ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
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Description
Division of labor, whereby different group members perform different functions, is a fundamental attribute of sociality. It appears across social systems, from simple cooperative groups to complex eusocial colonies. A core challenge in sociobiology is to explain how patterns of collective organization are generated. Theoretical models propose that division of labor self-organizes, or emerges, from interactions among group members and the environment; division of labor is also predicted to scale positively with group size. I empirically investigated the emergence and scaling of division of labor in evolutionarily incipient groups of sweat bees and in eusocial colonies of harvester ants. To test whether division of labor is an emergent property of group living during early social evolution, I created de novo communal groups of the normally solitary sweat bee Lasioglossum (Ctenonomia) NDA-1. A division of labor repeatedly arose between nest excavation and guarding tasks; results were consistent with hypothesized effects of spatial organization and intrinsic behavioral variability. Moreover, an experimental increase in group size spontaneously promoted higher task specialization and division of labor. Next, I examined the influence of colony size on division of labor in larger, more integrated colonies of the harvester ant Pogonomyrmex californicus. Division of labor scaled positively with colony size in two contexts: during early colony ontogeny, as colonies grew from tens to hundreds of workers, and among same-aged colonies that varied naturally in size. However, manipulation of colony size did not elicit a short-term response, suggesting that the scaling of division of labor in P. californicus colonies is a product of functional integration and underlying developmental processes, rather than a purely emergent epiphenomenon. This research provides novel insights into the organization of work in insect societies, and raises broader questions about the role of size in sociobiology.
ContributorsHolbrook, Carter Tate (Author) / Fewell, Jennifer H (Thesis advisor) / Gadau, Jürgen (Committee member) / Harrison, Jon F. (Committee member) / Hölldobler, Berthold (Committee member) / Johnson, Robert A. (Committee member) / Arizona State University (Publisher)
Created2011
Description
Endocrine disruptors are chemicals that interact with the hormone system to negative effect. They ‘disrupt’ normal processes to cause diseases like vaginal cancer and obesity, reproductive issues like t-shaped uteri and infertility, and developmental abnormalities like spina bifida and cleft palate. These chemicals are ubiquitous in our daily lives, components in everything from toothpaste to microwave popcorn to plastic water bottles. My dissertation looks at the history, science, and regulation of these impactful substances in order to answer the question of how endocrine disruptors appeared, got interpreted by different groups, and what role science played in the process. My analysis reveals that endocrine disruptors followed a unique science policy trajectory in the US, rapidly going from their proposal in 1991 to their federal regulation in 1996, even amid intense and majority scientific disagreement over whether the substances existed at all. That trajectory resulted from the work of a small number of scientist-activists who constructed a concept and category as scientific, social, and regulatory. By playing actors from each sphere against each other and advancing a very specific scientific narrative that fit into a regulatory and social window of opportunity in the 1990s, those scientist-activists made endocrine disruptors a national issue that few could ignore. Those actions resulted in the Endocrine Disruptor Screening Program, a heavily-criticized and ineffective regulatory program. My dissertation tells a story of the past that informs the present. In 2018, the work of researchers, public media, and policymakers in the 1990s continues to play out, evident in the deep scientific division over endocrine disrupting effects and the inability of the European Union to settle on even a definition of endocrine disruptors for regulation purposes.
ContributorsAbboud, Alexis J (Author) / Maienschein, Jane A (Thesis advisor) / Crow, Michael M. (Committee member) / Hurlbut, J. Benjamin (Committee member) / Marchant, Gary E (Committee member) / Arizona State University (Publisher)
Created2018
Description
The most abundantly studied societies, with the exception of humans, are those of the eusocial insects, which include all ants. Eusocial insect societies are typically composed of many dozens to millions of individuals, referred to as nestmates, which require some form of communication to maintain colony cohesion and coordinate the activities within them. Nestmate recognition is the process of distinguishing between nestmates and non-nestmates, and embodies the first line of defense for social insect colonies. In ants, nestmate recognition is widely thought to occur through olfactory cues found on the exterior surfaces of individuals. These cues, called cuticular hydrocarbons (CHCs), comprise the overwhelming majority of ant nestmate profiles and help maintain colony identity. In this dissertation, I investigate how nestmate recognition is influenced by evolutionary, ontogenetic, and environmental factors. First, I contributed to the sequencing and description of three ant genomes including the red harvester ant, Pogonomyrmex barbatus, presented in detail here. Next, I studied how variation in nestmate cues may be shaped through evolution by comparatively studying a family of genes involved in fatty acid and hydrocarbon biosynthesis, i.e., the acyl-CoA desaturases, across seven ant species in comparison with other social and solitary insects. Then, I tested how genetic, developmental, and social factors influence CHC profile variation in P. barbatus, through a three-part study. (1) I conducted a descriptive, correlative study of desaturase gene expression and CHC variation in P. barbatus workers and queens; (2) I explored how larger-scale genetic variation in the P. barbatus species complex influences CHC variation across two genetically isolated lineages (J1/J2 genetic caste determining lineages); and (3) I experimentally examined how CHC development is influenced by an individual’s social environment. In the final part of my work, I resolved discrepancies between previous findings of nestmate recognition behavior in P. barbatus by studying how factors of territorial experience, i.e., spatiotemporal relationships, affect aggressive behaviors among red harvester ant colonies. Through this research, I was able to identify promising methodological approaches and candidate genes, which both broadens our understanding of P. barbatus nestmate recognition systems and supports future functional genetic studies of CHCs in ants.
ContributorsCash, Elizabeth I (Author) / Gadau, Jürgen (Thesis advisor) / Liebig, Jürgen (Thesis advisor) / Fewell, Jennifer (Committee member) / Hölldobler, Berthold (Committee member) / Kusumi, Kenro (Committee member) / Arizona State University (Publisher)
Created2016
Description
This dissertation investigates how ideas of the right relationships among science, the public, and collective decision-making about science and technology come to be envisioned in constructions of public engagement. In particular, it explores how public engagement has come to be constructed in discourse around gene editing to better understand how it holds together with visions for good, democratic governance of those technologies and with what effects. Using a conceptual idiom of the co-production of science and the social order, I investigate the mutual formation of scientific expertise, responsibility, and democracy through constructions of public engagement. I begin by tracing dominant historical narratives of contemporary public engagement as a continuation of public understanding of science’s projects of social ordering for democratic society. I then analyze collections of prominent expert meetings, publications, discussions, and interventions about development, governance, and societal implications human heritable germline gene editing and gene drives that developed in tandem with commitments to public engagement around those technologies. Synthesizing the evidence from across gene editing discourse, I offer a constructive critique of constructions of public engagement as expressions and evidence of scientific responsibility as ultimately reasserting and reinforcing of scientific experts' authority in gene editing decision-making, despite intentions for public engagement to extend decision-making participation and power to publics. Such constructions of public engagement go unrecognized in gene editing discourse and thereby subtly reinforce broader visions of scientific expertise as essential to good governance by underwriting the legitimacy and authority of scientific experts to act on behalf of public interests. I further argue that the reinforcement of scientific expert authority in gene editing discourse through public engagement also centers scientific experts in a sociotechnical imaginary that I call “not for science alone.” This sociotechnical imaginary envisions scientific experts as guardians and guarantors of good, democratic governance. I then propose a possible alternatives to public engagement alone to improve gene editing governance by orienting discourse around notions of public accountability for potential shared benefits and collective harms of gene editing.
ContributorsRoss, Christian (Author) / Hurlbut, James B. (Thesis advisor) / Maienschein, Jane (Thesis advisor) / Collins, James P. (Committee member) / Crow, Michael M. (Committee member) / Sarewitz, Daniel R. (Committee member) / Arizona State University (Publisher)
Created2021