Mutants exhibit increased long term facilitation (LTF) at the neuromuscular junction.
Homozygous females do not lay eggs. Approximately 50% of homozygous larvae survive the pupal stage to eclosion. By the adult stage, 43% of homozygous females have germlineless ovaries, 32% have "differentiated ovaries" (containing recognisable egg chambers and/or germline cells in at least one ovariole) and 25% of females have one germlineless and one differentiated ovary. Homozygous female germline clones induced at the third larval instar stage produce ovarioles that contain on average 4.2 +/- 2.0 mature egg chambers but no other germ cells. Females containing homozygous female germline clones achieve an oviposition efficiency of 56% (for absolute number of eggs laid by the females). These eggs (derived from females containing homozygous germline clones mated to homozygous males) are sometimes capable of developing into adulthood.
Small ovary phenotype. None of the germ cells appear to undergo asymmetric divisions. Ovarioles contain only two clusters of apparently undifferentiated germline cells. Some ovaries in newly eclosed females completely lack germline cells though individual ovarioles are visible, in other ovaries the ovarioles are not recognisable. A small number of ovarioles contain 2-3 normally developing egg chambers that eventually develop into morphologically normal mature oocytes. Preoogenic germline development is also aberrant, germline stem cells of late third instar larval ovaries have no obvious spectrosome organisation.
Females are not able to maintain a normal germarial structure: instead of retaining active stem cells each ovariole houses only one or two germ line derivatives. When the non-functional egg chambers leave the germarium they are not replaced, the germarium assumes the appearance of a thin tube. Stem cells cannot be maintained and instead differentiate into cystoblast-like cells.