Teaching for Understanding with Technology

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
1.5 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
2.3 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
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
5.4 Chemical composition of Kheper pheromones 95
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
Joseph Tomkins and Wade Hazel

6.1 Introduction 107
6.2 The environmental threshold model 109
6.3 Applying the threshold model 118
6.4 Future directions 123

7 Evolution and development: Onthophagus beetles and the evolutionary development genetics of innovation, allometry and plasticity 126
Armin Moczek

7.1 Introduction 126
7.2 Evo-devo and eco-devo - a brief introduction 127
7.3 Onthophagus beetles as an emerging model system in evo-devo and eco-devo 128
7.4 The origin and diversification of novel traits 132
7.5 The regulation and evolution of scaling 140
7.6 The development, evolution, and consequences of phenotypic plasticity 148
7.7 Conclusion 151

8 The evolution of parental care in the onthophagine dung beetles 152
John Hunt and Clarissa House

8.1 Introduction 152
8.2 Parental care theory 154
8.3 Testing parental care theory using onthophagine dung beetles 157
8.4 Conclusions and future directions 174

9 The visual ecology of dung beetles 177
Marcus Byrne and Marie Dacke

9.1 Introduction 177
9.2 Insect eye structure 179
9.3 Eye limitations 181
9.4 Dung beetle vision 182
9.5 Visual ecology of flight activity 187
9.6 Sexual selection and eyes 190
9.7 Ball-rolling 192
9.8 Conclusions 198

10 The ecological implications of physiological diversity in dung beetles 200
Steven L. Chown and C. Jaco Klok

10.1 Introduction 200
10.2 Thermoregulation 201
10.3 Thermal tolerance 207
10.4 Water balance 208
10.5 Gas exchange and metabolic rate 215
10.6 Conclusion and prospectus 218

11 Dung beetle populations: structure and consequences 220
Tomas Roslin and Heidi Viljanen

11.1 Introduction 220
11.2 Study systems 221
11.3 Range size 224
11.4 Habitat and resource selection 227
11.5 Dung beetle movement 230
11.6 The genetic structure of dung beetle populations 235
11.7 Consequences: spatial population structures and responses to habitat loss 238
11.8 Perspectives 243

12 Biological control: ecosystem functions provided by dung beetles 245
T. James Ridsdill-Smith and Penny B. Edwards

12.1 Introduction 245
12.2 Functions of dung beetles in ecosystems 246
12.3 Dung beetles in pasture habitats 250
12.4 Seasonal occurrence and abundance of native dung beetles in Australia 251
12.5 Distribution and seasonal occurrence of introduced dung beetles in Australia 254
12.6 Long-term studies of establishment and abundance 257
12.7 Competitive exclusion 262
12.8 Optimizing the benefits of biological control 264

13 Dung beetles as a candidate study taxon in applied biodiversity conservation research 267
Elizabeth S. Nichols and Toby A. Gardner

13.1 Introduction 267
13.2 Satisfying data needs to inform conservation practice 268
13.3 The role of dung beetles in applied biodiversity research in human-modified landscapes 270
13.4 Dung beetle conservation 286
13.5 Some ways forward 290

References 293
Subject index 340
Taxonomic index 343