DDX4 and cyst: To investigate the toxicological effects of Sb exposure in Drosophila testes, we examined the numbers of GSCs and elongated spermatid clusters in Drosophila testes following Sb exposure at 0, 0.3, 0.6, and 1.2 mg/mL.Vasa was used to label germ cells, and De-cad marked somatic hub cells and cyst cells in testes (Fig. S1).