DIVERSITY IN A TROPICAL MARINE MUTUALISM By CHRISTIAN SEABIRD HOLLIS MCKEON A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2010 1 © 2010 Christian Seabird Hollis McKeon 2 To my teachers in their many forms 3 ACKNOWLEDGMENTS I would like to express my appreciation for the support of my family and friends over the long path towards this goal. My parents have been so unwavering in their support that at times I have forgotten that not everyone has the opportunity to chase their dreams. Thank you. My other families, the Veneskys and the Reinemans have helped me realize how lucky I am to be surrounded by such wonderful people. The Department of Zoology, as a community, and the Paulay lab have made my time at the University of Florida an educational experience of the best kind. 4 TABLE OF CONTENTS page ACKNOWLEDGMENTS .................................................................................................. 4 LIST OF TABLES ............................................................................................................ 8 LIST OF FIGURES .......................................................................................................... 9 ABSTRACT ................................................................................................................... 10 CHAPTER 1 DIVERSITY IN A TROPICAL MARINE MUTUALISM: INTRODUCTION AND GOALS ................................................................................................................... 11 Context and Goals of this Dissertation .................................................................... 11 The Study System .................................................................................................. 13 Rationale and Context ............................................................................................ 13 An Outline ............................................................................................................... 16 2 PHYLOGENETICS, SPECIATION, AND CHARACTER EVOLUTION IN TRAPEZIA .............................................................................................................. 19 Introduction ............................................................................................................. 19 Methods .................................................................................................................. 23 Collection Methods ........................................................................................... 23 Extraction and Sequencing ............................................................................... 23 Sequence Analysis ........................................................................................... 24 Speciation ......................................................................................................... 24 Morphology and ecology .................................................................................. 25 Results .................................................................................................................... 25 Phylogeny and Species Boundaries ................................................................. 25 Evolution of color patterning ............................................................................. 27 Host Specificity ................................................................................................. 27 Geographic differentiation ................................................................................ 27 Discussion .............................................................................................................. 29 Species Boundaries and Taxonomic Implications ............................................ 29 Color Patterns .................................................................................................. 30 Host Specificity ................................................................................................. 31 The development of sympatry, microsympatry, and geographic ranges in Trapezia ........................................................................................................ 32 5 3 DIVERSITY IN MUTUALIST SERVICES OFFERED BY CORAL CRABS .............. 40 Introduction ............................................................................................................. 40 Study system .................................................................................................... 43 Objectives ......................................................................................................... 45 Methods .................................................................................................................. 46 Study Locations ................................................................................................ 46 Removal of Sediment ....................................................................................... 46 Effectiveness against corallivores .................................................................... 47 Effectiveness against Drupella ................................................................... 47 Effectiveness against Culcita ..................................................................... 49 Response to Acanthaster Outbreak ........................................................... 50 Results .................................................................................................................... 51 Effectiveness against Sedimentation ................................................................ 51 Three Species and Large-grain Sediment ................................................. 51 Two Species and Small-grain Sediment .................................................... 52 Defensive efficacy against corallivores ............................................................. 52 Trapezia vs. Drupella ................................................................................. 52 Trapezia vs. Culcita ................................................................................... 52 Response to Acanthaster Outbreak ........................................................... 53 Live Coral Cover ........................................................................................ 53 T. flavopunctata and Acanthaster .............................................................. 53 Associational Defense ............................................................................... 54 Discussion .............................................................................................................. 54 4 MULTIPLE DEFENDER EFFECTS MODIFY THE BENEFITS OF SPECIES STACKING: SYNERGISTIC CORAL DEFENSE BY MUTUALIST CRUSTACEANS ..................................................................................................... 70 Introduction ............................................................................................................. 70 Methods .................................................................................................................. 73 Study Species .................................................................................................. 73 Experimental design ......................................................................................... 74 Deterrence trials ......................................................................................... 74 Test for Emergent Multiple Defender Effects ............................................. 75 Behavioral observations ............................................................................. 75 Data analysis .................................................................................................... 76 Results .................................................................................................................... 79 Deterrence trials ............................................................................................... 79 Emergent Multiple Defender Effects ................................................................. 79 Behavioral observations ................................................................................... 80 Discussion .............................................................................................................. 81 Study Limitations .................................................................................................... 82 Conclusion .............................................................................................................. 83 6 5 FULL HOUSE: ENDOSYMBIONT-EXOSYMBIONT CONNECTIONS IN REEF CORALS ................................................................................................................. 89 Introduction ............................................................................................................. 89 Methods .................................................................................................................. 92 Results .................................................................................................................... 95 Discussion .............................................................................................................. 95 6 CONCLUSION: DIRECTIONS AND IMPLICATIONS FOR THE STUDY OF THE TRAPEZIA-POCILLOPORA MUTUALISM ................................................... 102 Phylogeny, Speciation,