THE INFLUENCE OF URBANIZATION ON ARTHROPOD WATER DEMAND AND LIPID AND PROTEIN CONSUMPTION IN MESIC ENVIRONMENTS Jamie Becker A Thesis Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 2017 Committee: Kevin McCluney, Advisor Shannon Pelini Karen Root ii ABSTRACT Kevin McCluney, Advisor Water is vital for terrestrial life, but water sources are often scarce, and environmental conditions are often desiccating. For example, the urban heat island effect causes areas with high impervious surfaces to have much hotter and drier conditions than rural locations. In chapter one, I examined the frequency of water demand behavior across variable landscapes in mesic NW OH, along with the effects of environmental factors and taxonomic identity. Overall, water demand occurred 11% of the time, but some areas experienced it 53.8% of the time. Ants accounted for much of the response (38% overall, but 62.8% and 57.4% in both high-impervious surface sites). Water demand behavior increased when soil moisture declined, especially below 30%. These results suggest that invertebrates experience water demand in a cool mesic region, even those living outside of urban areas. Further, invertebrates inhabiting cooler sites were most susceptible to periodic droughts or sudden weather changes, which could be due to arthropods at those locations having fewer xeric-adapted traits. When water is scarce, arthropods can obtain water by metabolizing dry food. Because lipids provide twice as much metabolic water as other macromolecules, eating high-lipid foods can reduce the need to forage for moist food. In chapter two, I examined the effects that arthropod water demand and impervious surface have on macronutrient consumption within 32 sites across Toledo, OH. Two artificial diets high in lipid or protein were offered at six trees at each site, three of which had wet water pillows and three had dry pillows. Lipid demand (L: P) was positively associated with impervious surface (χ2 = 8.36, df = 1, p < 0.01), and water iii pillows reduced the magnitude of this effect; this suggests that water balance likely played a role in driving lipid demand, matching predictions. Ants accounted for much of the response in high impervious surface areas. Because ants play key roles in food webs and ecosystems, increased demand for lipids with urbanization or climate change could have major consequences for urban food webs and ecosystem services. Future work should investigate how shifts in L: P preferences alter food webs. iv ACKOWLEDGEMENTS My committee, Kevin McCluney, Shannon Pelini, and Karen Root, have been invaluable in their insights into my work and supporting me to help cultivate my skills in research. I thank Kevin for his kind and honest criticism that has helped me to become a more rigorous, disciplined writer and researcher. His collaborative nature and emphasis on the importance of academic family has made me a more well-rounded individual. Shannon’s insights into alternative analytical methods have invoked clarity, and she has helped me think about the importance of brown food webs and the effects that climate change has on my results. Karen’s influence has improved the way I think about how landscape features influence patterns and processes at multiple scales. Her background and advice has inspired me to pursue a career in conservation and applied research. I also thank Mary Gardiner and Arianne Cease for their academic advice and support. I collectively thank all members of the McCluney lab for offering help with projects, giving advice, and offering academic and mental support. Lab meetings and get-togethers have given me a sense of camaraderie – something that is lacking in many labs, and something for which I am very grateful. I especially thank Ashley Everett, Haley Ingram, Nadejda Mirochnitchenko, Lily Murnen, Melanie Queener, and Matt Zach who have all aided me in my research, from running some of my experiments to engaging in extremely tedious tasks. I thank those who have given permission to conduct my field work on their property: Toledo Parks and Recreation, Wood County Parks and Recreation, City of Northwood, City of Perrysburg, City of Rossford, City of Walbridge, Springfield Township, Calvary Assembly of God, Calvary Cemetery, Cedar Creek Church, Grace United Methodist Church of Perrysburg, v Grove Patterson Academy, Rosary Cathedral Parish, St. Frances de Sales School, Sunrise Banquet Center, Walbridge Apartments, and Winterfield Venture Charter Academy. Finally, I wish to thank my family for their encouragement and support. I thank my sister, Lauren, and her husband, Matt, for sharing their experiences of graduate school and offering career advice. Finally, I thank J.D. for being an awesome husband. vi TABLE OF CONTENTS Page CHAPTER I. FREQUENCY OF ARTHROPOD WATER DEMAND IN MESIC ENVIRONMENTS ............................................................................................................... 1 Introduction ............................................................................................................... 1 Materials and methods .............................................................................................. 5 Results ....................................................................................................................... 8 Discussion ................................................................................................................. 9 CHAPTER II. CLIMATE-INDUCED CHANGES IN ANIMAL WATER DEMAND DRIVE HIGHER LIPID AND LOWER PROTEIN CONSUMPTION AMONG URBAN ARTHROPODS .................................................................................................................... 12 Introduction ............................................................................................................... 12 Materials and methods .............................................................................................. 15 Lab experiments ............................................................................................ 15 Field experiments .......................................................................................... 15 Results ....................................................................................................................... 19 Lab experiments ............................................................................................ 19 Field experiments .......................................................................................... 19 Discussion ................................................................................................................. 20 REFERENCES ..................................................................................................................... 23 APPENDIX A. TABLES ....................................................................................................... 33 APPENDIX B. FIGURES .................................................................................................... 50 1 CHAPTER I. FREQUENCY OF ARTHROPOD WATER DEMAND IN MESIC ENVIRONMENTS Introduction Water is vital for terrestrial life because it is a universal solvent, aids in material transport, maintains cell membrane fluidity, maintains turgor pressure, and regulates biochemical reactions (Hadley 1994). Thus, severe dehydration disrupts an individual’s ability to function normally. In some organisms, dehydration could decrease muscle performance (Claussen et al. 2000), growth rate (Jindra and Sehnal 1990, McCluney and Date 2008), survival (Dinh et al. 1988, Finkler 1999), and reproduction (Coe and Rotenberry 2003, Tieleman et al. 2004). A lack of adequate water availability can ultimately affect species distributions (Buckley and Jetz 2007), species richness (Hawkins et al. 2005, Keil et al. 2008), community composition (Schowalter et al. 1999, McCluney and Sabo 2012), and trophic interactions (Lensing and Wise 2006, Spiller and Shoener 2008, Sabo et al. 2008, Allen et al. 2014, McCluney et al. 2012, McCluney and Sabo 2009, 2016, Deguines et al. 2016). Multiple factors can influence water availability and water balance (difference between water gain and loss), including distribution of water in space and time and organismal traits (Chown et al. 2011, McCluney 2017). Water availability can depend upon regional and seasonal differences in precipitation, distribution of above-ground water bodies, and groundwater stores. Differences in land use can also influence water availability (Groffman et al. 2014, Steele and Heffernan 2014). Overuse of machinery and improper soil management techniques compact soil in both agricultural (Hamza and Anderson 2005) and urban (Gregory et al. 2006) landscapes. Urban areas also have a high density of impervious surfaces that limit groundwater infiltration (Forman 2014). Since soil compaction and impervious surfaces prevent infiltration, water is 2 redistributed to other locations. While some land use types are dry, certain land use types also provide water, like irrigated croplands, urban greenspaces such as parks, yards, gardens, and commercial landscaping. Other water sources along an urban-rural gradient include artificial ponds, swimming pools, and water fountains. Since several factors influence water availability, maintaining water balance can be a challenge. Water is gained in organisms through ingestion, water vapor absorption, and release of water through metabolism