Debraining and diapause development in Manduca sexta pupae

Debraining experiments with wounded and normal controls were done at three different ages on diapausing Manduca sexta pupae of Kentucky and Illinois stocks. With early ages of both stocks debrained pupae escaped from diapause over an extended period of time, but wounded insects developed much earlier and at the same time as the normals. With later ages of Kentucky insects there was an immediate developmental response to wounding, and debrained insects showed initiation of pharate adult development over an extended period of time. With later ages of Illinois pupae both wounded and debrained animals showed an immediate developmental response. The responses of Illinois insects to debraining were shown to occur in insects overwintering under natural conditions. The results indicate that at least four endocrine states are possible for diapausing Lepidoptera pupae.