Defensive Traits during White Spruce () Leaf Ontogeny.

Changes during leaf ontogeny affect palatability to herbivores, such that many insects, including the eastern spruce budworm ( (Clem.)), are specialist feeders on growing conifer leaves and buds. Developmental constraints imply lower toughness in developing foliage, and optimal defense theory predicts higher investment in chemical defense in these vulnerable yet valuable developing leaves.