The impact of plant genetic variation, drought, and leaf nitrogen on plant-herbivore interactions

Plant genotype, drought stress, and their interaction are among the factors contributing to the susceptibility of plants to herbivory. The plant's nitrogen concentration, a critical and often limiting nutrient, differs with plant genotype and drought. Still, few studies have investigated the impact of the interaction of genotype and drought on herbivory and plant nitrogen. We established a common garden in Duluth, MN, of tall goldenrod, Solidago altissima, collected from a local Minnesota site to analyze the effects of goldenrod genotype and drought stress on leaf nitrogen and the preference and performance of the chrysanthemum lace bug, Corythucha marmorata. Lace bugs had oviposition, nymph, and adult preferences among host plant genotypes, water treatments, and among genotype and water treatment combinations. Nymph and adult survival and adult mass varied significantly due to plant genotype, water treatment, the interaction of plant and water treatment, and the interaction of treatment with lace bug density. Oviposition preference and offspring performance were significantly positively related. Leaf nitrogen increased with the increasing severity of the water limitation in the absence of lace bugs. However, in the presence of lace bugs, there was no difference in nitrogen among water treatments.