Fig. 6.

DSK peptides inhibit male courtship behavior. a Predicted amino acid sequence and mature peptides from the Dsk gene in wild-type, ∆Dsk1 and ΔDsk2 flies. b Validation of ∆Dsk mutants by anti-DSK staining. Representative of 5 male brains each. Arrows indicate cell bodies of MP neurons. Scale bars, 50 μm. c Dsk mutant males have normal courtship toward virgin females. Genotypes as indicated. n = 24 for each. p = 0.22, Kruskal–Wallis test. d Dsk mutant males do not show abnormal male–male courtship. n = 20 for each. p = 0.42, Kruskal–Wallis test. e Courtship inhibition by activating DskGAL4 neurons is dependent on the DSK-2 peptide. n = 24 for each. p < 0.001, Kruskal–Wallis test. **p < 0.001, ***p < 0.001 and p > 0.1 (n.s.), post hoc Dunn’s multiple comparisons test. f Down-regulation of Dsk gene expression using UAS-DskRNAi as revealed by anti-DSK staining in males raised at 22 °C. Scale bars, 50 μm. g Quantification of anti-DSK signal in the brain. n = 7 and 6. ***p < 0.01, Mann–Whitney U test. h Courtship inhibition by activating DskGAL4 neurons is dependent on DSK, as knocking down Dsk by RNAi restores courtship by DskGAL4/UAS-dTrpA1 males at 30 °C. n = 24 for each. p < 0.001, Kruskal–Wallis test. ***p < 0.001 and p = 0.85 (n.s.), post hoc Dunn’s multiple comparisons test. i Acutely over expression of DSK peptides two days before courtship test significantly suppresses male courtship. n = 24, 21, 20, and 20, respectively. p < 0.001, Kruskal–-Wallis test. ***p < 0.001 and p > 0.99 (n.s.), post hoc Dunn’s multiple comparisons test. n.s. not significant. Error bars indicate SEM. Source data are provided as a Source Data file