While the highest altitude a bird has been recorded flying is 11,278 meters (37,000 feet), some insects have also been seen flying at surprisingly high altitudes. Some flies and butterflies have been seen flying at 6,000 meters (19,685 feet).
Life at high altitude is a challenge, so there is an overall reduction in the diversity and abundance of all kinds of organisms. Flying organisms including birds and insects face the challenges of low temperatures, low oxygen, and low air density.
Specifically, flying insects face a number of setbacks at high altitudes. They’re unable to regulate their body temperatures independent of their surroundings, so the cold temperatures at high altitudes could shut them down and prevent them from moving through large parts of the day and night. Insects also must be able to supply oxygen to their tissues through aerobic respiration to function, which can be problematic at high altitudes where there is reduced oxygen. Also, insects need to generate much more energy to generate lift at the low air density found at high altitude. At high elevation, insect wings have fewer air molecules to push against to keep their bodies in the air.
Although insects face setbacks in high-altitude areas, some have developed adaptations that give them unusual flight capabilities. A study published in the journal Biology Letters placed alpine bumblebees into a low-pressure chamber to simulate high-altitude conditions and observe their flight patterns. They discovered that the bumblebees are able to hover in thinner air by moving their wings in a wider arc. They also found that they could hover at an air pressure approximating 9,000 meters (29,528 feet), higher than Mount Everest. However, the low temperatures disable the bees from actually flying at this altitude.