Animal Signals

by Maynard-Smith, John; Harper, David

• ISBN13: 9780198526858
• ISBN10: 0198526857
• Format: Paperback
• Copyright: 2004-01-08
• Publisher: Oxford University Press

Summary

Why are animal signals reliable? This is the central problem for evolutionary biologists interested in signals. Of course, not all signals are reliable; but most are, otherwise receivers of signals would ignore them. A number of theoretical answers have been proposed and empirical studies made, but there still remains a considerable amount of confusion. The authors, one a theoretician the other a fieldworker, introduce a sense of order to this chaos. A significant cause of confusion has been the tendency for different researchers to use either the same term with different meanings, or different terms with the same meaning. The authors attempt to clarify these differences. A second cause of confusion has arisen because many biologists continue to assume that there is only one correct explanation for signal reliability. The authors argue that the reliability of signals is maintained in several ways, relevant in different circumstances, and that biologists must learn to distinguish between them. In this book they explain the different theories, give examples of signalling systems to which one or another theory applies, and point to the many areas where further work, both theoretical and empirical, is required.

Author Biography

John Maynard Smith is an eminent evolutionary biologist and author of many books on evolution, both for scientists and the general public. He is professor emeritus at the University of Sussex, UK, Fellow of the Royal Society, winner of the Darwin Medal, and laureate of the Crafoord Prize of the Swedish Academy of Sciences. David Harper is Senior Lecturer in Evolution, School of Biological Sciences, University of Sussex, UK.

Table of Contents

1 Introduction: what are signals?	1	(15)
1.1 Introduction	1	(2)
1.2 Signals and cues	3	(3)
1.3 The problem of reliability	6	(3)
1.4 The forms of signals	9	(2)
1.4.1 Efficacy	9	(1)
1.4.2 Evolutionary origin	9	(1)
1.4.3 Mimicry	10	(1)
1.4.4 Sensory manipulation	10	(1)
1.5 Action-response games, and some alternatives	11	(1)
1.6 Sexual selection	12	(3)
1.6.1 Paternal care	13	(1)
1.6.2 Sexually attractive sons	13	(1)
1.6.3 'Good genes'-indices and handicaps	14	(1)
1.6.4 The female gets nothing (sensory exploitation)	14	(1)
1.7 Definitions and terminology	15	(1)
2 The theory of costly signalling	16	(16)
2.1 Introduction	16	(1)
2.2 A brief history of the handicap principle	17	(3)
2.3 The Philip Sidney game	20	(7)
2.3.1 The discrete model	21	(1)
2.3.2 A model with continuously varying signallers	22	(2)
2.3.3 A model with continuously varying signals and responses	24	(1)
2.3.4 Perceptual error	25	(1)
2.3.5 Conclusions	26	(1)
2.4 'Pooling equilibria'-a more radical proposal	27	(2)
2.5 Non-signalling equilibria	29	(1)
2.6 Must honest signals always be costly?	29	(1)
2.7 Conclusions	30	(2)
3 Strategic signals and minimal-cost signals	32	(13)
3.1 Introduction	32	(1)
3.2 Strategic signals	33	(4)
3.2.1 Stalk-eyed flies	33	(1)
3.2.2 Musth in elephants	34	(1)
3.2.3 Chick begging	35	(2)
3.3 Minimal-cost signals	37	(7)
3.3.1 When can minimal-cost signals be evolutionary stable?	37	(2)
3.3.2 Signals between unrelated individuals with a common interest	39	(2)
3.3.3 Relatedness	41	(1)
3.3.4 Kin recognition	42	(2)
3.4 Conclusions	44	(1)
4 Indices of quality	45	(23)
4.1 Introduction	45	(1)
4.2 Are mammalian sounds reliable indices of size?	45	(2)
4.3 The evolution of indices	47	(1)
4.4 Indices in different contexts	48	(12)
4.4.1 Indices of condition	48	(2)
4.4.2 Indices of size and RHP	50	(1)
4.4.3 Performance indices	51	(2)
4.4.4 Parasites	53	(1)
4.4.5 Indices of ownership	54	(5)
4.4.6 Signals in contests, and in mate choice	59	(1)
4.5 Indices and handicaps	60	(1)
4.6 Some problem cases	61	(7)
4.6.1 Stotting	61	(2)
4.6.2 Fluctuating asymmetry	63	(3)
4.6.3 Displays of weapons	66	(2)
5 The evolution of signal form	68	(22)
5.1 Ritualization	68	(5)
5.2 Efficacy	73	(1)
5.3 Arms races, manipulation and sensory bias	74	(7)
5.3.1 Introduction	74	(2)
5.3.2 A model, and an experiment	76	(1)
5.3.3 The response to novel signals	77	(3)
5.3.4 The comparative data	80	(1)
5.3.5 Conclusions	81	(1)
5.4 Sensory manipulation	81	(5)
5.4.1 Frogs and swordtails	81	(3)
5.4.2 Nuptial gifts in insects	84	(1)
5.4.3 Further examples of sensory manipulation	85	(1)
5.5 Mimicry and cheating	86	(4)
6 Signals during contests	90	(22)
6.1 Introduction	90	(2)
6.2 Badges of status	92	(4)
6.2.1 An avian example	92	(2)
6.2.2 ESS models of badges	94	(1)
6.2.3 Conclusions	95	(1)
6.3 Can signals of need settle contests?	96	(3)
6.3.1 The war of attrition	96	(1)
6.3.2 The war of attrition with random rewards	97	(1)
6.3.3 A model of conventional signals of need	97	(1)
6.3.4 Conclusions	98	(1)
6.4 Punishment	99	(1)
6.5 Protracted contests and varied signals	100	(9)
6.5.1 Varied signals-the evidence	101	(1)
6.5.2 Cichlid fishes and the sequential assessment game	102	(2)
6.5.3 Spider fights, and a motivational model	104	(4)
6.5.4 Territorial behaviour and the negotiation game	108	(1)
6.6 Conclusions	109	(3)
7 Signals in primates and other social animals	112	(25)
7.1 Introduction	112	(1)
7.2 Vervet Monkeys: a case study	113	(3)
7.3 How does the ability to signal develop?	116	(2)
7.4 Questions about what is going on in an animal's head	118	(3)
7.4.1 Do signals convey information about the external world?	118	(1)
7.4.2 Do signallers intend to alter the behaviour of receivers?	119	(2)
7.4.3 Conclusions	121	(1)
7.5 Social reputation and the honesty of signals	121	(3)
7.5.1 Introduction	121	(1)
7.5.2 A model	122	(1)
7.5.3 Evidence for direct reputation	123	(1)
7.6 Emotional commitment	124	(6)
7.6.1 Cultural and innate behaviour	124	(1)
7.6.2 'Altruistic punishment' in humans	125	(1)
7.6.3 Mutual displays	126	(2)
7.6.4 The interpretation of group displays	128	(2)
7.7 Human language	130	(7)
7.7.1 Cultural inheritance in Chimpanzees	131	(1)
7.7.2 The peculiarities of human language	132	(1)
7.7.3 The evolution of language	133	(4)
Glossary of scientific names	137	(4)
References	141	(20)
Index	161