Leaf traits and insect herbivory levels in two Mediterranean oaks and their hybrids through contrasting environmental gradients.

This article investigates insect herbivory and its relationship with leaf traits, climatic gradients, and hybridization in two Mediterranean oak species—*Quercus faginea* subsp. *faginea* and *Quercus pyrenaica*—and their hybrids. Over two years and across a temperature gradient in central-western Spain, the study found that hybrids exhibited lower herbivory damage than both parental species despite having intermediate leaf traits, supporting the "hybrid resistance hypothesis." Leaf area was identified as the primary leaf trait influencing herbivory levels, with larger leaves experiencing more damage; leaf size also increased with mean annual temperature. The findings suggest that factors other than leaf traits, possibly genetic or ecological, contribute to the hybrids' greater resistance, and that temperature influences herbivory intensity partly through effects on leaf size and phenology.