Meeting Abstract
Predators are known to affect population size and demography of their prey by increasing mortality. However, the nonlethal effects of predators are sometimes overlooked. Predators can alter foraging behavior and habitat selection in prey animals, as well as reproductive physiology and phenology. In this study, we sampled side-blotched lizards in eastern Oregon from a single metapopulation occupying adjacent canyons along the Owyhee River, but separated by a perennial stream. The primary difference between sample sites was the presence or absence of collared lizards, a large, predatory lizard that preys upon side-blotched lizards. Side-blotched lizards occurring with collared lizards had lower body condition and delayed vitellogenesis, likely due to more cautious foraging or reduced foraging opportunities. Additionally, side-blotched lizards occurring without collared lizards had higher baseline corticosterone concentrations and a stronger response to a uniform stressor. Although stress response is adaptive for escaping predators, chronic stress can cause deleterious effects to cognitive, immune, and reproductive systems, reducing overall fitness. Thus we infer that constant pressure from a large and conspicuous predator may have caused side-blotched lizards to adopt a blunted stress response.
