The body and wings of the dragonfly Pantala flavescens have evolved in a way that lets the insect glide extraordinary distances on weather currents. Credit: Greg Lasley
A dragonfly barely an inch and a half long appears to be animal world’s most prolific long distance traveler – flying thousands of miles over oceans as it migrates from continent to continent – according to newly published research in the journal PLOS ONE.
Biologists at Rutgers University found that populations of this dragonfly in locations as far apart as Texas, eastern Canada, Japan, Korea, India, and South America, have genetic profiles so similar that there is only one likely explanation. Apparently, these insects are traveling extraordinarily long distances, and they are breeding with each other, creating a common worldwide gene pool that would be impossible if they did not intermingle.
“This is the first time anyone has looked at genes to see how far these insects have traveled,” said Jessica Ware, senior author of the study. “If North American Pantala only bred with North American Pantala, and Japanese Pantala only bred with Japanese Pantala, we would expect to see genetic results that differed from each other. Because we don’t see that, it suggests the mixing of genes across vast geographic expanses.”
But how do insects from different continents manage to meet and hook up? These are not large birds or whales that one would expect to travel thousands of miles. Ware says it appears to be the way their bodies have evolved.
“These dragonflies have adaptations such as increased surface areas on their wings that enable them to use the wind to carry them. They stroke, stroke, stroke and then glide for long periods, expending minimal amounts of energy as they do so.” Dragonflies, in fact, have already been observed crossing the Indian Ocean from Asia to Africa. “They are following the weather,” says Daniel Troast, who analyzed the DNA samples in Ware’s lab while working toward his master’s degree in biology, which he earned at the university in 2015. “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.”
For more information:
A Global Population Genetic Study of Pantala flavescens