Scientist at Caltech have discovered why oh why one of the most basic artifacts on earth, the looming swatter, fails against its winged nemesis, the fly. In fact, using high-resolution, high-speed digital imaging, they have found out what's the secret to the fly's 100 milliseconds evasive manoeuvring. Which is why I hate them so much, and fully explains why my favourite videos are the ones of the wingless fly and the legless fly trying to escape (which I guess makes me some kind of a psycho).
For example, the videos showed that if the descending swatter—actually, a 14-centimeter-diameter black disk, dropping at a 50-degree angle toward a fly standing at the centre of a small platform—comes from in front of the fly, the fly moves its middle legs forward and leans back, then raises and extends its legs to push off backward. When the threat comes from the back, however, the fly (which has a nearly 360-degree field of view and can see behind itself) moves its middle legs a tiny bit backwards. With a threat from the side, the fly keeps its middle legs stationary, but leans its whole body in the opposite direction before it jumps.
[Caltech—Videos Copyright 2008 by Current Biology, Card & Dickinson. Used with permission. Thanks Kathy]