Forest Health Hot Topic. Mountain pine beetle, another insect native to our area, is a member of a group of insects known as bark beetles. It spends its entire life cycle underneath the bark of its host tree until it emerges as an adult and flies away in search of a new tree to lay its eggs. The beetle can reproduce in all species of pine, but outbreaks often develop in dense stands of large, older lodgepole pine and dense stands of mid-sized ponderosa pine. In Glacier, the mountain pine beetle can also attack whitebark pine found in higher elevations. Skip to footer. Unlike the western spruce budworm, a single generation of mountain pine beetles can kill a tree. In their quest for food, the beetles end up girdling the tree, disrupting the essential flow of food and water throughout the tree. Dying trees will generally begin to appear “red and dead” 8-10 months after an attack. National Park Service Logo.