THE EVOLUTION OF MONOGAMY IN PRIMATES: A PHYLOGENETIC APPROACH A thesis submitted to Kent State University in partial fulfillment of the requirements for the degree of Master of Arts by Alana Hope Muhlberger May, 2011 Thesis written by Alana Hope Muhlberger B.A., Ohio University, 2009 M.A., Kent State University, 2011 Approved by _________________________________, Advisor Marilyn A. Norconk _________________________________, Chair, Department of Anthropology Richard S. Meindl _________________________________, Associate Dean, College of Arts and Sciences John Stalvey ii TABLE OF CONTENTS LIST OF FIGURES ............................................................................................................ v LIST OF TABLES ............................................................................................................. vi ACKNOWLEDGEMENTS .............................................................................................. vii CHAPTER 1: INTRODUCTION ....................................................................................... 8 1.1 Social System Terminology .................................................................................. 11 1.2 Monogamy ............................................................................................................ 12 1.3 Previous Work ...................................................................................................... 19 1.4 Research Questions ............................................................................................... 22 CHAPTER 2: METHODS ................................................................................................ 25 2.1 Characters and Coding .......................................................................................... 25 2.1.1 Social Organization ...................................................................................... 25 2.1.2 Pair-Bond ..................................................................................................... 26 2.1.3 Duet Vocalizations ....................................................................................... 28 2.1.4 Paternal Care ................................................................................................ 29 2.1.5 Territorial Exclusivity .................................................................................. 30 2.1.6 Mechanisms of Territorial Defense ............................................................. 31 2.1.7 Sexual Dimorphism in Body Mass .............................................................. 32 2.2 Species Used in the Analysis .......................................................................... 33 2.3 Sources of Data ..................................................................................................... 36 2.4 Phylogenetic Reconstruction ................................................................................ 37 iii CHAPTER 3: RESULTS .................................................................................................. 41 3.1 Social Organization .............................................................................................. 41 3.2 Pair-Bond .............................................................................................................. 45 3.3 Duet ....................................................................................................................... 47 3.4 Paternal Care ......................................................................................................... 49 3.5 Territorial Exclusivity ........................................................................................... 51 3.6 Mechanisms of Territorial Defense ...................................................................... 53 3.7 Sexual Dimorphism .............................................................................................. 56 3.8 Multi-Trait Comparisons ...................................................................................... 63 CHAPTER 4: DISCUSSION ............................................................................................ 65 4.1 Potential Confounding Factors .................................................................................. 65 4.2 Discussion of Research Questions .............................................................................. 66 CHAPTER 5: CONCLUSIONS ....................................................................................... 77 APPENDICES Appendix A: Summary Database with Abbreviations ...................................................... 80 REFERENCES ................................................................................................................. 83 iv LIST OF FIGURES FIG. 1.1 Phylogenetic Reconstruction From Komers And Brotherton (1997) ................ 21 FIG. 2.1 Primate Phylogeny of Species Used in This Study ........................................... 40 FIG. 3.1 Reconstruction of Social Organization .............................................................. 44 FIG. 3.2 Reconstruction of Pair-Bonding ........................................................................ 46 FIG. 3.3 Reconstruction of Duetting ................................................................................ 48 FIG. 3.4 Reconstruction of Paternal Care ........................................................................ 50 FIG. 3.5 Reconstruction of Territorial Exclusivity .......................................................... 52 FIG. 3.6 Reconstruction of Mechanisms of Territorial Defense ..................................... 55 FIG. 3.7 Reconstruction of Sexual Dimorphism in Lemuroidea ..................................... 58 FIG. 3.8 Reconstruction of Sexual Dimorphism in Lemuroidea ..................................... 59 FIG. 3.9 Reconstruction of Sexual Dimorphism in Tarsiidae ......................................... 60 FIG. 3.10 Reconstruction of Sexual Dimorphism in Cebidae ......................................... 61 FIG. 3.11 Reconstruction of Sexual Dimorphism in Atelidae ......................................... 62 FIG. 3.12 Lineage-Specific Evolution of Monogamy ..................................................... 64 v LIST OF TABLES TABLE 1.1. General Patterns of Primate Social Systems ................................................ 10 TABLE 2.1 Coding the Category “Social Organization” ................................................ 26 TABLE 2.2. Coding the Category “Pair-Bond” ............................................................... 27 TABLE 2.3. Coding the Category “Duet Vocalizations” ................................................. 29 TABLE 2.4. Coding the Category “Paternal Care” .......................................................... 30 TABLE 2.5. Coding the Category “Territorial Exclusivity” ............................................ 31 TABLE 2.6. Coding the Category “Mechanisms of Territorial Defense” ........................ 32 TABLE 2.8. Primate Taxonomy Used in This Study ....................................................... 36 vi ACKNOWLEDGEMENTS First, I would like to thank my advisor, Marilyn Norconk, for her openness to my ideas and her support and encouragement throughout the thesis process. Chi-hua Chiu is responsible for my interesting topic, and Mary Ann Raghanti was a patient and helpful sounding board and source of advice throughout my time at Kent. These three women have been inspiring and I am glad to have had the opportunity to work with them. The department of Anthropology would not be the same without our wonderful secretary, Caroline Tannert, whose organization and desire to help made the road to completion easier for myself and my peers. I would also like to thank Cynthia Thompson, Tremaine Gregory, Eric Seemiller, and Michael Veres for their input in our advisor meetings. My office-mate Cyndie has been especially invaluable, and I am grateful for her patient answers to my questions and for being a friend. Thank you to my parents, Beth and Gordon, to my brother, Eric, and to my boyfriend, Randy, for reading my drafts and sending me your love and support. This thesis has been possible and enjoyable because of all the people mentioned here. vii CHAPTER 1 INTRODUCTION 1.1 Social System Terminology In early studies of animal social systems, mating systems were equated with social systems, but observations of extra-group matings, reproductive suppression, and varying mating patterns of solitary foragers have prompted researchers to separate mating behavior from social behavior (Palombit, 1994; Manson, 2011; Goldizen, 1990). This has led to a modern terminology that subsumes mating system under the umbrella term ‘social system’, which also encompasses social organization and social structure (Zinner et al., 2003; Sterling, 1993; Kappeler and van Schaik, 2002). While mating system describes patterns of mating behavior and considers the genetic composition of the group's offspring (Emlen and Oring 1977), social organization is composed of group size, sexual composition, and cohesion of a group (Müller and Thalmann, 2000; Kappeler and van Schaik, 2002), and social structure describes the social relations among individuals (Zinner et al 2003). There are several generally accepted types of social systems. A list of mating systems, which are a part of social systems, might include monogamy (one breeding male and one breeding female), polygyny (one breeding male, multiple breeding females), polyandry (one breeding female, multiple breeding