Depending on the insertion used, 31-43% of Scer\GAL4^179Y, Kal1^Scer\UAS.cAa larvae fail to hatch from the egg, and the surviving larvae show a delay in hatching. When two Kal1^Scer\UAS.cAa insertions are used, 72% of larvae fail to hatch.

Embryos bearing Scer\GAL4^179Y and two Kal1^Scer\UAS.cAa insertions show appreciable head skeleton alterations, but no other defects. With high penetrance, the mouth hooks lack the sclerotic material that forms the base of the hook. The dorsal and ventral processes of the hooks are variably reduced, leaving only the anterior curved part in the strongest cases. With lower penetrance, the whole cephalopharyngeal skeleton shows a deformed structure, especially the median tooth, the H-piece, and the lateralgraten.

Flies expressing Kal1^Scer\UAS.cAa with Scer\GAL4^Bx-MS1096 at 18[o]C do not show any appreciable phenotype. At 25[o]C, these flies show splitting of the L4 vein into anterior and posterior branches with low penetrance.

Flies expressing two copies of Kal1^Scer\UAS.cAa with Scer\GAL4^Bx-MS1096 at 18[o]C show a slight reduction in the proximal-distal axis of the wing and a reduction of the L2-L3 intervein territory, often leading to the fusion of the two veins. Notching of the L3-L5 wing margin is occasionally seen. There is also appreciable lethality during the pupal stage. At 25[o]C, these flies show a high lethality with only some escapers showing a dramatic reduction of the whole wing.