1;Preface;6 2;Further Reading;7 3;Contents;8 4;Evolutionary Ecology of Plant Signals and Toxins: A Conceptual Framework;10 4.1;Introduction;10 4.2;What Is Communication?;11 4.2.1;What Is Information?;11 4.2.2;What Is Biological Communication?;11 4.2.3;What Is a Signal?;12 4.2.4;What Is Allelopathy?;13 4.2.5;What Is the Difference Between a Toxin and a Signal?;14 4.2.6;Differences Between Plant and Animal Communication;15 4.3;How Can Communication Between Plants Evolve?;16 4.3.1;Evolution of Signaling Through Individual Selection;17 4.3.2;Evolution of Signaling Through Kin or Group Selection;21 4.3.3;Evolution of Signaling Through Sexual Selection;22 4.4;A Conceptual Framework for the Evolutionary Ecology of Plant Signals;23 4.5;Conclusions;23 4.6;References;25 5;The Chemistry of Plant Signalling;29 5.1;Introduction;29 5.2;Approaches to the Isolation and Identification of Plant and Insect-Derived Signals;30 5.2.1;Collection of Biological Samples for Analysis;30 5.2.1.1;Dynamic Headspace Collection;30 5.2.1.2;Solid Phase Microextraction (SPME);31 5.2.1.3;Vacuum Distillation;32 5.2.1.4;Liquid-Liquid Extraction;32 5.2.1.5;Solid Phase Extraction (SPE);32 5.2.1.6;Stir Bar Sorptive Extraction (SBSE);33 5.2.1.7;Other PDMS Materials;33 5.2.1.8;Vapour Phase Extraction (VPE);33 5.2.1.9;In-Situ Derivatisation;34 5.3;Recent Advances;34 5.3.1;Plant Derived Chemical Signals;36 5.3.1.1;cis-Jasmone;36 5.3.1.2;Oxylipins and Phytohormones;36 5.3.2;Insect-Derived Chemical Signals;38 5.3.2.1;Bruchins;38 5.3.2.2;Volicitin and Related Compounds;38 5.3.2.3;Caeliferins;40 5.4;Structure-Activity Relationships;40 5.5;Biosynthetic Studies;42 5.6;Future Prospects;43 5.7;References;45 6;Plant Defense Signaling from the Underground Primes Aboveground Defenses to Confer Enhanced Resistance in a Cost-Efficient Ma;50 6.1;Introduction;50 6.2;Perception of PGPR by the Plant;51 6.3;ISR Signal Transduction;52 6.4;Priming for Enhanced Defense;54 6.5;Mechanisms of Priming of Defense Responses;56 6.6;Costs of Induced Defenses;57 6.7;Fitness Benefits of Priming Under Disease Pressure;58 6.8;To What Extent are Plants in the Field Already Primed?;60 6.9;Outlook;61 6.10;References;62 7;Allelopathy and Exotic Plant Invasion;68 7.1;Introduction;68 7.2;Allelopathy and Exotic Plant Invasion;69 7.3;Allelopathy and Microbial Accomplices in Invasion;72 7.3.1;Nitrogen Fixers;75 7.3.2;Mutualists;76 7.4;Future Directions;77 7.5;References;77 8;Volatile Interaction Between Undamaged Plants: A Short Cut to Coexistence;81 8.1;Introduction;81 8.2;Role of Plant Volatiles;83 8.2.1;The Role of Plant Volatiles in Allelopathy;84 8.2.2;VOCs as Cues in Plant-Plant Interaction;85 8.3;Plant Responses to Allelobiosis, Methyl Salicylate and Methyl Jasmonate;87 8.4;Conclusions;88 8.5;References;89 9;Volatile Chemical Interaction Between Undamaged Plants: Effects at Higher Trophic Levels;93 9.1;Introduction;93 9.2;Increased Plant Genetic Diversity Affects Higher Trophic Levels;94 9.2.1;Between Species Diversity;94 9.2.2;Within-Species Genotype Diversity;95 9.3;Volatile Interactions Between Undamaged Plants Affect Higher Trophic Levels;95 9.3.1;Allelobiosis Between Different Plant Species;96 9.3.2;Allelobiosis Between Different Genotypes of the Same Plant Species;98 9.4;Does Plant Genetic Diversity Affect Natural Enemies Via Volatile Interaction and Diversity?;101 9.5;Conclusions;102 9.6;References;103 10;Within-Plant Signalling by Volatiles Triggers Systemic Defences;105 10.1;Introduction;106 10.2;Talking Trees;107 10.3;VOCs as Within-Plant Signals;109 10.3.1;Shortcomings of Signalling by VOCs;109 10.3.2;Benefits of VOCs as Plant Signals;111 10.3.3;Airborne Cues as Within-Plant Signals: Exotic Cases or Common Strategy?;113 10.4;References;114 11;Volatile Interactions Between Undamaged Plants: Effects and Potential for Breeding Resistance to Aphids;119 11.1;Introduction;120 11.2;Aphids as Herbivores in Plant-Plant Chemical Interactions;120 11.3;Effects of Plant Diversity on Herbivore Abundance;121