Fig. 3. Head swinging behavior of wild-type strains and larvae with mutations in genes involved in phototransduction during the ON/OFF assay. Head swings, defined as an abrupt movement of the anterior portion of the larva away from original path choice, were counted in light (stippled bar) and dark (gray bar) pulses on a per larva basis, and an average for each genotype was derived. There is a significant increase in head swinging by wild-type larvae (CS,n = 30; OR, n = 30) during light pulses, relative to that during dark (ANOVA:CS, F(1,58) = 15.69,p < 0.001; OR,F(1,58) = 20.51, p < 0.001). This difference is abolished in the phototransduction mutants norpAP24
(n = 30), norpAP12
(n = 20), and ninaC5
(n = 20) but not in theninaC2
(n = 18),ninaE17
(n = 20), and ninaE8
(n = 20) mutants (ANOVA:norpAP24
,F(1,58) = 0.09, NS;norpAP12
,F(1,38) = 2.58, NS;ninaC5
,F(1,38) = 0.05, NS;ninaC2
,F(1,34) = 11.53, p < 0.001; ninaE17
,F(1,38) = 30.82, p < 0.001; ninaE8
,F(1,38) = 29.81, p < 0.001).