Photo by Yogesh Ghadigaonkar
Every year, millions of dragonflies fly thousands of kilometres across the sea from southern India to Africa. So says a biologist in the Maldives, who claims to have discovered the longest migration of any insect.
If confirmed, the mass exodus would be the first known insect migration across open ocean water.
It would also dwarf the famous trip taken each year by Monarch butterflies, which fly just half the distance across the Americas…
Each year, millions of dragonflies arrive on the Maldive Islands, an event which is well known to people living there.
“But no-one I have spoken to knew where they came from,” says Charles Anderson, an independent biologist who usually works with organisations such as the Maldivian Marine Research Centre to survey marine life around the islands…
Anderson noticed the dragonflies after he first arrived in the Maldives in 1983. He started keeping detailed records each year from 1996 and now collates data collected by local observers at other localities in the Maldives, in India and on vessels at sea.
When Anderson compared these observations with those made of dragonflies appearing in southern India, he found a clear progression of arrival dates from north to south, with dragonflies arriving first in southern India, then in the Republic of Maldives’ capital Male, and then on more southern atolls…
The dragonflies are clearly migrating from India across the open sea to the Maldives, says Anderson.
“That by itself is fairly amazing, as it involves a journey of 600 to 800km across the ocean,” he says.
“As there is no freshwater in Maldives for dragonflies, what are they doing here?” asks Anderson.
“I have also deduced that they are flying all the way across the western Indian Ocean to East Africa.”
Apparently…the dragonflies take advantage of the moving weather systems and monsoon rains to complete an epic migration from southern India to east and southern Africa, and then likely back again, a round trip of 14,000 to 18,000km.
“The species involved breeds in temporary rainwater pools. So it is following the rains, taking sequential advantage of the monsoon rains of India, the short rains of East Africa, the summer rains of southern Africa, the long rains of East Africa, and then back to India for the next monsoon,” says Anderson.
“It may seem remarkable that such a massive migration has gone unnoticed until now. But this just illustrates how little we still know about the natural world.”
RTFA. I will look around for more detailed info – probably from Anderson. If you have more to add – please do.