Air Date: Week of May 19, 2006

A swamp darner (Epiaeschna heros) with a radio-transmitter attached to its thorax warming up at Cape May, NJ, before continuing its migratory flight. (Photo: Christian Ziegler)

Bobby Bascomb reports on the surprising migratory patterns of dragonflies.

Transcript

CURWOOD: It’s Living on Earth. I’m Steve Curwood and coming up: Why the Roof of Africa is losing its crown of ice. First this note on emerging science from Bobby Bascomb.

[SCIENCE NOTE THEME]

BASCOMB: New research shows that dragonflies can travel up to 100 miles a day in patterns that are very similar to migrating birds. Scientists at Princeton University attached radio transmitters – weighing 1/100th of an ounce – to the undersides of 14 Green Darner dragonflies and monitored their habits for 12 days.

The results: both birds and dragonflies start migrating when temperatures begin to drop in the fall. Each groups builds up reserves of body fat before migrating, wait for favorable winds, take extended periods of rest, reorient themselves if they get lost and use the same navigational markers on the landscape.

Of the 5,200 dragonfly species in the world, 50 of them migrate. And of those, nine are found in North America. The Green Darner migrates from the Northern United States and Canada as far south as Mexico. But the trip South is a one-way ride. The adult dragonflies mate in the south and only their offspring return North in the spring.

Fossil records show dragonflies appeared about 140 million years before birds. So, instead of saying dragonflies migrate like birds, it might be more accurate to say that birds migrate like dragonflies. That’s this week’s note on emerging science. I’m Bobby Bascomb.

 

Links

Princeton University Physiological Ecology Lab