Heterozygous flies often have a patch of tergite tissue on the dorsal surface of T3, which has characteristics of A2, A3 or A4. The haltere shows a transformation towards wing. A1 shows a transformation to T3 on the dorsal surface, and a transformation of the ventral surface to that of a more posterior segment.

Heterozygotes with wild type allele show strong transformation of haltere to wing. Ubx²⁵/+/+ show partial suppression of the phenotype. Ubx²⁵/Ubx²⁵/+ flies are inviable. Ubx²⁵/Ubx²⁵ and Ubx²⁵/deficiency-for-Ubx show null Ubx phenotype.