Beside Dalgety Bay station platform, Fife, Scotland.
June 29th 2009, about 15:30BST.
I heard loud buzzing, and saw it came from these two bumblebees in one flower. That struck me as unusual: earlier that afternoon, I’d noted how bees seeking flowers to feed from skirted around blooms already occupied by other bees; and how bees on flowers seemed ready to fend off (with raised legs) other insects that approached.
However these two bees did not seem to be combative, and remained together for maybe half a minute.
A single such bee, that I observed in a flower by itself, also was making the buzzing noise as it fed. So the buzzing was not an indication of conflict. Nor were the buzzing bees hovering or about to take off.
I wonder whether this distinctive buzzing (which was commenced once inside the flower and continued intermittently while the bee remained there) serves some practical purpose?
-Does it keep away other foragers, signifying ‘This flower’s taken; I’m inside’? This shot suggests not.
However it’s possible that these two actually are sisters, and recognize one another as members of the same colony; if so, they may be tolerant of each other’s closeness more than they would be with strangers.
-Does it keep the bee warm? This was a warm sunny day but with a cooling breeze. While not in flight, especially during prolonged feeding in one spot, does the bee risk cooling below optimal temperature and so need to buzz to keep its temperature up?
-Does it loosen pollen for pick-up, or stimulate nectar release?
I wonder whether the buzz of a bee is not incidental but instrumental in the life of the plant, which it both serves (by pollinating) and is served by (receiving sustenance)?