Line-dependent differences in locomotor performance: a comparative climbing analysis in wild-type and classical mutants of Drosophila melanogaster

Negative geotaxis climbing assays are widely used to assess neuromuscular integrity in Drosophila melanogaster, but standardized comparisons across multiple classical mutants remain limited. We compared wild-type Oregon-R flies with four mutant lines (w1118, e1, vg1, and Ser1) at 5 cm and 17.5 cm thresholds, using 2,000 flies (5 lines × 2 sexes × 20 tubes × 10 flies). Climbing height and time-to-threshold were scored from video, and climbing speed (cm/s) was calculated. Tube-level means were analysed using Kruskal-Wallis with Bonferroni-corrected Dunn's tests for line, and the Scheirer-Ray-Hare test for line × sex effects. Performance differed significantly among lines for all metrics (H ≈ 187-191, df = 4, all p < 0.001, ε2 > 0.93). Oregon-R performed best (16.25 ± 0.06 cm; long-distance speed 0.926 ± 0.011 cm/s), whereas vg1 flies were severely impaired (3.40 ± 0.07 cm; 0.029 ± 0.001 cm/s). The hierarchy Oregon-R > w1118 > e1 > Ser1 > vg1 was preserved across all metrics, in both sexes analysed as independent cohorts, in 2,000 split-half partitions and in 5,000 bootstrap resamples. Neither sex nor the line × sex interaction was significant. Because the lines were not backcrossed to a common background, the hierarchy reflects line-level differences that cannot be attributed exclusively to the focal mutations. These results support classical mutant lines as reproducible models for movement-related phenotypes.