Homozygous females have tiny ovaries which almost completely lack egg chambers beyond oogenic stage 7. Most early, vitellogenic egg chambers have nurse cells and a single oocyte. Egg chambers in which the oocyte has begun to take up yolk are seen but are rare. Occasionally egg chambers contain two oocytes, which are always located at nearly opposite poles of the egg chamber. Approximately once per ovary, an egg chamber has twice the normal number of nuclei. Older egg chambers appear to degenerate. Homozygous, Nup154^zk-1/Nup154^k07701b and hemizygous males have tiny testes which appear to contain no germ cells. Some germ cells are occasionally present in homozygous larval gonads, unlike the completely empty adult testes. However, very few germ cells per testis are seen (usually 0-10 cells) and the germ cells present are spermatocytes not organised into normal germline cysts. Small cells present at the apical tip in wild type are absent in mutants, suggesting absence of renewing germline during late larval stages. Nup154^zk-1/Nup154¹⁰⁴³² males have an "intermediate" testis phenotype with what appear to be degenerating germ cells and occasional spermatocytes.

Males have tiny testis due to an absence of developing germline.