Bad buzz. A deadly parasite, possibly carried by European bees imported for pollination, is infecting Patagonia's native giant bumblebee, Bombus dahlbomii.

Carolina Morales

Bumblebees prefer pollen on windy days

Fuzzier, bigger, and less aggressive than their honeybee cousins, common eastern bumblebees (Bombus impatiens) are world champion multitaskers who can carry more than half their body mass in food. But how they choose their prey—pollen or nectar—is little understood. Now, researchers propose that wind conditions might play a role in that decision. To test their hypothesis, researchers trained bees to fly toward an artificial flower in a wind tunnel. They strapped small steel bearings to the bees’ legs or abdomens to mimic the weight and location of typical pollen and nectar loads. Pollen is always carried on the bees’ hairy legs, where it dangles further from the insects’ center of mass. But nectar is stored almost directly in the center of the bees’ abdomens. After testing the bees’ flight stability and maneuverability in windy and nonwindy conditions, researchers found that bees carrying a pollen load are more stable, but less able to maneuver in strong winds, whereas bees carrying a nectar load are less stable but better able to maneuver. As a result, the researchers concluded that bumblebees face a tradeoff between stability and maneuverability when choosing which food to carry home. This tradeoff may explain why some bumblebees prefer to forage for pollen during windy days. The study is published online today in the Proceedings of the National Academy of Sciences.