Every autumn millions of the Pantala Flavescens dragonfly appear suddenly in the Maldives 600 miles off the coast of Southern India.
Independent biologist Charles Anderson thinks the insects are coming from India before continuing on the trade winds to south eastern Africa. If his theory is correct it would mean the 5cm dragonflies are flying a round trip of up to 12,000 miles – the longest migration of any insect.
In a study published in the Journal of Tropical Ecology, Mr Anderson argues that the dragonflies must be migrating from India because there is no surface fresh water for the insects to breed on in the Maldives. He noticed the insect turn up on the Maldives in October just after being spotted in India. Swarms are found a few months later in Uganda and Mozambique before appearing in India again.
Mr Anderson, an independent biologist who usually works with organisations such as the Maldivian Marine Research Centre, thinks the insects are flying a round trip from Southern India to the Maldives and onto Africa before returning on the same route.
“No one I have spoken to knew where they came from,” Mr Anderson he told the BBC. “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.”