Open Access. Powered by Scholars. Published by Universities.®

Biology Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 11 of 11

Full-Text Articles in Biology

Hitchhiker's Guide To Migration: Effects Of Experimental Parasitic Infection And Other Immune Challenges On Migratory Traits Of Sparrows, Tosha R. Kelly Nov 2018

Hitchhiker's Guide To Migration: Effects Of Experimental Parasitic Infection And Other Immune Challenges On Migratory Traits Of Sparrows, Tosha R. Kelly

Electronic Thesis and Dissertation Repository

Seasonal migration exposes animals to a variety of habitats and parasites, and if infected migratory birds migrate successfully there is great potential for birds to transport infectious diseases long distances. Our current understanding of whether birds contribute to the spread of disease relies upon observational field studies that are limited in their ability to discern cause from effect. Using captive and field-based experiments for my doctoral research, I answered three research questions: (1) are nocturnal migratory restlessness (Zugunruhe) and body condition affected by mounting an acute phase immune response during migration; (2) what are the impacts of parasitic …


The Effect Of Multiple Environmental Stressors On The Growth And Toxicity Of The Red Tide Alga Heterosigma Akashiwo, Malihe Mehdizadeh Allaf Nov 2018

The Effect Of Multiple Environmental Stressors On The Growth And Toxicity Of The Red Tide Alga Heterosigma Akashiwo, Malihe Mehdizadeh Allaf

Electronic Thesis and Dissertation Repository

Heterosigma akashiwo (Y.Hada) Y.Hada ex Y.Hara & M.Chihara is a golden-brown phytoflagellate with high potential to kill fish. These cells create large, nearly mono-specific blooms that persist from weeks to months. Although bloom persistence and frequency remain a mystery, environmental factors such as light, temperature, salinity and CO2 level are proposed as drivers for both bloom initiation and toxicity. As timing and locations of nature blooms are difficult to predict, most of the information on this species comes from laboratory experiments on isolated cells. In this age, when multiple stressors occur simultaneously the traditional “One-factor-at-a-time” (OFAT) approach limits our …


Growth And Toxicity Of Geographically-Distinct Isolates Of The Fish-Killing Phytoflagellate, Heterosigma Akashiwo, Veerta Singh Nov 2018

Growth And Toxicity Of Geographically-Distinct Isolates Of The Fish-Killing Phytoflagellate, Heterosigma Akashiwo, Veerta Singh

Electronic Thesis and Dissertation Repository

Harmful Algal Blooms (HABs)—an accumulation of toxic phytoplankton—often result from environmental changes reflecting the increasing global human footprint and climate change. One HAB species drawing attention is Heterosigma akashiwo, a fish-killing flagellate that can cause extensive fish loss or be benign, depending on location or environmental conditions. Here, I investigate if this difference in toxicity is regulated by environmental conditions or differences in cellular physiology. Six strains were examined. Three originate from the Salish Sea, where fish-kills are common, and three from Japan, where blooms of Heterosigma are common but fish-kills are rare. By measuring growth and toxicity of cells …


Adaptation Mechanisms Of Two-Spotted Spider Mite, Tetranychus Urticae, To Arabidopsis Indole Glucosinolates, Golnaz Salehipourshirazi Oct 2018

Adaptation Mechanisms Of Two-Spotted Spider Mite, Tetranychus Urticae, To Arabidopsis Indole Glucosinolates, Golnaz Salehipourshirazi

Electronic Thesis and Dissertation Repository

The two-spotted spider mite Tetranychus urticae Koch is a key agricultural pest that causes significant yield losses in a wide range of economically important crops. Rapid development of resistance to several classes of pesticides in T. urticae necessitates introduction of alternative management strategies to control this pest. Indole glucosinolates (IGs) are secondary metabolites found in Brassicaceae plants (including Arabidopsis thaliana) that have been shown to be effective against T. urticae and could be potential candidates to control spider mites. However, a laboratory population selected on IG-containing Arabidopsis was able to evolve adaptation to this plant. The overall objective of …


Mechanisms Underlying Freeze Tolerance In The Spring Field Cricket, Gryllus Veletis, Jantina Toxopeus Sep 2018

Mechanisms Underlying Freeze Tolerance In The Spring Field Cricket, Gryllus Veletis, Jantina Toxopeus

Electronic Thesis and Dissertation Repository

Freeze tolerance has evolved repeatedly across insects, facilitating survival in low temperature environments. Internal ice formation poses several challenges, but the mechanisms that mitigate these challenges in freeze-tolerant insects are not well understood. To better understand how insects survive freezing, I describe a novel laboratory model, the spring field cricket Gryllus veletis (Orthoptera: Gryllidae). Following acclimation to six weeks of decreasing temperature and photoperiod (mimicking autumn), G. veletis juveniles becomes moderately freeze-tolerant, surviving freezing at -8 °C for up to one week, and surviving temperatures as low as -12 °C. Acclimation is associated with increased control of the temperature and …


Rnai Targeting Of Manduca Sexta Using Chloroplast-Encoded Long Dsrna, William Burke Sep 2018

Rnai Targeting Of Manduca Sexta Using Chloroplast-Encoded Long Dsrna, William Burke

Electronic Thesis and Dissertation Repository

Pest management strategies are crucial for reducing insect crop damage, and methods with species-specific effect are particularly desirable. Expressing dsRNA with sequence complementarity to a vital gene of feeding pests is a strategy that has shown potential. I modified the chloroplast genome of cultivated tobacco, Nicotiana tabacum, by adding a sequence encoding a 2222 base pair dsRNA complementary to the vacuolar-type H+-ATPase subunit A mRNA of Manduca sexta and demonstrated expression of the product in leaves of the plants. Although feeding this same dsRNA that was synthesized in vitro to larvae knocked down expression of the target …


Plant Stimuli-Responsive Biodegradable Polymers For The Use In Timed Release Fertilizer Coatings, Spencer Heuchan Aug 2018

Plant Stimuli-Responsive Biodegradable Polymers For The Use In Timed Release Fertilizer Coatings, Spencer Heuchan

Electronic Thesis and Dissertation Repository

The use of nitrogen-based fertilizers continues to accelerate with human population growth and increases in global food requirements. Enhanced efficiency fertilizers (EEFs) have been developed to improve the synchronization between nutrient supply and crop nutrient demand. However, many of the current controlled release fertilizers are coated with non-degradable polymers that contribute to accumulation of microplastics within ecosystems. This thesis describes research towards the development of a new class of fertilizer coatings using a self-immolative polymer known as poly (ethyl glyoxylate) (PEtG). PEtG itself does not have suitable properties to produce a viable coating but once blended with another degradable polyester …


A Bioinformatics Analysis Of Contributors To False Discovery For A Mouse Genotyping Array, Nisha Patel Aug 2018

A Bioinformatics Analysis Of Contributors To False Discovery For A Mouse Genotyping Array, Nisha Patel

Electronic Thesis and Dissertation Repository

Microarray experiments employing massively-parallel hybridization are valuable for the study of genetic variation, however, errors during hybridization and limitations of single-species design must be considered for use within and across species. The Mouse Diversity Genotyping Array (MDGA) is a low cost, high-resolution microarray with probes that bind to target DNA for variant detection. Errors associated with probe design and incomplete protein removal from target DNA lead to false discovery and thus necessitate examination of probe suitability and target DNA availability. Bioinformatics methods were used to carry out confirmation of probe annotations, assessment of DNA accessibility for hybridization to probes, and …


Characterizing The Role Of The Mir156-Spl Network In Heat Stress Response In Medicago Sativa, Craig Matthews Aug 2018

Characterizing The Role Of The Mir156-Spl Network In Heat Stress Response In Medicago Sativa, Craig Matthews

Electronic Thesis and Dissertation Repository

Heat stress negatively impacts plant development by disrupting regular plant functions, including molecular, physiological and anatomical processes, reducing crop production. Alfalfa (Medicago sativa) is an important forage crop and developing abiotic stress resistant cultivars would help mitigate crop losses. Members of the miR156 family regulate SPL genes, impacting plant growth and development and are involved in stress response. Here, alfalfa with miR156 overexpression (miR156OE) and SPL13 RNAi knockdown (SPL13i) showed increased tolerance to heat stress (40°C) while SPL9 RNAi alfalfa did not. Heat-stressed miR156OE and SPL13i plants had increased antioxidant levels, including anthocyanins. Additionally, …


Trophic And Competitive Interactions Among Egg Parasitoids Of Stink Bugs, Joanna K. Konopka Jul 2018

Trophic And Competitive Interactions Among Egg Parasitoids Of Stink Bugs, Joanna K. Konopka

Electronic Thesis and Dissertation Repository

The intra- and inter-trophic interactions in ecosystems can be disrupted by invasive species, with lasting effects on population dynamics of native organisms. An invasive species may be attractive as a prey or host to native species, but if unsuitable for consumption or for development of the natural enemy’s progeny, it constitutes an ‘evolutionary trap’. A possibility of such a trap for native egg parasitoids (Hymenoptera: Scelionidae) exists with the introduction of the exotic brown marmorated stink bug, Halyomorpha halys (Hemiptera: Pentatomidae). The objective of this thesis is to enhance the understanding of Pentatomidae-Scelionidae host-parasitoid interactions from a behavioural ecology perspective, …


Nest Predation By Brown-Headed Cowbirds (Molothrus Ater), David C. Swan Mar 2018

Nest Predation By Brown-Headed Cowbirds (Molothrus Ater), David C. Swan

Electronic Thesis and Dissertation Repository

The reproductive success of parasites is entirely dependent on their ability to encounter suitable hosts. Obligate brood parasitic birds may increase host encounter rate, and consequently their reproductive output, if they cause unsuitable late-stage host nests to fail thereby stimulating the host to create another nest that they can parasitize. I tested key predictions of this ‘farming’ hypothesis for the brown-headed cowbird (Molothrus ater). I found evidence that cowbird attacks are not uncommon, a basic requirement of the hypothesis. Furthermore, I found multiple lines of evidence that cowbird attacks are not indiscriminate, but directed at non-parasitized nests and …