ABSTRACT
This chapter reviews the characteristics of prey that affect their vulnerability and ultimately their contribution to energy and matter flux within food webs of ecosystems. We will learn that one of the most important factors affecting the susceptibility of prey is age and development, with the relative production of biomass at vulnerable life stages influencing stability of food webs. Prey are not helpless and have many physical, behavioral, and chemical characteristics that may reduce predation. Some of these traits are permanent. Others are induced by the presence of predation. These trait-mediated interactions are an important frontier in the study of trophic ecology. Humans are able to work around prey defenses and often target life stages that are typically well protected from predators. This leads to instability in food webs.
