Matching Items (1,026)
Description
Human-induced rapid environmental change (HIREC) influences nearly all of Earth's ecosystems through processes such as urbanization. Previous studies have found that urbanization influences biodiversity patterns, often yielding an increase in the abundance of a few urban-adapted taxa at the expense of native species diversity. The western black widow spider, Latrodectus hesperus, is a medically-important pest species that often forms dense urban subpopulations (i.e., infestations) relative to the low-density subpopulations found throughout undisturbed, desert habitat. Here, I employ field and laboratory studies to examine the population ecology and stoichiometry of this urban pest to increase our understanding of the mechanisms underlying its success. The population ecology of ten black widow subpopulations spread across metropolitan Phoenix, AZ was examined during the peak breeding season (June-August). This study revealed that arthropod prey abundance, female mass and population density of females showed significant spatial variation across the ten subpopulations. Additionally, prey abundance and foraging success, measured as the number of carcasses found in webs, were a strong determinant of female mass and population density within each subpopulation. To test the mechanisms that drive black widow infestations, I used ecological stoichiometry to examine the nutrient (nitrogen and phosphorus) composition of spiders and arthropod prey from urban habitat, desert habitat and a laboratory diet regime. These studies revealed that (1) spiders are more nutrient rich than cricket prey in the field, (2) spider subpopulations exhibit significant spatial variation in their nitrogen composition, (3) nutrient composition of urban spider subpopulations does not differ significantly from Sonoran desert subpopulations, (4) laboratory-reared spiders fed a diet of only laboratory-reared crickets are more nitrogen and phosphorus limited than field-captured spiders, and (5) cannibalism by laboratory-reared spiders alleviated phosphorus limitation, but not nitrogen limitation, when compared to field-captured spiders. This work highlights the need to examine the population ecology of species relationships, such as predator-prey dynamics, to fully understand the fecundity and population growth of urban pest species. Moreover, the integration of population ecology and stoichiometry illustrates the need to address mechanisms like nutrient limitation that may explain why urban pest populations thrive and native species diversity suffers following HIREC.
ContributorsTrubl, Patricia (Author) / Johnson, James C. (Thesis advisor) / Rutowski, Ronald (Thesis advisor) / McGraw, Kevin (Committee member) / Arizona State University (Publisher)
Created2012
Description
Foraging has complex effects on whole-organism homeostasis, and there is considerable evidence that foraging behavior is influenced by both environmental factors (e.g., food availability, predation risk) and the physiological condition of an organism. The optimization of foraging behavior to balance costs and benefits is termed state-dependent foraging (SDF) while behavior that seeks to protect assets of fitness is termed the asset protection principle (APP). A majority of studies examining SDF have focused on the role that energy balance has on the foraging of organisms with high metabolism and high energy demands ("high-energy systems" such as endotherms). In contrast, limited work has examined whether species with low energy use ("low-energy systems" such as vertebrate ectotherms) use an SDF strategy. Additionally, there is a paucity of evidence demonstrating how physiological and environmental factors other than energy balance influence foraging behavior (e.g. hydration state and free-standing water availability). Given these gaps in our understanding of SDF behavior and the APP, I examined the state-dependency and consequences of foraging in a low-energy system occupying a resource-limited environment - the Gila monster (Heloderma suspectum, Cope 1869). In contrast to what has been observed in a wide variety of taxa, I found that Gila monsters do not use a SDF strategy to manage their energy reserves and that Gila monsters do not defend their energetic assets. However, hydration state and free-standing water availability do affect foraging behavior of Gila monsters. Additionally, as Gila monsters become increasingly dehydrated, they reduce activity to defend hydration state. The SDF behavior of Gila monsters appears to be largely driven by the fact that Gila monsters must separately satisfy energy and water demands with food and free-standing water, respectively, in conjunction with the timescale within which Gila monsters balance their energy and water budgets (supra-annually versus annually, respectively). Given these findings, the impact of anticipated changes in temperature and rainfall patterns in the Sonoran Desert are most likely going to pose their greatest risks to Gila monsters through the direct and indirect effects on water balance.
ContributorsWright, Christian (Author) / Denardo, Dale F. (Thesis advisor) / Harrison, Jon (Committee member) / McGraw, Kevin (Committee member) / Sullivan, Brian (Committee member) / Wolf, Blair (Committee member) / Arizona State University (Publisher)
Created2014
Description
This dissertation examines the ways ABC/Disney's Ugly Betty (ABC 2006-2010) manufactures diversity to create an illusion of the U.S. as a site of multiple pluralisms and equality by re-scripting the ugly duckling parable as a Latino de-racialization project and assimilation narrative. The success of the show's original version, Colombian telenovela, Yo Soy Betty, La Fea (RCN 1999-2001), escalated into an international franchise, licensed by and culturally adapted for television markets around the globe. The image the United States promotes of itself, as seen through its media products (especially Disney products) valorize and export discourses of The American Dream around the globe. In order to maintain this carefully crafted self-image, one that masks the ongoing racial oppression and colonial holdings, depictions of diversity are manufactured.
This study examines the Disney affiliated series Ugly Betty to assess how the culture and identity of Betty Suarez, its titular character, as a Mexican-American woman is manufactured. Of particular interest is how she is coded as a diverse member of U.S. workforce, and how her transformative makeover from ugly duckling can be read as an assimilation narrative from racialized ethnic invader to white American professional. Using criteria extracted from scholarship and cultural production regarding Latina identity formation, I locate Betty within what I call the spectrum of assimilation among U.S. Latinas. Because there are various ways in which one negotiates, expresses and balances the multiple cultural, racial and classed components of their self-identity, I tease out markers from existing theories to locate Betty's self-projected cultural identity within the series narrative.
Building on the evidence gathered regarding Betty's rejection of a politicized Latina identity, this project analyzes the implications of the choice of New York City as site of Betty's transformation and how the use of queer visibility and American Dream discourse inform a reading of Betty as assimilation narrative. This dissertation concludes with a brief analysis of two shows featuring Latina titular characters. Both Cristela (ABC 2014-) and Jane the Virgin (CW 2014-) are successors of Ugly Betty yet diverge in the way their portrayals of Latinidades include more nuanced and pluralistic representations.
This study examines the Disney affiliated series Ugly Betty to assess how the culture and identity of Betty Suarez, its titular character, as a Mexican-American woman is manufactured. Of particular interest is how she is coded as a diverse member of U.S. workforce, and how her transformative makeover from ugly duckling can be read as an assimilation narrative from racialized ethnic invader to white American professional. Using criteria extracted from scholarship and cultural production regarding Latina identity formation, I locate Betty within what I call the spectrum of assimilation among U.S. Latinas. Because there are various ways in which one negotiates, expresses and balances the multiple cultural, racial and classed components of their self-identity, I tease out markers from existing theories to locate Betty's self-projected cultural identity within the series narrative.
Building on the evidence gathered regarding Betty's rejection of a politicized Latina identity, this project analyzes the implications of the choice of New York City as site of Betty's transformation and how the use of queer visibility and American Dream discourse inform a reading of Betty as assimilation narrative. This dissertation concludes with a brief analysis of two shows featuring Latina titular characters. Both Cristela (ABC 2014-) and Jane the Virgin (CW 2014-) are successors of Ugly Betty yet diverge in the way their portrayals of Latinidades include more nuanced and pluralistic representations.
ContributorsMartinez, Michelle (Author) / Haggins, Bambi (Thesis advisor) / Danielson, Marivel (Committee member) / Himberg, Julia (Committee member) / Arizona State University (Publisher)
Created2015
Description
For animals that experience annual cycles of gonad development, the seasonal timing (phenology) of gonad growth is a major adaptation to local environmental conditions. To optimally time seasonal gonad growth, animals use environmental cues that forecast future conditions. The availability of food is one such environmental cue. Although the importance of food availability has been appreciated for decades, the physiological mechanisms underlying the modulation of seasonal gonad growth by this environmental factor remain poorly understood.
Urbanization is characterized by profound environmental changes, and urban animals must adjust to an environment vastly different from that of their non-urban conspecifics. Evidence suggests that birds adjust to urban areas by advancing the timing of seasonal breeding and gonad development, compared to their non-urban conspecifics. A leading hypothesis to account for this phenomenon is that food availability is elevated in urban areas, which improves the energetic status of urban birds and enables them to initiate gonad development earlier than their non-urban conspecifics. However, this hypothesis remains largely untested.
My dissertation dovetailed comparative studies and experimental approaches conducted in field and captive settings to examine the physiological mechanisms by which food availability modulates gonad growth and to investigate whether elevated food availability in urban areas advances the phenology of gonad growth in urban birds. My captive study demonstrated that energetic status modulates reproductive hormone secretion, but not gonad growth. By contrast, free-ranging urban and non-urban birds did not differ in energetic status or plasma levels of reproductive hormones either in years in which urban birds had advanced phenology of gonad growth or in a year that had no habitat-related disparity in seasonal gonad growth. Therefore, my dissertation provides no support for the hypothesis that urban birds begin seasonal gonad growth because they are in better energetic status and increase the secretion of reproductive hormones earlier than non-urban birds. My studies do suggest, however, that the phenology of key food items and the endocrine responsiveness of the reproductive system may contribute to habitat-related disparities in the phenology of gonad growth.
Urbanization is characterized by profound environmental changes, and urban animals must adjust to an environment vastly different from that of their non-urban conspecifics. Evidence suggests that birds adjust to urban areas by advancing the timing of seasonal breeding and gonad development, compared to their non-urban conspecifics. A leading hypothesis to account for this phenomenon is that food availability is elevated in urban areas, which improves the energetic status of urban birds and enables them to initiate gonad development earlier than their non-urban conspecifics. However, this hypothesis remains largely untested.
My dissertation dovetailed comparative studies and experimental approaches conducted in field and captive settings to examine the physiological mechanisms by which food availability modulates gonad growth and to investigate whether elevated food availability in urban areas advances the phenology of gonad growth in urban birds. My captive study demonstrated that energetic status modulates reproductive hormone secretion, but not gonad growth. By contrast, free-ranging urban and non-urban birds did not differ in energetic status or plasma levels of reproductive hormones either in years in which urban birds had advanced phenology of gonad growth or in a year that had no habitat-related disparity in seasonal gonad growth. Therefore, my dissertation provides no support for the hypothesis that urban birds begin seasonal gonad growth because they are in better energetic status and increase the secretion of reproductive hormones earlier than non-urban birds. My studies do suggest, however, that the phenology of key food items and the endocrine responsiveness of the reproductive system may contribute to habitat-related disparities in the phenology of gonad growth.
ContributorsDavies, Scott (Author) / Deviche, Pierre (Thesis advisor) / Sweazea, Karen (Committee member) / McGraw, Kevin (Committee member) / Orchinik, Miles (Committee member) / Warren, Paige (Committee member) / Arizona State University (Publisher)
Created2014
Description
Warning coloration deters predators from attacking prey that are defended, usually by being distasteful, toxic, or otherwise costly for predators to pursue and consume. Predators may have an innate response to warning colors or learn to associate them with a defense through trial and error. In general, predators should select for warning signals that are easy to learn and recognize. Previous research demonstrates long-wavelength colors (e.g. red and yellow) are effective because they are readily detected and learned. However, a number of defended animals display short-wavelength coloration (e.g. blue and violet), such as the pipevine swallowtail butterfly (Battus philenor). The role of blue coloration in warning signals had not previously been explicitly tested. My research showed in laboratory experiments that curve-billed thrashers (Toxostoma curvirostre) and Gambel's quail (Callipepla gambelii) can learn and recognize the iridescent blue of B. philenor as a warning signal and that it is innately avoided. I tested the attack rates of these colors in the field and blue was not as effective as orange. I concluded that blue colors may function as warning signals, but the effectiveness is likely dependent on the context and predator.
Blue colors are often iridescent in nature and the effect of iridescence on warning signal function was unknown. I reared B. philenor larvae under varied food deprivation treatments. Iridescent colors did not have more variation than pigment-based colors under these conditions; variation which could affect predator learning. Learning could also be affected by changes in appearance, as iridescent colors change in both hue and brightness as the angle of illuminating light and viewer change in relation to the color surface. Iridescent colors can also be much brighter than pigment-based colors and iridescent animals can statically display different hues. I tested these potential effects on warning signal learning by domestic chickens (Gallus gallus domesticus) and found that variation due to the directionality of iridescence and a brighter warning signal did not influence learning. However, blue-violet was learned more readily than blue-green. These experiments revealed that the directionality of iridescent coloration does not likely negatively affect its potential effectiveness as a warning signal.
Blue colors are often iridescent in nature and the effect of iridescence on warning signal function was unknown. I reared B. philenor larvae under varied food deprivation treatments. Iridescent colors did not have more variation than pigment-based colors under these conditions; variation which could affect predator learning. Learning could also be affected by changes in appearance, as iridescent colors change in both hue and brightness as the angle of illuminating light and viewer change in relation to the color surface. Iridescent colors can also be much brighter than pigment-based colors and iridescent animals can statically display different hues. I tested these potential effects on warning signal learning by domestic chickens (Gallus gallus domesticus) and found that variation due to the directionality of iridescence and a brighter warning signal did not influence learning. However, blue-violet was learned more readily than blue-green. These experiments revealed that the directionality of iridescent coloration does not likely negatively affect its potential effectiveness as a warning signal.
ContributorsPegram, Kimberly Vann (Author) / Rutowski, Ronald L (Thesis advisor) / Hoelldobler, Berthold (Committee member) / Liebig, Juergen (Committee member) / McGraw, Kevin (Committee member) / Smith, Brian H. (Committee member) / Arizona State University (Publisher)
Created2015
Description
Parental care provides many benefits to offspring. One widely realized benefit is enhanced regulation of offspring's thermal environment. The developmental thermal environment during development can be optimized behaviorally through nest site selection and brooding, and it can be further enhanced by physiological heat production. In fact, enhancement of the developmental thermal environment has been proposed as the initial driving force for the evolution of endothermy in bird and mammals. I used pythons (Squamata: Pythonidae) to expand existing knowledge of behavioral and physiological parental tactics used to regulate offspring thermal environment. I first demonstrated that brooding behavior in the Children's python (Antaresia childreni) is largely driven by internal mechanisms, similar to solitary birds, suggesting that the early evolution of the parent-offspring association was probably hormonally driven. Two species of python are known to be facultatively thermogenic (i.e., are endothermic during reproduction). I expand current knowledge of thermogenesis in Burmese pythons (Python molurus) by demonstrating that females use their own body temperature to modulate thermogenesis. Although pythons are commonly cited as thermogenic, the actual extent of thermogenesis within the family Pythonidae is unknown. Thus, I assessed the thermogenic capability of five previously unstudied species of python to aid in understanding phylogenetic, morphological, and distributional influences on thermogenesis in pythons. Results suggest that facultative thermogenesis is likely rare among pythons. To understand why it is rare, I used an artificial model to demonstrate that energetic costs to the female likely outweigh thermal benefits to the clutch in species that do not inhabit cooler latitudes or lack large energy reserves. In combination with other studies, these results show that facultative thermogenesis during brooding in pythons likely requires particular ecological and physiological factors for its evolution.
ContributorsBrashears, Jake (Author) / DeNardo, Dale (Thesis advisor) / Harrison, Jon (Committee member) / Deviche, Pierre (Committee member) / McGraw, Kevin (Committee member) / Smith, Andrew (Committee member) / Arizona State University (Publisher)
Created2012
Description
This study explored the perspectives and experiences of eight women active within a particular location of the collective social media landscape. One aspect of the research centered around critiquing mainstream media diets for encouraging fat stigma and deepening the negative effects of stereotyping larger bodies. The research questions centered around transgressive media diets, specifically those that were body positive, and focused on if they could help to eradicate fat stigma and educate the masses on false stereotypes. To examine this, eight plus-size fashion bloggers and/or plus-size models were interviewed following a semi-structured format. These women, as bloggers and Instagrammers with a strong presence in the plus-size fashion industry, were both content producers as well as consumers, and their personal narratives enabled the study to better understand the complex interconnections between production and consumption, self-expression and the politics of self-representation, the cooptation of these self-representations by profit-oriented media interest, and how commodification shapes the transgressive potential of these representations. The research also found that many content creators came to transgressive media diets because they saw a lack of representation and decided that they must make that representation for themselves. The study also examined what community building meant within the porous landscape of social media platforms and the relationship between identity building and community building as social processes. Many of the participants brought up examples of fat discrimination yet many defined themselves as "confident" or "badass", thus finding ways to empower themselves despite the pressure of societal norms. Some of this empowerment came from finding a community online. Finally, these plus-size models and fashion bloggers moved through a thin ideal industry by demanding and being examples of diversity.
ContributorsValentine, Erin (Author) / Katsulis, Yasmina (Thesis advisor) / Himberg, Julia (Committee member) / McGibbney, Michelle (Committee member) / Arizona State University (Publisher)
Created2018
Description
Reproduction is energetically costly and seasonal breeding has evolved to capitalize on predictable increases in food availability. The synchronization of breeding with periods of peak food availability is especially important for small birds, most of which do not store an extensive amount of energy. The annual change in photoperiod is the primary environmental cue regulating reproductive development, but must be integrated with supplementary cues relating to local energetic conditions. Photoperiodic regulation of the reproductive neuroendocrine system is well described in seasonally breeding birds, but the mechanisms that these animals use to integrate supplementary cues remain unclear. I hypothesized that (a) environmental cues that negatively affect energy balance inhibit reproductive development by acting at multiple levels along the reproductive endocrine axis including the hypothalamus (b) that the availability of metabolic fuels conveys alterations in energy balance to the reproductive system. I investigated these hypotheses in male house finches, Haemorhous mexicanus, caught in the wild and brought into captivity. I first experimentally reduced body condition through food restriction and found that gonadal development and function are inhibited and these changes are associated with changes in hypothalamic gonadotropin-releasing hormone (GnRH). I then investigated this neuroendocrine integration and found that finches maintain reproductive flexibility through modifying the release of accumulated GnRH stores in response to energetic conditions. Lastly, I investigated the role of metabolic fuels in coordinating reproductive responses under two different models of negative energy balance, decreased energy intake (food restriction) and increased energy expenditure (high temperatures). Exposure to high temperatures lowered body condition and reduced food intake. Reproductive development was inhibited under both energy challenges, and occurred with decreased gonadal gene expression of enzymes involved in steroid synthesis. Minor changes in fuel utilization occurred under food restriction but not high temperatures. My results support the hypothesis that negative energy balance inhibits reproductive development through multilevel effects on the hypothalamus and gonads. These studies are among the first to demonstrate a negative effect of high temperatures on reproductive development in a wild bird. Overall, the above findings provide important foundations for investigations into adaptive responses of breeding in energetically variable environments.
ContributorsValle, Shelley (Author) / Deviche, Pierre (Thesis advisor) / McGraw, Kevin (Committee member) / Orchinik, Miles (Committee member) / Propper, Catherine (Committee member) / Sweazea, Karen (Committee member) / Arizona State University (Publisher)
Created2018
Description
Aside from uplifting and tearing down the mood of a young LGBTQ+ kid, journalistic media has the potential to alter the way audiences understand and react to individuals of the LGBTQ+ community. Looking at the rhetorical approaches, frameworks, and expanded narratives of news sources, this project engages with the concepts of same-sex marriage, lifestyles, bans, and children in education in order to attain an understanding of what media messages are being shared, how they are being communicated, and what the implications of such rhetoric are. Summary of the findings:
• Same-sex marriage as the win that cannot be repeated.
Infamously known as the central legal battle for the LGBTQ+ community, same-sex marriage finds itself in many political speeches, campaigns, and social commentaries. Interestingly, after being legalized through a Supreme Court decision in the United States, Same-Sex Marriage finds itself framed as the social inevitability that should not be repeated in politics or any legal shift. In other words, “the gays have won this battle, but not the war.”
• There are risks around the “LGBTQ+ lifestyle” and its careful catering to an elite minority and the mediation through bans.
The risks of the LGBTQ+ “lifestyle” date back far, with many connotations being attached to being LGBTQ+ (AIDS epidemics, etc.). In modern journalism, many media outlets portray LGBTQ+ individuals to be a tiny minority (.001% according to some) that demands the whole society to adhere to their requests. This framework portrays the LGBTQ+ community as oppressors and obsessed advocates that can never “seem to get enough” (ex: more than just marriage). The bans are framed as the neutralizing factor to the catering.
• LGBTQ+ children and topics in academic and social spaces are the extreme degree.
When it comes to LGBTQ+ issues and conversations as they revolve around children, media outlets have some of the most passionate opinions about them. Often portrayed as “the line that shouldn’t be crossed,” LGBTQ+ issues, as they find themselves in schools and other spaces, are thus portrayed as bearable to a certain degree, never completely. Claims of indoctrination are also presented prominently even when institutional efforts are to protect LGBTQ+ kids.
• Same-sex marriage as the win that cannot be repeated.
Infamously known as the central legal battle for the LGBTQ+ community, same-sex marriage finds itself in many political speeches, campaigns, and social commentaries. Interestingly, after being legalized through a Supreme Court decision in the United States, Same-Sex Marriage finds itself framed as the social inevitability that should not be repeated in politics or any legal shift. In other words, “the gays have won this battle, but not the war.”
• There are risks around the “LGBTQ+ lifestyle” and its careful catering to an elite minority and the mediation through bans.
The risks of the LGBTQ+ “lifestyle” date back far, with many connotations being attached to being LGBTQ+ (AIDS epidemics, etc.). In modern journalism, many media outlets portray LGBTQ+ individuals to be a tiny minority (.001% according to some) that demands the whole society to adhere to their requests. This framework portrays the LGBTQ+ community as oppressors and obsessed advocates that can never “seem to get enough” (ex: more than just marriage). The bans are framed as the neutralizing factor to the catering.
• LGBTQ+ children and topics in academic and social spaces are the extreme degree.
When it comes to LGBTQ+ issues and conversations as they revolve around children, media outlets have some of the most passionate opinions about them. Often portrayed as “the line that shouldn’t be crossed,” LGBTQ+ issues, as they find themselves in schools and other spaces, are thus portrayed as bearable to a certain degree, never completely. Claims of indoctrination are also presented prominently even when institutional efforts are to protect LGBTQ+ kids.
ContributorsNieto Calderon, Ramon Antonio (Author) / Himberg, Julia (Thesis director) / Sturges, Robert (Committee member) / Department of English (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
The purpose of this essay is to explain how celebrities manage their brand, as an image and commodity, using social media. Merriam-Webster defines "celebrity" as the "state of being celebrated." This essay will continue to explain how this state of celebration is a manufactured idea by the individual and the media's portrayal. Celebrities are "well-known for their well-knowness" (Boorstin, 1961, p. 58). Boorstin (1961) explains celebrities achieve fame not for their achievements, but by creating a unique personality (as cited in Turner, 2004). Crowd culture, networks, and audience knowledge are tools celebrities must use to navigate digital nuances. They must manage performance of self, adhere to internet social norms, and the obsessive fame culture. Celebrities are often referred to have "star power" and have a certain "charisma." This cultural identity is "negotiated and formed" contrived by a team through promotion, publicity, and advertising (Turner, 2004). Celebrities market themselves through branded content, media used to promote a product, on their social media pages while targeting crowd cultures. Networks truly define how celebrities must brand themselves on social media. This person-to-person contact establishes fan and consumer connections that build the celebrity's base and following. Despite campaigning in a digital world, it goes back to people connecting with people, not accounts linking to accounts. Celebrities manufacture all of these strategies and tactics as they market themselves as a commodity to target crowd culture audiences. This is why targeting crowd cultures is vitally important for celebrities. This essay explores the techniques of select celebrities as they succeed and fail navigating digital nuances.
ContributorsPierce, Ellen (Author) / Jacoby, Jim (Thesis director) / Himberg, Julia (Committee member) / Department of English (Contributor) / Walter Cronkite School of Journalism and Mass Communication (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12