2010 Volume 54 Issue 3 Pages 97-106
The camphor tree weevil Pimelocerus hylobioides is a major pest insect injurious to Illicium anisatum trees whose cut branches are used as an offering to the spirits by Buddhists and which are cultivated mainly in western Japan. We reared the weevil under various photoperiod and temperature conditions. Under both 15L9D and 12L12D photoperiods, larvae developed into pupae without entering diapause at 18, 20 and 25°C. Larvae passed through five to 13 instar stages before pupation. The numbers of larval molts increased under low-temperature conditions. The developmental zero temperature and the total effective temperature for egg, larva and pupa were 10.45°C and 137.42 degree-days (DD), 15.19°C and 1,361.58 DD, and 10.28°C and 177.34 DD, respectively. Life cycles in the warm temperate lowland and the mountain zone of Kochi Prefecture were estimated. In the warm temperate lowland, eggs laid in early summer developed into adults and emerged from the host tree in autumn, but eggs laid in mid-summer to autumn developed into adults in the second year. In the mountain zone, eggs laid in summer and autumn developed into adults in the second and third year, respectively.
