T-maze (light vs dark)
24h before the experiment, anesthetize 3-6 d old flies under CO2, and clip 2/3 from both wings to half of them.
In the same vial, place around 30 flies with clipped wings and another 30 intact flies.
Let them recover from anaesthesia until experiment begins.
Place the flies in the entrance tube (see figure) and let them adapt for 10 min.
Turn on the light source.
Transfer the flies to the elevator by gently tapping the apparatus, and pull the movable part down in order to close it.
Flies are kept in the elevator for 30 sec.
Pull down the movable part, so that the elevator is placed between the transparent and the opaque tubes.
Allow the flies to choose between dark and light for 30 sec.
Close all tubes by pulling up the movable part, in order to lock the flies in the tube they have selected.
Count the number of flies with and without wings in each tube.
Calculate the Choice Index (see Guidelines for formula).
