Figure 5. painless mutant larvae are impaired in rolling responses to noxious heat.

(A and C) Graphs show head angle, crabspeed and normalized crawling speed as a function of time, as in Fig. 2. Dark lines, mean value. Light lines, ± s.e.m. Grey lines at 0 s mark stimulus onset and duration. Data from the control painless¹>w1118 (light green, N = 53), painless³>w1118 (dark green, N = 45) and piezoKO>w1118 (blue, N = 51) is compared to painless¹ (orange, N = 126), painless³ (red, N = 181) and piezoKO (red, N = 130) mutants, respectively. In both painless¹ and painless³ mutants the peaks in the mean crabpseed and the mean normalized speed functions are highly reduced compared to controls. They show virtually no escape crawl. (B and D) Bar charts show head casting and rolling probability and the mean value of the maximum stride frequency as in Fig. 2E. Error bars indicate s.e.m. * (light green star), * (dark green star) and * (blue star) indicate p<0.001 when painless¹, painless³ and piezoKO is compared to painless¹>w1118, painless³>w1118 and piezoKO>w1118, respectively. In response to noxious heat stimulus, the rolling probability of painless¹ (11.9%, N = 126) and painless³ (6.1%, N = 181) larvae, defective in thermal nociception, is significantly reduced compared to the hemizygous controls (49.1%, N = 53, p<10⁻⁶ and 31.1%, N = 45, p = 0.000054). The mutants also have significantly reduced stride frequency and stride speed following stimulation and reduced stride frequency prior to stimulation (see Table S1 for further details). In contrast, piezoKO mutant larvae defective in mechanical nociception roll slightly, but not significantly more than the hemizygous controls. Interestingly they are significantly defective in escape crawl and in stride speed prior to stimulation.