HOW DOES AN INVASIVE ANT, NYLANDERIA FULVA, AFFECT PRAIRIES? Dissertation Submitted to The College of Arts and Sciences of the UNIVERSITY OF DAYTON In Partial Fulfillment of the Requirements for The Degree of Doctor of Philosophy in Biology By Ryan William Reihart, M.S. Dayton, Ohio August 2021 HOW DOES AN INVASIVE ANT, NYLANDERIA FULVA, AFFECT PRAIRIES? Name: Reihart, Ryan William APPROVED BY: Chelse M. Prather, Ph.D. Albert J. Burky, Ph.D. Advisory Committee Chairman Committee Member Assistant Professor Professor Department of Biology Department of Biology Karolyn M. Hansen, Ph.D. Committee Member Associate Professor Chair, Department of Biology Ryan W. McEwan, Ph.D. Kirsten M. Prior, Ph.D. Committee Member Committee Member Professor Assistant Professor Department of Biology Department of Biological Sciences Binghamton University ii © Copyright by Ryan William Reihart All rights reserved 2021 iii ABSTRACT HOW DOES AN INVASIVE ANT, NYLANDERIA FULVA, AFFECT PRAIRIES? Name: Reihart, Ryan William University of Dayton Advisor: Dr. Chelse M. Prather Invasive species are a global threat that cause major ecological and economic harm, as they are a major contributor to loss of biodiversity and ecosystem function. Introduced ants becoming increasingly ubiquitous in terrestrial ecosystems and some of the most destructive invaders can extreme numerical densities, displace native ants and non-ant arthropods, and as a result, can alter the structure and function of natural ecosystems. A recent invader of emerging importance, the tawny crazy ant, Nylanderia fulva (Hymenoptera: Formicidae), is highly successful in coastal ecosystems in the Southeastern United States. We investigated the causes and consequences of invasion by N. fulva on coastal tallgrass prairies by determining: 1) diet, trophic position, and their potential to affect large, aboveground insects; 2) the effect of invasion on native above- and belowground insect communities; 3) the factors that limit N. fulva abundance; and 4) the mechanisms of N. fulva nutrient limitation and stress. In summary, N. fulva is an omnivorous ant that obtains most of its nitrogen from plants but has the capabilities to attack and kill large aboveground arthropods, like grasshoppers. In recently invaded habitats, N. fulva invaded areas were associated with lower native ant and grasshopper abundance, but these areas also contained greater abundances of hemipteran mutualists, which likely contribute to their extreme densities and success. Additionally, in litter iv communities, N. fulva numerically dominated the composition of litter-dwelling arthropods, and their abundance was limited by the availability of calcium but tended to be stressed by increased concentrations of potassium and sodium in the soil. Colonies of N. fulva that were fed diets with increased levels of calcium showed the ability to increase colony biomass. Based on these findings we show the great potential of this invasive ant to rapidly decrease the abundance and richness of native arthropods, which could have long-term negative impacts on native biodiversity, and show the factors that allow this invasive ant to reach numerical dominance in invaded ecosystems. v To my family – Mom, Dad, Mandy, and Derek – for always loving, supporting, and listening to me, even when I wouldn’t shut up about ants Although he likely won’t read this, to Dave Matthews – for all the crazy ants marching tawny antennas waving And lastly, to the insects, especially the few that sacrificed their lives to help me write this story… vi ACKNOWLEDGEMENTS Thank you to my advisor, Chelse Prather, who took me in as the first Insect Ecology Lab graduate student, supported and encouraged my intellectual curiosity, and taught me the meaning of prairie madness. Some of my favorite memories include when we finished spreading 10 tons of fertilizer, that time I got fleas, and the smell of Saltgrass after a long day in the field. I appreciate your patience with me and everything you have taught me. You are an amazing advisor and future graduate students will be lucky to work with you. I am grateful to have worked with many mentors, colleagues, and great students. Many thanks to my committee – Albert Burky, Karolyn Hansen, Ryan McEwan, and Kirsten Prior – for your support and helpful advice throughout my dissertation and my career. Thank you to Dr. Steve Pennings for allowing me to work at the University of Houston Coastal Center and your helpful feedback on my writing. Thank you to Dr. Angela Laws for being a great mentor in the field and teaching me how to identify many prairie plants and insects. Thank you to Tim Becker for helping me get my fieldwork done, cooking me delicious Texas food, and for being a friend in the prairie. A special thank you to Jack Cuellar, Denise Montelongo, Kiersten Angelos, Shania Hurst, Kaitlin Gawkins, and Troy Lampenfeld for all your assistance and laughs in the field. Thank you to the many of undergraduates who helped sort insects and process soil samples in the lab, I couldn’t have done this without you. vii Funding for this work was supported by the University of Dayton Graduate Student Summer Fellowship, the University of Dayton STEM Catalyst Initiative, and the Prairie Biotic Inc., Small Grant Program. viii LAND ACKNOWLEDGEMENT I humbly acknowledge that the fieldwork for this dissertation was collected on the traditional territory and homelands of the Karankawa (Karen-kawar), Coahuiltecan (KOE-ha_HWEE-ta-kanz), Atakapa-Ishak (ee-SHAK), and Akokisa people, and I recognize and acknowledge their history, their elders both past and present, as well as future generations. As stewards of the land, this acknowledgment and the information in this dissertation serve to help relearn how to care for the land and is commitment to begin dismantling the ongoing legacies of settler colonialism. ix TABLE OF CONTENTS ABSTRACT ...............................................................................................................iv DEDICATION ...........................................................................................................vi ACKNOWLEDGMENTS .........................................................................................vii LAND ACKNOWLEDGEMENT .................................................................ix LIST OF FIGURES ...................................................................................................xiii LIST OF TABLES .....................................................................................................xv LIST OF ABBREVIATIONS AND NOTATIONS ..................................................xvii CHAPTER 1: DOES NYLANDERIA FULVA AFFECT ABOVEGROUND ARTHROPODS? .......................................................................................................1 ACKNOWLEDGMENTS .............................................................................6 LITERATURE CITED ..................................................................................7 FIGURES .......................................................................................................9 SUPPLEMENTAL MATERIALS.................................................................11 Study Site ...........................................................................................11 Stable Isotope Field and Laboratory Methods ..................................11 Stable isotope delta (δ) values calculation ........................................12 Stable Isotope Trophic Position (TP) Calculation.............................12 SUPPLEMENTAL TABLES ........................................................................14 SUPPLEMENTAL LITERATURE CITED ..................................................15 CHAPTER 2: HOW DOES NYLANDERIA FULVA AFFECT INSECT COMMUNITIES?......................................................................................................16 x ABSTRACT ...................................................................................................16 INTRODUCTION .........................................................................................17 METHODS ....................................................................................................20 RESULTS ......................................................................................................23 DISCUSSION ................................................................................................25 ACKNOWLEDGMENTS .............................................................................29 LITERATURE CITED ..................................................................................31 TABLES ........................................................................................................36 FIGURES .......................................................................................................39 CHAPTER 3: WHAT FACTORS LIMIT THE ABUNDANCE OF NYLANDERIA FULVA? .....................................................................................................................42 ABSTRACT ...................................................................................................42 INTRODUCTION .........................................................................................43 METHODS ....................................................................................................46 RESULTS ......................................................................................................48 DISCUSSION ................................................................................................50