Digital Commons Network^™

Linking Physiology And Biogeography: Disentangling The Constraints On The Distributions Of Ant Species, Lacy Danikas Chick

Doctoral Dissertations

Understanding the factors that limit the distribution of species is at the core of ecological and biogeographical research, and is critical if we are to predict the responses of key ecosystem components to ongoing climatic changes. My doctoral research seeks to provide an understanding of how thermal physiology influences species’ distributions and better define the mechanisms underlying geographic variation in biodiversity. By using natural temperature gradients (both elevational and latitudinal) and coupling controlled laboratory experiments with field observations and null modeling approaches, I was able to document the role of inter-specific variation in thermal physiology and, more interesting, inter-population variation …

Phylogenetic Analysis And Revision Of The Nearctic Androprosopa Mik (Diptera: Thaumaleidae) With An Emphasis On The Western Species, Robert John Pivar

Masters Theses

The family Thaumaleidae, also known as seepage midges, is an uncommonly encountered, understudied family of aquatic Diptera compared to its sister group, the Simuliidae. The goal of this project was to assess species diversity of the Nearctic Thaumaleidae and determine relationships among them. The western Nearctic fauna of Androprosopa Mik is revised to include twenty-eight species, six of which are described as new to science. Descriptions of the adult males of A. apache, A. arnaudi, A. magnipelvim, A. rainierensis, A. sierra and A. uvas are provided. Redescriptions of all remaining species are also provided, as well …

Interactions Among Insect Defoliation, Insecticide Treatments, And Growth Rate In American And Hybrid Chestnuts, Ashley Elizabeth Case

Masters Theses

The American chestnut, Castanea dentata, was once one of the most useful and abundant canopy trees in eastern North American forests. Over the last 200 years, the species has been decimated by two exotic pathogens, Phytophthora cinnamomi and Cryphonectria parasitica, killing millions of trees and reducing surviving Castanea dentata to short-lived sprouts. Cryphonectria parasitica-resistance breeding programs are currently producing advanced backcross generations, which are being compared with pure American chestnut in field tests of growth performance and Cryphonectria parasitica resistance. The Asiatic oak weevil, Cyrtepistomus castaneus, has been identified as a common defoliator of chestnut seedlings in these …

Potential Interaction Between Pre- And Post-Emergence Herbicides And The Efficacy Of Insecticide And Fungicide Seed Treatments In Cotton, Cory Joseph Vineyard

Masters Theses

An apparent reduction in the performance of neonicotinoid seed treatments in controlling thrips, especially in cotton, has been observed, which has coincided with the increased use of both pre- and post-emergence herbicides to control glyphosate-resistant weeds. The objective of this research was to evaluate the potential interactions of both pre- and post-emergence herbicides on the efficacy of insecticide and fungicide seed treatments in cotton

Aldicarb along with imidacloprid and thiamethoxam seed treatments reduced thrips numbers compared with non-treated seed. However, thiamethoxam did not provide effective control. Some pre-emergence herbicide treatments reduced plant health. While there was evidence that thrips injury …

Evolution And Phylogeny Of The Parasitoid Subfamily Phasiinae (Diptera: Tachinidae), Jeremy Daniel Blaschke

Doctoral Dissertations

The first molecular phylogenetic analysis of the agriculturally important parasitoid subfamily Phasiinae (Diptera: Tachinidae) is presented, estimated from 128 worldwide taxa (80 genera) and approximately 7.6 kilobases of nuclear data. Special emphasis is placed on taxa with controversial taxonomic placement. The resultant phylogenetic tree is used to reconstruct ancestral character states, trace the evolution of significant adaptive traits within the Tachinidae, and test hypotheses about the classification of Phasiinae. Subfamily placements of the taxa Eutherini, Epigrimyiini, Litophasia, Strongygastrini, and Parerigonini are confidently resolved, the former three within Dexiinae and the latter two within Phasiinae. Due to sparse molecular evidence, …

The Greenhouse Effect: Decomposition Rates In Human Remains Wrapped In Plastic, Barbara R. Forman

Masters Theses

Determining an accurate estimation of the postmortem interval (PMI) of human remains is important for several reasons. First, it is used to determine whether the individual is recently deceased, and therefore of medicolegal concern. If so, the estimated PMI is used in narrowing the possible identities of the deceased. PMI can also be used in excluding, or convicting, a murder suspect.

Though deviations may occur, it has been found that PMI can be calculated from the decomposition stages with reasonable accuracy (Galloway 1989, Megyesi 2001, Megyesi et al. 2005, Schiel 2008, Simmons et al. 2010). Some factors, such as low …

A Comprehensive Evaluation Of Benthic Invertebrate Communities In The Emory River, Watts Bar Reservoir, Tn, Suzanne Jane Young

Masters Theses

The release of fly ash at the Tennessee Valley Authority (TVA) Kingston Fossil Plant (KIF) on 22 December 2008 discharged approximately 4.1 million cubic meters of coal ash into the adjacent aquatic and terrestrial systems. Previous benthic invertebrate investigations conducted by TVA and collaborative researchers concluded that benthic invertebrates in the Emory River were at moderate risk from ash-related constituents, primarily arsenic, in ash-contaminated sediment that remained in the Emory River following extensive dredging efforts. These conclusions were based on the observation of statistically significant reductions in growth and biomass in laboratory toxicity tests with Emory River sediment. Benthic invertebrate …

Identifying Avian Malaria Vectors: Sampling Methods Influence Outcomes, Jenny S. Carlson, Erika Walther, Rebecca Trout Fryxell, Sarah Staley, Lisa A. Tell, Ravinder N.M. Sehgal, Christopher M. Barker, Anthony J. Cornel

Entomology & Plant Pathology Publications and Other Works

Background

The role of vectors in the transmission of avian malaria parasites is currently understudied. Many studies that investigate parasite-vector relationships use limited trapping techniques and/or identify potential competent vectors in the field in such ways that cannot distinguish between an infected or infectious vector. Without the use of multiple trapping techniques that address the specific biology of diverse mosquito species, and without looking at the infection status of individual mosquitoes, it is not possible to make dependable conclusions on the role of mosquitoes in the transmission of avian malaria parasites.

Methods

We conducted two years of mosquito collections at …

Map Supplements For The Metallic Woodboring Beetles (Coleoptera: Buprestidae) Of Tennessee, William E. Klingeman Iii, Jason A. Hansen, Joshua P. Basham, Jason B. Oliver, Nadeer N. Youssef, Whitney Swink, Christine A. Nalepa, Donna C. Fare, J. Kevin Moulton

Plant Sciences Publications and Other Works

Following compilation of distribution records and seasonal flight activity information for 106 metallic wood-boring beetle (Coleoptera: Buprestidae) species for Tennessee, maps were updated to provide county-level collection notations for 10,543 published records and specimen collections made from 1934 to 2013. County collection tallies across the ecoregions in Tennessee are also presented. Maps for individual species highlight gaps in key geographic areas where specimens have not been collected and can be valuable for future biosurveillance, monitoring and management efforts for these economically and ecologically important insects.

Characterization Of The Role Of Alpha-Arylphorin In The Heliothis Virescens Midgut Response To Cry1ac Toxin From Bacillus Thuringiensis, Jerreme Jamael Jackson

Doctoral Dissertations

Homeostasis of the intestinal epithelium in Heliothis virescens is mediated by the proliferation and differentiation of multipotent intestinal stem cells (ISCs) that lie adjacent to the basal lamina. In response to extrinsic and intrinsic signals, ISC proliferation and differentiation promotes epithelial growth and regeneration following the loss of integrity. We tested the in vivo effects of the ISC mitogen, a [alpha]-arylphorin, on ISC proliferation and the morphological changes of the midgut during larval development. Additionally, we examined how these changes affected the intestinal epithelium response to Cry1Ac toxin from Bacillus thuringiensis. Histological and in vitro evidence supported two distinct …

Trapping Methods For Ixodid Ticks And Pathogen Associations Of Amblyomma Maculatum (Gulf Coast Tick) In Western Tennessee, Sarah Elizabeth Mays

Masters Theses

Ticks are vectors of disease agents and pests of humans and animals. Various methods are used for tick monitoring and pathogen surveillance to assess tick distributions, pathogen prevalence and control measures, such as monitoring the changing geographic distribution of the Gulf Coast tick, Amblyomma maculatum. This project (1) compared the effectiveness of six trapping methods for the collection of hard (Ixodid) ticks in a typical grassland-forest habitat in southwestern Tennessee, and (2) examined pathogen associations of A. maculatum collected in western Tennessee.

To compare trapping methods across time and habitat types, a temporal study was conducted in 2013 and …

Assessment Of Pityophthorus Juglandis Colonization Characteristics And Implications For Further Spread Of Thousand Cankers Disease, Jackson Audley

Masters Theses

Nonnative, invasive forest insect pests are a significant threat to the health of global forest resources. Thousand cankers disease, a recently described disease threatening walnuts, is the result of an invasive insect-pathogen complex in which the walnut twig beetle (Pityophthorus juglandis Blackman) is a vector to the associated fungal pathogen, Geosmithia morbida. Both are native to the southwestern U.S. into northern Mexico, however, have been found well beyond their historic range, and now threaten black walnut (Juglans nigra) in the eastern U.S. Beetles have likely been spread via the transport of infested walnut logs.

The goal …

A Molecular And Morphological Investigation Of The Springtail Genus Orchesella (Collembola: Entomobryomorpha: Entomobryidae), Catherine Louise Smith

Masters Theses

Chapter 1 is devoted to a molecular overview of the North American members of the springtail genus Orchesella using mitochondrial and nuclear DNA. Both genes strongly support the presence of four major clades within Orchesella. Chapter 2 is a morphological revision of the species near Orchesella celsa Christiansen & Bellinger. Five new species are described based largely on chaetotaxonomical differences in. Chapter 3 is an investigation into the origins of United States populations of two introduced European members of the genus, Orchesella cincta Linnaeus and Orchesella villosa Linnaeus. Mitochondrial data between populations from the two continents indicates multiple introductions for …