Most homozygotes complete embryogenesis and become motile larvae, but die at some point during the larval stage - no viable adults are recovered.

Hakai¹ homozygotes partially rescued by Scer\GAL4^da.G32-mediated expression of Hakai^{Scer\UAS.T:Ivir\HA} exhibit minor morphological abnormalities including small wings, kinked legs and short life span. Some of the rescued flies are sterile.

Hakai¹ wing disc clones proliferate at a rate comparable to their wild type twin clones. Adult flies carrying Hakai¹ clones develop wings of normal size and shape - the only noticeable defect is occasional duplications of mechanosensory bristles.

Hakai¹ germline clones complete normal oogenesis but most fertilized embryos die before hatching. Cuticle defects range from poorly formed denticles, to discontinuity/loss of denticle belts, to a near absence of exoskeleton. Head involution and dorsal closure are also defective. Segmentation is disrupted and epithelial integrity is lost. In rare cases, paternally rescued escapers develop to adulthood.

Endoderm and visceral mesoderm fail to reach the proper positions in embryos lacking maternal and zygotic Hakai, leading to defective midgut formation.

Migrating tracheal cells of Hakai¹ germline clone-derived embryos have misshapen and misrouted dorsal branch termini - some cells are only loosely associated with the rest of the branch. Duplication of terminal cells is frequent. Abnormally long filopodia are found extending in the wrong direction.