Thought
Bombus was a genus of slow flying insects that look awkward in the air? Think again, Sherlock. True, they have oversized bodies and comparatively tiny wings, but some of the 250 species of
Bombus are capable of flying over the Himalayas. Bumblebees in Nepal occurr naturally as high as 5600m where the air is thin. Scientists supported in part by
National Geographic captured six males of the species
Bombus impetuosus at 10,600 feet
[photo] and studied their flying in a pressure chamber where the atmosphere could be reduced in increments corresponding to an increase in altitude of 1500 feet. Their results were published in the journal,
Biology Letters (Dillon & Dudley). All of the tested bees could fly above 7500m. Three of the intrepid insect aviators flew at altitudes in excess of 8,000 meters, and two of the six managed an altitude exceeding the peak of Mt. Everest! The bees achieved lift in the rarified atmospheres by increasing the angular amplitude of their wing motion (wider flaps). Having a large thorax seemed to also give a slight advantage. That they are able to perform this prodigy of high-altitude flight when their bodies' need for oxygen is at its peak is remarkable.
The study authors suggest that this ability to fly at high altitudes aid alpine bees in long-distance foraging across elevation gradients, and produces sudden bursts of speed required in mating and predator avoidance. Whether female bumblebees can perform at extreme altitudes with their smaller bodies and wing size remains to be studied.
