Last year the researchers conducted field tests on cicadas, which are easier to follow and recapture than dragonflies, because they fly slower and don't travel as far.
Based on these tests, Wikelski said, the tags have little impact on insect flight, except perhaps making them slightly heavier. The extra weight allows the bugs to move faster when flying with a tailwind.
The researchers plan to publish their preliminary results in a peer-reviewed scientific journal later this year. In the meantime, they offer up a few speculations on how dragonflies migrate.
May said the southbound dragonflies appear to take advantage of tailwinds generated by cold fronts blowing from the north. The northbound migrants likely ride the warm fronts blowing from the south.
Greater uncertainties exist on how dragonflies navigate. May noted they have huge eyes, which they use to detect their insect prey. Perhaps they also steer by visual landmarks, he said. Or, like some birds, they could use an internal compass.
And while the research certainly advances understanding of dragonfly migration, Wikelski said it also demonstrates the feasibility of a global tracking system for insects. Satellites, if funded, could easily detect the transmissions sent by these tags.
"We can now track small insects, like locusts in Africa, before they get to the stage where they are a problem," he said.
The work could also be applied to tracking birds with radio tags, which might have widespread implications for human health.
"There's a call out for a million people dead from avian influenza, but we have no clue where these birds are going," he added. "It's absolutely mind-boggling."
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