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Full-Text Articles in Life Sciences

The Potential For Dickeya Dianthicola To Be Vectored By Two Common Insect Pests Of Potatoes, Jonas K. Insinga Dec 2019

The Potential For Dickeya Dianthicola To Be Vectored By Two Common Insect Pests Of Potatoes, Jonas K. Insinga

Electronic Theses and Dissertations

Dickeya dianthicola (Samson) causing blackleg and soft rot was first detected in potatoes grown in Maine in 2014. Previous work has suggested that insects, particularly aphids, may be able to vector bacteria in this genus between plants, but no conclusive work has been done to confirm this theory. In order to determine whether insect-mediated transmission is likely to occur in potato fields, two model potato pests common in Maine were used: the Colorado potato beetle (Leptinotarsa decimlineata Say) and the green peach aphids (Myzus persicae Sulzer). Olfactometry and recruitment experiments evaluated if either insect discriminates between infected and …


Does Thermotolerance In Daphnia Depend On The Mitochondrial Function?, Rajib Hasan Aug 2019

Does Thermotolerance In Daphnia Depend On The Mitochondrial Function?, Rajib Hasan

Electronic Theses and Dissertations

Thermotolerance limit in aquatic organism is set by the ability to sustain aerobic scope to sudden temperature shifts. This study tested the genetic and plastic differences in thermotolerance of Daphnia that can be explained by the differences in the ability to retain mitochondrial integrity at high temperatures. Five genotypes with different biogeographic origins were acclimated to 18C and 25C. We developed a rhodamine 123 in-vivo assay to measure mitochondrial membrane potential and observed higher fluorescent in heat damaged tissues as the disruption of the mitochondrial membrane potential. Significant effects on temperature tolerance were observed with CCCP …


Landscape Pattern And Wild Bee Communities In Maine, Brianne Du Clos May 2019

Landscape Pattern And Wild Bee Communities In Maine, Brianne Du Clos

Electronic Theses and Dissertations

Commercial production of lowbush blueberry (Vaccinium angustifolium Aiton) in Maine relies primarily on managed honeybee hives; however, naturally occurring wild bees are more efficient pollinators of the crop. Wild bees have short foraging distances and must nest near crop fields to provide pollination services. After crop bloom, the surrounding landscape must provide sufficient forage to maintain wild bee populations for the remainder of the growing season. Lowbush blueberries in Maine are produced in a mixed-use landscape with two distinct landscape contexts. Here, we document bee communities and habitat resources (nesting and floral) in power line rights-of-way and eight land …


Differentiating Black Bears (Ursus Americanus) And Brown Bears (U. Arctos) Using Linear Tooth Measurements And Identification Of Ursids From Oregon Caves National Monument, Emily Bogner May 2019

Differentiating Black Bears (Ursus Americanus) And Brown Bears (U. Arctos) Using Linear Tooth Measurements And Identification Of Ursids From Oregon Caves National Monument, Emily Bogner

Electronic Theses and Dissertations

North American black bears and brown bears can be difficult to distinguish in the fossil record due to similar dental and skeletal morphologies. Challenges identifying ursid material from Oregon Caves National Monument (ORCA) called for an accurate tool to distinguish the species. This study utilized a large database of lower tooth lengths and ratios in an attempt to differentiate black and brown bears in North America. Further, this project examined how these linear measurements differ geographically. Analysis of variance (ANOVA) found significant differences between black and brown bears from across North America for every variable studied. Stepwise discriminant analyses (DA) …


Seascape Genetics And Rehabilitation Efficiency In The Florida Manatee, Madison Hall Jan 2019

Seascape Genetics And Rehabilitation Efficiency In The Florida Manatee, Madison Hall

Electronic Theses and Dissertations

The Florida manatee (Trichechus manatus latirostris) was recently downlisted federally from "endangered" to "threatened" despite acknowledgments of remaining threats to long term population persistence. Challenges to future manatee conservation include, but are not limited to, increases in frequency of harmful algal blooms, intensifying anthropogenic disturbance, and loss of warm-water habitat. The goals of this dissertation were 1) to assess threats to the manatee via a comprehensive, long-term (1973-2016), retrospective analysis of the manatee rescue and rehabilitation partnership (MRRP) and 2) to use seascape genetics analysis to examine whether abiotic, biotic, or anthropogenic seascape variables could significantly describe genetic distance patterns …


Effects Of Climate Variability: A Long-Term Perspective On Leaf Litter Processing In The Ogeechee River, Jose A. Sanchez Jan 2019

Effects Of Climate Variability: A Long-Term Perspective On Leaf Litter Processing In The Ogeechee River, Jose A. Sanchez

Electronic Theses and Dissertations

The Intergovernmental Panel for Climate Change (IPCC) predicts a rise in temperatures and changes to precipitation patterns for the 21st century. These changes are expected to lead to a higher frequency of extreme events such as drought and floods which lead to the alteration of the hydrology, communities, and processes of freshwater ecosystems. Leaf litter decomposition in stream ecosystems is an important component of the energy and nutrient cycle representing a food source for aquatic organisms. This has made it a tool for assessing long term responses to disturbance due to changes in the assemblage of macroinvertebrates that …