Thomas LoFaro and Richard Gomulkiewicz
Washington State University

We consider the spread of a rare favorable allele in a "black-hole
sink" population sustainable by recurrent immigration from a source
population.  It was shown by Gomulkiewicz et. al. 
that in the case of periodic population dynamics, the geometric mean 
fitness determines the spread of a rare favorable allele.  We use 
ergodic theory to generalize this result to population dynamics that 
may or may not be periodic.