Tracheal septate junctions are functional in embryos lacking both maternal and zygotic ed function (mutant embryos derived from homozygous female germline clones), as assayed by a standard dye diffusion assay. There are no obvious defects in luminal chitin organisation in the trachea of these embryos.

Mutant embryos lacking both maternal and zygotic ed function show defects in head involution.

Mutant embryos lacking both maternal and zygotic ed function have highly convoluted tracheal tubes compared to wild type. This convoluted morphology is not caused by increased tube length, but appears to be due to deformation of the trachea which occurs due to the deep epidermal grooves and shorter than normal distance between embryonic segments which are seen in these embryos.

Mutant embryos lacking both maternal and zygotic ed function have interruptions in the dorsal and lateral tracheal tubes. Approximately 30% of fusion sites in the lateral trunk show breaks, and breaks are seen near the fusion sites of the dorsal trunk in 3.1% of cases. The mutant embryos have extra fusion cells at the tracheal fusion sites; only 34% of the sites have two fusion cells (the phenotype seen in 95% of wild-type fusion sites), while 37% contain 3 and 28% contain between 4 and 7 fusion cells.