Incorporating multiple prey into a predator's functional response.
Harmon, Jason*,1, 2, Andow, David2, 1 University of California-Davis, Davis, CA, USA2 University of Minnesota, St. Paul, MN, USA
ABSTRACT- The presence of multiple prey species can have tremendous effects on their shared predator, its foraging behavior, and ultimately its predation on a target prey species. Functional response models that have incorporated multiple prey have led to a general prediction that alternative prey should distract predation on the target prey compared to when the target is the only available resource. We suggest that these current models are insufficient for exploring the diversity of ways prey may interact through a shared predator's foraging behavior. We use a previously derived, probability-based functional response model to incorporate explicitly predator experience, including effects of alternative and target predation. This framework allows us to model the first-order effects of different foraging behaviors and ask how alternative prey affect target predation under each scenario. The resulting curves demonstrate that the presence of alternative prey can qualitatively and quantitatively alter the predator's functional response to a target prey. Moreover, when two of these simple effects on foraging are modeled simultaneously, we can see more complex patterns, including numerous scenarios where target predation can increase or decrease with the addition of alternative prey, depending upon relative prey densities. These results encourage additional exploration into the ways multiple prey species shape their shared predator's foraging and the consequences for community level interactions.
Key words: foraging behavior, functional response, shared predation
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