Readers who remember playing the popular video game series “Mario Kart” will understand this research. In the game, players had to make a tradeoff when choosing characters: Embrace the agility of a lightweight character like Yoshi but risk getting knocked around, or eschew maneuverability for stability with a heavier character like Bowser? According to researchers from Harvard University and the Royal Melbourne Institute of Technology, bumblebees make the same tradeoff with pollen.
Researchers Andrew Mountcastle, Sridhar Ravi and Stacey Combes had a simple question: How do different loads of pollen affect the ways bumblebees fly? To test it, they mail ordered a bunch of bumblebees, outfitted them with varying weights meant to simulate pollen loads and filmed them flying in a specialized wind tunnel.
Bees are naturally good flyers, even carrying heavy loads. Bees carry pollen on their legs and flower nectar in pouches on their abdomens, and research has shown that bees can carry up to half their weight in pollen and 100% of their weight in nectar. Even at maximum loads, bees are able to fly with astounding speed and precision.
But at least in the case of bumblebees, that payload comes at a price – maneuverability. When filmed with a high speed camera in the wind tunnel, the researchers noticed that the bees carrying heavier pollen loads were less agile in flight than their unburdened counterparts.
On the other hand, the heavier bumblebees were more stable in flight, which would give them a distinct advantage in windier conditions. Based on this information, the researchers think that the bees may actually choose how much pollen and nectar to collect depending on wind conditions. In windier days they may opt for the stabilizing pollen, while on still days they would prefer nectar, as it’s location closer to the bee’s center of mass affects flight less.