Split violin plots of piRNA expression fold change between AcGFP (control) and piRNA factor(s) overexpressed libraries. Overexpression of Siwi-D670A, BmVasa-E339Q and both mutants increase non-TE-derived piRNA (red, 626 genes) while TE-derived piRNA (blue, 818 genes) does not change. Bonferroni-corrected P-values and the effect sizes (r) were calculated by Asymptotic Wilcoxon rank sum test. 