Table of Contents

1 Introduction.- 1.1 Distinguishing features of aphids.- 1.2 Origin of aphids.- 1.3 Host plant associations.- 1.4 Classification.- 1.5 Distribution.- 2 Feeding behaviour and food quality.- 2.1 Feeding behaviour.- 2.2 Food quality.- 2.3 Nitrogen metabolism.- 2.4 Symbionts.- 3 Host specificity and speciation.- 3.1 Proximate factors in host selection.- 3.2 Food quality.- 3.3 Evolution of host specificity.- 3.4 Speciation.- 4 Size.- 4.1 Size within a species.- 4.2 Optimum body size.- 4.3 Species size diversity.- 4.4 Geometrical similarity.- 4.5 Size of migrants.- 4.6 Reproduction.- 5 Resource tracking: mechanism — cyclical parthenogenesis.- 5.1 Telescoping of generations.- 5.2 Intra-clonal variation.- 5.3 Adaptability of aphid clones.- 5.4 Genetic structure.- 5.5 Sex.- 5.6 Why reproduce sexually?.- 5.7 Timing of sex.- 5.8 Sex ratios.- 5.9 Mate guarding.- 5.10 Why lay eggs?.- 6 Resource tracking: mechanism — polyphenism.- 6.1 Defence.- 6.2 Dispersal.- 6.3 Reproduction.- 6.4 Parthenogenetic reproduction.- 6.5 Sexual reproduction.- 6.6 Aestivation and hibernation.- 6.7 Ecological patterns.- 7 Resource tracking in time.- 7.1 Host alternation.- 7.2 The historical debate.- 7.3 Experimental evidence.- 7.4 Autoecious way of life.- 7.5 Generation-specific strategies.- 7.6 Habitat predictability and tactical diversity.- 7.7 Response to habitat quality.- 8 Resource tracking in space.- 8.1 Mechanisms.- 8.2 Timing.- 8.3 Distance travelled.- 8.4 Adaptive significance.- 9 Population dynamics.- 9.1 Dynamics of aerial populations.- 9.2 Intensive studies.- 9.3 Patterns.- 9.4 Processes.- 9.5 Natural enemies.- 9.6 Intraspecific differences in abundance.- 9.7 Interspecific differences in abundance.- 9.8 Abundance and global warming.- 9.9 Forecasting of pest aphid outbreaks.- 9.10 Spatialdynamics.- 10 Community structure and species diversity.- 10.1 Mutualism between plants and aphids.- 10.2 Aphids and plant growth.- 10.3 Aphids and the seeding of plants.- 10.4 Ants and plant fitness.- 10.5 Mutualism between aphids and ants.- 10.6 Endophyte-enhanced plant resistance to aphids.- 10.7 Energy and nutrient flow.- 10.8 Competition.- 10.9 Species diversity and plant architectural complexity.- 10.10 Size diversity.- 10.11 Distribution, abundance and variability.- 10.12 Rarity.- 10.13 Why are there so few species of aphids, especially in the tropics?.- 11 Epilogue.- References.