Table of Contents

Preface ix

Dedication and Acknowledgments xv

Chapter 1: Sexual Selection and Sperm Competition 1

1.1 Sexual Selection 1

1.2 Sexual Differences and the Evolution of Anisogamy 5

1.3 Sperm Competition and Sexual Selection 10

1.4 Summary 20

Chapter 2: Sperm Utilization: Concepts, Patterns, and Processes 22

2.1 Introduction 22

2.2 Classification and Definition of Terms Used in the Sperm Competition Literature 23

2.3 Quantifying Paternity 29

2.4 Patterns of Sperm Utilization: An Overview 37

2.5 Mechanisms 40

2.6 Sperm Utilization and Multiple Mating 53

2.7 Sperm Utilization in Natural Populations 55

2.8 Mechanisms and the Potential for Selection 56

2.9 Summary 60

Chapter 3: Avoidance of Sperm Competition I: Morphological Adaptations 69

3.1 Introduction 69

3.2 Internal Fertilization 69

3.3 Sperm Removal and Repositioning 70

3.4 Alternative Explanations for Complex Genitalia 82

3.5 Summary 89

Chapter 4: Avoidance of Sperm Competition II: Physiological Adaptations 91

4.1 Introduction 91

4.2 Mating Plugs 97

4.3 Seminal Products 114

4.4 Pheromones 141

4.5 Summary 142

4.6 Avoidance of Sperm

Chapter 5: Competition III: Behavioral Adaptations 144

5.1 Introduction 144

5.2 Theoretical Models of Mate Guarding 146

5.3 Evidence for Mate Guarding in Insects 149

5.4 Alternative Hypotheses 168

5.5 Adaptations for Efficient Guarding 179

5.6 Male Mate Choice 183

5.7 Summary 186

Chapter 6: Copula Duration 198

6.1 Introduction 198

6.2 Sperm Displacement: Optimal Copula Duration in Dung Flies 202

6.3 Copula Duration with Sperm Mixing 212

6.4 Evidence Consistent with an Optimization of Copula Duration 213

6.5 Female Influences 218

6.6 Alternative Explanations 220

6.7 Summary 221

Chapter 7: Sperm in Competition I: Strategic Ejaculation 223

7.1 Introduction 223

7.2 Sperm Competition Games 227

7.3 Cryptic Male Choice 245

7.4 Cryptic Female Choice 247

7.5 Summary 249

Chapter 8: Sperm in Competition II: Sperm Morphology 250

8.1 Introduction 250

8.2 Sperm Size 252

8.3 Sperm Polymorphism 263

8.4 Intraejaculate Sperm Competition 274

8.5 Summary 275

Chapter 9: Ejaculate Manipulation: Mechanisms of Female Choice 277

9.1 Introduction 277

9.2 Influence over Remating 279

9.3 Influence over Sperm Transfer 282

9.4 Influence over Sperm Storage 288

9.5 Sperm Selection 299

9.6 Summary 317

Chapter 10: Social insects 319

10.1 Introduction 319

10.2 Multiple Mating and Multiple Paternity 320

10.3 Social Consequences of Sperm Competition 325

10.4 Alternative Hypotheses for Multiple Mating 334

10.5 Summary 341

Chapter 11: Broader Significance 349

11.1 Sperm Competition and Sexual Selection 349

11.2 Life History Evolution 350

11.3 Speciation 354

11.4 Concluding Remarks 356

References 357

Taxonomic Index 427

Subject Index 432