Doctor of Philosophy, The Ohio State University, 2021, Entomology

Global populations of bees are in decline, threatening the stability of crop production and disrupting ecological communities. Unexpectedly, cities can harbor rich assemblages and sometimes rare species of bees. Thus, urban areas are increasingly recognized as potential refuge habitats for declining pollinators and as important targets for future bee conservation. Current urban bee populations are thought to be supported by residential gardens, parks, vacant lots and urban farms, which can contain a high floral abundance and therefore foraging resources for bees. Yet, there is no clear consensus about what drives the abundance and distribution of wild bees across cities. We also have little knowledge about how urbanization affects bee fitness, including their reproduction and health. For cities to achieve their conservation potential, we need to better understand what constitutes a high-quality urban habitat and how management can optimize urban greenspace for bee foraging and nesting. Herein, I examine patterns of bee biodiversity, nesting success, and resource capture within Cleveland, Ohio, USA as a case study for urban pollinator conservation. Cleveland is one of 350 legacy cities worldwide which are promising candidates for future bee conservation due to their high abundance of vacant urban land. For example, following protracted economic decline, Cleveland, Ohio now contains over 27,000 vacant properties, representing 1,600 ha of vacant land. While extensive vacant land can be perceived as blight, it has also provided a transformative opportunity for the city of Cleveland to invest in urban greening initiatives, including more than 235 urban farms/community gardens and the large-scale urban field experiment which I conducted this research in. To contextualize current knowledge of urban pollinators, I first review how greenspace design, management, and landscape context alter urban habitat's value for bees (Chapter 1). In addition, I assert that pollina (open full item for complete abstract)

Committee: Mary Gardiner (Advisor); Carol Anelli (Committee Member); Reed Johnson (Committee Member); Norman Johnson (Committee Member) Subjects: Conservation; Ecology; Entomology; Urban Planning

Master of Science, University of Akron, 2019, Biology

Ecological study of the spatial aspects of plant-pollinator interactions tends to follow lines of inquiry that begin with either plants as habitat or pollinators as decision-making agents. Small-scale insect behavior in response to flowering plants does not necessarily extend to larger scales. How insects navigate a landscape between patches of foraging habitat remains difficult to assess. The discrete distribution and self-incompatibility of Apocynum cannabinum facilitated this study of the effects of patch density and distribution on pollinator visits and plant reproductive output. No effect of density or inter-patch distance on pollinator visits or fruit set was observed. Density had a positive effect on seed set, which ranged from 65-103 seeds per fruit. Pollinator visits were dominated by species in the orders Hymenoptera and Lepidoptera and included previously unreported species. The reproductive strategy of Apocynum cannabinum suggests that abundant and prolonged flowering encourages sufficient between-patch movements by an effective pollinator able to access and transfer pollen from the modified flower. Visible landscape structure was an indicator of ecological connectivity - pollinators easily traversed the distance between the furthest apart patches - but the study scale did not shed light on barriers or gaps in connectivity.

Committee: Randall J. Mitchell (Advisor); Linda R. Barrett (Committee Member); Stephen C. Weeks (Committee Member) Subjects: Botany; Ecology; Entomology; Plant Biology

Doctor of Philosophy, The Ohio State University, 2018, Entomology

While numerous factors currently impact the health of honey bees and other pollinating Hymenoptera, poor floral resource availability due to habitat loss and land conversion is thought to be important. This issue is particularly salient in the upper Midwest, a location which harbors approximately 60 percent of the US honey bee colonies each summer for honey production. This region has experienced a dramatic expansion in the area devoted to crop production over the past decade. Consequently, understanding how changes to landscape composition affect the diversity, quality and quantity of available floral resources has become an important research goal. Here, I developed molecular methods for the identification of bee-collected pollen by adapting and improving upon the existing amplicon sequencing infrastructure used for microbial community ecology. In thoroughly benchmarking our procedures, I show that a simple and cost-effective three-step PCR-based library preparation protocol in combination with Metaxa2-based hierarchical classification yields an accurate and highly quantitative pollen metabarcoding approach when applied across multiple plant markers. In Chapter 1, I conducted one of the first ever proof-of-concept studies applying amplicon sequencing, or metabarcoding, to the identification of bee-collected pollen. In this work, we used rudimentary laboratory and bioinformatic methods to apply the method to a single nuclear marker, ITS2. In doing so, we found the method to be highly inaccurate with respect to quantitative inference of the relative abundances of different plant taxa represented within our sample. Thus, in Chapter 2 I used the same methods and turned my attention to two alternative chloroplast markers, matK and rbcL, in addition to ITS2. In this study, I found that the chloroplast markers were more useful for quantification of pollen abundance relative to ITS2. With an improved understanding of the behavior of different plant markers, I began op (open full item for complete abstract)

Committee: Reed Johnson (Advisor); John Christman (Committee Member); Mary Gardiner (Committee Member); Roman Lanno (Committee Member) Subjects: Agriculture; Bioinformatics; Biology; Ecology; Entomology; Pollen

Doctor of Philosophy, The Ohio State University, 2016, Entomology

The unifying thesis of my dissertation is that the biology of a honey bee colony cannot be understood apart from the landscape in which it lives; this influence of landscape applies especially to honey bee foraging biology and toxic exposure, and consequently to apicultural outcomes. In Chapter 1, I present and elaborate this thesis in the context of existing literature and lay out the scope of my dissertation accordingly. In Chapter 2, I describe a study in which I collaborated with volunteer beekeepers to measure the success of honey bee colonies surrounded by different types of landscape in Ohio, USA. The results of this study showed that the most successful colonies tended to be those surrounded by agricultural land as opposed to those in forested or urban landscapes, which was contrary to the prevailing opinion that agricultural landscapes are too dominated by crop monocultures and too contaminated with pesticides to support healthy honey bees. This led me to hypothesize that the relationship between honey bee success and landscape is driven mainly by the availability of certain key floral taxa that, in Ohio, occur most abundantly in the interstices of the agricultural landscape. Chapter 3 further pursues the question of whether honey bees prefer agricultural or urban land use by setting up a foraging choice test between these two landscape types. Using a combination of dance language analysis and pollen identification, I monitored the spatial and taxonomic patterns of honey bee foraging at an apiary located on the interface of urban and agricultural land use. The results indicate a strong and consistent preference for the agricultural landscape, corroborating the results of Chapter 1 with an independent data set and using different lines of evidence. In Chapter 4, I turn my attention to the issue of toxic exposure, constructing a critical review of existing approaches to modeling toxic exposure in honey bees. All existing approaches suffer from seriou (open full item for complete abstract)

Committee: Reed Johnson (Advisor); Casey Hoy (Committee Member); Mary Gardiner (Committee Member); Karen Goodell (Committee Member) Subjects: Biology; Ecology; Entomology; Toxicology

Master of Science, University of Akron, 2005, Biology

Invasive plant species have been studied for some time now but little attention has been given to their reproductive competitive abilities. I hypothesized that visitation rate to native Lythrum alatum would be increased in the presence of invasive Lythrum salicaria and that this facilitative effect would diminish with distance. I also hypothesized that seed set in L. alatum would be decreased in the presence of L. salicaria. To test these hypotheses I set up plots of L. salicaria and placed L. alatum mixed, 5m, 20m, and 50 m away from the L. salicaria. Pollinator visitation data, seed set per plant, and germination proportion per plant were recorded and analyzed. I found that visitation rate to L. alatum by large bees (Bombus and Apis) decreased significantly as a function of distance from L. salicaria and visitation rate by small bees (Ceratina, Lasioglossum, etc.) showed a trend of increasing as function of distance. Seed set showed no significant difference as a function of distance and proportion of seeds germinated in L. alatum showed a trend of increasing as a function of distance.

Committee: Randall Mitchell (Advisor) Subjects: Biology, Ecology