Distribution of the Cone Insect, Dioryctria disclusa,in Red Pine Trees.

摘要

Within tree distributions of early and late larvae of Dioryctria disclusa Heinrich,were related to distributions of their respective foods:early larvae and male strobili concentrated in the lower two crown thirds,whereas late larvae and cones concentrated in the upper two crown thirds. Neither larval stage showed significant differences in density associated with crown aspect. Between tree distributions of larvae were significantly related to quantity of food in only 2of 5years. Larvae were more abundant on trees having large crops of both male strobili and cones but quantities of male strobili and cones per tree are seldom correlated. Cone damage per tree increased linearly with cone abundance when insect population densities were large relative to cones. Percentage cone damage per tree was not significantly correlated with cone abundance. A general mathematical model of predation successfully described cone predation per tree by D. disclusa.