I've been asked before to help friends rid themselves of fruit flies. I
thought myself quite the hero the first time I gave someone of trap of yeast
and fly food with paper funnel top. A few days later, the friend came back
to me with an empty trap and a reduced impression of my Drosophila
knowledge. What went wrong? Well, my theory is that wildtype fruit flies
are too smart to fall for a normal trap, but the same trap will work in the
lab due to the excesive manipulation and inbreeding of lab stocks causing a
much dumber fly.
So how does one catch brainy fruit flies? I recomend an open can of
beer. At home or in the lab, I never fail to get dozens of drowned flies in
my beer. Mmmmmmm....