<Original>Studies on the Autecology of Lyctus brunneus (STEPHENS) (Coleoptera, Lyctidae) : VI. Larval Development and Instars with Special Reference to an Individual Rearing Method

Abstract

The larval development and instar number of the powder-post beetle, Lyctus brunneus (STEPHENS) were investigated mainly by the "individual rearing method" with powder-state diet and a gelatin capsule. Most of the larvae reared by this method passed through 4-6 instars under constant conditions of 24.5℃ and 70% R.H. though a few exceptionally had much more instars. In general, larval instar number varied among individuals, and tended to increase with the prolonged larval period. When larvae were in starving condition and/or in want of support for boring action, they showed supernumerary molts and weight decrease, resulting in death. Prepupa could pupate readily even without the support. The pupal duration in the present condition was ca. 10-12 days. SEM observation showed morphological changes of palpi, antennae and legs in the course of larval development with succeeding instars.