Nutrient supply alters goldenrod’s induced response to herbivory

Recent interest in using trait-based approaches to understand and predict ecosystem processes and evolutionary responses to environmental change (both biotic and abiotic), highlights the need to understand the relative importance of genetic and environmental sources of intraspecific trait variation within local populations of dominant species. Here, I combine plant defense theory with functional approaches to quantify genetic trait variation and phenotypic trait plasticity of nine goldenrod (Solidago altissima) genotypes derived from a local field population in Connecticut, USA to herbivory along a nutrient supply gradient. I found that increasing nutrient supply changed the dominant plant defense strategy from tolerance to induced resistance. Induced resistance was detected through decreased herbivore growth rates and a behavioral feeding shift of grasshoppers to older leaf tissue. This could not be fully accounted for through stoichiometric changes in leaf tissue quality. A multi-dime...