WTB Drosophila larvae were placed in the center of an agar plate containing plain agar on one half and agar supplemented with salt on the other half.
Larval distribution after 3 minutes was quantified as a preference index under red and blue light conditions.

5 days old larvae (3rd instar) were tested for their salt (1.5 M) avoidance behavior. Dopaminergic neurons from the TH-D’ cluster were activated upon ChR2-XXL expression and blue light exposure, respectively.