Figure 7
From: Role of serotonergic neurons in the Drosophila larval response to light
Disruption of the optic neuropil 5-HT arborization does not affect the larval response to light. A, Response to light of 3rd instar UAS-hid/+;Rh6-GAL4/+ larvae and of UAS-hid/+ and Rh6-GAL4/+ parental control larvae. B, Response to light of 3rd instar GMR-GAL4/+;UAS-slit/+ larvae and parental control GMR-GAL4/+ and UAS-slit/+ larvae. Consistent with previous results [15], 3rd instar foraging larvae lacking the Rh6 photoreceptors due to targeted expression of hid show normal response to light (UAS-hid/+;Rh6-GAL4/+, n = 12, RI = 0.32; Rh6-GAL4/+, n = 18, RI = 0.32; UAS-hid/+, n = 17, RI = 0.32; ANOVA: F(2,44) = 0.06, p = 0.95). Similarly, early wandering 3rd instar stage lacking the Rh6 cells displayed the characteristic low response to light (UAS-hid/+;Rh6-GAL4/+, n = 22, RI = 0.1; Rh6-GAL4/+, n = 24, RI = 0.09; UAS-hid/+, n = 21, RI = 0.07; ANOVA: F(2,64) = 2.94, p = 0.06). In the case of larvae over-expressing Slit in the larval photoreceptors and their respective control larvae, we found significant differences among the response to light of these strains at early foraging 3rd instar stage (ANOVA: F(2,68) = 5.77, p < 0.05). Nevertheless, post hoc analysis of paired mean comparisons revealed that expression of Slit under control of the GMR-GAL4 driver caused a small decrease in the larval response to light when compared to the response to light of GMR-GAL4/+ larvae but not to that of UAS-slit/+ larvae (GMR-GAL4/+;UAS-slit/+, n = 20, RI = 0.33; GMR-GAL4/+, n = 31, RI = 0.38; UAS-slit/+, n = 20, RI = 0.34). At early wandering stage, no differences were found between GMR-GAL4/+;UAS-slit/+ larvae and parental controls (GMR-GAL4/+;UAS-slit/+, n = 20, RI = 0.06; GMR-GAL4/+, n = 13, RI = 0.07; UAS-slit/+; n = 20, RI = 0.07; ANOVA: F(2,50) = 0.23, p = 0.80).