Experimental Techniques in Host-Plant Resistance


Book Description

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.



















Host-Plant Selection by Phytophagous Insects


Book Description

For more than 20 years insect/plant relations have been a focus for studies in ecology and evolution. The importance of insects as crop pests, and the great potential of insects for the biological control of weeds, have provided further impetus for work in this area. All this attention has resulted in books on various aspects of the topic, and reviews and research papers are abundant. So why write another book? It seems to us that, in the midst of all this activity, behavior has been neglected. We do not mean to suggest that there have not been admirable papers on behavior. The fact that we can write this book attests to that. But we feel that, too often, behavior is relegated to a back seat. In comparison to the major ecological and evolutionary questions, it may seem trivial. Yet the whole process of host-plant selection and host-plant specificity amongst insects depends on behavior, and selection for behavioral differences must be a prime factor in the evolution of host-plant specificity. In writing this book, we hope to draw attention to this central role of behavior and, hopefully, encourage a few students to attack some of the very difficult questions that remain unanswered.




Insect Life History Patterns


Book Description

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.