stochastic community dynamics

Gavrilets S & Michalakis Y 2008 Effects of environmental heterogeneity on victim–exploiter coevolution. Evolution 62:3100-3116.

• such heterogeneity in fitness may help to maintain polymorphism and population differentiation as has been observed in simulation studies using more complex stepping-stone systems and/or more complex genetics and/or genetic drift (Gandon et al. 1996; Lively 1999; Gandon and Michalakis 2002)
• genetic drift can contribute to maintaining polymorphism by desynchronizing different populations

• similar behavior, that is the maintenance of genetic variation under spatially homogeneous selection, can be observed in our much simpler island model
• this suggests that isolation by distance, genetic drift, and complex genetics are not necessary for the maintenance of variation in host–parasite systems