Figure 6. Correlation of genotype-specific effects of transgenic mdIV nociceptor manipulation in a horizontal dry surface locomotion assay.

(A) Schematic representation of the horizontal dry surface locomotion assay(see Materials and Methods). (B) Horizontal locomotion behavior parallels genotypic differences in PHI. Wandering stage larvae of the indicated genotypes were assayed in an alternative protocol for larval locomotion on a dry horizontal glass surface under constant humidity. Higher scores represent increased distance of movement away from a moist filter over a dry glass surface(see Materials and Methods). Paralleling results from determination of PHI, ppk1-GAL4/UAS-PPK1[S551V] larvae expressing a constitutively active PPK1 isoform preferred to avoid extensive locomotion over the dry surface. The wild-type control ppk1-GAL4/+ larvae moved an intermediate distance and ppk1 null mutant larvae(w¹¹¹⁸; DfA/DfB) moved a significantly increased distance over the dry glass surface before becoming stranded. When assayed under the same conditions except at high humidity levels(75%), both ppk1-GAL4/UAS-PPK1[S551V] and ppk1-GAL4/+ larvae displayed significantly increased locomotion over the dry glass surface. Error bars represent SEM with n>15 for all values. **P<.01, ***P<.0001, one-way ANOVA with Tukey posttest.