Induced plant resistance and susceptibility to late-season herbivores of wild radish

Wild radish is an annual plant that exhibits broad spectrum induced resista nce to herbivores. In two experiments, we placed potted plants [control, ma nually clipped, and damaged by Pieris rapae (L.) larvae ] in the field and assayed for oviposition by P rapae (a specialist herbivore), damage by nea beetles (a specialist herbivore), and damage by rabbits (a generalist herbi vore). Induced responses attracted oviposition by P. rapae and increased da mage by flea beetles, while having a minimal effect on rabbit herbivory. Pl ant families had different levels of resistance to herbivory by rabbits and to oviposition by P. rapae, but not to herbivory by nea beetles. Manual cl ipping was a poor inducer of plant responses. Induced responses in wild rad ish can be a double-edged sword, increasing herbivory by some herbivores un der certain conditions. while reducing herbivory by other herbivores.