The virtual impossibility of extracting the many different species from a habitat with equal efficiency by a single method (e.g. Nef, 1960). 1.1 Population estimates Population estimates can be classified into a number of different types; the most convenient classification is that adopted by Morris (1955), although he used the terms somewhat differently in a later paper (1960). 1.1.1 Absolute and related estimates The animal numbers may be expressed as a density per unit area of the ground of the habitat. Such estimates are given by nearest neighbour and related techniques (Chapter 2), marking and recapture (Chapter 3), by sampling a known fraction of the habitat (Chapter 4-6) and by removal sampling and random walk techniques (Chapter 7). Absolute population The number of animals per unit area (e.g. hectare, acre). It is almost impossible to construct a budget or to study mortality factors without the conversion of population estimates to absolute figures, for not only do insects often move from the plant to the soil at different developmental stages, but the amount of plant material is itself always changing. The importance of obtaining absolute estimates cannot be overemphasized.

The papers in this volume were presented at a symposium/workshop on "The Estimation and Analysis of Insect Populations" that was held at the University of Wyoming, Laramie, in January, 1988. The meeting was organized with financial support from the United States - New Zealand Cooperative Science Program and the University of Wyoming. The purpose was to bring together approximately equal numbers of quantitative biologists and biometricians in order to (1) provide a synthesis and evaluation of currently available methods for modeling and estimating parameters of insect population, and to (2) stimulate research into new methods where this is appropriate. The symposium/workshop attracted 46 participants. There were 35 papers presented in four subject areas: analysis of stage-frequency data, modeling of population dynamiCS, analysis of spatial data, and general sampling and estimation methods. New results were presented in all these areas. All except one of the papers is included in the present volume.

The book, Estimation and Analysis of Insect Populations, is about estimation of population parameters in stage frequency structured populations and the subsequent use of this information in development of mathematical and computer models. The unique contribution of this work is the extensive, comparative review of statistical methods used in the estimation of stage frequency parameters, the review of modeling techniques, and presentation of new approaches to both parameter estimation and modeling. Thus, this book will be of value in both pedagogic and research applications. This book will be of interest to advanced undergraduate students, graduate students, and research scientists in the fields of statistics, entomology, and other areas of applied population ecology. It could well serve as either the primary text or as an important reference in courses involving estimation, analysis, and modeling of stage frequency structured populations. As such, advertisement should be directed toward academic, departments and research laboratories involved in natural resource management (e.g. Fisheries and Wildlife, Entomology, Forestry), or applied mathematics (e.g. Statistics).

Insects as a group occupy a middle ground in the biosphere between bacteria and viruses at one extreme, amphibians and mammals at the other. The size and gen eral nature of insects present special problems to the student of entomology. For example, many commercially available instruments are geared to measure in grams, while the forces commonly encountered in studying insects are in the mil ligram range. Therefore, techniques developed in the study of insects or in those fields concerned with the control of insect pests are often unique. Methods for measuring things are common to all sciences. Advances sometimes depend more on how something was done than on what was measured; indeed a given field often progresses from one technique to another as new methods are discovered, developed, and modified. Just as often, some of these techniques fmd their way into the classroom when the problems involved have been suffici ently ironed out to permit students to master the manipulations in a few labo ratory periods. Many specialized techniques are confined to one specific research laboratory. Although methods may be considered commonplace where they are used, in another context even the simplest procedures may save considerable time. It is the purpose of this series (1) to report new developments in methodology, (2) to reveal sources of groups who have dealt with and solved particular entomological problems, and (3) to describe experiments which might be applicable for use in biology laboratory courses.

Only one generation ago, entomology was a proudly isolated discipline. In Comstock Hall, the building of the Department of Entomology at Cornell University where I was first introduced to experimental science in the laboratory of Tom Eisner, those of us interested in the chemistry of life felt like interlopers. In the 35 years that have elapsed since then, all of biology has changed, and entomology with it. Arrogant molecular biologists and resentful classical biologists might think that what has happened is a hostile take-over of biology by molecular biology. But they are wrong. More and more we now understand that the events were happier and much more exciting, amounting to a new synthesis. Molecular Biology, which was initially focused on the simplest of organisms, bacteria and viruses, broke out of its confines after the initial fundamental questions were answered - the structure of DNA, the genetic code, the nature of regulatory genes - and, importantly, as its methods became more and more generally applicable. The recombinant DNA revo lution of the 1970s, the development of techniques for sequencing macromolecules, the polymerase chain reaction, new molecular methods of genetic analysis, all brought molecular biology face to face with the infinite complexity and the exuber ant diversity of life. Molecular biology itself stopped being an isolated diScipline, pre occupied with the universal laws of life, and became an approach to addressing fas cinating specific problems from every field of biology.

Covering a wide range of disciplines, this book explains the formulae, techniques, and methods used in field ecology. By providing an awareness of the statistical foundation for existing methods, the book will make biologists more aware of the strengths and possible weaknesses of procedures employed, and statisticians more appreciative of the needs of the field ecologist. Unique to this book is a focus on ecological data for single-species populations, from sampling through modeling. Examples come from real situations in pest management, forestry, wildlife biology, plant protection, and environmental studies, as well as from classical ecology. All those using this book will acquire a strong foundation in the statistical methods of modern ecological research. This textbook is for late undergraduate and graduate students, and for professionals.

The earliest land-plants evolved around 450 million years ago from aquatic plants devoid of vascular systems. The diversification of flowering plants (angiosperms) during the Cretaceous period is associated with speciation in insects. Early insect herbivores were mandibulate, but the evolution of vascular plants led to the co-evolution of other forms of herbivory, such as leaf feeding, sap-sucking, leaf mining, tissue borer, gall forming and nectar-feeding. Plant defense against biotic stress is an adaptive evolution by plants to increase their fitness. Plants use a variety of strategies to defend against damage caused by herbivores. Plant defense mechanisms are either inbuilt or induced. Inbuilt mechanisms are always present within the plant, while induced defenses are produced or mobilized to the site where a plant is injured. Induced defense mechanisms include morphological, physiological changes and production of secondary metabolites. Host plant resistance (HPR) is one of the eco-friendly methods of pest management. It protects the crop by making it less suitable or tolerant to the pest. While books on theoretical aspects of HPR are available, an exclusive book on the practical aspects is lacking. There is a wide gap between the theory and the experimental procedures required for conducting studies on plant resistance for the post graduate students and young researchers. A dire need for a book on practical aspects was strongly felt. Initially a practical manual was prepared which eventually evolved into the present book. We hope this book provides information on major aspects of screening crop germplasm, sampling techniques, genetic and biochemical basis of HPR, behavioural studies on pheromone and plant volatiles, and some of the recent approaches in HPR. Further, the references provide the scientific articles and books as additional information to readers and workers alike.