Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2016 Ecology and evolution of physiological phenotypes in garter snakes (Thamnophis spp.) Eric Joseph Gangloff Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Physiology Commons, and the Zoology Commons Recommended Citation Gangloff, Eric Joseph, "Ecology and evolution of physiological phenotypes in garter snakes (Thamnophis spp.)" (2016). Graduate Theses and Dissertations. 15914. https://lib.dr.iastate.edu/etd/15914 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Ecology and evolution of physiological phenotypes in garter snakes (Thamnophis spp.) by Eric Joseph Gangloff A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Ecology and Evolutionary Biology Program of Study Committee: Anne M. Bronikowski, Major Professor Lance H. Baumgard Brent Danielson Philip Dixon Fredric Janzen Iowa State University Ames, Iowa 2016 Copyright © Eric Joseph Gangloff, 2016. All rights reserved. ii DEDICATION With immense gratitude to my family, who have always chased snakes with me. iii TABLE OF CONTENTS Page DEDICATION ........................................................................................................... ii ACKNOWLEDGMENTS ......................................................................................... v ABSTRACT………………………………. .............................................................. vii CHAPTER 1 INTRODUCTION .......................................................................... 1 CHAPTER 2 GEOGRAPHIC VARIATION AND WITHIN-INDIVIDUAL CORRELATIONS OF PHYSIOLOGICAL STRESS MARKERS IN A WIDESPREAD REPTILE, THE COMMON GARTER SNAKE (THAMNOPHIS SIRTALIS) ....................................................................................... 21 Abstract ......................................................................................................... 21 Introduction ......................................................................................................... 22 Materials and Methods ......................................................................................... 26 Results ......................................................................................................... 33 Discussion ......................................................................................................... 35 Acknowledgements .............................................................................................. 40 References ......................................................................................................... 41 Tables ......................................................................................................... 47 Figures ......................................................................................................... 51 CHAPTER 3 HORMONAL AND METABOLIC RESPONSES TO UPPER TEMPERATURE EXTREMES IN DIVERGENT LIFE-HISTORY ECOTYPES OF A GARTER SNAKE ........................................................................................... 54 Abstract ......................................................................................................... 54 Introduction ......................................................................................................... 55 Materials and Methods ......................................................................................... 60 Results ......................................................................................................... 69 Discussion ......................................................................................................... 70 Acknowledgements .............................................................................................. 77 References ......................................................................................................... 78 Tables ......................................................................................................... 87 Figures ......................................................................................................... 90 iv CHAPTER 4 AMONG-INDIVIDUAL HETEROGENEITY IN BEHAVIOUR AND PHYSIOLOGY INTERACT TO INFLUENCE FITNESS IN A MODEL ECTOTHERMIC AMNIOTE, THE GARTER SNAKE THAMNOPHIS ELEGANS ......................................................................................................... 93 Abstract ......................................................................................................... 93 Introduction ......................................................................................................... 94 Materials and Methods ......................................................................................... 102 Results ......................................................................................................... 108 Discussion ......................................................................................................... 111 Acknowledgements .............................................................................................. 118 References ......................................................................................................... 119 Tables ......................................................................................................... 127 Figures ......................................................................................................... 131 CHAPTER 5 SUMMARY AND CONCLUSIONS ............................................. 135 APPENDIX A DEVELOPMENTAL AND IMMEDIATE THERMAL ENVIRONMENTS SHAPE ENERGETIC TRADE-OFFS, GROWTH EFFICIENCY, AND METABOLIC RATE IN DIVERGENT LIFE-HISTORY ECOTYPES OF THE GARTER SNAKE THAMNOPHIS ELEGANS ..................... 137 APPENDIX B FAST- AND SLOW-LIVING SNAKES DIFFER IN INFORMATION-GATHERING AND ACTIVITY IN OPEN-FIELD TESTS ....... 152 v ACKNOWLEDGMENTS First, my family: Becky, James, and Anna, whose immense support and patience made possible this adventure, and all our others. For my mom and dad, who tirelessly supported my pursuits even when they involved bringing home wild animals that sometimes escaped in the house. Mark, who has never held a snake but loves me anyway. Jason, whose passion for science and learning continues to inspire me. My Nina, who thinks that what I do is the greatest thing in the world. And Carol, Bill, Melissa, Matt, Bill, Shayna, Caleb, Ceci, Billy, and Ryan, whose love and support is remarkable. Thank you to Anne, a superlative scientist and incredible advisor. I am especially grateful for your patience and trusting support through this process. I’ve never had mentor for whom I’ve had more respect. My committee members, both current and past, have provided invaluable guidance: Lance Baumgard, Gordon Burghardt, Brent Danielson, Phil Dixon, Fred Janzen, Clint Kelly, and David Vleck. I am grateful for all that I’ve learned from each of you. My current collaborators, all of whom are also both mentors and friends: Antonio Cordero, Vianey Leos-Barajas, Dave Miller, Tonia Schwartz, Amanda Sparkman, and Rory Telemeco. My lab mates have both pushed my learning and given friendship: Liz Addis, Kaitlyn Holden, Dawn Reding, Gaby Palacios, Skiha Parsai, and Tonia Schwartz. I have had the excellent fortune of working with some dedicated and insightful undergraduate students, who have contributed a great deal to the projects included here: Mitch Barazowski, Caitlyn Corwin, Merritt Polomsky, Madeline Topf, and Alexander Wendt. vi My fellow EEB/EEOB students have made me a better scientist and person, especially Brooke Bodensteiner, Byran Juarez, Andy Kraemer, Rory Telemeco, Sean Satterlee, Melissa Telemeco, Rebecca Polich, Alex Walton, and Amy Worthington. The EEOB Department as a whole is tremendously supportive. I especially acknowledge the mentorship of faculty members Dean Adams, Bill Clark, John Nason, Jean Serb, and Amy Toth. Clark Coffman has been a tremendously supportive teaching mentor. And the families and friends who have kept our children safe and happy while I put in long hours and then had to the patience to listen to me talk about it afterward: the Toth-Miguez Family, the Schmoorte Family, and the Glenn Family. You have made Ames a home for us. And finally, thank you to Norm and Mira Boyczuk who continue to send me snake- themed birthday cards every year. See what you started? vii ABSTRACT Physiology is the mechanistic link between how an individual organism experiences its external environment and higher-level biological effects. Since natural selection acts on whole phenotypes, understanding the evolution of physiology requires integration with other traits, such as behavior and life-history, at both the phenotypic and genetic levels. Accumulating evidence suggests that within-individual plasticity of physiological and behavioral traits is limited, resulting in stable individual phenotypes and differences among individuals. Using the model systems of two widespread North American vertebrates (the garter snakes Thamnophis sirtalis and T. elegans), the research presented here quantifies