Measuring only an inch and a half long, a dragonfly species scientifically known as Pantala flavescens holds the world record for long-distance insect flight. Researchers estimate this tiny insect has a range that spans more than 4,400 miles, shattering the previous record set by the monarch butterfly, which flies about 2,500 miles each way during its migration across North America.
For their study, biologists from Rutgers University-Newark (RU-N) used DNA to examine how far this species is able to travel.
"This is the first time anyone has looked at genes to see how far these insects have traveled," senior author Jessica Ware, an assistant professor of biology on the faculty of RU-N's College of Arts and Sciences, said in a news release.
Populations of Pantala flavescens were found as far apart as Texas, eastern Canada, Japan, Korea, India and South America - however, each of the dragonflies had nearly identical genetic profiles. This, researchers say, has only one explanation: The insects are traveling very long distances, breeding at their destination sites and are creating a common worldwide gene pool.
"If North American Pantala only bred with North American Pantala, and Japanese Pantala only bred with Japanese Pantala, we would expect to see that in genetic results that differed from each other," Ware added. "Because we don't see that, it suggests the mixing of genes across vast geographic expanses."
Researchers were surprised by their findings, as relatively large animals are usually the only one's equipped to make such lengthy trips.
"These dragonflies have adaptations such as increased surface areas on their wings that enable them to use the wind to carry them," Ware explained. "They stroke, stroke, stroke and then glide for long periods, expending minimal amounts of energy as they do so."
Dragonflies mate and lay their eggs in freshwater pools created by rainstorms. It follows then that the insects travel as far as they do to breed under optimal weather conditions.
"They are following the weather," said Daniel Troast, one of the study researchers. "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."
However, not all dragonflies are seasoned fliers like the Pantala flavescens. Its cousin, the green darner (Anax junius), for instance, is the ultimate homebody and barely travels 36 feet away from the pond in which they were born its entire life.
Their findings were recently published in the journal PLOS ONE.
