Typically, the damage caused by native insects that had been recruited by exotic conifers without congeners was limited, whereas the damage caused by native insects that had been recruited by exotic conifers with congeners often led to severe outbreaks at the time the shift between hosts occurred.
On a aussi observé des différences de recrutement selon la guilde et les types alimentaires, avec une dominance des herbivores se nourrissant de manière externe sur le feuillage. Les insectes recrutés ne produisent que rarement des dégâts, voire des pullulations, sur les conifères sans congénères natifs.