Emergence of individual behaviour at the population level. Effects of density-dependent migration on population dynamics

The aim of this work is to study the effects of different individual behavi ours on the overall growth of a spatially distributed population. The popul ation can grow on two spatial patches, a source and a sink, that are connec ted by migrations. Two time scales are involved in the dynamics, a fast one corresponding to migrations and a slow one associated with the local growt h on each patch. Different scenarios of density-dependent migration are pro posed and their effects on the population growth are investigated. A genera l discussion on the use of aggregation methods for the study of integration of different ecological levels is proposed. (C) 2000 Academie des sciences / Editions scientifiques et medicales Elsevier SAS.