Indirect flight muscles in the rice water weevil,Lissorhoptrus oryzophilusKuschel, are greatly reduced in adults during winter. Muscle regeneration occurs in the spring just before adult exodus from overwintering sites. Once adults establish themselves in a flooded rice-field, the indirect flight muscles degenerate as females begin oviposition. First-generation adults possess well-developed indirect flight muscles; they exit fields in which they develop. Large numbers fly to aestivo-hibernation sites where muscle degeneration promptly occurs. Some first-generation adults move to young rice, if available, where muscle degeneration and oviposition occurs.