Spermatogenesis normal but mating behaviour fails because wild type females refuse to react to the courtship attempts of mutant males. Effect is not absolute, and depends on allele (there is a strong correlation between male sterility and severity of impairment in the female phenotype) and varies between affecting 6.7% (otu¹⁴) and 86.6% (otu¹²) of mutant males.

56.5% of homozygous ovarioles produce nurse cell/oocyte syncytia, 29% have tumorous oogonia and 14.5% produce pseudonurse cell chambers with no oocyte. Most otu¹¹/otu⁴ female flies are fertile although the nurse cells, unlike those of wild-type females, contain banded chromosomes. Differentiated (DIF) class allele.

Differentiated allele; over half of homozygous ovarioles contain differentiated cystocytes (forming pseudonurse cells, nurse cells or oocytes), a substantial number of tumorous ovarioles are also produced. 78% of hemizygous ovarioles are quiescent.

differentiated; ovarian chambers with pseudonurse cells or nurse cell/oocyte synctia