Radio-Tracking Orchid Bees in Panama

For the first time, scientists have tracked the movements of tropical orchid bees using radio-transmitters. The bees, studied at the Smithsonian Tropical Research Institute in Panama, fly up to 3 miles from their home areas and patrol up to 285 acres of rainforest in their hunt for food and mates.

Just thinking about orchid bees brings back the minty odor of methyl salicylate and the cinnamon scent of eugenol, fumes of which I inhaled nearly every day during my PhD research. Male orchid bees collect scents from the specialized orchids they pollinate, and an old tropical “magic trick” is to set out filter paper loaded with the gunk and watch these metallic bees appear. The bees likely harvest the scents for mating, but no one knows for sure. What scientists do know is these bees fly really fast and really far.

In one failed attempt to study the movements of orchid bees, my intrepid assistant Matt Medeiros balanced himself on the prow of our motorboat holding an airspeed gauge in one hand and a butterfly net in the other. The goal was to measure their flight speeds as they raced across the Panama canal. We could have used more horsepower. Our success rate was less than impressive.

Even then, I remember there was talk of attaching radio transmitters on bees. Martin Wikelski of the Max Planck Institute of Ornithology in Germany had set up a series of radio towers on Barro Colorado Island, which Megan Gambino recently wrote about for Smithsonian.com. The towers have allowed monkey, sloth, and frog researchers automatically track their research subjects, but back in 2002 radio-tracking insects still sounded pretty far-fetched. Then, in 2007, a graduate student Alex Eaton-Mordas of the University of Arizona at Tucson, told me it finally happened. He went to Panama that March, attached transmitters on the biggest bees, and managed to get up to 10 days' worth of data. For technical reasons, they had to track them with hand-held and helicopter-mounted antennas.

The study has now been published in the journal PLoS one and there’s even video. The study demonstrates once and for all that male bees are not “vagabonds," as one tropical ecologist has suggested, but they maintain a home area they retire to at night. It’s a nice coup, but the transmitters are still on the heavy side, weighing about half as much as the insects. The bees can normally carry that much nectar, but it definitely slows them down.

Brendan Borrell will be guest blogging this month. He lives in New York and writes about science and the environment; for Smithsonian magazine and Smithsonian.com, he has covered the ecology of chili peppers, diamonds in Arkansas and the world's most dangerous bird.