Molecular Aspects of Insect-Plant Associations

by S. Ahmed, L.B. Brattsten

Overview

Thanks to the meticulous and enthusiastic work of insect collectors and taxonomists over the past hundred years and more, we have today a large amount of information on the feeding habits and life styles of sev­ eral hundred thousands of insect species. Insects that feed on plants during at least one of their life stages constitute about half of the three-quarters of a million described species. Their numbers both in terms of species and individuals together with their small but macroscopic sizes makes the insect-plant biological interface perhaps the most conspicuous, diverse and largest assemblage of intimate interspecies interactions in existence. It is also perhaps the most important biological interface because of the plants' role as primary producers upon which all other forms of earthly life depend, thereby bringing herbivorous insects occasionally into direct competition with human food and fiber production. Early enthusiasm revealed many remarkable specializations and associ­ ations between insects and plants, and occasionally assigned chemical me­ diators for them. However, the modern practices of large scale crop pro­ tection by synthetic pesticides and their attendant problems, particularly with resistance in "pests" and destruction of natural enemies, have been in large measure responsible for drawing our attention to the mechanisms whereby plants control insect populations and insects adapt to the plants' defenses. These practices have also brought home the importance of chemical mediators in practically all aspects of insect activities and, in parti­ cular, the importance of plant allelochemicals in maintaining and balan­ cing insect-plant associations.

Product Details

ISBN-13:	9781461290407
Publisher:	Springer US
Publication date:	11/01/2011
Edition description:	1986
Pages:	358
Product dimensions:	7.01(w) x 10.00(h) x 0.03(d)

Table of Contents

The Perception of Plant Allelochemicals that Inhibit Feeding.- 1. Introduction.- 2. Insect Feeding Behavior.- 2.1. Generalized Sequence.- 2.2. Neuroethological Approach.- 3. The Contact Chemoreceptive System.- 3.1. Structure of Chemoreceptive Sensilla.- 3.2. Function of Chemosensilla.- 3.2.1. Contact Chemosensory Systems.- 3.2.2. Sensitivity of Contact Chemosensory Cells.- 3.2.3. Specificity of Contact Chemosensory Cells.- 3.2.4. Specificity of Chemoreceptor Sites.- 4. Inhibitory Plant Allelochemicals.- 4.1. Major Classes of Allelochemicals.- 4.2. Modes of Action on Chemosensory Cells.- 4.2.1. Potential Types of Action.- 4.2.2. Deterrent Chemosensory Cells.- 4.2.3. Effects of Alkaloids.- 4.2.4. Effects of Terpenes.- 4.2.5. Effects of Other Allelochemicals.- 4.3. Modes of Action on Other Excitable Cells.- 5. Summary.- 6. Acknowledgement.- 7. References.- Allelochemicals and Alimentary Ecology: Heterosis in a Hybrid Zone?.- 1. Introduction.- 1.1. A Case Study of Insect-Plant Interactions. The Insects.- 1.2. Estimation of Growth Characteristics.- 1.3. The Plant Allelochemicals.- 2. Hybridization Studies and Experimental Approach.- 3. Results.- 4. Discussion.- 5. Summary.- 6. Acknowledgement.- 7. References.- Enzymes Involved in the Metabolism of Plant Allelochemicals.- 1. Introduction.- 2. Cyhrome P-450.- 2.1. Occurrence.- 2.1.1. Occurrence in Species.- 2.1.2. Age-Related Distribution of Activity.- 2.1.3. Tissue Distribution and Subcellular Localization.- 2.2. Biochemical Characteristics of Microsomal Cyhrome P-450.- 2.3. Apparent Reactions Catalyzed by Cyhrome P-450.- 2.3.1. CH-Hydroxylations.- 2.3.2.—-Bond Oxygenations.- 2.3.3. Oxygenation at an Unshared Electron Pair.- 2.4. Measurements of Cyhrome P-450-catalyzed Reactions in Insects.- 2.5. Inhibition of Cyhrome P-450.- 2.5.1. Endogenous Inhibitors.- 2.5.2. Synergists as Inhibitors.- 2.5.3. Plant Allelochemicals as Inhibitors.- 2.6. Induction of Cyhrome P-450.- 2.7. Regulation of Cyhrome P-450 Activity.- 3. Other Biological Oxidations.- 3.1. FAD-Monooxygenase.- 3.2. Dehydrogenases.- 4. Biological Reductions.- 4.1. Nitro-, Azo-, and Tertiary Amine Oxide Reduction.- 4.2. Carbonyl Reductases.- 5. Hydrolases.- 5.1. Esterases.- 5.1.1. Carboxylesterases.- 5.2. Glycosidases.- 5.3. S-Glycosyl Hydrolases.- 5.4. Ether Hydrolases.- 5.5. Other Hydrolases.- 6. Group Transfer Enzymes.- 6.1. Glutathione Transferases.- 6.2. Hexose Transferases.- 6.3. Amino Acid Conjugations.- 6.4. N-Acetylation.- 6.5. Phosphate Conjugation.- 6.6. Sulfotransferases.- 6.7. Thiosulfate Sulfur Transferase.- 7. Summary.- 8. Acknowledegment.- 9. References.- Consequences of Induction of Foreign Compound-Metabolizing Enzymes in Insects.- 1. Introduction.- 2. Induction of Cyhrome P-450-Dependent Monooxygenases.- 3. Induction of Glutathione Transferases.- 4. Induction of Esterases.- 5. Induction of Epoxide Hydrolases.- 6. Consequences of Enzyme Induction.- 6.1. Toxicological Implications.- 6.2. Ecological Implications.- 7. Summary.- 8. Acknowledgement.- 9. References.- Adaptive Divergence of Chewing and Sucking Arthropods to Plant Allelochemicals.- 1. Introduction.- 2. Plant Resistance to Chewing and Sucking Insects.- 3. Susceptibility Differences to Toxicants.- 3.1. Susceptibility to Synthetic Toxicants.- 3.2. Susceptibility to Naturally-Derived Toxicants.- 4. The Aphid as a Model Phytophage of Phloem Chemicals.- 4.1. Phloem Toxicology.- 4.2. Chemical Ecology of Aphids.- 5. Adaptive Detoxification.- 5.1. Sequestration.- 5.2. Excretion.- 5.3. Metabolism of Plant Allelochemicals.- 5.4. Metabolism of Pesticides and Other Synthetic Toxicants.- 5.5. Alternative Detoxification Strategies.- 6. Target Site Selectivities.- 7. Summary.- 8. Acknowledgement.- 9. References.- Fate of Ingested Plant Allelochemicals in Herbivorous Insects.- 1. Introduction.- 2. Terpenes.- 2.1. Monoterpenes.- 2.1.1. Bark Beetle Pheromones.- 2.1.2. Pyrethrins.- 2.1.3. Iridoid Glycosides.- 2.2. Sesquiterpenes.- 2.2.1. Juvenile Hormones.- 2.2.2. Sesquiterpene Antifeedants.- 2.3. Diterpenes.- 2.4. Triterpenes.- 3. Steroids.- 3.1. Phytosteroids.- 3.2. Ecdysones.- 3.3. Cardenolides.- 4. Phenylpropanoids.- 4.1. Precocenes.- 4.2. Furanocoumarins.- 4.3. Phenolics.- 5. Flavonoids.- 6. Amino acids.- 7. Cyanogenic Glycosides.- 8. Glucosinolates.- 9. Alkaloids.- 9.1. Tobacco Alkaloids.- 9.2. Pyrrolizidine Alkaloids.- 10. Summary.- 11. Acknowledgement.- 12. References.- Target Site Insensitivity in Insect-Plant Interactions.- 1. Introduction.- 2. TSI and Synthetic Insecticides.- 2.1. The Sodium Gate.- 2.2. The Synapse.- 3. TSI in Natural Systems.- 4. Examples of TSI in Insect-Plant Interactions.- 4.1. Cardenolide Insensitivity.- 4.2. Cyanide Insensitivity.- 4.3. Canavanine Insensitivity.- 4.4. Nicotine Insensitivity.- 5. Coevolutionary Consequences of TSI.- 5.1. Consequences for the Insects.- 5.2. Consequences for the Plants.- 6. Summary.- 7. Acknowledgement.- 8. References.- Behavioral Adaptations in Insects to Plant Allelochemicals.- 1. Introduction.- 2. Avoiding Defenses in Time.- 3. Avoiding Defenses in Space.- 4. Mechanisms to Avoid Triggering Defenses.- 5. Overwhelming Plant Defenses.- 6. Blocking Plant Defenses.- 7. The Cost of Avoiding Plant Defenses.- 8. Summary.- 9. Acknowledgement.- 10. References.- Devising Pest Management Tactics Based on Plant Defense Mechanisms, Theoretical and Practical Considerations.- 1. Introduction.- 2. General Strategies to Devising Pest Management Schemes.- 3. Key Processes in Plant-Insect Encounters.- 3.1. Examples from a Model System.- 3.2. A Generalized Model.- 4. Manipulating Plant-Insect Interactions.- 5. Can Pest Management Tactics Bases on Plant Defenses Favor Stability?.- 6. Summary.- 7. Acknowledgement.- 8. References.