Thesis (Ph.D.) -- University of Texas at Arlington, 2009.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 134-150).

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 112-124). Also available on the Internet.

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Ecology and Evolution." Includes bibliographical references.

Thesis (Ph. D.)--University of Oregon, 2000. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 150-160). Also available for download via the World Wide Web; free to University of Oregon users.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 112-124). Also available on the Internet.

Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 2003. / Vita. Includes bibliographical references (leaves 219-228).

Thesis (Ph. D.)--University of Hong Kong, 1989.

This thesis considers a physical perspective to an insect's maintenance of a clean body surface.  Flying insects are faced with a barrage of particles in their environment, including dust, pollen, pollutants, and parasitic mites, the last of which are responsible for the modern decline of honey bees, of critical importance to agriculture around the world.  In this combined experimental, theoretical, and numerical study, we elucidate the mechanisms by which insects stay clean.  These mechanisms all rely on the insect’s coverage by a dense array of hairs.  We show that these bristles divert incoming flow, reducing deposition of particles, especially onto the eyes.  We replicate this mechanism with microfabricated pillar arrays, demonstrating the feasibility by which they may be incorporated into self-cleaning sensors. During grooming, the bristles on the limbs interact with those on the body and particle removal is achieved through combing and catapulting, driving particles at over 1000 gravities. We show that the three million hairs covering the body of a honey bee are crucial for the efficient removal of accumulated pollen.

Similar forces of selection operating on multiple taxa can cause convergent evolution of quantitative traits. When those same forces of selection occur across an environmental gradient a phenotypic cline may evolve. I have conducted an experiment in central Texas to test whether seed oil melting points and proportions of saturated fatty acids have repeatedly evolved to germinate as predicted by theory. Species with lower seed oil melting points and proportions of saturated fatty acids are expected to germinate at cooler temperatures than ones that germinate at warmer temperatures. Field observations were conducted at two sites for one year to characterize germination temperatures of sixteen species. Gas chromatography was utilized to describe the fatty acid compositions and melting points of those species’ triacylglycerol (oil) stores. The field sites produced conflicting results. At one site, all analyses supported the theory. Whereas evidence from the other site either contradicted expectation or was equivocal. Likewise there was some evidence that plants with annual life histories are under stronger selection to evolve melting points that approximate germination temperature than species with perennial life histories. Finally, evidence was found that a higher level of variation in seed oil melting point and percent of saturated fatty acids is maintained in species that were observed to germinate at low temperatures relative to species observed to germinate at higher temperatures. / text