Analysis of Cyp301a1^f02301 flies reveal a variable expressivity cuticle phenotype in both males and females. About 63% of Cyp301a1^f02301 flies show no phenotype. The rest shows cuticle abnormalities ranging from a slight malformation of the cuticle between the tergites to a complete loss of the tanned cuticle layer down the dorsal midline of the abdomen. The banding on the abdomen appear severed, causing a misalignment of symmetry between the tergites. Transverse sections of the abdominal cuticle of mutants at eclosion reveals that there appears to be an intact cuticle layer (albeit thinner and non-pigmented), which spans the two sides of the tergites. Calcofluor staining shows that chitin is not secreted in these areas, although the remaining cuticle appears correctly pigmented, similar to control sections.

Compared to control flies, where transverse sections clearly show an even distribution of abdominal sensory bristles lining the cuticle layer, in Cyp301a1^f02301 flies there appears to be a lack of abdominal sensory bristles in regions surrounding the central cavity, where this cuticle is improperly formed.

Cyp301a1^f02301 larvae fed 20-hydroxyecdysone during development eclose with a significantly reduced incidence of the severe and mild abdominal phenotype, and significantly increased incidence of the wild-type cuticle phenotype when compared with those fed control food.

Cyp301a1^f02301 mutants show reduced survival, compared with wild-type, with only 80% of larvae forming pupae and of these, only 90% eclose to adults.