Buzz-pollinating bees shake pollen loose with rapid vibrations and biting, study shows

Bumblebees collect pollen by various methods. Some types of flowers, such as potato plants, need tougher treatment to make them release their pollen. In these cases, the bee uses a technique called “buzz pollination” where it bites the flower’s anthers and shakes them.

Charlie Woodrow, postdoctoral fellow at the Department of Ecology and Genetics, has been studying how this works in detail and has made new discoveries. The work is published in the journal Current Biology.

“Instead of brushing the pollen straight from the flower, the bumblebee uses the muscles in its thorax, which it uses for flight, and contracts these very quickly, which causes the bee to vibrate. As it does so, it shakes the pollen out of flowers with tube-shaped geometry. How rapidly the muscles vibrate and how loud the vibrations are affects how much pollen is released,” Woodrow says.

Intense buzzing sound

Bumblebees need pollen both as food for themselves and for their larvae. During buzz pollination, they make an intense buzzing sound. In the new study, researchers used high-speed cameras to see in detail how this happens.

“We recently found that these vibrations are actually transmitted from the muscles of the thorax to the head of the bumblebee, and when this happens the head moves backwards and forwards up to 400 times the acceleration of gravity. So these are really fast movements.

“As the bee does this, it bites onto the flower. This allows the pollen to be released really rapidly compared to normal brushing of pollen from the flower or vibrations transmitted straight from the muscles themselves.”