This time I tried to induce a kind of Garcia effect (eating something, feeling sick and then avoiding eating that again) in Drosophila. As one can see in the video below, Drosophila show inhibited proboscis extension response (PER) right after the onset of the US (intestinal discomfort).

However, the conditioned response is extinguished after several hours. I tried to use groups of 20 starved flies on yeast+water for 2h, food + 0.1% hydrogen peroxyde for 1h, starving with nothing for 1h (always inside vials), and then testing with conditioned food against another food for 2h (inside Petri dishes). It didn’t work: in the end they show the same preference as controls (without hydrogen peroxyde). I tried to condition sucrose, glycine, pineapple juice (and then test against apple juice) and nothing, the flies avoid at first but once the swelling goes away, they forget or don’t associate anything bad or sufficiently bad with that food anymore, and continue to prefer it.

I also confirmed the PER suppression following conditioning with quinine reported in [C. Keene A, Masek P. Optogenetic Induction of Aversive Taste Memory. Neuroscience. 2012;222:173-180]. However, it is also extinguished minutes (~30) after the conditioning, as their results also show (in my case, I used sucrose instead of fructose):

(my results:)

(their results:)