Larval Diapause in the Spotted Cutworm, Xestia c-nigrum LINNE (Lepidoptera : Noctuidae)

Abstract

The spotted cutworm, Xestia c-nigrum LINNE, from three localities in northern Japan was reared under a long (16L-8D) and a short (8L-16D) day at 18, 23 or 26°C. In general, the larval development in the short day was much delayed, often with extra moults and high mortality before pupation, as compared with that in the long day. This delay of development began at the third larval instar and was followed inhibition of growth and feeding at older instars. This diapause syndrome was more pronounced at lower temperatures. Local differentiation in the intensity of diapause was suggested by comparison of the three stocks.