Prepupal Changes in the Ventricular Epithelium of the European Corn Borer, Pyrausta Nubilalis (Hubn.)1

Abstract

An investigation of the digestive epithelium of the European corn borer during the winter diapause was carried out in conjunction with nutrition and food habit studies of the larvae of this insect. Histological changes associated with metamorphosis were observed at the onset of diapause, and the study became one of tracing the prepupal changes in the epithelium of the mid-gut. The European corn borer passes the winter as a mature larva in diapause. The larva pupates in the spring without further feeding. The use of the overwintering generation of larvae for studies of prepupal changes has an advantage in that the rate of the developmental changes that occur is greatly retarded by the low environmental temperatures. The several phases of metamorphosis are therefore more distinctly separate than is the case with the generation which matures and pupates during the summer. The observations reported here were repeated in studies of the histological changes associated with metamorphosis in larvae which pupated during the summer, and the same developmental changes were found to occur.