A large-population limit for a Markovian model of group-structured populations

A Markovian model of group-structured (two-level) population dynamics features births, deaths, and migrations of individuals, and fission and extinction of groups. These models are useful for studying group selection and other evolutionary processes that occur when individuals live in distinct groups. We show that the sample paths of a properly scaled sequence of these models converge in an appropriate Skorohod space to a deterministic trajectory that is a unique solution to a quasilinear evolution equation. The PDE model can therefore be justified as an approximation to the Markovian one.