The Evolutionary Ecology of Autotomy in Leaf-Footed Bugs (Insecta: Hemiptera: Coreidae)

THE EVOLUTIONARY ECOLOGY OF AUTOTOMY IN LEAF-FOOTED BUGS (INSECTA: HEMIPTERA: COREIDAE) By ZACHARY EMBERTS 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 2019 © 2019 Zachary Emberts To my family ACKNOWLEDGMENTS I would like to thank my husband, Cody Coyotee Howard, for his support throughout this endeavor. I would also like to thank my advisors, Colette M. St. Mary and Christine W. Miller, for their guidance along the way. Finally, I would like to thank those who have assisted, encouraged, and challenged me to become the scientist that I am today. 4 TABLE OF CONTENTS page ACKNOWLEDGMENTS .................................................................................................. 4 LIST OF TABLES ............................................................................................................ 8 LIST OF FIGURES ........................................................................................................ 10 LIST OF ABBREVIATIONS ........................................................................................... 12 ABSTRACT ................................................................................................................... 14 CHAPTER 1 THE ECOLOGY AND EVOLUTION OF AUTOTOMY............................................. 16 A Working Definition of Autotomy ........................................................................... 18 Evolution of the Autotomy Phenotype ..................................................................... 19 Evolutionary Origins and Losses of Autotomy .................................................. 19 Elaboration of Autotomizable Appendages....................................................... 22 Variation in the Costs and Benefits of Autotomy ..................................................... 25 Benefits of Autotomy ........................................................................................ 25 Costs of Autotomy ............................................................................................ 31 Economic Theory of Autotomy: Predicting When an Individual Should Autotomize ........................................................................................................... 38 Implications of Autotomy on Organismal and Environmental Interactions .............. 41 Predator–prey Interactions ............................................................................... 41 Intraspecific Competition .................................................................................. 43 Movement and Habitat Selection ...................................................................... 44 Applications of Autotomy Research ........................................................................ 45 Future Directions .................................................................................................... 46 Conclusions ............................................................................................................ 47 2 COREIDAE (INSECTA: HEMIPTERA) LIMB LOSS AND AUTOTOMY .................. 53 Methods .................................................................................................................. 54 Results .................................................................................................................... 56 Missing Legs in Wild Populations ..................................................................... 56 Experimental Induction of Autotomy ................................................................. 56 Discussion .............................................................................................................. 57 Autotomy and Sexually Selected Weaponry..................................................... 58 Autotomy and Natural Selection ....................................................................... 59 3 AUTOTOMIZING INJURED LIMBS INCREASES SURVIVAL ................................ 69 Methods .................................................................................................................. 71 5 Study Organism ................................................................................................ 71 Study Design .................................................................................................... 72 Insect rearing ............................................................................................. 72 Experiment 1 .............................................................................................. 73 Experiment 2 .............................................................................................. 74 Data and Statistical Analyses ........................................................................... 75 Experiment 1 .............................................................................................. 75 Experiment 2 .............................................................................................. 76 Results .................................................................................................................... 77 Experiment 1 .................................................................................................... 77 Experiment 2 .................................................................................................... 78 Discussion .............................................................................................................. 79 4 COREIDAE THAT AUTOTOMIZE THEIR SEXUALLY-SELECTED HIND LEGS HAVE DECREASED FIGHTING ABILITY AND MATING SUCCESS ..................... 95 Methods .................................................................................................................. 98 Rearing of Study Species ................................................................................. 98 Experimental Design ........................................................................................ 99 Ethical Note .................................................................................................... 101 Statistical Analyses ........................................................................................ 101 Results .................................................................................................................. 103 Effects of Losing a Weapon on Fighting Ability and Behavior ........................ 104 Effects of Losing a Weapon on Mating Success ............................................ 105 Effects of Losing One Limb Versus Two ........................................................ 106 Discussion ............................................................................................................ 106 5 THE EVOLUTION OF AUTOTOMY IN LEAF-FOOTED BUGS ............................ 118 Methods ................................................................................................................ 122 Behavioral and Morphological Data ................................................................ 122 Molecular Data and Sequence Alignment ...................................................... 123 Phylogeny and Divergence Time Estimation .................................................. 125 Statistical Analyses ........................................................................................ 128 Results .................................................................................................................. 129 Phylogenetic Relationships ............................................................................ 129 Dating Analyses ............................................................................................. 130 Autotomy ........................................................................................................ 131 Discussion ............................................................................................................ 132 APPENDIX A STOCHASTIC CHARACTER SIMULATIONS REVEAL THAT AUTOTOMY AND AUTOTOMIZABLE LIMB ELABORATIONS HAVE EVOLVED MULTIPLE TIMES THROUGHOUT ANIMALIA ...................................................................... 155 6 B BODY SIZE, LATITUDE, AND THE PRESENCE OF ENLARGED HIND LEGS ALL EXPLAIN VARIATION IN THE RATE AT WHICH SPECIES AUTOTOMIZE ACROSS THIS CLADE, REGAURDLESS OF OUR MEASURE OF CENTRAL TENDENCEY ........................................................................................................ 158 C OUR DATING ANALYSES REVEALED YOUNGER AGE ESTIMATES THAN PREVIOUSLY REPORTED .................................................................................. 160 D BOTH MALE AND FEMALE LEAF-FOOTED BUG ANCESTORS AUTOTOMIZED THEIR HIND LEGS SLOWLY .................................................... 161 LIST OF REFERENCES ............................................................................................. 162 BIOGRAPHICAL SKETCH .......................................................................................... 185 7 LIST OF TABLES Table page 2-1 Percentage of missing limbs by limb location. .................................................... 61 2-2 Data and analyses of wild caught specimens. .................................................... 62 2-3 Experimental autotomy data and analyses for ‘one-hour escape from entrapment’ scenario. ......................................................................................... 64 2-4 Experimental autotomy data and analyses for ‘60 seconds escape

Load more