Homozygotes (zygotic mutants) die during the first larval instar stage, while embryos lacking both maternal and zygotic Rbsn-5 function die early during embryogenesis.
Homozygous clones in the wing disc show defects in endocytosis.
Adult wings containing homozygous clones have patches of tissue with planar cell polarity defects; hairs are deflected from the proximodistal axis and orient towards either the posterior or anterior margin. Occasionally, cells within the presumed clone have double or shorter hairs than normal. Cells within homozygous clones in the pupal wing at pre-hair initiation consistently have emerging trichomes that are misoriented, pointing away from the clone, and the emerging hairs are shorter than in controls. Mutant cells fail to acquire the expected hexagonal shape. Mutant cells have a narrower apical cross section (characteristic of vein cells) in approximately 25% of clones, and these clones are usually adjacent to vein areas and positioned at the pupal wing border. Adult wings containing homozygous clones often have patches of extra or thickened wing veins. There is a weak proximal non-autonomy in trichome polarity, such that in proximal cells near to homozygous clones, trichomes point away from the clone, hexagonal packing is altered and occasionally cells abutting the clone are multi-haired.