Comparative Analysis of Mortality Factors of Artificial Larval Populations of the Gypsy Moth, Lymantria dispar(Lepidotera : Lymantriidae) in Hokkaido : I. Mortality Factors in Five Different Types of Forests

抄録

Mortality factors were investigated for artificial populations of Lymantria dispar larvae in 5 different types of forests in Hokkaido, Japan. In a larch plantation, a main mortality factor was predation by birds. In a natural mixed forest, the major contributors to the gypsy moth population decline were predation by insects and voles in addition to birds.No effective mortality factor was found in an open grassland. Predation rates between 2 trees in close proximity were similar, but parasitism rates varied from tree to tree.