The production of diapause eggs is a strategy for survival adopted by microcrustaceans living under adverse environments. This strategy also, aids dispersion and colonization in new environments. In the long term, this colonization process can enhanced genetic isolation as the first step in the process of species evolution. The present study is: (a) wider review of the diapause process in inland water crustaceans and its ecological, evolutionary and biogeographical implications, and (b) it’s application to microcrustacean assemblages in inland waters in southern Patagonia. In the literature the diapause strategy was described from anostracans, cladocerans and copepods as microcrustaceans, and amphipoda in malacostracan crustaceans. High crustacean species richness was recorded from Southern Patagonia, this region having species of southern South American and Sub-Antarctic islands origin. Their spatial distribution is probably explained by the presence of migratory birds. Also, many habitats of the microcrustaceans are ephemerals, that would be studied under metapopulation and metacommunities view point.