I simply must inform you of this crucial bee fact: When bees get trapped in water, they use their wings as hydrofoils to surf back to the safety of land.
While bees can float, they cannot fly with wet wings, and worse, they aren’t strong enough to free their wings from the water’s surface. That might sound like a death sentence should they accidentally fall into a pool or puddle. But never fear. They’ve figured it out.
Researchers Chris Roh and Morteza Gharib at the Caltech Graduate Aerospace Laboratories collected honeybees from a garden in Pasadena, California, put them in plastic tubes, and gently tapped the tubes until the bees fell into around an inch or two of water. Then, the duo filmed the bees with high-speed cameras, observing the strength and frequency of their wingbeats and how quickly they moved. They also shined lights above the bees to see the shadow patterns produced by the waves.
The bees puttered along the water, flapping with slower, shallower wingbeats than they use for flying. The fluttering created asymmetric wave patterns that differed in front of and ahead of the bee, demonstrating that the bees were actually using their wings to kick up waves that would push them forward. The bees traveled at rates of up to three bee-lengths per second. You go, bee!
Nonetheless, it’s clear the water isn’t bees’ preferred habitat. “Compared to water surface locomotion of other insects, neither the speed nor the efficiency achieved by the honeybee’s hydrofoiling impresses,” the authors write in the paper published in the Proceedings of the National Academy of Sciences. But the hydrofoil technique appears to be unique among insects that can move in water, according to the paper.
The flapping was enough for bees at a local pond to push themselves out of the water. They traveled several meters to reach land to dry off before returning to regular bee business.
There are limitations to this work; they only modeled the most general features of wing motion and didn’t include wing bending. Nor did the model account for gravity or surface tension in the water.
As for why a pair of engineers at an aerospace lab were studying bees, well, the mechanism might inspire hybrid aerial-aquatic vehicles, the authors write, where flapping provides both aerial and aquatic propulsion without drastic changes to the vehicle’s shape. The team modeled the bee wings in action, and perhaps their work could bee used some day to actually create such a vehicle.