The nonrandom distribution of insect herbivory among plants is generally thought to reflect variation in plant-defense strategies and/or insect preferences for particular plant genotypes, where less-defended plants suffer the most damage. However, we postulated that aggregated distributions of herbivory may occur when (a) plants support greater herbivore densities under conditions with better resources (plant's choice), (b) plants with more nutrient-rich leaves are preferred more by herbivores (herbivore's choice), or (c) both, where plants living in better conditions can support more herbivores and have higher-quality leaves that herbivores also prefer. We tested these hypotheses using a population of black tupelo, Nyssa sylvatica Marshall (Cornales: Nyssaceae) and the tupelo leafminer, Antispila nysaefoliella Clemens (Lepidoptera: Heliozelidae). We found that the among-tree variation in herbivore density was positively associated with nutrient-cycling rate and not with leaf-nitrogen content, which supports the plant's choice hypothesis. Our results suggest that environmental conditions may have a more important role than host plant quality per se in determining the distribution of herbivores among trees.