruvai: Maldives' dragonfly season

Ruby Amir
24 December 2022, MVT 12:47
These dragonflies perform the longest insect migration ever documented, exceeding the distance covered in North America by the celebrated Monarch butterflies. PHOTO: "Lone dragonfly" in Laamu Atoll, Maldives by Maeed via Flickr
Ruby Amir
24 December 2022, MVT 12:47

Dragonflies need freshwater to breed. In the Maldives, surface freshwater is extremely scarce owing to how the islands are formed. They are composed mainly of coral reefs and sandbars that connect to the saltwater sea. But why is it that millions of dragonflies turn up every year?

This was a question that Dr. Charles Anderson asked. He moved to the Maldives from the UK in 1983, and over the course of his stay, he contributed greatly to the country with his maritime research and conservation, earning various accolades. His curiosity led him to research the migration of the dragonflies, which coincides with the transition of the south-west monsoon (Hulhangu Moosun) to the north-east monsoon (Iruvai Moosun).

Year by year, the sight of the striking dragonflies swarming across the atolls was rather taken for granted by the locals. From adults to children, dragonfly spotting was something that was habitual to living in a tropical nation. The "why" behind the widespread phenomenon was not widely considered; it was simply a sight that was enjoyable to look at, a sight that appeared in folktales, a sight that ties to childhood memories of attempting to "catch one" in a jar.

The Maldivian tradition has long observed the "Iruvaiy dhondhooni aun," which translates to "the return of the dragonflies for the north-eastern monsoon." It is a time of year the locals look forward to; to look up and see the sight of thousands of Dhondhooni simply hovering over.

Dr. Charles Anderson approached this phenomenon with wonder, but also as a scientist: he kept meticulous records of the sighting from 1996 onwards. And in 2009, the naturalist published his research on dragonflies in the Maldives. His findings suggested that these conventional visitors were actually marathon migrants doing the longest insect migration ever documented, exceeding the distance covered in North America by the celebrated Monarch butterflies.

Around 98 percent of dragonflies spotted in the Maldives are of the Wandering Glider or Globe Skimmer species. In the northern atolls, they are referred to as "Hei Nakaiy Dhooni," a reference to the two-week weather window between October 18 and October 3 (or, Hei Nakaiy, per the indigenous weather observations) when they first arrive in large numbers. The traditional Dhivehi calendar states that Iruvai Moosun begins on December 10th.

Dhondhooni sightings peak in November and December before they wander off. The dragonflies arrive in waves, with each staying for no more than a few days. Lesser numbers of dragonflies are spotted between April and June. The globe skimmers' fluttering along the borders of islands and across atolls is a welcome sight since it benefits human health and agriculture, unlike other migratory insects that are pests.

For experts, it is a riveting mystery why a mediocre little insect that weighs no more than 300 milligrammes embarks on a transoceanic voyage that traverses thousands of kilometers. Dr. Anderson’s study suggests that the Inter-Tropical Convergence Zone (ITCZ) is thought to be carrying these high-altitude skimmers as it drifts south over the Maldives during the inter-monsoon season.

Though globe skimmers have shown up over and over again for generations, the impact of climate change may hinder the migration pattern of these fragile creatures. According to Dr. Anderson's research, climate change may have an impact on whether the ITCZ moves more quickly, more slowly, or earlier. If climate change has an impact on rainfall, it might have a significant impact on dragonflies.

Since the inception of Dr. Anderson’s hypothesis in 2009, scientists across the globe have shown interest in the migration of the global skimmers. The hypothesis is a valuable contribution that attests to the unique ecosystems that surround the Maldives. The likelihood that these humble dragonflies are making a regular, seasonal transoceanic migration is a fascinating wonder that is married into the traditions and stories of the island nation.