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University of Kentucky

2014

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Factors Limiting The Spread Of The Protective Symbiont Hamiltonella Defensa In Aphis Craccivora Aphids, Hannah R. Dykstra, Stephanie R. Weldon, Adam J. Martinez, Jennifer A. White, Keith R. Hopper, George E. Heimpel, Mark K. Asplen, Kerry M. Oliver Sep 2014

Factors Limiting The Spread Of The Protective Symbiont Hamiltonella Defensa In Aphis Craccivora Aphids, Hannah R. Dykstra, Stephanie R. Weldon, Adam J. Martinez, Jennifer A. White, Keith R. Hopper, George E. Heimpel, Mark K. Asplen, Kerry M. Oliver

Entomology Faculty Publications

Many insects are associated with heritable symbionts that mediate ecological interactions, including host protection against natural enemies. The cowpea aphid, Aphis craccivora, is a polyphagous pest that harbors Hamiltonella defensa, which defends against parasitic wasps. Despite this protective benefit, this symbiont occurs only at intermediate frequencies in field populations. To identify factors constraining H. defensa invasion in Ap. craccivora, we estimated symbiont transmission rates, performed fitness assays, and measured infection dynamics in population cages to evaluate effects of infection. Similar to results with the pea aphid, Acyrthosiphon pisum, we found no consistent costs to infection using …


Biomechanical Properties Of Hemlocks: A Novel Approach To Evaluating Physical Barriers Of The Plant-Insect Interface And Resistance To A Phloem-Feeding Herbivore, Paul Ayayee, Fuqian Yang, Lynne K. Rieske Jun 2014

Biomechanical Properties Of Hemlocks: A Novel Approach To Evaluating Physical Barriers Of The Plant-Insect Interface And Resistance To A Phloem-Feeding Herbivore, Paul Ayayee, Fuqian Yang, Lynne K. Rieske

Entomology Faculty Publications

Micromechanical properties that help mediate herbivore access may be particularly important when considering herbivorous insects that feed with piercing-sucking stylets. We used microindentation to quantify the micromechanical properties of hemlock, Tsuga spp., to quantify the hardness of the feeding site of the invasive hemlock woolly adelgid, Adelges tsugae. We measured hardness of the hemlock leaf cushion, the stylet insertion point of the adelgid, across four seasons in a 1 y period for four hemlock species growing in a common garden, including eastern, western, mountain, and northern Japanese hemlocks. Leaf cushion hardness was highest in the fall and winter and …


Ultraviolet Radiation, Aging And The Skin: Prevention Of Damage By Topical Camp Manipulation, Alexandra Amaro-Ortiz, Betty Yan, John A. D’Orazio May 2014

Ultraviolet Radiation, Aging And The Skin: Prevention Of Damage By Topical Camp Manipulation, Alexandra Amaro-Ortiz, Betty Yan, John A. D’Orazio

Markey Cancer Center Faculty Publications

Being the largest and most visible organ of the body and heavily influenced by environmental factors, skin is ideal to study the long-term effects of aging. Throughout our lifetime, we accumulate damage generated by UV radiation. UV causes inflammation, immune changes, physical changes, impaired wound healing and DNA damage that promotes cellular senescence and carcinogenesis. Melanoma is the deadliest form of skin cancer and among the malignancies of highest increasing incidence over the last several decades. Melanoma incidence is directly related to age, with highest rates in individuals over the age of 55 years, making it a clear age-related disease. …


What Kind Of Seed Dormancy Might Palms Have?, Jerry M. Baskin, Carol C. Baskin Mar 2014

What Kind Of Seed Dormancy Might Palms Have?, Jerry M. Baskin, Carol C. Baskin

Biology Faculty Publications

Palm diaspores are reported to have various kinds of dormancy. However, (1) the embryo is underdeveloped; (2) the endocarp is water permeable; and (3) the diaspores take a long time to germinate. Thus, we conclude that the diaspores of the majority of palm species have morphophysiological dormancy (MPD). The ones that do not have MPD are morphologically dormant.


A Plant Trait-Based Approach To Evaluate The Ability Of Native C3 And C4 Grasses To Restore Functionality To A Remnant Bluegrass Savanna-Woodland In Kentucky, Usa., Jann E. Fry Jan 2014

A Plant Trait-Based Approach To Evaluate The Ability Of Native C3 And C4 Grasses To Restore Functionality To A Remnant Bluegrass Savanna-Woodland In Kentucky, Usa., Jann E. Fry

Theses and Dissertations--Biology

Temperate Midwestern oak savannas are considered imperiled ecosystems with < 1 % remaining since the time of European settlement and are identified as critical areas for preservation. Restoration of Midwestern oak savannas is challenging due to the lack of accurate historical data, few intact remnants remaining to study, and lack of restoration ecology studies. A plant trait-based approach was used to evaluate the ability of six C3 and three C4 native bunchgrasses to restore functionality to a remnant savanna–woodland of the Bluegrass Region of Kentucky. The response and effect framework was used to assess the response of the nine native grasses according to the habitat filters of interannual precipitation, inter- vs. intra-specific competition, and simulated grazing. The effect traits associated with plant-soil nitrogen and carbon cycling were also assessed. The response traits of interannual competition and inter- vs. intra-specific competition along with the effect traits plant-soil nitrogen and carbon cycling were measured in a monoculture experiment …


Convergence Of Dune Topography Among Multiple Barrier Island Morphologies, Jackie Ann Monge Jan 2014

Convergence Of Dune Topography Among Multiple Barrier Island Morphologies, Jackie Ann Monge

Theses and Dissertations--Geography

Wave-dominated and mixed tidal and wave energy barrier islands are assumed to have characteristic dune topographies that link to their macroscale form. However, there has been no systematic attempt to describe the linkage between barrier island macroscale form and dune topography. The goal of this thesis was to investigate how dune topographies correspond to a number of barrier island morphologies found along the southeastern U.S. Atlantic coast. Macroscale process-form variables were used to classify 77 islands into seven morphologic clusters. Islands from each cluster were selected and sites characteristic of the range of dune topographies within islands were characterized using …


The Role Of Surface Chemistry In The Toxicity Of Manufactured Cerium Dioxide Nanomaterials To Caenorhabditis Elegans, Emily Kay Oostveen Jan 2014

The Role Of Surface Chemistry In The Toxicity Of Manufactured Cerium Dioxide Nanomaterials To Caenorhabditis Elegans, Emily Kay Oostveen

Theses and Dissertations--Plant and Soil Sciences

Manufactured CeO2 nanomaterials (CeO2-MNMs) are used for a wide variety of applications including diesel fuel additives and chemical/mechanical planarization media. To test the effects of CeO2-MNM surface coating charge on to model organism Caenorhabditis elegans, we synthesized 4 nm CeO2 with cationic (DEAE-), anionic (CM-), and neutral (DEX) coatings. In L3 nematodes exposed for 24 hours, DEAE-CeO2 induced lethality at lower concentrations than CM- or DEX-CeO2. Feeding slightly decreased CeO2 toxicity, regardless of coating. In L2 nematodes exposed for 48 hours with feeding, DEAE-CeO2 caused lethality at the …


Distribution Of Wildlife Rabies In Central Appalachia And Analysis Of Factors Influencing Human Exposure, Sara J. Reilly Jan 2014

Distribution Of Wildlife Rabies In Central Appalachia And Analysis Of Factors Influencing Human Exposure, Sara J. Reilly

Theses and Dissertations--Public Health (M.P.H. & Dr.P.H.)

Abstract Background: The rabies virus is a Lyssavirus of the family Rhabdoviridae which affects all mammals and causes progressive encephalomyelitis that is fatal in nearly one hundred percent of untreated cases. In the United States, wildlife act as the primary reservoir for rabies and prevention, surveillance, and control costs remain high. The purpose of this study is to understand the current distribution of wildlife rabies in Central Appalachia, as well as identify any demographic or geographic factors which may affect the risk of human exposure at the county level. Methods: A spatial statistical analysis using StatScan was performed to identify …