fs(1)h4/fs(1)h1 females are fertile at 18[o]C, but lose fertility at 26.5[o]C.
Approximately 50% of progeny from fs(1)h4/fs(1)h1 mothers, raised at semipermissive temperatures (22[o]C), do not survive embryogenesis. Cuticle analysis reveals a weak pair-rule phenotype, which is most consistently observed in even parasegments. 75% of defects seen involve the second abdominal segment.
Mutation does not affect the level of w expression in ph-plac+3 flies.
Females heterozygous for fs(1)h4 that also carry Df(3R)red-P93 give rise to progeny with a high frequency of homeotic transformation of T3 to T2.