Females containing homozygous germline clones produce phenotypically normal eggs. However, 84.5% of the embryos derived from these eggs fail to hatch. Two different cuticle phenotypes are seen for the dead embryos. The first category appear to be normally developed, although they fail to hatch. The second category arrest early in development and appear to have defects at the anterior of the embryo. All of the surviving adult progeny from females containing homozygous germline clones are female, suggesting zygotic rescue by the paternal X chromosome. These female survivors are fertile (there is no "grandchildless" phenotype).

Imp^H44/Imp^H149 third instar larvae show a significant decrease in the number of boutons per muscle area at the neuromuscular junction compared to controls. The mutant larvae appear somewhat sluggish.

Imp^H44/Imp^H149 adult escapers have severe locomotor defects, having highly uncoordinated twitching and grooming leg movements. They frequently fall over as they try to walk and cannot readily right themselves.