Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2013 Understanding biodiversity: The importance of sexual dimorphism in the micro- and macroevolution of hummingbirds Chelsea Marie Berns Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Biology Commons, and the Ecology and Evolutionary Biology Commons Recommended Citation Berns, Chelsea Marie, "Understanding biodiversity: The importance of sexual dimorphism in the micro- and macroevolution of hummingbirds" (2013). Graduate Theses and Dissertations. 13244. https://lib.dr.iastate.edu/etd/13244 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]. Understanding biodiversity: The importance of sexual dimorphism in the micro- and macroevolution of hummingbirds by Chelsea M. Berns 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: Dean C. Adams, Major Professor Bonnie Bowen Anne Bronikowski Stephen Dinsmore Carol Vleck Iowa State University Ames, Iowa 2013 Copyright © Chelsea M. Berns, 2013. All rights reserved. ii TABLE OF CONTENTS Page LIST OF FIGURES ...................................................................................................... iv LIST OF TABLES ........................................................................................................ vi ACKNOWLEDGEMENTS .......................................................................................... vii ABSTRACT .................................................................................................................. x CHAPTER 1. GENERAL INTRODUCTION Introduction ............................................................................................................. 1 Dissertation organization ........................................................................................ 7 Literature cited ........................................................................................................ 10 CHAPTER 2. THE EVOLUTION OF SEXUAL DIMORPHISM: UNDERSTANDING MECHANISMS OF SEXUAL SHAPE DIFFERENCES Abstract ................................................................................................................... 14 Sexual Size Dimorphism ......................................................................................... 17 Sexual Shape Dimorphism ...................................................................................... 19 Conclusion .............................................................................................................. 30 Acknowledgements ................................................................................................. 33 Literature cited ........................................................................................................ 34 CHAPTER 3. BILL SHAPE AND SEXUAL SHAPE DIMORPHISM BETWEEN TWO SPECIES OF TEMPERATE HUMMINGBIRDS: BLACK-CHINNED HUMMINGBIRD (ARCHILOCHUS ALEXANDRI) AND RUBY-THROATED HUMMINGBIRD (A. COLUBRIS) Abstract ................................................................................................................... 41 Introduction ............................................................................................................. 42 Materials and methods ............................................................................................ 47 Results ..................................................................................................................... 52 Discussion ............................................................................................................... 56 Acknowledgements ................................................................................................. 61 Literature Cited ....................................................................................................... 62 Appendix ................................................................................................................. 69 iii CHAPTER 4. BECOMING DIFFERENT BUT STAYING ALIKE: PATTERNS OF SEXUAL SIZE AND SHAPE DIMORPHISM IN HUMMINGBIRDS Abstract ................................................................................................................... 72 Introduction ............................................................................................................. 73 Materials and methods ............................................................................................ 78 Results ..................................................................................................................... 83 Discussion ............................................................................................................... 89 Acknowledgements ................................................................................................. 95 Literature cited ........................................................................................................ 96 Appendix A .............................................................................................................100 Appendix B .............................................................................................................102 Appendix C .............................................................................................................112 CHAPTER 5. MACROEVOLUTIONARY PATTERNS OF SEXUAL SIZE AND SHAPE DIMORPHISM IN HUMMINGBIRDS Abstract ...................................................................................................................118 Introduction .............................................................................................................119 Materials and methods ............................................................................................125 Results .....................................................................................................................132 Discussion ...............................................................................................................140 Acknowledgements .................................................................................................144 Literature cited ........................................................................................................146 Appendix A .............................................................................................................153 Appendix B .............................................................................................................160 CHAPTER 6. GENERAL CONCLUSIONS Introduction .............................................................................................................167 Chapter summaries ..................................................................................................167 Literature cited ........................................................................................................175 CURRICULUM VITAE ...............................................................................................177 iv LIST OF FIGURES Chapter 2 Figure 1. Differences between the sexes in coloration are common in many species, including the Eclectus parrot ........................................................................... 14 Figure 2. Sexual size dimorphism in the poison dart frog ........................................... 17 Figure 3. Rensch’s Rule, where in species above the broken line (broken line denoting where female and male sizes are equal) females are larger than males and below, males are larger than females ............................................................................ 18 Figure 4. Sets of linear distances ................................................................................. 20 Figure 5. Maximum height and width taken on two different shapes results in the same linear measurement on both ................................................................................. 21 Figure 6. Example of biologically homologous landmarks ......................................... 22 Figure 7. Sexual shape dimorphism in eye stalks of Teleopsis dalmann ..................... 29 Chapter 3 Figure 1. Curvature indices and landmark-based morphometrics, shown on a Black-chinned Hummingbird ........................................................................................ 49 Figure 2. Results of principal component analysis of all specimens (relative warp scores). Thin-plate spline deformation grids are shown to visualize patterns of shape variation .............................................................................................................. 54 Figure 3. Thin-plate spline deformation grids and magnitude of sexual shape dimorphism ................................................................................................................... 55 Chapter 4 Figure 1. a) Exposed culmen representing bill length. b) Landmark-based geometric morphometrics. c) Representative individual from the species with extreme bill curvature (Calothorax lucifer), and d) from the species with the straight bills