published_or_final_version / Politics and Public Administration / Master / Master of Philosophy

Female choice is an important selective force shaping the evolution of communication and speciation in animals. However, predation risk can impose severe costs on longer searches and choosiness, thereby limiting the expression of female preferences for specific male traits. The work detailed in this dissertation explores how mate choice and sexual selection can be influenced by predation risk in túngara frogs. I begin by examining the effects of multiple simulated cues of predation risk on female search behavior and mate choice, taking a departure from the standard presence/absence paradigm used in similar studies to explore responses to quantitative variation in perceived predation risk. I demonstrate that light, longer travel times, and acoustic cues of predators are all sufficient to sway females away from otherwise more attractive conspecific males. Next, I explore the role of predation risk in altering female permissiveness, or the range of signals females will respond to. Using an artificial series of calls intermediate between heterospecific and conspecific, I demonstrate that predation risk dramatically increases the range of signals females will respond to, including a small number of females choosing pure heterospecific calls. Next I attempt to bridge a logical gap with our understanding of search costs, testing questions about how female search paths change with increasing distance. I demonstrate that females use more direct paths and move faster under higher light conditions, potentially reducing sampling but also reducing encounter rates with predators. Lastly, I examine factors that influence how individual females vary in their response to perceived risk, particularly hormonal state and experience. I demonstrate that naïve, captive-bred females respond to acoustic cues produced by natural predators in a manner similar to wild females and that, while hormonal state is obviously important in determining female receptivity, it has little effect directly on how females respond to predators. Together, these studies demonstrate that predation risk not only changes how females respond to conspecific males, but also increases female permissiveness and constrains search behavior. Predation risk can strongly influence and potentially even negate the expression of female preferences, having profound consequences for communication and the evolution of reproductive isolation between populations. / text

In the last several years, student mode choice has increasingly become an important area of study. Findings from these studies can be applied to regional travel demand modeling efforts, campus planning efforts, and sustainability initiatives, among others. This paper presents an analysis of student mode choice at the University of Texas at Austin, using statistical and geographic information systems analysis, based on the University of Texas Parking and Transportation Services mode choice survey administered during the spring 2014 semester. Results showed that within this sample, more students take alternative modes than drive alone, though the proportion of students driving alone to campus remains substantial. Among other conclusions, analysis also indicated clustering of respondent residential locations, and drive alone hotspots in several zip codes primarily in south/southeast Austin. These results point to a geographic area where it may be beneficial to concentrate resources aimed at inducing drivers to switch to an alternative mode of transportation, in order to support UT’s mobility and sustainability goals. / text

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Currently, the argument that markets cannot provide public goods underlies the justification of political authority most widely accepted by political theorists. Yet, as theorists usually depict the problem, public goods could be voluntarily produced at levels of efficiency comparable to those attainable by coercion. Once we allow that the real problem is much more messy than its theoretical models led us to believe, we have to admit that coercion may be necessary after all. At the same time, we have to admit that the moral problem of justifying coercion is also more messy than we thought, and for precisely the same reason. I discuss contractual mechanisms for voluntary public goods provision, arguing that with such a mechanism, voluntary contribution levels might be much higher than conventional theories predict. My theory is borne out in laboratory experiments. Still, it remains an open question whether it would be worth the trouble to switch from the coercive methods presently employed to noncoercive (or less coercive) methods of public goods provision. A strictly efficient method is not among our options. We have to assess the efficiency of various methods in a relative sense. Should we find cases in which public goods cannot be provided by contract, or should we decide that in some cases we do not even want to risk trying voluntary methods, we are forced to face the moral issue squarely. I offer a traditional analysis of justice, although I employ it in a somewhat unorthodox way in drawing conclusions about the moral status of private property in a well-ordered society. I then use this analysis to develop a foundation for property rights, exploring its implications for questions concerning what people are morally obliged to do, and what they can legitimately be forced to do, for the sake of public goods production.

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