Beat-Va neurons undergo local neurite pruning or cell death. (A) Gal4 lines generated by Janelia were screened in silico, 87 drivers that label sparse populations were verified for consistency and driver strength and 28 of those were chosen for further evaluation at 6 h APF, 12 h APF (HE), and 18 h APF. (B–B″) Z-projection of ventral nerve cords labeled by BeatVa-Gal4 driving an UAS-mCD8::GFP transgene at wL3 (B), 6 h APF (B′), and HE (B″). Surviving lateral neurons are noted by green circles, and dead or dying lateral neurons are pink. Yellow arrows denote neurite debris. (C–C″) Surface rendering of single-cell morphology of the anterior Beat-Va lateral cell (Beat-VaL) at wL3 (C), 6 h APF (C′), and (C″) HE. (D–D″) Surface rendering of posterior lateral cells at wL3 (D), 6 h APF (D′), and HE (D″). (E–E″) Surface rendering of Beat-Va medial cells (Beat-VaM) at wL3 (E), 6APF (E′), and HE (E″). Intact neurites in magenta and fragmented neurites in cyan. (F) Quantification of the number of branch points in Beat-VaM cells. Error bars are SEM. (G) Quantification of the total combined length of all filaments in Beat-VaM cells. Error bars are SEM. (H) Composite model of both Beat-VaL and Beat-VaM neurons. (F and G) Each data point represents one cell. wL3 cells were imaged from five animals. HE cells were imaged from three animals. Comparisons by Student’s t test. Scale bar is 20 µm. The boxed region is magnified below each panel. Colored data points correspond to the representative image shown in the figure.