NPR had a fascinating story today about how many bugs live up in the sky -- "a vast teaming highway invisible to you," reported Robert Krulwich. Laby bugs at 6,000 feet, beetles and fruit flies at 3,000 feet. We're talking a lot, like 3 billion passing though a single mile of air space in a month. I've posted the audio above but the web link to the story has a nice animation as well.
Which makes me think, how effective can pesticides really be? The buggers are out there -- I mean, best to figure out a way to deal with them, without spraying chemicals, because frankly we will never be able to spray enough, because more will arrive, and then evolve to live with the chemicals and then lift off again and end up in another field thousands of miles away. But enough of my soapbox. Just listen to the piece.