Researchers studying populations of numerous moth and butterfly species across Papua New Guinea have developed a new technique to study the spread and diet of insect pests--DNA barcoding, which involves the identification of species from a short DNA sequence.

DNA barcodes showed that migratory patterns and caterpillar diets are very dynamic. In one case, a tiny moth that is distributed from Taiwan to Australia, had recently crossed thousands of miles of Pacific Ocean.

The research is detailed in this week's edition of PNAS.

"DNA barcoding was developed for rapid identification but it also provides information about the habits and history of species," says University of Minnesota researcher George Weiblen. This technique, he says, is of particular interest in Papua New Guinea, a country slightly larger in size than California with an insect diversity more than three times that of the United States.

"New Guinea is one of those special places on Earth where we know very little about its biodiversity. This rich natural environment is increasingly threatened by economic development, and I'm concerned about how much biodiversity might be lost before we've had a chance to understand it. DNA barcoding helps to increase the pace of discovery."

The Asota caricae moth has a two-inch wingspan and a 2,500 mile distribution.

(Photo Credit: Lauren Helgen, Smithsonian Institution)

Weiblen says that DNA barcoding can play an important role in studying the arrival of invasive species, such as the emerald ash borer, a species recently introduced from Asia. "We need to understand the genetic history of invasion in order to combat the pests that threaten trees and crops," Weiblen says. "DNA barcoding can pinpoint the geographic source of an invading species and measure the distances over which pest species can travel."

Citation: Craft et al., 'Population genetics of ecological communities with DNA barcodes: An example from New Guinea Lepidoptera', March 2010; doi:10.1073/pnas.0913084107