title: Coevolution in a one predator-two prey system.
abstract: BACKGROUND
  Our understanding of coevolution in a predator-prey system is based mostly on pair-wise interactions.
  
  
  RESULTS
  Here I analyze a one-predator-two-prey system in which the predator's attack ability and the defense abilities of the prey all evolve. The coevolutionary consequences can differ dramatically depending on the initial trait value and the timing of the alternative prey's invasion into the original system. If the invading prey species has relatively low defense ability when it invades, its defense is likely to evolve to a lower level, stabilizing the population dynamics. In contrast, if when it invades its defense ability is close to that of the resident prey, its defense can evolve to a higher level and that of the resident prey may suddenly cease to evolve, destabilizing the population dynamics. Destabilization due to invasion is likely when the invading prey is adaptively superior (evolution of its defense is less constrained and fast), and it can also occur in a broad condition even when the invading prey is adaptively inferior. In addition, invasion into a resident system far from equilibrium characterized by population oscillations is likely to cause further destabilization.
  
  
  CONCLUSIONS
  An invading prey species is thus likely to destabilize a resident community.
authors.affiliation: Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan. mougi@bio-math10.biology.kyushu-u.ac.jp
authors.forename: Akihiko
authors.initials: A
authors.lastname: Mougi
mesh_terms: D000465:Algorithms; D000818:Animals; D005075:Biological Evolution; D017753:Ecosystem; D008954:Models, Biological; D011157:Population Dynamics; D011235:Predatory Behavior / Q000502:physiology*