Population genetics of incipient speciation in two species of jumping spiders (Salticidae: Habronattus) on the sky islands of southeast Arizona Item Type text; Dissertation-Reproduction (electronic) Authors Masta, Susan Elaine Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 02/10/2021 15:02:36 Link to Item http://hdl.handle.net/10150/284016 INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly firom the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, vs^e others may be from any type of computer printer. 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Kgher quality 6" x 9** black and white photographic prints are available for any photographs or illustrations appearing m this copy for an additional charge. Contact UMI directly to order. UMI A Bdl & Howell bifijnnation Conqany 300 North Zed> Road. Ann Aibor MI 48I06-I346 USA 313/761-4700 800/521-0600 POPULATION GENETICS OF INCIPIENT SPECIATION IN TWO SPECIES OF JUMPING SPIDERS (SALTIODAE: HABRONATTUS) ON THE SKY ISLANDS OF SOUTHEAST ARIZONA by Stisan Elaine Masta A Dissertation Submitted to the Facidty of the DEPARTMENT OF ECOLOGY AND EVOLUTIONARY BIOLOGY In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY In the Graduate College THE UNIVERSITY OF ARIZONA 1999 DMT Ntanber: 9927470 UMI Microform 9927470 Copyriglit 1999, by UMI Company. All rights reserved. This microform edition is protected against miauthorized copying mider Title 17, United States Code. UMI 300 North Zeeb Road Ann Arbor, MI 48103 2 THE UNIVERSITY OF ARIZONA « GRADUATE COLLEGE As members of the Final Examination Committee, we certify that we have Susan Elaine Masta read the dissertation prepared by entitled Populat-ion Ctenet-.ics of Tncipient Sppriattinn in 7W» Species nf .1imipin9 Spiders H;:ihmnat-i-ng^ on tJie .qky Islands of Snirt-hf^asi- Ari^nna and recommend that it be accepted as fulfilling the dissertation [3octor of PhilosoE*iy requirement for the Degree of f Date Wayne Maddison ^ ^ , , ^ Michael Nachman Date C-C\., ~~2 I "2^/ ^ ^ 8 Nancy Moran Date Lucinc^ McDade Date T[^ l/V nilthf J. Bruce W&lsh Date Final approval and acceptance of this dissertation is contingent upon the candidate's submission of the final copy of the dissertation to the Graduate College. I hereby certify that I have read this dissertation prepared under my direction and recommend that it be accepted as fulfilling the dissertation requirement. H/1^/11 Disserta^on Director Date 3 STATEMENT BY AUTHOR This dissertation has been submitted in partial fulfillment of requirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers imder the rules of the Library. Brief quotations from this dissertation are allowable without special permission, provided that accurate acknowledgment of source is made- Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his or her judgment the proposed use of the material is in the interests of scholarship. In eiU other instances, however, permission must be obtained from the author. 4 ACKNOWLEDGEMENTS I am grateful to the many people who generously shared their time, thoughts, and expertise with me. I am especially indebted to my committee. My advisor, Wayne Maddison, first introduced me to the wonders of jimiping spiders and the amazing diversification of Habronattus pugillis in southeast Arizona. His willingness to share his knowledge and insight into phylogenetic biology helped clarify my thoughts, and greatly improved this dissertation. Luanda McDade was always available for lively discussions on phylogenetics and the Arizona sky islands, and for general advice on making it through graduate school. Her enthusiasm for science continues to inspire me. Nancy Moran has been an incredible mentor - not only has she provided scientific insight and opportunities for me, she generously allowed me to carry out the molecular aspects of this dissertation in her laboratory. Michael Nachn:\an edso generously allowed me the full use of his laboratory, and provided many hours of stimtdating discussions on population genetics. Bruce Walsh provided genetic and statistical expertise, and a sense of humor. I am also indebted to the members of the Maddison laboratory. Greta Binford, Gita Bodner, Peggy Gerba, Eileen Hebets and Marshal Hedin were a wealth of arachnological toowledge and assistance. Marshal also provided the initial "spider primers" that allowed my first foray into spider DNA sequencing. I am particularly grateful to Gabe Bien-Willner and James Borgmeyer who provided conscientious care in helping maintain jimiping spiders in the laboratory. The participants in two discussion groups - the Population Genetics and Molecular Evolution and the Phylogenetics Discussion Group - have provided countless hours of thought-provoking discussion over the years. Joana Silva and Patrick O'Grady were invaluable not only in these discussions, but also in helping implement many analyses. I am especially thankful for the many graduate students and postdoctoral fellows at the University of Arizona who have brightened my life in graduate school. They have been some of the brightest, most fun-loving, and generous people I have known. Their friendship has truly made graduate school a memorable experience. I am also grateful for generous financial support from a number of sources. A Doctoral Dissertation Improvement Grant from the National Science Foundation provided research support, and the Flinn Foundation Genetics Program provided fellowship and research support. I was also generously supported by the NSF-funded Research Training Grant in the Analysis of Biological Diversification, by the Department of Ecology and Evolutionary Biology, and by the Graduate College at the University of Arizona. And finally, it is difficult to express my gratitude to my husband. Jay Withgott. He provided me with tireless assistance - in collecting spiders, discussing science, reading dissertation chapters, and taking care of day-to-day tasks. His friendship, love, and encouragement provided the impetus that made completing this dissertation possible. 5 DEDICATION This dissertation is dedicated to the people working to preserve the sky island ecosystems of Arizona. 6 TABLE OF CONTENTS ABSTRACT 7 1 INTRODUCTION 9 2 PRESENT STUDY 14 A HISTORICAL POPULATION GENETICS OF MORPHOLOGICALLY DIVERGENT POPULATIONS OF THE SPIDERS HABRONATTUS OREGONENSIS AND H. PUGILUS (SALTIODAE) IN SOUTHEAST ARIZONA 17 B PHYLOGEOGRAPHY OF HABRONATTUS PUGEUS (ARANEAE: SALHCIDAE) ON THE SKY ISLANDS OF SOUTHEAST ARIZONA.... 81 C UNUSUAL EVOLUTION OF MITOCHONDRIAL RNA GENE SEQUENCES IN SPIDERS (ARANEAE: SALTIODAE: HABRONATTUS) 123 REFERENCES 156 7 ABSTRACT The population genetic forces that promote spedation, although well understood theoretically, are poorly known in nature. This dissertation focuses on the population genetics of allopatric speciation, using a system of jumping spiders (Araneae: Saltiddae) whose populations are subdivided among the disjimct patches of moimtain woodland habitat called "sky islands" in southeastern Arizona. I studied two spedes of saltidds that apparently share similar histories of range fragmentation but differ greatiy in their amoimt of rntraspedfic phenot5q5ic divergence. Using sequence data from neutrally evolving mitochondrial genes, I investigated the population genetic factors influencing divergence. Analyses of gene trees for Habronattus oregonensis and H. pugillis revealed that neither gene flow, effective population size, mutation rate, nor differences in divergence time can explain the interspecific difference in phenotypic divergence. Instead, selection - in these animals, presimiably sexual selection - must have acted differentially on traits encoded by nuclear lod to produce the discrepancy. A phylogeographic study of populations of H. pugillis may help clarify the influence of post-Pleistocene vegetational change on organisms dependent upon montane woodlands. Gene trees suggest limited migration between mountain ranges, but offer stronger evidence for incomplete lineage sorting. The trees provide no clear indication of the chronological