Phallus in wonderland

Abstract

Promiscuity: An Evolutionary History of Sperm Competition and Sexual Conflict, T.R. Birkhead, Faber & Faber, 2000.£9.99 pbk (viii 11 272)ISBN 0 571 19360 9This is a truly excellent book. The fact that it is addressed to a nonacademic audience should not deter serious students of biology from reading it. It presents a very authoritative and up-to-date account of our knowledge and understanding of sperm competition and of other aspects of sexual competition in animals and provides a fresh a stimulating theoretical framework for this rapidly developing field.Behavioural ecology is currently in a somewhat stagnant phase, its journals full of numerous, rather similar studies, albeit of a rich diversity of animals. The loss of momentum in what has been an exciting field for many years is largely due to a concentration on functional questions; behavioural ecology has largely forgotten its roots in ethology and its emphasis on a pluralistic approach that embraces development and causation, as well as function. Tim Birkhead shows the way forward, insisting that we cannot understand sperm competition fully until we really get to grips with the mechanisms involved. Ranging widely over anatomy, physiology and genetics, as well as behaviour and evolutionary theory, Birkhead shows us what the study of animal behaviour should be like. At its best, it is not an esoteric discipline cut off from the rest of zoology; rather, it can and should provide a comprehensive approach to animals that embraces many aspects of biology and helps to knit them together.The title of the book does not really reflect what it is about; the use of a word that has particular human connotations that are not appropriate to animals is perhaps unfortunate. The core theme of the book is that the propensity of animals, of both sexes, to mate with multiple partners has profound and wide-ranging consequences that have influenced many aspects of their biology. A secondary theme is the conflict of interests that exists between the sexes that arises from the differences between male and female gametes.Birkhead develops his theoretical framework by describing, often in entertaining detail, many specific examples of animal sexual behaviour. He has a very keen eye for the bizarre and the exotic but shows great skill in using his examples to make points that are relevant to his arguments and which illustrate key concepts and theoretical principles. His writing is beautifully clear and uncluttered with jargon and reveals his enormous enthusiasm for the subject. He also avoids the temptation, all too common in popular books about animal sex, to use prurience to gain a cheap laugh; sex is quite interesting enough and does not require such devices to engage the reader. In this respect, Birkhead's approach to his subject differs markedly from that adopted by Robin Baker in his public writings about human sexuality.His coverage of Baker's writings is the most interesting and enthralling part of the book. In just a few, carefully crafted pages, he dismantles Baker's thesis piece by piece, primarily by revealing the inadequacies of the data on which it is based. His characterization of Baker as ‘phallus in wonderland’ provides a phrase to cherish. In another interesting diversion from his central theme, Birkhead discusses Darwin's writings about sexual matters and the degree to which he was probably constrained in revealing his full knowledge and understanding by the social attitudes of the Victorian age, not least among members of his own immediate family.As I read this book, I was reminded of the realization that dawned on me when I was studying the use of sperm by female newts. Sperm have their own natural history, life-cycle, physiology and behaviour and, to understand them, we really need to study them as if they were another species. We know nothing whatever about the biology of sperm in all but a very few species, a massive area of ignorance that will require a major research effort, involving input from many disciples, to redress. Fortunately, Tim Birkheads's book provides an excellent blueprint for how biologists can set about this daunting but exciting task.