Life Sciences Commons^™

Effects Of A Novel Dsrna-Based Insecticide On The Colorado Potato Beetle, Samuel J. Pallis

Electronic Theses and Dissertations

The Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) is one of the most destructive pests of the cultivated potato, Solanum tuberosum. Colorado potato beetles have been devastating potato crops for the past 150 years and have expanded their range during that time, becoming a globally distributed agricultural pest. Potato beetles are well-suited to agricultural environments and have evolved some degree of resistance to virtually all chemical insecticides. As such, the development of novel control methods to both control potato beetle populations and manage the evolution of insecticide resistance are in constant demand

The knockdown of gene functioning through ribonucleic acid …

Adaptation Strategies For Wild Blueberry Growers In A Changing Climate: Mulching Effects On Crop Productivity And Fertility Effects On Blueberry Gall Midge, Rebecca Gumbrewicz

Electronic Theses and Dissertations

Wild blueberry (Vaccinium angustifolium Aiton.) cropping systems are considered resilient to environmental changes due to ecological and genetic diversity within each field. However, wild blueberries can be sensitive to weather fluctuations that cause extreme temperature or moisture regimes. Climate change in Maine is represented by increasing rates of warming temperatures, more intense precipitation events, and more frequent atmospheric “blocking” patterns. Warming temperatures result in the northward expansion of pest ranges and altered growing seasons. More extreme rainfall events lead to damaged plantings and soil erosion. Atmospheric blocking leads to an increased likelihood of heat waves and drought. Two experiments were …

Community Structure And Dynamics Of Benthic Macroinvertebrates In A Recreated Headwater Stream System On A Valley Fill In A Retrofitted Watershed Located In The Appalachian Coalfields Of Southeastern Kentucky (U.S.A.), Steven W. Bailey

Electronic Theses and Dissertations

The extraction of coal from steep-gradient surface mining sites such as in the Appalachian Coalfields of the U.S. produces excess debris that is often placed in adjacent valleys resulting in the creation of valley fills. Not only are headwater streams buried in the process, but watershed functions are either destroyed outright, or become fragmented and disconnected from adjacent ecosystems resulting in adverse effects to downstream biological communities. In this dissertation, the dynamics of stream macroinvertebrate community structure, composition, diversity, and biotic integrity are assessed at a “proof of concept” stream system recreated on a retrofitted valley fill. For comparison, two …

The Bees Of Two Sites In The Big Thicket National Preserve, Texas, With A Consideration Of The Effects Of A Rare Flooding Event, Archie Ray Sauls Jr.

Electronic Theses and Dissertations

Native bees are an important part of terrestrial ecosystems due to their coevolution with flowering plants. This study catalogued the bee fauna of two sandyland sites in the Big Thicket National Preserve and assessed whether a community was impacted by a historic hurricane-induced flooding event. It was hypothesized that a change in diversity metrics would be evident following the flood. Datasets were analyzed for differences in species richness, abundance, evenness, and Shannon’s diversity. Similarities between datasets were also assessed using the multivariate tests analysis of similarity (ANOSIM) and similarity of percentages (SIMPER). At two sites over two years of sampling …

Evaluation Of Biotype 4 Aphis Glycines (Hemiptera: Aphididae) Induced Susceptibility On Soybean And Soja, Jakob David Hicks

Electronic Theses and Dissertations

Soybean aphids have been a significant pest of soybeans in North America since 2000. Before 2000, soybeans did not face significant insect pest pressure from any arthropods with piercing-sucking mouthparts. It is estimated that economic damage from soybean aphids range from $1billion to $4.7 billion annually. Research efforts focused on the identification of host plant resistance genes in soybean and discovered many resistant to Aphis glycines genes (i.e., Rag genes) in soybean. However, the adoption of commercially released Rag soybean cultivars has been limited. The prospect of management with Rag genes was further complicated by the identification of three virulent …

Transcriptional Regulation Of Duox-Dependent Reactive Oxygen Species Production Against Bacterial Infection In The Gut Of Cat Fleas (Ctenocephalides Felis)., Ryne W. Maness

Electronic Theses and Dissertations

Fleas (Order Siphonaptera) are opportunistic blood feeders that parasitize a wide variety of mammals and birds. They also transmit bacterial pathogens that cause diseases in humans (e.g., murine typhus, flea-borne spotted fever, cat scratch disease, and plague). Because they acquire infectious pathogens while blood feeding, the flea gut is considered to be the initial site of infection. While immune responses have been well documented in other disease vectors, few studies have identified the immune mechanisms involved in defense of the flea gut. In other hematophagous insects, the synthesis of reactive oxygen species (ROS) is the immediate immune defense mechanism against …

Macroinvertebrate Responses To Hydrological Variation In Experimental Wetlands., Sergio A. Sabat-Bonilla

Electronic Theses and Dissertations

Predicted increases in the frequency of intense storms and periods of severe drought due to climate change represent a threat to wetland macroinvertebrate communities through alterations to the hydrological regime. I used experimental ponds to assess the effects of water permanence (i.e., duration of flooding) on the communities of aquatic macroinvertebrates. I predicted that permanent ponds would harbor higher diversity of longer-lived taxa whereas temporary ones will favor colonization by quick turnover, short-lived taxa and support lower consumer diversity. Results show differences in macroinvertebrate communities between permanent and temporary ponds can be mostly explained by hydrology and the amount of …