Mhc^Y583S homozygosity in a Mhc¹⁰ background induces a flightless phenotype and adults typically display a wings-up phenotype; the heterozygosity condition in a Mhc¹⁰ background also leads to a significant and progressive decrease in flight ability.

In the Mhc^Y583S, Mhc¹⁰ double homozygosity condition, pupal and 2h-old adult indirect flight muscles show regularly packed myofibrils, with six thin filaments around each thick filament and well-formed sarcomeres; however, 2 days-old adult indirect flight muscles show some disruption in myofibril morphology (thick and thin filaments disperse into neighboring myofibrils), and 7 days-old adult indirect flight muscles show continued filament dispersion (some fusion of neighboring myofibrils). In the Mhc^Y583S/+, Mhc¹⁰/Mhc¹⁰ condition, the pupal and 2h-old adult indirect flight muscles show no obvious defects; however, 2 days-old adult indirect flight muscles show some disruption in myofibril morphology (thick and thin filaments beginning to disperse from myofibrils and possibly fusing with neighboring myofibrils); 7 days-old adult indirect flight muscles show thick and thin filaments merging into neighboring myofibrils.