Bumblebees Capable of Flying as High as Mt. Everest [VIDEO]
Wild bumblebees captured at alpine altitudes were able to fly in a chamber where the air pressure was less than it would be at the peak of Mount Everest, according to new research, which suggests the insect not known for its prowess of flight is capable of flying higher than we imagined.
Writing in the journal Biology Letters, a team of scientists suggests that alpine bumblebees posses "substantial aerodynamic reserves" and can sustain flight at elevations in excess of 9,000 meters (29,500 feet). Mt. Everest, the highest mountain on Earth, measures 8,848 meters (29,029 feet) above sea level at its peak.
"It turns out they can fly very high," said lead study author Michael Dillon, an ecologist at the University of Wyoming, Laramie. "We did not expect that. It's a pretty remarkable feat to be up there."
Dillon and his colleague Robert Dudley, an ecologist at the University of California, Berkeley, conducted the research in conjunction with the Smithsonian Tropical Research Institute in Panama.
"Though commonly considered poor fliers, bumblebees regularly forage in high alpine regions where thin air should make flight difficult," Dillon said. "We challenged wild bumblebees, caught at 3,250 meters, to fly at higher simulated altitudes in a field flight chamber."
The six bumblebees (all males) used in the experiment were captured near Rilong, in China's Sichuan province.
Once inside the pressure-controlled chamber, the bees were tested in a simulated environment of increasing altitude, as determined by the air pressure inside the chamber. Although the bees struggled to accommodate to the pressure at first, all of them were able to control a sustained flight at atmospheric pressure equivilant to 7,500 meters above sea level, an elevation higher than six of the highest mountain summits in the world.
Three bees were able to fly in air pressure equal to about 8,000 meters and two were reportedly able to fly in pressures experienced at 9,000 meters above sea level, effectively meaning they could fly over the top of the world's tallest peak.
Incidentally, the two highest-flying bees have the largest thoraxes compared to the other bees that were tested. The thorax contains 95 percent of a bumblebee's "flight muscles," Dillon said. But the key to flying so high is the bee's ability to stay vertical and beat their wings at a wider arc.
"To fly at these extreme altitudes, bumblebees increased the maximum angle through which they beat their wings while keeping the wing-beat frequency constant," Dillon said.
The results, while interesting, are not exactly rooted in reality. A bumblebee's main reason for flying anywhere is to collect pollen, which would not be found at the summit of Mt. Everest. Even alpine bumblebees like the ones studied would have no reason to fly as high as Mt. Everest.
But if they did, Dillon said, it would be more difficult for them to ascend to that height than it would be for a human.
"For a person to walk up Everest, it's athletically challenging," he said. "But, it's nowhere near the effort it takes for a bee to fly there because of the oxygen demand. A bumblebee needs to supply its tissue oxygen 10-15 times that of an elite athlete exercising."
Dillon and his colleagues suggest that their research could have future applications in micro-vehicle and micro-air technology.
"The technology is based on mimicry of insects," Dillon said. "Right now, micro-air vehicles are limited, but Amazon is talking about using Quadcopters to make (home) package deliveries."
In the video below, an alpine bumblebee flies at a simulated height of 6,000 meters in a field flight chamber. The height is simulated by dropping the air pressure in the chamber.
This article was edited to clairfy that as altitude increases, air pressure decreases. Thanks to our readers for pointing out the error.