Monday, August 3, 2009 - 2:50 PM

OOS 2-5: Predator and prey spatial games in varying patches

Barney Luttbeg, Oklahoma State University

Background/Question/Methods

The spatial distributions of predators and prey have been predominantly studied with the assumption that the other species is relatively fixed in space. For many biological systems this is an unrealistic depiction. Predators and prey are often capable of moving and changing their spatial distributions in response each other. Recent models and empirical studies have begun to reveal that predator and prey movement rules and their resulting spatial distributions are the products of spatial games. From several models it has been predicted that predators will favor patches that have more of the prey’s resources present when the predator’s movement rule has been shaped by the potential movement rules of the prey. This spatial distribution has been found in some empirical systems and there has been evidence that predators are cueing on the presence of the prey’s resources. However, most of these models of predator and prey game dynamics have not included the dynamics of the prey’s resources growing and being depleted.
Results/Conclusions

I will present a model that examines how resource dynamics affect predator and prey spatial games and how the resulting games affect ecological dynamics. The model is a genetic algorithm in which the movements of predators and prey can be influenced by the distributions of different resources, competitors, and predators and by the characteristics of different patches. Non-game models have assumed that predators should cue on the distributions of their competitors and their prey, while the game models have predicted they should cue on the prey’s resources. By varying which of these cues are available for the predator’s movement rule, I will show how the addition of predator and prey spatial games alters predictions about ecological dynamics. The resulting rules also depend on the relative timing of opportunities for movement and foraging. For many parameter values predators favor patches that either have more of the prey’s resources or more nutritious resources, but whether they cause prey to avoid those patches depends on the relative rates of predator and prey movements. I will show that this can have large effects on the abundance and distributions of predators, prey, and resources.