Bumblebees Are Misnamed
They don’t bumble. They use efficient techniques to get the most bang of weightlifting for the buck of wing flaps.
No bee is a bumbler, including the humble bumblebee. It should be named the smart bee or sherpa bee. Stacey Combes and three colleagues say in Science Advances, “Kinematic flexibility allows bumblebees to increase energetic efficiency when carrying heavy loads.”
Foraging bees fly with heavy loads of nectar and pollen, incurring energetic costs that are typically assumed to depend on load size. Insects can produce more force by increasing stroke amplitude and/or flapping frequency, but the kinematic response of a given species is thought to be consistent. We examined bumblebees (Bombus impatiens) carrying both light and heavy loads and found that stroke amplitude increased in proportion to load size, but did not predict metabolic rate. Rather, metabolic rate was strongly tied to frequency, which was determined not by load size but by the bee’s average loading state and loading history, with heavily loaded bees displaying smaller changes in frequency and smaller increases in metabolic rate to support additional loading. This implies that bees can increase force production through alternative mechanisms; yet, they often choose the energetically costly option of elevating frequency, suggesting associated performance benefits that merit further investigation.
Remember when we were told that bumblebee flight is impossible? These flyers are smarter than scientists. After four scientists examined these bees carrying loads, they still could not figure out how the bees increase energetic efficiency. What the flapping flyers accomplish instinctively is not only efficient, but merits “further investigation.”
In summary, our findings suggest that bumblebees have greater flexibility than previously recognized in how they respond to requirements for increased force production. Bees increase force production, in part, by increasing stroke amplitude, but this must be coupled either with an increase in flapping frequency or with other more economical force production mechanisms, which remain to be elucidated by future studies. Depending on their current loading state and recent history, bees can choose whether to increase force production by using these alternative kinematic mechanisms, thereby minimizing energetic costs, or by elevating flapping frequency. Although increasing frequency is more costly, this strategy may provide other performance benefits, such as enhanced stability or maneuverability, which have just begun to be explored.
The paper, uncluttered by Darwin just-so stories, discusses various ideas but couldn’t match the smarts of the bumblebee. The scientists leave it to futureware developers to figure this out. Undoubtedly, when they do, some biomimetic application is sure to follow.
The smartest bee right now is the Babylon Bee.