Cover image for Promiscuity : an evolutionary history of sperm competition
Promiscuity : an evolutionary history of sperm competition
Birkhead, Tim.
Personal Author:
Publication Information:
Cambridge, Mass. : Harvard University Press, [2000]

Physical Description:
xiii, 272 pages, 8 pages of plates : illustrations (some color) ; 22 cm
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QL761 .B57 2000 Adult Non-Fiction Central Closed Stacks

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Males are promiscuous and ferociously competitive. Females--both human and of other species--are naturally monogamous. That at least is what the study of sexual behavior after Darwin assumed, perhaps because it was written by men. Only in recent years has this version of events been challenged. Females, it has become clear, are remarkably promiscuous and have evolved an astonishing array of strategies, employed both before and after copulation, to determine exactly who will father their offspring. Tim Birkhead reveals a wonderful world in which males and females vie with each other as they strive to maximize their reproductive success. Both sexes have evolved staggeringly sophisticated ways to get what they want--often at the expense of the other. He introduces us to fish whose first encounter locks them together for life in a perpetual sexual embrace; hermaphrodites who joust with their reproductive organs, each trying to inseminate the other without being inseminated; and tiny flies whose seminal fluid is so toxic that it not only destroys the sperm of rival males but eventually kills the female. He explores the long and tortuous road leading to our current state of knowledge, from Aristotle's observations on chickens, to the first successful artificial insemination in the seventeenth century, to today's ingenious molecular markers for assigning paternity. And he shows how much human behavior--from the wife-sharing habits of Inuit hunters to Charlie Chaplin's paternity case--is influenced by sperm competition. Lucidly written and lavishly illustrated, with a wealth of fascinating detail and vivid examples, Promiscuity is the ultimate guide to the battle of the sexes.

Author Notes

Tim Birkhead is Professor of Behavioral Ecology at the University of Sheffield.

Reviews 2

Publisher's Weekly Review

When mammals have sex, many sperm race to fertilize one egg. Does chance alone decide which sperm succeeds? What happens when sperm from different males chase the same egg or eggs? How are things different for the male and female gametes of squid, poultry, starfish or sharks? And how might female organisms benefit from choosing more than one mate? Such questions are the province of biologists who study sperm competition, an intriguing, sometimes bizarre field that draws on evolutionary theory, biochemistry and old-fashioned animal watching. Birkhead (Great Auk Islands), professor of behavioral ecology at Britain's University of Sheffield, has written an engrossing, accessible explanation of sperm competition and related elements of animal biology. Birkhead succeeds on two levels at once. He sets out evolutionists' nuanced arguments about sperm competition and sexual selection, and shows how their hypotheses have been tested. He also offers a fantastic array of biological believe-it-or-nots. The fish called capelin in effect mate in threes; two males at once assist the female capelin in pushing spawn out of her body. Male giant squid shoot long needlelike spermatophores from a penis nearly three feet long; the spermatophores stick in the female's skin, and no one knows how the sperm reach the eggs from there. Nobody's sure why such systems evolve: studies of house mice, Australian fairy wrens and Panamanian pseudoscorpions, though, might help explain them. Birkhead's work is solid and intriguing, a clear picture of many out-there phenomena: no one who cares for biology should miss it. (Oct.) (c) Copyright PWxyz, LLC. All rights reserved

Choice Review

For biologists, nothing makes more exciting reading than reports of new discoveries or discussion of perceived paradigm shifts. In Promiscuity, Birkhead (behavioral ecology, Univ. of Sheffield, UK) brings to light a relatively new emphasis in reproductive biology. The phenomena of sperm competition and postcopulatory sexual selection, as well as their possible consequences, cannot help but provide interesting subject matter regardless of whether interests are voyeuristic, prurient, or simply scientific. The contention that multiple male sex partners contribute gametes to a final selection event at conception is supported by numerous studies cited by the author. Birkhead excels not only in providing lucid analysis of these studies, but in showing how widespread these events are in organisms ranging from protozoan to mammalian. A series of color plates, showing diverse gametes, genitalia, and copulatory events, bring the text to life. The author's witty prose combined with his recognized competence as a scientist create a most enjoyable book. Effective fusion of such areas as reproductive biology, behavioral ecology, natural history, molecular genetics, and physiology make this book attractive to a very wide audience. Upper-division undergraduates through professionals. G. L. Kreider; Albright College

Table of Contents

List of Platesp. vii
Prefacep. ix
1 Competition, Choice and Sexual Conflictp. 1
2 Paternity and Protectionp. 33
3 Genitaliap. 58
4 Sperm, Ejaculates and Ovap. 106
5 Copulation, Insemination and Fertilizationp. 136
6 Mechanisms of Sperm Competition and Sperm Choicep. 164
7 The Benefits of Polyandryp. 195
Referencesp. 235
Bibliographyp. 245
Appendix Species mentioned in the textp. 263
Indexp. 265