Mis-expression of Rbp6Scer\UAS.cSa under the control of Rbp6Scer\UAS.cSa causes male germ cell loss in the testis due to cell death. Over half of the Scer\GAL4nos.UTR.T:Hsim\VP16>Rbp6Scer\UAS.cSa lack germ cells in the testis, while the remainder have large spermatocytes abutting the somatic hub.