(A) The Q system was used to drive srb-13 expression in male amphid sensory neurons under the osm-6 promoter. QA addition induces SRB-13 expression. (B) Diagram showing male developmental stage and QA treatment period. Red line indicates the spermatogenesis period. Arrow indicates start of mating and sperm navigation assay. (C) Wild-type hermaphrodite uteri images 1 hour after mating to males incubated with and without QA (panel B). Fluorescent sperm are red due to MitoTracker labeling. Spermathecae are outlined in yellow. Bar, 20 μm. (D) Quantification of sperm distribution values (mean ± SEM) from males incubated with and without QA (panel B). Number of scored uteri is on the right. *, p < 0.005 compared to transgenic srb-13(xm1) males with the Q system but without QA. 1, control is in the fog-2(q71) background. The transgenic strain is in the him-8(e1489) background. Additional underlying data can be found in S1 Data. E, embryo; L1–L4, 4 larval stages; QA, quinic acid; QF, quinic acid 1F transcriptional activator; QS, quinic acid 1S transcriptional repressor.