Chordotonal organs and class IV da neurons were involved in sensing gentle touch. UAS-shits were expressed under control of chordotonal-organ-specific driver iav-GAL4 or class IV da neuron-specific driver ppk1.9-GAL4. After gentle touch, larval navigational pattern (A, C) and withdrawal response (B, D) were examined. The performance of larvae at restrictive temperature (32°C, dark bars) was compared to that of same-genotype larvae at permissive temperature (22°C, light bars). *p<0.05, **p<0.01, ***p<0.005, “ns” indicates p>0.05, t-test. (A) Navigational pattern of 3rd-instar larvae in response to 1 mN stimulus. (B ) Withdrawal response of larvae after gentle touch of 1 mN. Larvae tested in A and B: W-1118, n=20; UAS-shits, n=20; iav-GAL4 + UAS-shits, n=26; ppk1.9-GAL4 + UAS-shits, n=20. (C) Navigational pattern of 3rd-instar larvae in response to 7 mN stimulus. (D) Withdrawal response of larvae after gentle touch of 7 mN. Larvae tested in C and D: W-1118, n=19; UAS-shits, n=19; iav-GAL4 + UAS-shits, n=20; ppk1.9-GAL4 + UAS-shits, n=20. Note that expression of shits driven by iav-GAL4 or ppk1.9-GAL4 at restrictive temperature significantly affected navigational pattern and withdrawal response in response to 1 mN stimuli. However, no significant effects were observed when the intensity was increased to 7 mN. Error bars represent SEM.