The expression of Reepl1Scer\UAS.P\T.A under the control of Scer\GAL4nos.UTR.T:Hsim\VP16 leads to males exhibiting significant increases in the number of Bam-positive spermatogonial cysts (which present insignificant changes in apoptosis and only rarely present an abnormal 8-cell number) and in male fecundity, and a small but significant increase in the mitotic index, but not in the number, of the germline stem cells, as compared to controls.