Meeting Abstract

38.2  Saturday, Jan. 5  Sensory signals and predator search performance at the low prey density limit HEIN, A. M.*; MCKINLEY, S. A.; University of Florida; University of Florida amhein@ufl.edu

Organisms of all types collect sensory measurements from their environments. In some cases, these measurements contain information about the locations of resources such as prey. We show how simple mathematical models of predator sensing and search decision-making can be scaled up to describe one of the fundamental rate functions associated with predator-prey interactions: the predator functional response, which describes how the per-capita rate at which predators encounter and consume prey depends on prey density. Most classic models of functional response assume that, until a predator locates a prey item, the predator moves through its environment in a manner that is independent of the locations of prey. We show that relaxing this assumption and allowing predators to detect and modify search behavior in response to noisy sensory signals emitted by prey causes a qualitative change in functional response. Predators that alter their movement behavior in response to prey signals encounter prey more frequently than predators that search without using information about prey positions. Interestingly, this difference in search performance is strongest at low prey densities, where predators that utilize even minimal noisy prey signals have a huge advantage over predators that forage without using sensory data. We suggest that evolution of long-range prey sensory mechanisms such as sensitive olfaction and the corresponding decision-making machinery may be driven by the need to reliably locate prey when prey density is extremely low. More generally, our methodology provides a means of scaling up individual-level sensory processes to describe a fundamental population-level rate parameter that has bearing on species interactions, population dynamics, and food web stability.