Diet of intraguild predators affects antipredator behavior in intraguild prey

In two-predator, one-prey systems with intraguild predation and patchily distributed prey, the intraguild prey may face a choice between prey patches with and without intraguild predators. To minimize falling victim to intraguild predation, intraguild prey are expected to perceive cues specifically associated with the presence of intraguild predators. We investigate whether intraguild prey avoided intraguild predators and which cues triggered this behavior in a system composed of plant-inhabiting arthropods. We found that intraguild prey recognized intraguild predators from a distance, based on their diet: they avoided odors of intraguild predators that had consumed shared prey but did not avoid odors of intraguild predators that had fed on other diets, including a diet of conspecifics. When intraguild prey were foraging on a patch, detection of intraguild predators led to longer periods of immobility and to fewer captures of the shared prey. However, intraguild predators that were either starved or had previously consumed intraguild prey posed a higher risk to intraguild prey than did intraguild predators that had consumed the shared prey. We conclude that the cues used by intraguild prey to avoid intraguild predators are associated with the circumstances under which they encounter intraguild predators in the field and not to different degrees of danger. Key words: food webs, intraguild predation, predator avoidance, predator diet. [Behav Ecol 16:364–370 (2005)] Predators affect prey populations not only by killing preybut also by inducing antipredator behavior (Lima, 1998; Werner and Peacor, 2003). Prey may attempt to escape from predators to avoid being killed, but this comes at the expens