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The Effects of Sympatry on Patterns of Bill Morphology THE EFFECTS OF SYMPATRY ON PATTERNS OF BILL MORPHOLOGY BETWEEN CLOSELY RELATED SPECIES OF BIRDS, WORLDWIDE by STEPHANIE SOUN KIM A thesis submitted to the Department of Biology in conformity with the requirements for the degree of Master of Science Queen’s University Kingston, Ontario, Canada June 2016 Copyright © Stephanie Soun Kim, 2016 ii Abstract When closely related species co-occur in sympatry, they face a significant challenge. They must adapt to the same local conditions in their shared environment, which favours the convergent evolution of traits, while simultaneously minimizing the costs of competition for shared resources that typically favours the divergent evolution of traits. Here, we use a comparative sister lineage approach to test how most species have responded to these conflicting selection pressures in sympatry, focusing on a key ecological trait: the bill morphology of birds. If similar bill morphologies incur fitness costs due to species interactions, then we predicted that the bill morphologies of closely related species would differ more in sympatry compared with allopatry. Alternatively, if similar bill morphologies incur fitness benefits due to local adaptation, then we predicted that the bill morphologies would be more similar in sympatry compared with allopatry. We used museum specimens to measure five aspects of bill (maxilla) morphology – depth, length, width, side shape, and bottom shape – in diverse bird species from around the world to test our alternative hypotheses. We found support for both divergent evolution and convergent evolution (or trait retention) in one ecological trait: closely related sympatric species diverged in bill depth, but converged in side shape. These patterns of bill evolution were influenced by the genetic distance between closely related sister taxa and the geographic distance between allopatric lineages. Overall, our results highlight species interactions as an important mechanism for the evolution of some (bill depth), but not all (bill shape), aspects of bill morphology in closely related species in sympatry, and provide strong support for the bill as a key ecological trait that can adapt in different ways to the conflicting challenges of sympatry. iii Co-Authorship Chapter 2 was co-authored with P.R. Martin. Author contributions: P.R. Martin and S. Kim conceived and/or designed the study. S. Kim performed data collection. P.R. Martin and S. Kim performed analyses and wrote the paper. iv Acknowledgements First, I have to thank my supervisor, Paul Martin, for giving me the opportunity to work on this amazing project. Thank you for your patience, understanding, and constant help and support – you took a chance on a student without a strong background in ornithology and for that, I’m extremely grateful. I know it’s been said before, but I honestly couldn’t have asked for a better supervisor. To Bob Montgomerie and Virginia Walker, thank you for being supportive, helpful, and critical members of my supervisory committee and for striving to make my project great. I’d also like to thank Fran Bonier and everyone in the Bonier/Martin labs for insightful lab meetings that were at first intimidating, but later instrumental in helping me develop not only critical thinking and communication skills, but also confidence throughout these past two years. I would like to thank all the students in this department who welcomed me with open arms and helped me realize my deep-seated inner nerd and love of plaid. I want to especially thank Haley Kenyon, Liz Purves, Sara Burns, Harley English-Dixon, and Rachael Hornsby for your friendship, which has kept me sane and endlessly optimistic. Lastly, I would like to thank my family for their love and support throughout all my educational endeavours, with a special acknowledgement to my mother who decided to show her support by only buying bird-related Christmas ornaments for the past two years. This project would have been impossible without the cooperation of several museums across North America. I, therefore, am indebted to the curators, collection managers, and staff at the following museums: American Museum of Natural History, California Academy of Sciences, Canadian Museum of Nature, Carnegie Museum of Natural History, Cornell University Museum of Vertebrates, Field Museum of Natural History, Kansas University Natural History Museum, Los Angeles County Museum of Natural History, Louisiana State University Museum of Natural v Science, Moore Laboratory of Zoology, Museum of Comparative Zoology (Harvard University), Museum of Southwestern Biology (University of New Mexico), Museum of Vertebrate Zoology (University of California), Royal Ontario Museum, United States National Museum (Smithsonian), University of Colorado Museum, University of Michigan Museum of Zoology, and Yale University Peabody Museum. Funding for this research was provided by the Natural Sciences and Engineering Council of Canada (NSERC), the Frank M. Chapman Memorial Fund from the American Museum of Natural History, and the Field Museum Visiting Scholarship. vi Table of Contents Abstract........................................................................................................................................... ii Co-Authorship................................................................................................................................ iii Acknowledgements........................................................................................................................ iv List of Figures.............................................................................................................................. viii List of Tables.................................................................................................................................. ix Chapter 1: General Introduction..................................................................................................... 1 Divergent traits in sympatry: character displacement and ecological sorting............................ 2 Similar traits in sympatry: local adaptation in a shared environment......................................... 4 Key ecological traits and species diversity................................................................................. 6 Conclusions................................................................................................................................. 8 Chapter 2: The effects of sympatry on patterns of bill morphology between closely related species of birds, worldwide............................................................................................................. 9 Introduction................................................................................................................................. 9 Divergent or convergent bill morphologies in sympatry?..................................................... 11 Methods..................................................................................................................................... 15 Study species......................................................................................................................... 15 Museum data......................................................................................................................... 17 Linear data............................................................................................................................. 18 Shape data............................................................................................................................. 19 Additional factors.................................................................................................................. 20 Relative sympatry of A and B............................................................................................ 21 Mass.................................................................................................................................. 21 Annual temperatures/relative difference in annual temperatures.................................... 22 Mean and lineage-specific latitudes.................................................................................. 23 Geographic distance between lineages A and C............................................................... 24 Genetic distance between lineages................................................................................... 24 Overlap of non-focal congeners........................................................................................ 25 Dominance data................................................................................................................ 25 Statistical analyses................................................................................................................ 26 Controlling for phylogeny................................................................................................. 27 vii Post-hoc testing................................................................................................................. 28 Results....................................................................................................................................... 29 Side shape............................................................................................................................. 29 Bill depth............................................................................................................................... 30 Other
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