Abstract
The predation effect of Oxyopes badius YAGINUMA upon young larval colony of the pine moth, Dendrolimus spectabilis BUTLER, was investigated. Egg masses which contained different numbers of eggs (20-300) were attached on black pine trees and the emerged immature larvae were exposed to the predation of O. badius. O. badius mainly preyed on the 1st-2nd instar larvae. The larvae in colonies of small size suffered from predation more intensively than those of large one, and this tendency was well expressed by the following equation Y=51.4 log X-63.9 (r=0.814) (Y: survival rate, X: the number of immature larvae at the time of emergence).
