Very few females containing presumptive homozygous germline clones lay eggs, and these females lose the ability to lay eggs after 1-2 days.

Homozygous lethality occurs mostly during the second larval instar stage or at the second to third instar larval moult, with the remaining animals dying as third instar larvae that fail to pupariate. Feeding of second instar homozygous larvae with 20-hydroxyecdysone provides substantial rescue of the developmental defects. Most dare⁴/dare³⁴ larvae pupariate, but then undergo premature lethality, mostly dying late in metamorphosis or early in adult life. The adults show an extreme behavioural phenotype; they are unable to stand, lying on the substratum with legs and wings twitching. Striking degeneration is seen in the adult nervous system; large vacuoles are seen in a variety of brain regions including the antennal lobes, the optic lobes, the ellipsoid body and the fan-shaped body of the central complex and in the thoracic nervous system. The vacuoles in the optic lobes appear after optic lobe assembly is complete or largely complete, and enlarge as the animal ages. Other brain regions and the thoracic nervous system also appear to assemble normally and then undergo degeneration. The earliest evidence of vacuoles is seen in the ellipsoid body and fan-shaped body, where degeneration first becomes apparent during the late pupal stages. Gross degeneration is not seen in the antenna.