Ecology and Evolution of Dung Beetles

This book describes the evolutionary and ecological consequences of reproductive competition for scarabaeine dung beetles. As well as giving us insight into the private lives of these fascinating creatures, this book shows how dung beetles can be used as model systems for improving our general understanding of broad evolutionary and ecological processes, and how they generate biological diversity. Over the last few decades we have begun to see further than ever before, with our research efforts yielding new information at all levels of analysis, from whole organism biology to genomics. This book brings together leading researchers who contribute chapters that integrate our current knowledge of phylogenetics and evolution, developmental biology, comparative morphology, physiology, behaviour, and population and community ecology. Dung beetle research is shedding light on the ultimate question of how best to document and conserve the world's biodiversity. The book will be of interest to established researchers, university teachers, research students, conservation biologists, and those wanting to know more about the dung beetle taxon.

Auteur

Leigh Simmons was born and educated in the UK, and is
currantly Professor of Evolutionary Biology at the University of
Western Australia. His research interests lie in all aspects of
reproductive biology, from the evolution of sperm form and
function, to mate searching and courtship behaviour.

James Ridsdill-Smith was born and educated in the UK but
carried out all his research in Australia working for CSIRO
Entomology. He has been developing biological and ecological
solutions to various pest problems and 15 years involved in the
biological control of dung with scarabaeine dung beetles.

Contenu

Preface xiii

Acknowledgements xv

Contributing authors xvii

1 Reproductive competition and its impact on the evolution and ecology of dung beetles 1
Leigh W. Simmons and T. James Ridsdill-Smith

1.1 Introduction 1

1.2 Competition for mates and the evolution of morphological diversity 2

1.3 Competition for resources and the evolution of breeding strategies 9

1.4 Ecological consequences of intraspecific and interspecific competition 14

1.4.1 Niche expansion 15

1.4.2 Regional distribution and seasonal activity 17

1.4.3 Community dynamics 18

1.5 Conservation 19

1.6 Concluding remarks 20

2 The evolutionary history and diversification of dung beetles 21
T. Keith Philips

2.1 Introduction 21

2.2 Scarabaeinae diversity and tribal classification issues 22

2.2.1 Dichotomiini and Coprini 24

2.2.2 Canthonini 25

2.2.3 Eucraniini 25

2.2.4 Phanaeini 25

2.2.5 Phanaeini + Eucraniini 26

2.2.6 Scarabaeini 26

2.2.7 Gymnopleurini 26

2.2.8 Eurysternini 26

2.2.9 Sisyphini 26

2.2.10 Onitini 27

2.2.11 Oniticellini 27

2.2.12 Onthophagini 27

2.3 Scarabaeine dung beetle phylogenies 27

2.4 The sister clade to the Scarabaeinae 31

2.5 The origin of the dung beetles 33

2.6 The oldest lineages and their geographical origin 34

2.7 Evolution of activity period 36

2.8 Evolution of feeding habits 36

2.9 Evolution of derived alternative lifestyles 37

2.10 Evolution of nidification: dung manipulation strategies 40

2.11 Evolution of nidification: nesting behaviour and subsocial care 42

2.12 Conclusions 44

2.13 Future work/gaps in knowledge 45

3 Male contest competition and the evolution of weapons 47
Robert Knell

3.1 Introduction 47

3.2 Dung beetle horns as weapons 49

3.3 Functional morphology of horns 50

3.4 Horns as predictors of victory 53

3.5 Are beetle horns simply tools? 55

3.6 The evolution of horns: rollers vs. tunnellers 56

3.7 The evolution of horns: population density 59

3.8 The evolution of horns: sex ratio 63

3.9 Future work 64

4 Sexual selection after mating: the evolutionary consequences of sperm competition and cryptic female choice in onthophagines 66
Leigh W. Simmons

4.1 Introduction 66

4.2 Sperm competition theory 68

4.3 Evolution of ejaculate expenditure in the genus Onthophagus 71

4.4 Evolutionary consequences of variation in ejaculate expenditure 72

4.5 Theoretical models of female choice 75

4.6 Quantitative genetics of ejaculate traits 76

4.7 Empirical evidence for adaptive cryptic female choice in Onthophagus taurus 78

Box 4.1 Indirect genetic benefits of cryptic female choice in Onthophagus taurus 81

4.8 Conclusions and future directions 83

4.9 Dedication and acknowledgement 86

5 Olfactory ecology 87
G.D. Tribe and B.V. Burger

5.1 Introduction 87

5.2 Orientation to dung and other resources 87

5.3 Olfactory cues used in mate attraction and mate recognition 91

5.3.1 Morphology of pheromone-producing and -dispersing structures 93

5.3.2 Pheromone-dispersing behaviour 94

5.4 Chemical composition of Kheper pheromones 95

5.4.1 Electroantennographic detection 98

5.4.2 Comparison of the responses of beetle species to attractant compounds 98

5.4.3 The pheromone-disseminating carrier material 102

5.5 Kairomones 103

5.6 Defensive secretions 104

5.7 Conclusions and future directions 105 6 Explaining phenotypic diversity: the conditional strategy and threshold trait expression 107
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