Competition, coercion, and choice: The sex lives of female olive baboons (Papio anubis) DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Jessica Terese Walz Graduate Program in Anthropology The Ohio State University 2016 Dissertation Committee: Dawn M. Kitchen, Chair Douglas E. Crews W. Scott McGraw Copyrighted by Jessica Walz 2016 Abstract Since Darwin first described his theory of sexual selection, evolutionary biologists have used this framework to understand the potential for morphological, physiological, and behavioral traits to evolve within each sex. Recently, researchers have revealed important nuances in effects of sexual coercion, intersexual conflict, and sex role reversals. Among our closest relatives living in complex societies in which individuals interact outside of just the context of mating, the sexual and social lives of individuals are tightly intertwined. An important challenge to biological anthropologists is demonstrating whether female opportunities for mate choice are overridden by male- male competitive and male-female coercive strategies that dominate multi-male, multi- female societies. In this dissertation, I explore interactions between these various mechanisms of competition, coercion, and choice acting on the lives of female olive baboons to determine how they may influence expression of female behavioral and vocal signals, copulatory success with specific males, and the role of female competition in influencing mating patterns. I found females solicit specific males around the time of ovulation. Although what makes some males more preferred is less clear, there is evidence females choose males who might be better future protectors – males who will have long group tenures and are currently ascending the hierarchy. Preference translates into higher copulation rates and success at consort takeovers, there is little support that this is simply ii based on male aggression toward females. Outside the fertile window female copulations were more likely related to male aggression and male dominance rank. Additionally, I found evidence that copulation calls of female olive baboons indicate ovulation and may function to encourage specific males to guard or continue mating with females. However, some of the temporal features of calls indicate a function for paternity confusion. Finally, cycling females were targeted for more aggression than they gave, suggesting aggression among females may limit reproductive competition. However, among ovulating females in consort with preferred males, most aggression was directed toward lactating females. These are females who present the biggest threat for cycling females to develop a bond with a future male “friend.” In baboons, establishing nonsexual friendships is valuable in terms of mother and infant protection. Overall, I showed that the social and sexual lives of female olive baboons differ as they approach periods in their ovulatory cycles when they are more likely to conceive, and provide support for hypotheses suggesting female strategies, like darting, copulation calls, and proceptive behaviors toward males with certain qualities appear to serve as a graded signal that allows females to both encourage mating from preferred partners when near conception, but also encourage competition or paternity confusion when not fertile. Female strategies seem most focused on ensuring conception, but also may be important for establishing bonds with males for future protection. I also highlight important similarities and differences in male and female reproductive strategies across three savanna baboon species and consider how a synthesis of these unique strategies can help resolve questions about evolved sexual conflicts in the context of complex societies. iii For my family iv Acknowledgements The work that went into this dissertation could not have been completed without the encouragement, help, and support of many people. First, I would like to thank my advisor, Dawn Kitchen. You have been such an amazing mentor, supporter, and friend. Your tireless energy and long phone conversations with words of encouragement and advice allowed me to push forward. I could not have done this without you. I also want to thank Doug Crews for your guidance through this process. You have always encouraged me and supported me in all my endeavors. Thanks also to Scott McGraw for pushing me to think critically and broadly about my perspective and approach and encouraging me to “dock the ship.” Each of your teaching and mentoring styles helped me grow, not only as a researcher, but also as a college educator. Thank you also to Clark Larsen and The Ohio State University Department of Anthropology for always supporting my research and teaching endeavors. Thank you to my many financial contributors and institutions, especially The Leakey Foundation, International Primatological Society, American Society of Primatology, Animal Behavior Society, American Society of Mammalogists, both the national and the Ohio State University chapters of Sigma Xi, Ohio State’s Graduate School, Office of International Affairs, and the Department of Anthropology. To all of the people at Gombe Stream National Park who befriended me and assisted me in my work: asante sana! I am especially thankful to Anton Collins who I am v proud and humbled to call a friend and mentor. Your limitless knowledge of the park, the baboons, and their habitat helped me complete my project in a comprehensive and methodical way. Thank you to Deus Mjungu for your guidance and assistance in my transition to life at Gombe. Thank you also to the team of baboon researchers, especially Marini Bwenda. The many hours you spent helping me identify baboons and learn their ranges was integral to the success of my project. I could never have started this endeavor without our intense “baboon bootcamp.” Special thanks also to Andrea Bailey for being an amazing friend, supporter, and collaborator. Without your help I quite literally would have been lost in the woods. I am also forever indebted to Hashim Issa and Hamimu Mbwama. Your ability to find and track baboons (and their “sampos”) constantly amazed me and I could not have completed this project without your help. Thanks also to Ashura Issa for your friendship and masterful cooking skills. Coming home from a long day in the field to find a home-cooked meal waiting for me was often what helped me get through tough days in the field. Thanks to Iddi Lipende and Juma Baranyikwa for allowing me to share space in the Gombe lab, helping me find and purchase necessary supplies to complete hormone extractions, and weighing fecal samples. My time at Gombe would not have been as enjoyable without the friendship of Kara Walker- Schroepfer and Lisa O’Bryan. From sun-downers to commiserating about trials and tribulations of conducting fieldwork, your friendship helped shape my experience at Gombe. Thank you to Jacinta Beehner and Teera Parr and the rest of the Core Assay Facility team. Housing and processing the hundreds of fecal samples I collected to vi complete this project would not have been possible without your help. Thank you to Jacinta for the many correspondences along the way and to Teera for spending time training me in important fecal hormone sample assay techniques. All of my anthropology friends and friends outside of the field have also been incredibly supportive in this process. Special thanks go to Jill Murphey and Bryan Johnson for always taking me in to your home and treating me like family. Liz Perrin Beggrow (and Adam), Britney Kyle, and Laurie Reitsema: you are my anthropology “sisters” and I could not have made it through coursework and life’s trials and tribulations without your support. Thank you also to Michelle Rodrigues for a formative experience in the Costa Rican rainforest that helped me recognize my true passion for field primatology. Thanks also to Leslie Williams, Giuseppe Vercellotti, Adam Kolatorowicz, Tim Gocha, Megan Ingvoldstad, Lori Critcher, Dara Adams, Erin Kane, Ashley Edes, and Noah Dunham for helping shape my graduate school experience. Thank you to the many friends I have made at UW-Whitewater as well. Special thanks to Ellie Schemenauer for her mentorship. Thanks to Chandra Waring for being a friend and confidant. Thanks to Tracy Hawkins, Veronica Fruiht, Rachel Chaphalkar, and Courtney Luedke for the time spent writing (and chatting) together. Finally, thank you to my family for your constant encouragement, support, and guidance. Thank you so much to Karl and Janet Olson and the rest of the Olson clan. Our many dinners, game nights, and conversations have been a welcome reprieve from the academic grind. You keep me grounded and sane and I appreciate all that you have done for me along the way. To my niece and nephew, Avery and Thomas Horst, your smiles vii and laughter are the light that has made this process a little easier. To my brothers-in-law, John Horst and Stuart Jones, I appreciate all our conversations and the advice you have provided me along the way. To my sisters, Sara Horst and Emily Walz, I would not be where I am today without your constant support and guidance. Sara, you are a force to be reckoned with and going through this process has been easier because I know that you will always have my back. Emily, as a roommate, friend, and unofficial counselor, I know I could not have survived graduate school or the writing of this dissertation without you. To my parents, Nick and Becky Walz, it is difficult to sum the appreciation I have for all you have done for me over the years. From financial support to hours of editorial work on this document to dozens of hours of travel time so you could literally be by my side through this process, I am forever grateful. Without you, this dream would never have been a reality. Finally, to my husband, Jeff Olson, you are my rock and my voice of reason.