Preface

Summary

The spatial dimension of ecology, until recently rather unfashionable, is currently the subject of a surge of interest that appears to have arisen independently in a number of fields. Spatial heterogeneity and the spatiotemporal processes of dispersal and migration, and invasion and colonisation, are now receiving attention not only from ‘island biogeographers’ but also from population ecologists and geneticists, evolutionary biologists and applied ecologists. A recent editorial in the journal Ecology declared spatial dynamics to be ‘the final frontier for ecological theory’ (Kareiva, 1994). Geographers have established a new sub-discipline, ‘landscape ecology’, to integrate the biological, economic and cultural aspects of environmental heterogeneity. Technical advances in remote sensing (of both habitats and migratory movements), geographic information systems, geostatistics, biotelemetry, meteorology and climatology have spurred and sustained all of these approaches.

Central to any consideration of spatial dynamics in ecology must be the processes by which organisms move, or are moved, from one habitat location to another. Migration has been studied in many taxa, but work on insects has been particularly intense and productive, primarily because several of the world's most damaging pests are migratory, but also because insects' short life cycles make the inter-relations of migration with life history and the seasonal cycle especially evident and accessible to study.

Progress in understanding insect migration, and indeed animal migration in general, has been hampered for many years by confusion, in both concepts and terminology, about what constitutes ‘migration’.