Life History and Reproduction of the Ambrosia Beetle, Scolytoplatypus mikado BLANDFORD (Coleoptera, Scolytidae)

Life history and reproduction were studied for the ambrosia beetle, Scolytoplatypus mikado BRANDFORD. S. mikado passed two generations annually. The number of eggs deposited per gallery varied largely among galleries, ranging from 0 to 103 with an average of 23.9. The mean fecundity per gallery positively correlated with the diameter of an infested log, whereas there were no significant correlations between the fecundity per gallery and the attack density in each log. The sex ratio of offspring was approximately 1 : 1. The survival rate of offspring in each gallery was strongly correlated with the number of eggs deposited per gallery. These results suggested that S. mikado populations are likely to have the potential to increase rapidly in response to increasing availability of host trees.