Tiny dragonfly destroys records for insect migration

MARCH 3, 2016

by Brett Smith

Even though it’s only an inch and a half long, the dragonfly Pantala flavescens is capable of migrating from continent to continent and over oceans, according to a new study published in the journal PLOS ONE.

Using genetic analyses, the study team found populations in eastern Canada, Japan, and South America. They research said the only explanation for the common worldwide gene pool is an ability to migrate over long distances and breed in new locales.

“This is the first time anyone has looked at genes to see how far these insects have traveled,”  an assistant professor of biology at Rutgers University-Newark, said in a press release.

“If North American Pantala only bred with North American Pantala, and Japanese Pantala only bred with Japanese Pantala,” Ware said, “we would expect to see that in genetic results that differed from each other. Because we don't see that, it suggests the mixing of genes across vast geographic expanses.”

Explained by evolution

Ware said this theory make sense when you consider the way these dragonflies appear to have evolved.

“These dragonflies have adaptations such as increased surface areas on their wings that enable them to use the wind to carry them,” she said. “They stroke, stroke, stroke and then glide for long periods, expending minimal amounts of energy as they do so.”

The study team noted that dragonflies have, in fact, been observed crossing from Asia to Africa over the Indian Ocean.

“They are following the weather,” said study author Daniel Troast, who analyzed the DNA samples in Ware's lab. “They're going from India where it's dry season to Africa where it's moist season, and apparently they do it once a year.”

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