Homozygous adults show a moderate, but highly significant reduction in flight ability compared to wild type (Oregon-R). They also tend to fly erratically compared to wild type, hovering for a few seconds on take-off before flying slowly and erratically upwards. Homozygotes show a significant reduction in wing beat frequency compared to wild type. Myofibrils of the indirect flight muscles appear normal by ultrastructural analysis.

Wings are held upright. Males cannot vibrate their wings to produce the courtship song, as expected males are less successful when courting wild-type females.

Heterozygotes are flightless with a normal wing posture at 22^oC, but are capable of hopping and flying short distances at 29^oC. Homozygotes are flightless with an abnormal wing posture.

RK1. Wings held straight up, nearly meeting over thorax. Appears to interfere with processing of certain muscle proteins (Mahaffey et al.). rsd strains analyzed in recent years also carry Act88F⁸. Viability and fertility normal.

rsd¹, up¹⁰¹ has visible | dominant | cold sensitive phenotype

Act88F⁸, rsd¹, up¹⁰¹ has visible | dominant phenotype

Act88F⁸, rsd¹ has viable phenotype

Act88F⁸, rsd¹ has fertile phenotype

Act88F⁸, rsd¹ has flightless | dominant phenotype

Act88F⁸, rsd¹ has wing phenotype

Act88F⁸, rsd¹ has indirect flight muscle cell phenotype