Interactions between cactus-specialist solitary bees and their host cacti Item Type text; Dissertation-Reproduction (electronic) Authors McIntosh, Margrit Elizabeth 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 06/10/2021 15:16:38 Link to Item http://hdl.handle.net/10150/280207 INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMl films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. 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ProQuest Information and Leaming 300 North Zeeb Road, Ann Arbor, Ml 48106-1346 USA 800-521-0600 [NTERACTIONS BETWEEN CACTUS-SPECIALIST SOLITARY BEES AND THEIR HOST CACTI by Vlargrit Elizabeth Mcintosh Copyright S Margrit Elizabeth Mcintosh 2001 A Dissertation Submitted to the Faculty 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 200 1 UMI Number: 3010212 Copyright 2001 by Mcintosh, Margrit Elizabeth All rights reserved. (g) UMI UMI Microform 3010212 Copyright 2001 by Bell & Howell Information and Learning Company. All rights reserved. This microfonn edition is protected against unauthorized copying under Title 17, United States Code. Bell & Howell Information and Leaming Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 THE UNIVERSITY OF ARIZONA ® GRADUATE COLLEGE As members of the Final Examination Committee, we certify that we have read the dissertation prepared by Ksargrit Elizabeth Mcintosh entitled Interactions between cactus-specialist solitary bees and their host cacti and recommend that it be accepted as fulfilling the dissertation requirement for the Degree of Doctor Of Philosophy CVifttiii i. •Bw/I.abm. Date , ' jLulith L. Bronstein , / ,\ v /c / Lucinda A. McDade Date I ;cj V r1 '3-' C ::r\ "T Date El izaCteth A. / r ' 'ot Daniel R. Papaj Dat Date Final approval and acceptance of this dissertation is contingent upon Che 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 ny direction and recommend that it be accepted as fulfilling the dissertation requirement. Disputation Director ^ Bronstein J 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 Librar>' to be made available to borrowers under 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 copvTight holder. SIGNED: ' 4 ACKNOWLEDGMENTS I am most grateful to all the members of my dissertation committee for their help, advice, enthusiasm, and constructive criticism. I thank my advisor. Dr. Judith L. Bronstein. for her unfailing support and assistance, for inspiring me to reach beyond my limitations, and for showing me the way through the labvTinths of academia. During the crises that inevitably plagued my research, she always managed to get me calmed down and back on track. She never failed to provide detailed, thoughtfiil input to my proposals, experimental designs, and papers. Her editing of this dissertation helped me learn how to integrate the components of my research, and. most importantly, how to present my work in terms of its relevance to biology in general. Dr. Lucinda A. McDade. my unofficial co-advisor, taught me most of what I know about plants, led me and others on numerous field adventures, and conducted her classes and lab group meetings with flair and distinction. Her single-minded dedication to intellectual rigor and scientific integrity continues to inspire me. and her meticulous editing of the first two appendices of this dissertation has vastly improved the quality of m\- scientific output, and has enhanced my ability to edit my own work and the work of others. The quality of her devotion to tropical biology, plant diversity and conservation taught me that one can be both a first-rate scientist and a passionate lover of nature. Dr. Elizabeth .A. Bemays has given me stellar support and encouragement in some of the more difficult parts of my work. She provided invaluable help with the planning, execution and analysis of the pollen-transfer experiments (.Appendix D). including the loan of a flight cage. Her research papers were my constant companions throughout my career as a Ph.D. student. The originality and impact of her work as a scientist will always be an inspiration to me. The work of Dr. Stephen L. Buchmann was one of the early influences on my decision to become a bee biologist. Having him on my committee added greatly to the quality and scope of my research, and he provided crucial technical assistance and equipment, including emergence cages. His gift of a collection of laboriously collected and purified pollens of many different plant species was the key to unlocking the pollen preferences of the cactus bees. Dr. Daniel R. Papaj gave valuable input to the design and interpretation of the pollen-transfer experiments, and his work on ovarian dynamics in herbivorous insects led me to a new hypothesis for some of the behavior displayed by the cactus bees I studied. My life partner. Patricia Eileen Perm, deserves my most heartfelt thanks for her love, support, understanding, and companionship. She has greatly contributed to my growth as a human being, and I am truly blessed to have her by my side. My fellow graduate students also contributed greatly to the success of my dissertation, not just through their companionship and support, but also through their advice and intellectual input, especially during the early stages of the formation of my dissertation topic. Outstanding co-conspirators include Sandy Adondakis. Betsy Arnold. .Amy Boyd. Goggy Davidowitz. Mark Fishbein. Laurie Henneman. Bruce Kendall, Rachel Levin. Jill Miller. Sarah Richardson. Mike Singer, and Jen Weeks. The main source of flmding for 5iis research was a Graduate Research Fellowship from the National Science Foundation. Further support was provided by the Department of Ecology and Evolution at the University of Arizona, a fellowship from the Graduate College of the University of Arizona, the Flinn Foundation, and the University of Arizona Research Training Group in the Analysis of Biological Diversification. 5 DEDICATION I dedicate this work to my mother. Marie-Louise Schuler Mcintosh, who gave me a scientist's love for and fascination with the natural world, and to my father. Donald Spencer Mcintosh, who gave me a scientist's unshakable faith in the U^th. I also dedicate this vvork to all those beings throughout space and time who reverence infinite diversity in infinite combinations. 6 TABLE OF CONTENTS ABSTRACT 7 CHAPTER 1: INTRODUCTION 9 Bees as pollinators versus bees as herbivores 10 Pollen host specificity in bees 12 Cactus-specialist bees 14 Explanation of Dissertation Format 15 CHAPTER 2: PRESENT STUDY 18 CHAPTER 3: GENER.4L DISCUSSION 22 APPENDIX A: PLANT SIZE. BREEDING SYSTEM. AND LIMITS TO REPRODUCTIVE SUCCESS IN TWO SISTER SPECIES OF FEROCACTUS (CACTACEAE) 33 APPENDIX B: FLOWERING PHENOLOGY AND REPRODUCTIVE OUTPUT IN TWO SISTER SPECIES OF FEROCACTUS {CACTACEAE) 84 APPENDIX C: POLLINATION OF TWO SPECIES OF FEROCACTUS: INTER.ACTIONS BETWEEN CACTUS-SPECIALIST BEES AND THEIR HOST PLANTS 123 APPENDIX D: POLLEN PREFERENCES OF FOUR SOLITARY. CACTUS- SPECIALIST BEES FORAGING FOR LARVAL PROVISIONS 171 REFERENCES 241 7 ABSTRACT Although bees are herbivorous insects, they are seldom studied as such. My dissertation research characterizes the interactions between a guild of solitarv' cactus- specialist bees and the cacti they visit, examining these bees both as herbivores and as pollinators. 1 first e.xamined the reproductive biology of two species of Ferocactus as background for the pollination study. Both F. cylindraceus and F. wislizeni were obligate outcrossers. and neither species was pollen-limited. Fruit set was high in both species,