University of South Florida Scholar Commons Graduate Theses and Dissertations Graduate School July 2019 Clinging in Plethodontid Salamanders Mary Kathleen O'Donnell University of South Florida, [email protected] Follow this and additional works at: https://scholarcommons.usf.edu/etd Part of the Biomechanics Commons Scholar Commons Citation O'Donnell, Mary Kathleen, "Clinging in Plethodontid Salamanders" (2019). Graduate Theses and Dissertations. https://scholarcommons.usf.edu/etd/8397 This Dissertation is brought to you for free and open access by the Graduate School at Scholar Commons. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Clinging in Plethodontid Salamanders by Mary Kathleen O’Donnell A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy with a concentration in Physiology and Morphology Department of Integrative Biology College of Arts and Sciences University of South Florida Major Professor: Stephen M. Deban, Ph.D. Philip J. Motta, Ph.D. Bradford J. Gemmell, Ph.D. David W. Murphy, Ph.D. Date of Approval: May 15, 2019 Keywords: adhesion, mucus, roughness, wetness, performance Copyright © 2019, Mary Kathleen O’Donnell Dedication Dedicated in thanks to my parents, family, friends, and teachers. To my parents, thank you for putting up with me as a child. Thank you for always being willing to go to beach with the cove, or let me bring my net in the car, or let me try to catch every animal and bring it home. I’ve come full circle and become the kind of adult who explains to kids why they should leave wild animals where they find them. For my family and friends, especially my brothers Joey, Luke, and Conan, and my godfather, Matt Hanlon, who not only let me talk endlessly about my research but also let me derail all outdoor activities based on where I think the cool animals might be; we don’t get anywhere quickly, but you make the journey fun. Finally, to my teachers, especially Ms. McDonald, Mr. Valente, Dr. Fingerut, Dr. Motta, and my advisor, Stephen Deban: the patience, encouragement, and confidence you gave me at every level of my education are the only reason that I’m here now. Acknowledgments Science is collaborative. This research would not have been possible without the time, animals, and expertise shared with me by Walter Smith, J. Gavin Bradley, Jim Spickler, Chris Evelyn, Mark Beshel, Enrico Lunghi, Sean Rovito, Dan Riskin, and Christian Brown. This research project was refined through many wonderful conversations with Charlotte Stinson Easterling, Jeffrey Olberding, Segall Bloom, Jeffrey Scales, Taylor Kelsay and Christian Brown. Funding for this research was provided in part by the Porter Foundation, the Fern Garden Club of Odessa, and Highlands Biological Station. Table of Contents List of Tables ................................................................................................................................. iii List of Figures ................................................................................................................................ iv Abstract ........................................................................................................................................... v I. Cling Performance and Surface Area of Attachment ......................................................... 1 Abstract ............................................................................................................................... 1 Introduction ......................................................................................................................... 1 Methods............................................................................................................................... 7 Animals ................................................................................................................... 7 Maximum Cling Performance................................................................................. 7 Surface Area of Attachment.................................................................................... 8 Field Tests ............................................................................................................. 10 Digitizing Images .................................................................................................. 11 Stress calculations ................................................................................................. 11 Statistical Analysis ................................................................................................ 12 Results ............................................................................................................................... 13 Discussion ......................................................................................................................... 16 Salamander clinging.............................................................................................. 16 Clinging in small salamanders .............................................................................. 18 Clinging in large salamanders ............................................................................... 19 Clinging in Ambystomatidae ................................................................................ 20 Clinging in a ventrally flattened species ............................................................... 20 Clinging in Bolitoglossa ....................................................................................... 21 Conclusions ....................................................................................................................... 22 References ......................................................................................................................... 23 II. Mechanisms of Attachment .............................................................................................. 47 Abstract ............................................................................................................................. 47 Introduction ....................................................................................................................... 47 Methods............................................................................................................................. 51 Animals ................................................................................................................. 51 Suction test ............................................................................................................ 52 Parallel (shear) stress test ...................................................................................... 53 Normal (tensile) stress test .................................................................................... 55 Digitizing shear stress images ............................................................................... 56 Salamander attachment area ................................................................................. 57 Statistical analyses ................................................................................................ 57 Results ............................................................................................................................... 58 i Suction .................................................................................................................. 58 Normal (tensile) stress .......................................................................................... 58 Shear stress............................................................................................................ 59 Salamander area of attachment ............................................................................. 60 Discussion ......................................................................................................................... 60 Salamander attachment mechanism ...................................................................... 60 Suction as an attachment mechanism ................................................................... 61 Attachment in small salamanders with high cling performance ........................... 62 Attachment in Aneides and Bolitoglossa .............................................................. 63 Attachment in salamanders with low cling performance ...................................... 64 Attachment in Desmognathus quadramaculatus ................................................... 66 Variation in adhesiveness ..................................................................................... 67 Conclusions ....................................................................................................................... 68 References ......................................................................................................................... 70 III. Effect of Roughness and Wetness..................................................................................... 88 Abstract ............................................................................................................................. 88 Introduction ....................................................................................................................... 89 Methods............................................................................................................................