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Friday Philosophicals - Winter Semester 2022

Friday Philosophicals with Shyanika Durayalage and Simone Miklosi

Shyanika Durayalage: Genome-wide investigation of rtl gene and its function in the mitochondrial genome of Volvocales.
Simone Miklosi: Evaluating the ability of nuclear environmental DNA (eDNA) to determine number of individuals and biomass of Atlantic salmon​.

Friday Philosophicals run most Fridays by Zoom (check the schedule). Seminars start at 3:30 pm and are expected to end by 4:20 pm.

Each week a Zoom invite will be distributed to bioseminar-ee@uwo.ca. Contact thain@uwo.ca if you are not on this list and need the Zoom login details.

April 1, 2022

Shyanika Durayalage: Genome-wide investigation of rtl gene and its function in the mitochondrial genome of Volvocales

Shyanika Durayalage photo Supervisor: Dr. David Smith

Volvocines are an interesting group of algae including the model organism Chlamydomonas reinhardtii. The mitochondrial genome of C. reinhardtii is fascinating, being a 16 kb linear molecule with few protein-coding genes, telomeres with overhangs and a free-standing ORF, encoding a reverse transcriptase-like protein (the rtl gene). The purpose of the rtl is unclear, but it is believed to be involved in mtgenome replication. I aim to investigate diversity of rtl across the Volvocales group and also the relationship between the rtl and the mtgenome conformation. A tblastx will be performed on assembled contigs of 55 strains of algae to determine the distribution of rtl using the custom databases created for each taxa. rtl genes will be retrieved and deduced amino acid sequences will be used to determine whether they are functional. Several other mining steps will be done to find out if they have the same architecture as C. reinharditii.

Simone Miklosi: Evaluating the ability of nuclear environmental DNA (eDNA) to determine number of individuals and biomass of Atlantic salmon​

Simone Miklosi photoSupervisor: Dr. Bryan Neff

Environmental DNA (eDNA) is an emerging population assessment tool with considerable potential for fishes. Current eDNA approaches largely focus on mitochondrial genes, which are used to determine the presence or absence of a species of a fish in a particular habitat. Nuclear genes, in particular microsatellites, have the potential to provide increased population-level information about fishes. Microsatellites are commonly used in population genetics because they typically have considerable standing genetic variation. Despite the potential use of microsatellites for eDNA, the reliability and consistency of the microsatellite genetic information obtained from water samples remains uncertain. Therefore, in my thesis I investigated the ability of microsatellite primer pairs to successfully recover microsatellite alleles from water samples. In my research, I collected eDNA water samples from experimental tanks and river systems, containing Atlantic salmon, to determine if microsatellite alleles could be consistently recovered under different circumstances.

March 25, 2022

Christian Buchanan-Fraser: Post-breeding survival of adult and first-year Bank Swallows in the Great Lakes ecoregion: a radio telemetry study

Christian Buchanan-Fraser photo Supervisor: Dr. Yolanda Morbey

The post-breeding period poses significant threats to newly fledged birds due to predation, starvation, exposure to inclement weather, and collision risk prior to their first southward migration. To address the gap in knowledge about this period for Bank Swallows (Riparia riparia), I aim to estimate and compare the survival rates of adults and first-years in the Great Lakes ecoregion. In 2018 and 2021, individuals were captured, and radio tagged. Detection data was obtained from the Motus Wildlife Tracking System. Detection data was used to generate movement paths and encounter histories for the estimation of post-breeding survival rates in mark-recapture models. Mark-recapture models will be created and compared in RMark. Comparisons between Bank Swallow age and habitat (lakeshore colony or aggregate pit colony) will be implemented in the models. Results will help determine if Ontario Bank Swallows have age dependent post-breeding survival and if post-breeding survival depends on habitat quality.

Lauren Witterick: The enduring effects of fear on the brain and behaviour in wildlife

Lauren Witterick photoSupervisor: Dr. Liana Zanette

Predators affect prey populations not only through direct killing, but also through perceived predation risk – the fear of predators. Responding to predation risk is critical for prey survival, however trade-offs from prolonged anti-predator behaviour can have enduring effects ranging from individual changes in neurobiology up to population and community level effects. To experimentally test the enduring effects of predator fear on the brain and behaviour I manipulated perceived predation risk using auditory playbacks of predators or non-predators in wildlife, starting with acoustic isolation in the lab, progressing to semi-natural conditions and then moving to free-living wildlife. I quantify the effects of fear on neural activation and neurogenesis, while corroborating these effects through behavioural assays. My research integrates biomedical research studying the enduring effects of fear on the brain with fear-induced behavioural changes documented by ecologists in the field, to understand the mechanisms leading the population and community level fear response.

March 18, 2022

Benjamin Souriol: Short-term vs long-term effects of nitrogen addition and warming on ecosystem nitrogen dynamics in a grass-dominated old-field

Benjamin Souriol photo Supervisor: Dr. Hugh Henry

Increased atmospheric nitrogen deposition and climate warming are two elements of global change likely to have significant impacts on plant and soil processes in temperate ecosystems in the coming decades. Nitrogen is the key limiting nutrient for plant growth in temperate ecosystems. In long-term global change experiments, while cumulative treatment effects on soil nitrogen dynamics can emerge over time, comparisons between short and long-term responses can potentially be confounded with interannual variability in the environment. I will be examining new nitrogen addition and warming plots added to a pre-existing field experiment to compare short-term (3 year) versus longer-term (16 year) treatment effects on net nitrogen mineralization, nitrogen leaching, and nitrogen retention, while controlling for the effects of interannual environmental variability. My research will be beneficial for determining to what extent results from short-term experiments on soil nitrogen responses can be extrapolated to the longer-term.

March 11, 2022

Mehra Balsara: >The effect of artificial selection on coat colour and horn characteristics in thinhorn sheep (Ovis dalli)

Mehra Balsara photo Supervisor: Dr. David Coltman

Selective harvesting through trophy hunting can have serious consequences for the maintenance of genetically healthy populations. Often this hunting results in a reduction in the size of secondary sexual characteristics (i.e. horns, antlers, tusks). To better understand the artificial selection pressures associated with trophy hunting, I will calculate the predicted evolutionary response to selection for three phenotypic traits (horn growth, horn morphology and coat colour) in a popular trophy hunted ungulate, thinhorn sheep (Ovis dalli). I will then define how the selection pressures acting on each of these traits influence the genetic structure of this species. To address these objectives, I will create a custom SNP array that will be used to genotype individuals, calculate heritability and assess trait and gene associations. This research will help identify the impact of harvesting selection on trait variation and determine how harvesting can be more sustainable to ensure the conservation of thinhorn sheep.

March 4, 2022

Shayla Kroeze: Using conservation genetics to inform the reintroduction of the endangered Mottled Duskywing (Erynnis martialis)

Shayla Kroeze photo Supervisor: Dr. Nusha Keyghobadi

Habitat loss and climate change have caused declines in species diversity and abundance across the globe, including in butterflies which are important components of many ecosystems. Reintroductions are increasingly used to reverse loss of diversity but are most effective when informed using genetic data. I developed 24 microsatellite markers and characterized genetic structure and diversity of the endangered Mottled Duskywing (Erynnis martialis) in Ontario and nearby locations. These were used to inform planned reintroductions in Ontario. I found that populations had moderate levels of genetic diversity and were differentiated from each other. My work forms part of a larger effort to achieve the overall recovery goal of the species in Ontario and will support a locally sourced model for insect species at risk recovery planning. Tools developed in my research may be used to inform future reintroductions of the species, and to monitor success and status of the introduced populations.

Patricia Rokitnicki: Differences in Wing Morphology and Flight Behaviours in Black-throated Blue Warblers

Patricia Rokitnicki photoSupervisor: Dr. Yolanda Morbey

Songbirds vary in physiological, morphological, and behavioral traits depending on their age and sex. This study focuses on how differences in sex and age class can affect wing shape and flight speed in Black-throated Blue Warblers. Birds were caught at Long Point Bird Observatory during their 2021 spring migration. These birds were aged and sexed based on plumage and photographed to assess differences in wing morphology. Birds were tagged with radio transmitters that emitted a signal detected by Motus towers throughout North America. The presentation will focus on how the data collected with radio telemetry in 2014, 2015, and 2021 was used to calculate flight speeds through inter-tower detections. Further investigation into how differences in wing morphology could influence estimated flight speeds for the Black-throated Blue Warblers will also be examined. Tracking songbirds throughout their migration at an increased spatial and temporal scale will improve our understanding of migratory movement.

February 18, 2022

Spencer Heuchan: Nitrogen transfer from cover crops in a changing climate

Spencer Heuchan photo Supervisors: Drs. Hugh Henry and Claudia Wagner-Riddle

Effective nitrogen (N) fertilizer management is crucial for the reduction of environmental pollutants associated with agricultural systems. Cover crops, which are used to provide ground cover after the harvest of the grain crop, can potentially improve the sustainability of agroecosystems by reducing nutrient losses. However, the overall success of cover crops in reducing N losses and benefiting the yield of the subsequent grain crop is contingent on the release of N from decomposing cover crop residues being well-synchronized with the grain crop’s N demand. The efficiency of this N transfer may be influenced by variation in winter temperatures, which can affect the survival of cover crops and the timing of the decomposition of their residues. I have used 15N isotopic tracer in field experiments to examine how cover crops alter the dynamics of N losses vs. N transfer to the grain crop in response to climate variability over the winter.

Kiana Lee: Evaluating the effects of warming on floral traits in cucumber

Kiana Lee photoSupervisor: Dr. Danielle Way

Pollination is an essential ecosystem service that is necessary for the reproduction of flowering plants. However, anthropogenic climate warming has the potential to change plant-pollinator interactions by affecting floral traits that are essential for pollination. My objective is to investigate how floral traits that are important for pollinator visitation change when plants are grown at ambient or +4°C temperatures. To address this, I will quantify the size and shape of UV floral guides (signals to pollinators that are only visible under UV wavelengths of light) using UV-visible photography. Additionally, I will evaluate changes in human- and UV-visible flower pigmentation using GC-MS. Finally, I will correlate changes in key floral traits with flower development and plant growth. From this research I will be able to determine how warming could alter how foraging pollinators receive visual cues and thus provide pollination services.

February 11, 2022

Corrine Génier: The role of aquatically derived lipids in determining fatty acid composition of aerial insectivorous bird

Corrine Genier photoSupervisor: Drs. Keith Hobson and Chris Guglielmo

Aerial insectivorous songbirds, which feed on insects while flying, have been declining for decades. A contributing factor could be the decline in the quality of insect prey. Fatty acids, the building blocks of fat, are known to be important for the health and growth of young birds and insects emerging from waterbodies supply more beneficial fatty acids (eg. omega-3) than terrestrial insects. Thus, diet quality is expected to vary across habitats and among species with differential access to aquatic insects. Yet, songbirds can make certain fatty acids to an extent. The ability to synthesize beneficial fatty acids may be vital if birds do not have access to aquatic insects. My thesis will compare the diet composition of different bird species nesting near waterbodies and further inland. I will also conduct experiments in captivity and in the wild to understand how fatty acids are converted inside the body of birds.

February 4, 2022

Trevor Pettit: Soil foodweb carbon cycling under warming

Trevor Pettit photo Supervisor: Dr. Zoë Lindo

In North America, future soil temperature and moisture conditions under climate change may be more extreme and more variable than originally thought. Extreme heat events affect both the predator and prey species that comprise soil communities, but this effect may differ in magnitude between predator and prey communities, also altering carbon flux. However, little is known about what effects these changes in soil community composition have on larger ecosystem functioning, like carbon sequestration. Thus, the objective of my proposed research is to quantify and model the effects of experimentally-imposed temperature and moisture conditions that simulate potential future climate disturbances, on peatland soil food web flux and soil carbon sequestration.

Jessica Deakin: Links between migration timing, wing morphology, and the environment

Jessica Deakin photoSupervisor: Dr. Yolanda Morbey

Migratory birds are under pressure to synchronize their arrival timing at the breeding grounds with phenology. Males are under additional pressure to arrive early (“protandry”) presumably to reduce intraspecific competition for access to breeding sites and mates. A primary mechanism underlying protandry is departure timing. Individuals use environment cues such as weather and food supply to time their departure. They may also use social cues; however, this has not been empirically tested. For my Ph.D., I experimentally modify the social environment of a songbird to investigate whether increased male-male competition accelerates migration timing. Another mechanism of protandry is migration speed. To test the relationship between wing shape sexual dimorphism and flight performance, I conducted a multi-season field study using a custom designed flight chamber equipped with qual-level infrared technology. I also modelled the relationship between wing length sexual dimorphism, phenology, and arrival timing using a long-term bird banding dataset.

January 28, 2022

Campbell McKay: Do some species of milkweed better prepare monarch butterflies for migration?

Campbell McKay photo Supervisor: Dr. Jeremy Macneil

Declines in the monarch butterfly (Danaus plexippus) population have been linked to declines in its larval host plant, milkweed (Asclepias spp.). While common milkweed (Asclepias syriaca) is generally considered the larval food of the monarch butterfly, and has been the subject of much study, monarch larvae live on many species within the milkweed genus Asclepias. Studies to date have examined the survivorship of larvae on these other species, and the different herbivore defenses they have, but not how well they prepare monarch butterflies for their fall migration to their overwintering site in Mexico. To study this, I will rear monarch butterfly caterpillars in both early and late summer on three different species of milkweed: Common milkweed, swamp milkweed (Asclepias incarnata), and butterfly milkweed (Asclepias tuberosa). Once they have reached adulthood, I will use their body weight, lipid mass, and wing morphology as indicators of their capability to migrate.

Scout Thompson: Selection and non-random mating at class I of the major histocompatibility complex (MHCI) in Melospiza melodia (song sparrows)

Scout Thompson photoSupervisor: Dr. Beth Macdougall-Shackleton

Evolutionary history is characterized by an endless arms race between pathogens and host immune systems. An important player in immune defense is the major histocompatibility complex (MHC), referring to a large family of genes responsible for pathogen detection. Given its important role, the MHC has been heavily subjected to selection - often reinforced by mate choice. While numerous studies have examined the evolutionary mechanisms of MHC class II (responsible for extracellular detection) not much care has been given to class I (responsible for intracellular detection). My research seeks to investigate these neglected loci to see if they will reveal similar findings, or if I will discover something completely different. Through the usage of genetic information, and long hours spent spying on birds, I plan to uncover which mode of selection has historically occurred at the MHCI of song sparrows, and whether genotype plays a significant role in their mate selection.

January 21, 2022

Timothy Hain: Musings on 40 years of Bluegill research (with some of those years featuring me)

Tim Hain photoLong-term studies offer ecologists fantastic opportunities to develop a deep knowledge of their study species. A danger that may arise from spending so much time working with one species is that ecologists may begin to feel like ‘experts’ who know all there is to know about their study species’ interactions with its environment. In this talk, I will discuss 40 years of research on bluegill (Lepomis macrochirus) at Lake Opinicon in Ontario by three generations of ecologists. Our serendipitous observations of the bluegill population have revealed that these are resilient creatures who dynamically respond to environmental stresses effected by invasive species and climate change. Furthermore, recent observations have led the youngest generation of researchers to abandon certain assumptions about the importance of parental care in bluegill. In this loving tribute, I will explain that the more I get to know bluegill, the more they surprise me.

January 14, 2022

Ala Abdel Rahman: The interaction of cover crops and entomopathogenic fungi to manage wireworm pest populations

Ala Abdel Rahman photo Supervisors: Drs. Ian Scott and Hugh Henry

Wireworms, the larval stage of click beetles (Coleoptera; Elateridae), are a significant pest of vegetable crops worldwide. Wireworms have caused considerable damage to corn, wheat, and potato crops in North America, Europe, and Asia. According to recent research, certain cover crops can reduce wireworm populations by using natural compounds released by the growing plant (allelopathy) or after being mulched into the soil (fumigants). I will investigate whether buckwheat, brown mustard, and sorghum-Sudan grass, combined with two different strains of Metarhizium brunneum, an entomopathogenic fungus, could be applied as a strategy to reduce wireworm populations in southwestern Ontario potato fields. This study will also focus on the potential interaction between these allelopathic cover crops and Metarhizium brunneum.

Rachel Rajsp: Investigating the soil microbiome of North American ginseng (Panax quinquefolius)

Rachel Rajsp photoSupervisor: Dr. Greg Thorn

Ginseng replant disease (GRD) is of high significance to the Ontario ginseng industry as it can cause the complete loss of ginseng crops. Replant disease occurs when a new ginseng crop is planted in a field where ginseng was grown previously. The prevalence of GRD has since limited the amount of land in North America that is available to grow ginseng. Several pathogens that have been discovered to cause rot include: Neonectria, Ilyonectria, Phytophthora and Pythium. This project will investigate new primers that permit identification of individual species of certain target fungi. Using new and pre-existing primers, I will compare the fungal and oomycete communities present in ginseng replant soil (collected in 2022) and the first and fourth years of a new healthy ginseng crop (collected in 2018 and 2022). Next-generation sequencing (NGS) will be used to identify what species are present in the soil for each garden site.