Evolution Of Insect Migration And Diapause

This volume is an outgrowth of a Symposium entitled "Evolution of Escape in Space and Time" held at the XV International Congress of Entomology in Washington, D. C., USA in August, 1976. The choice of topic was prompted by recent advances in evolutionary ecology and the apparent suitability of insect migration and dia pause as appropriate material for evolutionary studies. In the event, that choice seems amply justified as I hope a perusal of these papers will show. These Sympos ium papers hardly cover the topic of the evolution of escape mechanisms exhaustively, and I am sure everyone will have his favorite lacuna. Some of the more obvious ones are indicated by Professor Southwood in his Concluding Remarks at the end of the book. The purpose of the Symposium, however, was not complete coverage, but rather to indicate the potential inherent in insect migration and diapause for the study of evolutionary problems. In that I think we have succeeded reasonably well. These papers are expanded and in some cases somewhat altered versions of the papers delivered in Washington. This has allowed greater coverage of the topics in question. I suggested a format of a general overview of a topic emphasizing the author's own research con tributions. In general the papers follow this outline although emphases vary. Two of the authors, Dr. Rainey and Dr. Lumme, were unable to attend the Symposium. Dr. Rainey's paper was read by Mr. Frank Walsh, but Dr.

This book was developed out of a symposium at the XVII International Congress of Entomology held in Hamburg, Germany, on August 21, 1984. This symposium was organized by Drs. William Bradshaw and Hugh Dingle, who subsequently asked us to edit the proceedings. The chapters represent, for the most part, papers that were read in Hamburg but have been expanded and updated. The goal of this volume is to provide a comprehensive view of current research on insect life cycles, including field and laboratory studies, broad comparisons among species or local populations, and intensive studies of single populations, as well as theoretical research. Of necessity, given the magnitude of research now being carried out on insects, some important research programs are not included, and therein lie the makings of future volumes. This volume is divided into three parts. The first part, Geographical Patterns in Insect Life Cycles, explores various applications of a comparative method that has been valuable in investigating the potential for variability in life history parameters and the relation of these parameters to important variables in the environment.

This volume results from a symposium entitled "Species and Ufe History Patterns: Geographic and Habitat Variation", held during the National Meeting of the Entomo logical Society of America in Denver, Colorado, USA in November, 1979. The stimu lus to assemble papers on this theme emerged from continuing discussions with col leagues concerning controversies in ecology and evolutionary biology, namely those associated with plant-herbivore interactions, life history theory, and the equilibrium status of communities. The study organisms used in this series of reports are all either herbivorous insects or those intimately associated with plants. In this volume we stress the variation found in life history traits and address some of the problems inherent in current life history theory. We include as life history traits not only traditional variables such as fecundity, size of young, and age to first and peak reproduction, but also diapause and migration, traits that synchronize reproduction with favorable plant resources. Because life history traits of phytophagous insects are influenced in part by spatial and temporal variation in the quality and availability of their host plants, we also consider the role that dis continuities in plant quality play in reducing insect fitness. Lastly, much of the tra ditional life history theory concerns itself with differences between the evolution of traits or constellations of traits when populations incur primarily density-independent, compared to density-dependent, mortality. Consequently, we address this issue and attempt to shed light on the equilibrium status of several phytophagous insect com munities.

Recent studies have shown that genetic polymorphisms play an important role in structuring the seasonal life cycles of insects, complementing an earlier emphasis on the effects of environmental factors. This book presents current ideas and recent research on insect life--cycle polymorphism in a series of carefully prepared chapters by international experts, covering the full breadth of the subject in order to give an up-to-date view of how life cycles are controlled and how they evolve. By consolidating our view of insect life--cycle polymorphism in this way, the book provides a staging point for further enquiries. The volume will be of interest to a wide variety of entomologists and other biologists interested in the control and evolution of life cycles and in understanding the extraordinarily complex ecological strategies of insects and other organisms.

This balanced comprehensive account traces the alterations in body form undergone by insects as they adapt to seasonal change, exploring both theoretical aspects and practical issues. Topics explored include natural history, genetics, evolution, and management of insect adaptations.

No International Congress of Entomology would now be complete without a symposium on insect life-cycles. The latest Congress, held at Vancouver, BC (Canada), in July 1988, was no exception, with a symposium on the genetics, evolution, and coordination of insect life cycles organized by Bill Bradshaw and Valerie Brown. The present volume arose from papers contributed by most of the speakers at the symposium, together with papers from other invited authors. In editing the book, I have been assisted greatly by the other authors, particularly Bill Bradshaw, Val Brown and Fritz Taylor. All contributors agreed to referee two other chapters, a system that worked efficiently and effectively: I thank all authors for performing this task in the face of other demands on their time. I would also like to thank Philip Corbet, John Greenslade, Bryan Clarke, and Gillian Thompson of Springer for their help. Nottingham Francis Gilbert January 1990 Contents List of Contributors ....................................................... xiii SECTION I. Genetics of Life-Cycle Traits Introduction William E. Bradshaw ................................................. 3 1 Understanding the Evolution of Insect Life-Cycles: The Role of Genetic Analysis.

Captures the full scope of the literature, integrating ecological and molecular mechanisms that enable insects to enter a dormant state.