Flight Muscle Histolysis in the Female House Cricket, Acheta Domesticus.

Flight muscle histolysis was investigated in the dorsal longitudinal muscles (DLMs) of the cricket. Histolysis in the DLMs was characterized by analysis of total protein content, tissue wet weight, and relative percent muscle shortening. Initial declines of total protein indicated the JH signal initiating histolysis occurred by Day 2. Histolysis was essentially complete by Day 3. Ligation of Day 1 crickets prevented histolysis but this inhibition could be prevented by continual topical treatments with methoprene. Ligation of Day 2 crickets did not prevent histolysis. A requirement for active protein expression was demonstrated by analysis of synthesis block by cycloheximide and short-term incorporation of $\sp{35}$S-methionine. Cycloheximide treatments prevented histolysis. Disappearance of Z-disks was observed in DLMs of cycloheximide-treated crickets suggesting some aspects of histolysis may not require protein synthesis. Autofluorographic imaging of DLM proteins separated by electrophoresis revealed apparent coordinated regulation of protein expression. These results suggest flight muscle histolysis in the cricket is an example of active programmed cell death with requirements for hormonal control of protein expression.