Demographic characteristics of Callidiellum rufipenne Motschulsky populations on Japanese cedar logs, oviposition schedule of female adult, mortality factors within logs, and adult population parameters were investigated. The average longevity of adults on the rearing experiment was 18.0 d for males and 16.6 d for females. Female adults could lay eggs soon after emergence without maturation feeding, and average fecundity was 18.1. Two principal parasitoids, a braconid and an ichnneumonid, were found near dead larvae under the bark. Adults began to fly to the cedar logs about mid-April, 4 d after logs were placed on the forest floor, and disappeared in late May. Daily survival rates were 0.772 for males and 0.863 for females, and mean resident time on logs was 3.9 d for males and 6.8 d for females. There were fewer females than males throughout the season, especially early in the flight period. A comparison of population properties of C. rufipenne and Semanotus japonicus (Cerambycidae) clearly indicated that both were related closely to the specific characteristics of their habitats, i.e., C. rufipenne as a secondary insect uses dead trees, whereas S. japonicus as a primary insect uses living trees. The insect studied here formerly had been placed in the genus Palaeocallidium (Kusama & Takakuwa 1984). Reproduction; Reproductive behaviour; Reproductive productivity; Life cycle and development; Development; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Ecology; Land and freshwater zones; Palaearctic region Callidiellum rufipenne (Cerambycidae); Egg laying; Oviposition schedule; Fecundity; Longevity; Hymenopteran parasites; Braconidae & Ichneumonidae; Records; Population dynamics; Japan; Honshu; Nara Braconidae; Ichneumonidae; Coleopteran hosts; Callidiellum rufipenne; Records; Japan; Honshu; Nara; Records from coleopteran hosts