The objective of this book is to give students and research workers an introduction to herbivore–host dynamics using the interaction between aphids and trees as a model. The reason for this is that the biology and population dynamics of these aphids are well studied, and limiting the scope enables one to focus on the problem and not be distracted by the details of many different herbivore–host systems. I have tried to make the text comprehensible to undergraduate students by avoiding much of the ecological and entomological jargon that abounds in the literature.

As stated in the Introduction I am greatly indebted to past students for doing much of the work reported here and in particular to Pavel Kindlmann and Seamus Ward for help in developing the ideas. I wish to express special thanks to Simon Leather for allowing me access to his long-term census data on sycamore aphids, Professor Furuta for supplying the cover illustration, Diana Alden for preparing the figures and Jenny Gill for sorting out the many computing problems I encountered.

I dedicate the book to June, whose support made the task possible.