Resistance and tolerance to herbivory in Salix cordata are affected by environmental factors

TitleResistance and tolerance to herbivory in Salix cordata are affected by environmental factors
Publication TypeJournal Article
Year of Publication2005
AuthorsMacDonald KP, Bach CE
JournalEcological Entomology

1. Effects of sand burial and nutrients on the ability of sand-dune willow (Salix cordata) to tolerate or resist herbivory by the beetle Altica subplicata were evaluated in field experiments. 2. To assess tolerance, all combinations of sand burial (none, 50%), nutrients (presence, absence) and beetles (presence, absence) were applied to caged plants and growth responses to herbivory were measured. Sand burial increased plant growth rate, but decreased S. cordata's tolerance to herbivory. Although nutrients increased growth, tolerance to herbivory was unaffected. 3. To assess resistance, plants were exposed to all combinations of sand burial and nutrients, and then to natural beetle colonisation. The presence of nutrients, but not sand burial, significantly increased the percentage of plants with beetles, for both adults and larvae. This decreased resistance to beetles of plants grown with added nutrients occurred only in the absence of sand burial. 4. The performance and preference of beetles were examined in laboratory experiments. Larvae developed faster and had increased pupation success on plants with nutrients added. Beetles also showed a marginally significant feeding preference for leaves grown with added nutrients. Thus, S. cordata tolerance to herbivory was affected by sand burial, whereas resistance, preference, and performance were affected by nutrient level.