alt Hacker NewsThere are butterflies that do this as well! I hate that I can't seem to find the video anywhere, but I clearly remember a nature documentary where they showed a bunch of butterflies drinking the fermented juice from rotting fruit on the forest floor. This caused them to fly erratically, stumble around, and even fall over. It was pretty amusing!
I don't need documentaries for that, because I experienced that live.
One summer, walking around a large quay/wharf, lying fallow after being flattened and then raised, exploring how so called 'pioneer plants', grasses, flowers, trees took hold there, I noticed the strong smell of ripe blackberries from afar.
Found the few dozen bushes, surrounded by swarms of insects of all sorts, really darkening the air.
Stepped very slowly and carefully right into it, plucked my share from the upper parts of the bushes without being stung or them crawling on me.
Squatted down to take a closer look. Many overripe berries lying on the ground. Insects coming down in spirals like the finger of a tornado, but slowly. Big buzz and hum in the air. Feasting on the mushy berries on the ground. Flying out really low, just a few centimeters off ground, erratically as you described.
Amusing indeed! :-)
Edit: Detailing the most amusing things from memory:
Bumblebees swaying sideways and actually bumping into dandelions(which they are feeding on too, in more normal times), softly crashing into the ground, sometimes on their backs, only to jittery take off back into the air, slowly swaying away further for the next leg of a few meters, only to bump/crash again, and so on, until out of my sight. Other insects too, but with the bumblebees it was most noticable :-)