MS, University of Cincinnati, 2024, Arts and Sciences: Biological Sciences

Movement is a fundamental process in the life of many organisms, and is necessary for individuals to acquire resources, avoid predation, find mates, and thermoregulate. Movement allows individuals to track suitable temperatures; movement, however, can be impacted by meteorological conditions. Due to climate change, global temperature is predicted to increase by 1.5 °C between 2030 and 2052, resulting in higher mean temperatures and more frequent extreme temperature events. Increasing temperatures may decrease the ability of organisms to move in response to these higher temperatures. Understanding how species will respond to climate change requires understanding how temperature and environmental conditions affect their movement. The first chapter of this work looks at the literature that examines the effect of temperature on the flight of butterflies at their northern- and southernmost ranges, given reported thermal flight limits of each species. Due to their limited life spans, sensitivity to environmental changes in their habitats, and relatively rapid responses to these changes, butterflies are often used as biodiversity indicators to gauge shifts in ecological processes, making them a popular group of ectotherms used to examine the effect of temperature on movement. Current (2010-2019) daily maximum temperatures during flight seasons were significantly greater than those reported in the 1950s at both northern and southern range limits. At the southernmost ranges, the current average number of days that maximum temperatures exceeded the upper thermal limits for butterfly flight were significantly greater than in the 1950s, while there was no statistically significant difference at the northernmost ranges. Increases in ambient temperatures can restrict an organism's ability to escape extreme local temperatures. While I found very few papers that state the effect of ambient temperature on flight, my analysis shows that incorporating the environmental temperat (open full item for complete abstract)

Committee: Stephen Matter Ph.D. (Committee Chair); Elizabeth Hobson Ph.D. (Committee Member); Patrick Guerra Ph.D. (Committee Member) Subjects: Biology

Doctor of Philosophy, Case Western Reserve University, 2024, Biology

Organisms are shifting breeding phenology and thus exposing offspring to novel photoperiods. Rising global temperatures are also expanding the growing season and changing the relationship between photoperiod and temperature. This raises the question of whether species' responses to photoperiod that evolved prior to contemporary climate warming could lead to maladaptive responses under future global change. In Chapter 1, I examined how photoperiods representing two seasons affected freshwater communities composed of amphibians, phytoplankton, periphyton, and zooplankton. Both gray treefrogs and green frogs developed faster under the early-season photoperiod, and copepod nauplii abundance also increased. While there were taxa-specific effects of photoperiod, there were no widespread shifts in community composition nor strong indirect effects detected across the community. In Chapter 2, I explored the carryover effects of photoperiod and temperature, as well as their potential interaction, on gray treefrog life history. Both early- and late-season (shorter) photoperiods and the warm temperature treatment increased development rate but had opposing effects on size at metamorphosis: the shorter photoperiods reduced size, and the warm treatment increased size. While juveniles from the warm treatment grew slower during the short-term growth period after metamorphosis, there was no effect on long-term growth. Conversely, juveniles from the shorter photoperiods did not grow differently from the longer (average-season) photoperiod during the short-term growth period but grew slower during the long-term growth period. Overall, photoperiod had stronger effects across amphibian traits than that of temperature. In Chapter 3, I investigated the effects of three photoperiod treatments on traits associated with overwintering ability in gray treefrogs. Juveniles under the late-season photoperiod exhibited dramatically increased cryoprotectant levels, greater cold tolerance, and reduc (open full item for complete abstract)

Committee: Michael Benard (Advisor); Elliot Gardner (Committee Chair); Diana Koester (Committee Member); Jean Burns (Committee Member); Karen Abbott (Committee Member) Subjects: Biology; Climate Change; Ecology; Freshwater Ecology; Zoology

Doctor of Philosophy, Case Western Reserve University, 2022, Biology

Contemporary evolutionary change, once thought exceedingly rare, studied in the context of rapid urbanization and the novel selective pressures urbanization entails, provides a fortuitous albeit accidental, global experiment where evolutionary hypotheses can be tested with replication in real time. Cities are excellent venues to explore adaptation and evolution in response to novel selective pressures, and to examine the potential for rapid evolution along different dimensions of the phenotype. Here, I use common garden and reciprocal transplant approaches to examine evolved and plastic responses to urbanization in several focal traits for two arthropod taxa. Additionally, I assess whether evolutionary divergence between adjacent urban and rural populations has led to local adaptation and eco-evolutionary feedbacks. I focus on traits critical to persistence in the city—heat, cold, and desiccation tolerance, running speed, and body size interactions within several of these traits. I begin by examining body size in the acorn ant (Temnothorax curvispinosus) in relation to thermal tolerance, source population, and rearing temperature, finding that the evolution of heat tolerance and body size are decoupled in this system. I then examine the potential for evolution in heat and desiccation tolerance in response to urbanization in a terrestrial isopod (Oniscus asellus), finding support for the evolution of improved heat tolerance in urban populations, but no evidence for evolution in desiccation tolerance. Using this same isopod system, I next examine whether the urban populations' evolution in response to urbanization has conferred benefits in running speed (a trait critical for resource acquisition and predator avoidance) under chronic, stressfully hot rearing conditions. I find that the urban population has evolved higher running speed under stressful rearing temperatures. Lastly, I use a reciprocal transplant with the same isopod system to explore whether the urban pop (open full item for complete abstract)

Committee: Ryan Martin (Advisor); Sarah Diamond (Committee Member); Karen Abbott (Committee Member); Katie Stuble (Committee Member) Subjects: Biology; Climate Change; Ecology; Entomology; Evolution and Development; Morphology; Organismal Biology; Physiology; Zoology

Doctor of Philosophy (PhD), Ohio University, 2019, Biological Sciences (Arts and Sciences)

The Antarctic notothenioid fishes are among the most stenothermal animals on the planet and are likely to be vulnerable to the effects of global climate change. The physiological mechanisms that govern the thermal tolerance of Antarctic notothenioids are not fully understood. Membrane integrity and structure are highly sensitive to temperature and are critical to maintenance of cellular function. The two central hypotheses of this work are: (1) Variation in physical and biochemical membrane properties exists among notothenioids that display differences in thermal tolerance and thermal sensitivity of physiological processes; and (2) Membranes of Notothenia coriiceps undergo lipid remodeling in response to long-term thermal change in order to conserve membrane properties. Physical and biochemical properties of biological membranes from several tissues (cardiac ventricles and brain) were analyzed in several species of notothenioids in order to characterize variation in properties of biological membranes within this suborder of fishes. I also sought to determine whether notothenioids possess the capacity for acclimation to elevated temperature by determining the extent of compensation of membrane properties in several tissues (cardiac ventricles, brain, gill). Findings from this work provide novel insight into how notothenioids are likely to fare within a warmer climate. An interspecific comparative analysis was performed between notothenioids that exhibit variation in thermal tolerance (Chapters 2, 3). Membrane fluidity and composition were measured in several brain (synaptic, myelin, mitochondria) and cardiac (mitochondria) membranes from the red blooded (more thermotolerant) Notothenia coriiceps and the white-blooded Chaenocephalus aceratus. Synaptic membranes and cardiac mitochondria were more fluid in the icefish, compared to the red-blooded species. Hyperfluidization of membranes, particularly in the less thermotolerant species, C. aceratus, is consistent with the (open full item for complete abstract)

Committee: Elizabeth L. Crockett Ph.D. (Advisor); Janet Duerr Ph.D. (Committee Member); Daewoo Lee Ph.D. (Committee Member); Sarah Wyatt Ph.D. (Committee Member); Theresa Grove Ph.D. (Committee Member) Subjects: Animal Sciences; Aquatic Sciences; Biology; Physiology

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2019, Biological Sciences

Current declines in the abundance and diversity of bees and other pollinators has created uncertainty in their ability to reliably deliver pollination services. Recent studies examining urban bee communities show that bees respond to urbanization-mediated changes in land-use and environmental conditions. This includes increases in thermal and desiccation threats via urban heat island (UHI) effects that have not been well explored in bees. But it is unclear whether or how urbanization-related changes to pollinators influence pollination services. In this dissertation, I surveyed urban gardens and city parks across the metropolitan region of Toledo, Ohio (USA). First, I examined thermal and desiccation tolerances and safety margins for three bee species: silky striped sweat bees (Agapostemon sericeus), western honey bees (Apis mellifera), and common eastern bumble bees (Bombus impatiens). Second, I examined how urbanization and local habitat characteristics (herbaceous cover, floral abundance and color, tree abundance, canopy cover, soil moisture, gardens size) influenced bee communities (abundance, diversity, composition) and pollination services (visitation frequency). Third, I examined how bee species with specific functional traits and combinations of traits (functional guilds) were influenced by urbanization. The findings from this dissertation suggest that bees have differential sensitivities to urbanization, and managing for diverse bee communities in urban environments may require mitigating changes in temperature and water and increasing floral resource availability.

Committee: Kevin McCluney Ph.D. (Advisor); Mary-Jon Ludy Ph.D. (Other); Andrew Gregory Ph.D. (Committee Member); Helen Michaels Ph.D. (Committee Member); Shannon Pelini Ph.D. (Committee Member) Subjects: Biology; Ecology; Entomology; Zoology