Scientists use tiny trackers, plane to follow moths on move

NEW YORK (AP) – Trillions of insects migrate around the world every year, yet little is known about their journeys. So to find clues, scientists in Germany took to the skies, placed tiny trackers on the backs of giant kites and followed them with airplanes.

To the researchers’ surprise, the moths had a keen sense of where they were going. Even when the wind changes, insects stay on a straight path, scientists report The study was published Thursday in the journal Science.

Their flight paths suggest that these death-head hawk moths have some complex navigational skills, the authors said, challenging previous ideas that the insects are simply nomads.

“For many years, insect migration was thought to be carried mainly by wind and carried by the wind,” said lead author Myles Menz, a zoologist at James Cook University in Australia.

Menz said it’s difficult for scientists to get a close look at how insects travel because of their small size. Radio tags used to follow birds can be too heavy for small flyers.

But transmitters have become smaller. And it helps that the death’s-head hawk moth is quite large compared to other insects, with a wingspan of up to 5 inches (127 millimeters).

The iconic species — darkly colored with yellow underwings and skull-like markings — was able to fly better with a small tracker attached to its back, said study co-author Martin Wikelsky, a migration researcher at Germany’s Max Planck Institute for Animal Behavior.

It is believed that moths migrate thousands of miles between Europe and Africa in autumn, flying at night.

For the study, the researchers released tagged kites in Germany in hopes that they would fly towards the Alps on their migration route.

Wikelski, the study pilot, took off with his plane, circling the area and waiting for any moths to fly by. If it picks up a signal from a small passenger, it will follow its radio blips for hours.

“The little kite is guiding you,” he said.

The researchers followed the flight paths of 14 moths, the longest of which was about 56 miles (90 kilometers).

Not only do kites fly in a straight line, Menz said, they also work in wind conditions, flying low to the ground when the wind is against them or rising to catch a useful tailwind.

Although the number of moths tracked was very small, the close-up look at insect migration is significant, said Ryan Norris, an insect and bird migration researcher at the University of Guelph in Canada, who was not involved in the study.

“I was surprised how far they could track them,” Norris said. “And it’s certainly surprising that individual moths stay on this straight path.”

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The Associated Press Health and Science Department is supported by the Department of Science Education of the Howard Hughes Medical Institute. AP is solely responsible for all content.

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