Michael E. N. Majerus - Moths

Sarah A. Corbet ScD

S.M.Walters, ScD, VMH

Prof. Richard West, ScD, FRS, FGS

David Streeter, FIBiol

Derek A. Ratcliffe

The aim of this series is to interest the general reader in the wildlife of Britain by recapturing the enquiring spirit of the old naturalists. The editors believe that the natural pride of the British public in the native flora and fauna, to which must be added concern for their conservation, is best fostered by maintaining a high standard of accuracy combined with clarity of exposition in presenting the results of modern scientific research.

In nearly half a century since the publication of E. B. Fords New Naturalist Moths, there have been exciting advances in our understanding of the biology of moths. In particular, moths can now tell us more than ever before about the ways in which natural populations evolve, even over short periods within an ecologists lifetime. Michael Majerus brings us these developments in this new book. As a boy he eagerly devoured Fords earlier volume, which greatly influenced his subsequent career, and he sees this present book as a direct outcome of that early stimulus. Like his eminent predecessor, he combines an infectious enthusiasm for the natural history of the group with a disciplined scientific approach and a particular fascination for ecological genetics, a field in which moths provide excellent tools for digging into evolutionary questions. This book sets the rich complexity of moth biology in an evolutionary context and shows how the study of this group illuminates more general principles; in sharing his enthusiastic affection for moths the author brings us an alluring introduction to topics such as insect biology, mimicry, predation, dispersal and ecological genetics. By drawing attention to the many unsolved questions to which naturalists might contribute, even without expensive equipment, he tempts us to become active participants in the study of moths as they evolve before our eyes, adapting to the rapid environmental changes that result from human activities.

There are many things that this book is not. It is not a book about moth collecting. It is not a book about how to identify moths. It is not a book about how to study moths. But it is a book about moths: about their lives, their behaviour, their struggles to survive and reproduce within a hostile environment, their multitude of enemies, their extraordinary capabilities in avoiding them, and their future in the face of human-driven change. It is also a book about their beauty.

I was incredibly flattered when I was asked to write this book. I have been a fan of the New Naturalist series since I was ten and a fan of E.B. Ford for just as long, for it was on my tenth birthday that I was given a present of Fords Butterflies. To emulate Ford in writing two books for the New Naturalist series I felt was a great honour. However, I only accepted this undertaking after considerable thought and with some trepidation.

I think it necessary to make it clear that this book is neither a revision nor simply an updating of Fords wonderful New Naturalist Moths. Indeed, although professionally my field of expertise is that of ecological genetics, a field of science that Ford founded, I have tried to avoid the basic genetical ground covered in Fords Moths. This is largely because the fundamentals of genetics described so clearly by Ford nearly half a century ago have changed little, and I would still recommend anyone with an interest in the way that characteristics of moths are inherited to read Fords two books, Butterflies and Moths.

This book is concerned more with the place of moths in the biological world. It is thus a book on the natural history of moths, dealing with their behaviour, ecology and evolution. The first chapter introduces the subject of moths, discusses human perceptions of them and describes how they are related to what most people would recognise as the other group of the order Lepidoptera, the butterflies. Chapter 2 describes the basic life cycle of moths, treating each of the four major stages separately while showing how they fit together in the overall cycle from generation to generation. In Chapter 3, the basic processes of evolution that have moulded and continue to mould moths are discussed.

Chapters 4-8 consider how moths live their lives, in a context of their interactions with one another and the rest of their environment. The backdrop of these chapters is a very simple equation that is relevant to all populations of all organisms. It is simply that changes in population size depend on the birth rate, the death rate and any migration into or out of the population. Chapter 4 deals with reproduction and all that that entails, from sex determination through the various and complex aspects of courtship and mating to the point when females finally lay their eggs. Chapter 5 follows the life cycle through the main feeding stage, the larval stage, to the pupa and finally the adult. Here host plant preferences and habitat specialisations are considered. The adult theme is continued in Chapter 6 with a consideration of moths flying abilities, their dispersal, migration and distributions. Death rate is considered in Chapter 7, in which the various biotic enemies of moths, including man, and other causes of moth death, are described. Chapter 8 tells the other side of the story in a discussion of the many and various survival traits that moths have evolved to foil those that would make a meal of them.

Chapter 9 is the only chapter that appears to deal with one single phenomenon. It is the phenomenon of melanism. Here the case of the rise and fall of melanic Peppered moths is considered in the wider context of melanism, in relation both to industrialisation and otherwise. The importance of cases of melanism in moths as examples of the action of natural selection is stressed.

The final chapter considers the interrelationship between moths and man. Positive and negative interactions are considered from both the human and the moth point of view.

The book is furnished with a glossary to help with scientific words where I have felt that their use was either necessary or desirable. I have used references sparingly to avoid disrupting the flow of the text. All scientific references mentioned are included in the bibliography at the end of the book.

Throughout the book I have used the English names of moths (where I know them), giving the scientific name on first usage in each chapter. The names used follow Skinner (1984), Emmet (1991a) and Bradley (2000).

I have had a passion for moths from a very young age. I still have. I am also a trained scientist. My training has added tremendously to my appreciation for and fascination in the moths that I encounter. I hope that in this book I have introduced some readers to scientific ideas and principles that will enhance the way they look at these beautiful insects, while leaving untarnished the magic and mystery of moths.

Many people have assisted in bringing this book to publication. These may be reasonably divided into four groups. First, I am grateful to a number of people who have helped me with the illustrations. Many of the photographs are my own. However, nearly all of those that are not were taken by John Bebbington. These include Plates 2b, 2d, 3d, 4c, 4f, 5b, 6d, 6e, 6f, 7c, 8c, 8d, 9a, 9b, 9e, 9f, 10e, 10f, 11c, 11d, 11e, 12a, 12b, 12c, 13f, 16c, 16d and 16e. John also contributed a number of the black and white photographic figures. He is acknowledged where appropriate in the legends for these. I am extremely grateful to John for allowing me to use his pictures and for the many hours of interesting discussions on moths that we have had over the years. Dr Clair Brunton and Mr Jim Stalker were heavily involved in the research that led to Plates 14d and 14e. I am grateful to Anne Bebbington for her skill in producing a number of the line drawings for me. Tamsin Majerus produced several of the computer-generated line figures, and also helped with many other details of the production. Finally, I am grateful to Professor Charlie Ellington and to the journal