Temporal and spatial variations in leaf herbivory within a canopy of Fagus crenata.

This study investigated spatio-temporal variation in the leaf area consumed by insect herbivores within a canopy of Fagus crenata, with reference to the light conditions of leaf clusters. There was no clear relationship between photosynthetic photon flux density (PPFD) and consumed leaf area (CLA) in May, immediately after leaf flush, but CLA decreased with an increase in PPFD after June. Leaf mass per area, carbon concentration, C/N ratio, concentration of total phenolics, and condensed tannin concentration were higher in leaves under high light intensity than those of leaves under low light. On the other hand, the nitrogen concentration of leaves decreased as light availability increased. Consequently, within-tree variation in light availability affects the consumption of leaves by insect herbivores through temporal changes in leaf characteristics.