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MSpace is the University of Manitoba’s Institutional Repository. The purpose of MSpace is to acquire, preserve and provide access to the scholarly works of University faculty and students within an open access environment.

 

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Open Access
Seabird personality and individual behavioural consistency in the Canadian North Atlantic
(2025-04-25) Legard, Matthew; Fraser, Kevin (Biological Sciences); Kelly, Debbie (Psychology); Daunt, Francis (UK Centre for Ecology and Hydrology); Davoren, Gail
Animal personality (i.e., consistent individual behaviour over time/across contexts) is made up of distinct trait continuums (e.g., docile-aggressive; docility) that can play an important role in shaping the behavioural responses of animals, and therefore, can influence fitness. Understanding personality in animal populations can be a useful tool to aid conservation decisions. To date, limited research on personality has been carried out in seabirds, especially species from the family Alcidae. This family, which includes the razorbill (Alca torda), is characterised by a stout body which facilitates diving but results in high energetic costs of flight. In comparison to personality, individual consistency in seabird behaviour (e.g., migratory route) is well studied, but studies rarely compare across species. If individuals within a population behave consistently (e.g., migratory site fidelity), but differences are present among individuals (i.e., behavioural diversity), this variation may expose components of populations to varying threats (e.g., offshore wind development). Therefore, understanding this behavioural variation across and within species will aid in the protection of populations with lower diversity, which are more likely to experience population declines. The aims of this thesis were to: 1. Determine the best method for quantifying the docile-aggressive trait in razorbills (Ch.1). 2. Investigate relationships between docility and razorbill behaviour during the breeding (Ch.2) and non-breeding (Ch.3) periods. 4. Explore behavioural diversity in migratory routes of seabird species that breed in Atlantic Canada (Ch.4). In Chapter 1, I found that different behavioural tests had varying suitability for identifying docility in razorbills. Of the tests, standardized observer ratings were the best test for quantifying docility in razorbills and potentially other hard to observe species. In Chapter 2, I found that razorbills exhibit consistent behaviour during the breeding period, but this consistency is context dependent (i.e., varying prey availability periods) and not related to docility. Additionally, I found no relationship between fledging success and docility. In Chapter 3, I found individual consistency in razorbill non-breeding behaviours but no relationships between any observed non-breeding behaviours and docility. Finally, in Chapter 4, I found varying levels of behavioural diversity both within and across seabird families (Alcidae, Laridae and Sulidae).
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Open Access
Conservation of genetic diversity using life history predictors of adaptive potential
(2025-04) Goertz, Alyssa; Fraser, Kevin (Biological Sciences); Detwiler, Jillian (Biological Sciences); Garroway, Colin
Biodiversity loss is reducing population sizes globally, leading to a decline in genetic diversity. This is concerning, as genetic diversity is vital for species' survival and adaptation to future environmental change. Conservation frameworks, such as the International Union for Conservation of Nature (IUCN) Red List, assess extinction risk but overlook genetic diversity and adaptive potential. This is primarily because genetic data is not available for most species. My project directly addresses the lack of consideration of genetic diversity conservation framework by examining the relationship between adaptive potential and easy-to-measure life history traits. If easy-to-measure traits reflect adaptive potential, they can be used to guide conservation where direct estimates of adaptive potential are lacking. Adaptive potential reflects the additive genetic variance (VA) underlying fitness. VA reflects genetic diversity and capacity for adaptation and is used in calculating heritability. I hypothesized that life history traits (e.g., body mass, longevity, fecundity, and age of maturity) predict adaptive potential, measured by heritability. The data for heritability were derived from studies by Mittel et al. (2015), Holstad et al. (2024), and life history trait data from Myhrvold et al. (2016). Data inclusion consisted of heritability measured for morphological, life history, behavioural, and physiological traits, for terrestrial vertebrate species and from wild populations. The relationship between heritability and life history traits was measured using generalized linear mixed models. My results revealed significant relationships between heritability and life history traits. Larger body mass and longer lifespan were associated with low heritability, while larger litter/clutch sizes and earlier ages of maturity were associated with high adaptive potential. Morphological heritability estimates exhibited stronger correlations with life history traits compared to other heritability estimates, suggesting they may be a more reliable proxy for predicting adaptive potential. These findings highlight the potential of using life history traits to infer species’ genetic diversity and adaptive potential, offering a valuable tool to improve conservation prioritization.
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Open Access
Canopy-dependent environmental factors impact on nitrogen fixation in Shepherdia canadensis in the boreal forest and tundra
(2025-03) Tydings, Jason; Renault, Sylvie (Biological Sciences); Fraser, Kevin (Biological Sciences); Markham, John
Actinorhizal shrubs, plants that symbiotically associate with nitrogen-fixing bacteria and do not depend on soil nitrogen, can increase productivity and facilitate successional changes. High-latitude environments are characterized by harsh abiotic climatic conditions that limit nitrogen availability to plants. However, actinorhizal shrubs are less prevalent at higher latitudes, even though those environments are generally nitrogen-limited. Reduced year-round temperatures, water availability, and light availability are all thought to limit nitrogen fixation due to its energetic costs, making nitrogen fixation unfavourable at higher latitudes. Shepherdia canadensis (buffalo berry) is an actinorhizal shrub that is found in higher-latitude environments across Canada. We wanted to determine, within the northern edge of the boreal forest and tundra, how much nitrogen fixation is occurring in buffalo berry, and how it varies across naturally occurring habitat and canopy-dependent environmental factors. The natural abundance stable isotope technique was used to quantify nitrogen fixation, while canopy-dependent variables were measured using hemispherical image analysis. We found that buffalo berry shrubs were getting a majority of their nitrogen content through nitrogen fixation (55.32% - 94.74%) and that on average, fixation occurred at a higher rate in the forest (74.67%) compared to the tundra (68.00%). Notably, foliar δ13C values varied with canopy openness. Specifically, shrubs in more open areas and the tundra had higher δ13C values, which were interpreted to be a result of stomatal closure in response to reduced water availability. Nitrogen fixation was found to be sensitive to water availability, decreasing with canopy openness (17.99% – 99.79%). This limitation could reduce the productivity of nitrogen-fixing plants in response to warmer climate conditions.
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Open Access
The Role of Physical Movement in Spinal Cord Repair Using an Adult Zebrafish Model
(2025-03) David, Gabrielle; Xing, Lei (Biological Sciences); Stacey, Joy (Biological Sciences); Lindsey, Ben; Jeffries, Ken
Spinal cord injury (SCI) is a debilitating medical condition that can lead to lifelong paralysis. Failure to regain mobility and restore neurons can be attributed to the non-permissive microenvironment within the mammalian spinal cord that is characterized by prolonged inflammation and glial scarring. Unlike mammals, the zebrafish has a remarkable ability to regenerate neurons in the spinal cord following a complete transection. Aside from the activation of chemical pathways that promote growth, zebrafish also have ependymoglial (stem) cells surrounding the central canal that can proliferate and differentiate into all cell types of the spinal cord. Previous studies have investigated factors that promote neuronal regeneration, yet the contribution of locomotion remains unevaluated. Thus, we aimed to explore the role of physical movement in spinal cord repair by developing a swim column that elicited swimming activity (exercise treatment) from injured fish. This apparatus was developed using an aquarium pump to direct flow into a PVC tube placed within an acrylic tank. Adult male zebrafish from motor neuron reporter line, Tg(hb9:eGFP), were used. Results showed that the exercise treatment slowed the rate of recovery and diminished normal swimming behaviour. Downstream analysis of distance travelled, mean velocity, and mobility state duration revealed that SCI fish treated with exercise had delayed recovery compared to SCI fish that were untreated. Contrary to previous studies using mammalian models, we found that functional mobility was hindered, and swim restoration was limited. Furthermore, our findings contrast other zebrafish exercise studies that demonstrated increased neurogenesis in larvae, and attenuation of age-related diseases such as sarcopenia and cardiac failure. These contradictions may be attributed to sample size, experimental timeline, treatment duration, and stress levels. Although the current study did not yield statistically significant results, these preliminary findings lay the groundwork for deeper exploration of movement in regenerative models
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Open Access
Protecting plants against the fungal pathogen Sclerotinia sclerotiorum using host-induced gene silencing
(2025-04) Caners, Rhey; Whyard, Steve (Biological Sciences); Lee, Jae-Hyeok (Biological Sciences); Belmonte, Mark
Sclerotinia sclerotiorum is a fungal pathogen that affects Canadian crops every year. Brassica napus (canola) is particularly vulnerable. Chemical fungicides are widely used to control S. sclerotiorum. However, with increasing concerns about resistance and ecological effects, it is necessary to develop new and improved control methods. Host-induced gene silencing (HIGS) is an RNA interference technology that has the potential to be harnessed to create transgenic, pathogen-resistant crops. In this study, I analyzed the effectiveness of four independently transformed lines of Arabidopsis thaliana expressing RNA to silence the NOB1 gene (SS1G_07873) in S. sclerotiorum. Three of the lines expressed double-stranded (ds)RNA while the fourth line expressed paperclip (pc)RNA, a novel RNA structure which folds over itself on both ends to protect it from nucleases. The analysis was done through detached-leaf lesion assays and transcript knockdown analysis of the NOB1 target gene as well as three known interacting genes. Though improvements are required, the lesion assays show significant decreases in lesion size. Transcript knockdown analysis revealed insignificant changes in NOB1 expression. The interacting genes analyzed showed a significant reduction in transcript abundance, indicating that further experiments are required to understand the processing of foreign RNA in the plant. With further testing to optimize HIGS using SS1G_07873, this technology has the potential to be replicated in crop plants as a means of protection against S. sclerotiorum.
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Open Access
Using long-read sequencing to diagnose rare neuromuscular disorders: a pilot study
(2025-03) Martin, Alexandria Brooke; Wright, Galen (Max Rady College of Medicine); Lee, Jae-Hyeok (Biological Sciences); Hartley, Jessica; Belmonte, Mark
Many individuals with suspected genetic neuromuscular disorders (NMDs) remain undiagnosed despite extensive conventional genetic testing, which generally employs short-read sequencing (SRS) methods. Long-read sequencing (LRS) is a recently introduced technology which offers improved genome coverage and variant detection missed in standard approaches. Therefore, this pilot study aimed to investigate the application of long-read whole genome sequencing (LR-WGS) with the PacBio Revio platform for five participants (four families) with undiagnosed NMDs to identify causal genetic variants. Retrospective participant chart reviews were first conducted to assess phenotype, inheritance patterns, and other clinical factors. Following this, a novel bioinformatics pipeline was developed to enhance variant annotation and prioritization by integrating LRS population data with established genomic population frequency databases and in-silico predictions of deleteriousness. Finally, manual filtration was performed to further refine variant prioritization based on the clinical insights gained from chart reviews. Candidate variants of interest were found in three of four families analyzed (75%), including strong candidates in the FLNC and DMD genes, and a potential candidate in the TTN gene requiring functional validation. This pilot validates the pipeline for analysis of LRS data and provides evidence that LR-WGS could offer improvements over traditional SRS approaches in diagnosing NMDs, particularly in detecting complex variants. Improving accurate molecular diagnosis ultimately leads to better clinical outcomes for affected patients, including personalized treatment strategies and interventions. Future directions include the study of additional participants with NMDs to allow for a more comprehensive evaluation of diagnostic yield and applicability across diverse genetic backgrounds.
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Open Access
Factors Influencing Testes Size in the Cape Ground Squirrel (Xerus inauris)
(2025) Aston, Gemma; Garroway, Colin (Biological Sciences); Davoren, Gail (Biological Sciences); Waterman, Jane
When males compete through sperm competition, selection favours an increased investment in sperm production to streghten the male’s probability of siring offspring when females multiply mate. This increased investment in sperm quantity results in large testes relative to the species’ size. Thus, testes size can be used as a measure of reproductive fitness in males experiencing intense sperm competition. Despite this relationship, studies investigating testes size have focused on interspecific variation, leaving the factors driving intraspecific variation in testes size an underexplored area of study. I investigated the influence of age, body condition, rainfall, parasite abundance and testosterone concentration on the testes size of Cape ground squirrels, a sciurid known to be under intense sperm competition. Data was collected from males trapped on SA Lombard nature reserve in South Africa between the years 2013-2024 and the influence of each factor on testes mass was assessed using linear regression. Testes mass was found to increase with both age and body condition and body condition also increased with age. While the energetic demands of spermatogenesis appear to shape the relationship between body condition and testes size, declining oxidative stress with age and a terminal investment strategy may drive enhanced testes investment in older individuals. Parasite abundance negatively affected testes size suggesting parasites remove resources from their host that would otherwise be allocated to reproduction. Rainfall and testosterone concentration did not affect testes size. The lack of relationships between rainfall and testes size may have occurred due to the limitations of this study, while testosterone's lack of impact on testes size may be caused by the low testosterone demands of a year-round breeding strategy. These findings aid in our understanding of the factors influencing reproductive success in males experiencing sperm competition and the selective forces shaping intraspecific testes size variation.
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Embargo
Evaluating the impact of subsurface drainage and subirrigation on wheat production in heavy clay soils
(2025-05-08) Dasinija, Karikalan; Jian, Fuji (Biosystems Engineering); Mante, Afua (Soil Science); Sri Ranjan, Ramanathan
Effective water management is crucial for optimizing crop productivity. This study investigated the effectiveness of subsurface drainage and subirrigation in managing soil water for wheat production in heavy clay soils at Arborg, Manitoba. Field experiments were conducted at the Prairie East Sustainable Agriculture Initiative (PESAI) farm at Arborg, Manitoba. Different subsurface drainage designs (30-ft (9.1 m) and 45-ft (13.7 m) spacing) were used for subirrigation during the 2022 and 2023 growing seasons. Soil moisture response under these systems was assessed at 0.2, 0.6, and 0.9 m depths using soil moisture sensors for continuous monitoring throughout the growing season. In 2022, with above-average rainfall, controlled drainage removed adequate amount of water and resulted in significantly higher yield (p < 0.05) midway-between-tiles in the 30-ft spacing plot compared to the non-tiled control. In contrast, during the dry year of 2023, despite subirrigation, yield from the 30-ft plot was lower than the average yield in the Interlake region due to insufficient water. However, the on-tile treatment in the 45-ft plot and control (non-tile) plot produced significantly (p < 0.05) above-average yields in 2023 due to less water being drained from the field compared to the 30-ft plot. The data from this research was used to calibrate and validate the DRAINMOD model to assess the influence of tile drain spacing and subirrigation on relative yield in 2021, 2022 and 2023. Simulation results indicated that in 2022, relative yields in the 30-ft and 45-ft plots were 97.2% and 97.0%, respectively. Subirrigation reduced drought stress in the 15-ft plot during 2021, a dry year. A six-day planting delay caused a 5.2% yield loss in 2023. These findings demonstrated the importance of optimally managing controlled drainage systems to enhance wheat yield in heavy clay soils.
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Open Access
Effects of Infection with Brainworm Parasite (Parelaphostrongylus tenuis) on the Climbing Behaviour in a Host Gastropod Species (Deroceras laeve)
(2025-04) Dalling, Ness; Van Nest, Byron (Biological Sciences); Markham, John (Biological Sciences); Detwiler, Jillian
Brainworm parasite (Parelaphostrongylus tenuis) is a nematode parasite which typically infects white-tailed deer (WTD – Odocoileus virginianus) as a definitive host, where it often causes no severe harm. It develops through larval stages in terrestrial gastropods and is eventually ingested by the WTD to complete its life cycle. Brainworm can infect other ungulates accidentally, most commonly moose (Alces alces), where it causes serious neurological disease and often death. Here, I investigate the potential role of parasite-modified behaviour in influencing the ingestion of the gastropod hosts by the ungulate host. I hypothesize that when infected with P. tenuis larvae, a gastropod host, the meadow slug (Deroceras laeve) will display altered vertical climbing behaviour, predicting an increase in vertical climbing activity. Vertical climbing behaviour was assessed amongst 15 infected and 45 uninfected slug hosts at four different times throughout the day, on two separate days. I found a significant effect of the interaction between the weight of slugs, their infection status, and the time of day on vertical climbing behaviour. This is novel evidence to support the parasite-modified behaviour hypothesis in P. tenuis and suggests that climbing behaviours may play a role in the transmission of brainworm. Further research would be beneficial, as replicates in this study were low, and the presence of coinfection with a secondary parasite in some samples may have provided a confounding effect.
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Open Access
The short-term effects of peer tutoring in first-year biology labs on students with and without ADHD
(2025-03) Chambers, Amanda; Scott, Kevin (Biological Sciences); Waterman, Jane (Biological Sciences); Debets, Cassandra
Peer tutoring is an active learning strategy that has been implemented in many university-level courses. However, many studies that examine the effects of peer tutoring focus solely on the long-term impacts of peer tutoring on learning outcomes and student perceptions, without considering how peer tutoring may affect students with learning differences, such as attention-deficit/hyperactivity disorder (ADHD). Therefore, this study considers the short-term effects of peer tutoring on learning outcomes and perceptions related to understanding metabolic experiments and the ability to focus in students with different relationships with ADHD. Data was collected from students in BIOL 1020 labs at the University of Manitoba during the Fall 2024 semester through an experiment lab, peer tutoring lab, final lab exam, and demographic survey. The main results of this study revealed that peer tutoring had no significant effect on the learning outcomes of students who have different relationships with ADHD. However, peer tutoring did have a significant positive effect on all students’ perceived understanding of metabolic concepts, regardless of their relationship with ADHD. Peer tutoring also had no significant impact on students’ perceived ability to focus, regardless of their relationship with ADHD. The findings of this study not only provide useful information to educators who may want to implement peer tutoring in their labs, but also demonstrate how peer tutoring affects all students the same, and can therefore be considered an inclusive active learning strategy for students, regardless of their relationship with ADHD.