Two weekends ago I camped under a canopy of mesquite trees, which, like lots of other desert plants, were blooming vigorously. I awoke around dawn, but as it was a little chilly, I lingered in my cozy sleeping bag, dozing and waking intermittently. I could hear bees buzzing overhead, but took little notice. I waited until the sun rose high enough to shine over the mountains on the opposite shore of the lake, and bring some direct, radiant heat to my campsite. That's just when the bee buzzing volume was turned up to "11". That radiant heat must have energized the bees, as well as me. The volume was amazing, and the sound was quite like that made by a very large electrical transformer --- a little unnerving! Anyone knowledgeable about this phenomenon?