Supersonication

After a wee break abroad (partly spent trying to photograph the very captivating but very fast Hummingbird Hawkmoth) I'm back exploring the National Cycle Network and its wildness. Today I nipped out to NCN1 to do a bumbleebee and butterfly survey and, racing the clouds, saw three butterflies and my first male bumblebee of the season before the rain spatters started. The path wasn't very busy and I noticed for the first time a bumblebee changing the frequency of its buzz as it landed on a bramble flower. As I walked on, I noticed more and more bees doing this. A wee bit of office research on my return....buzz-pollination (or sonication) is when a bumblebee contracts their flight muscles to produce strong vibrations to access tightly-packed pollen on an anther - usually a poricidal anther. Brambles don't have poricidal anthers. What's going on? Having spent too long reading articles from Functional Ecology, the Journal of Insect Behaviour and (ahem) a 1985 edition of the Journal of the Kansas Entomological Society, I am not much clearer...time to pick the brains of my friends at Bumblebee Conservation Trust for more learning. What I do know is it's blooming hard to get a clear photo of a vibrating bee....