Speaker
Description
We consider a stochastic evolutionary game on a one-dimensional lattice with vacancies created by fitness-dependent death processes. Interactions between neighbors are mimicked by a prisoner’s dilemma game and an individual with higher payoff lives longer. In each time step, we choose a random site of the habitat. If the site is occupied, its inhabitant dies with probability depending its game payoff. If the chosen site is empty, the site is colonized by an offspring of its neighbors (provided at least one of the neighboring sites is occupied). We study the growth of populations from a single seed and find that its dynamics critically depends on the environment parameter. As the harshness of environment changes, phase transitions from growing population phases to vanishing population phases occur for both types of seeds, a cooperator and a defector. The transition point for cooperators is smaller than the transition point for defectors, implying the existence of a parameter region wherein only cooperative populations can exist. We also find that cooperators dominate defectors even when the environmental factor is moderate for surviving of defectors. Our observation shows that vacancies, introduced by fitness dependent death processes, provide a natural way to develop cooperative communities in a growing population.
