Friday Philosophicals

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William Laur: Exploring representations of and attitudes towards snakes in online media: an ethnozoological approach
Matheus Sanita Lima: Using third-generation RNA-Sequencing data to exploring organelle noncoding transcriptomes

Friday Philosophicals

A weekly seminar series run by the Ecology & Evolution group, allowing graduate students and others to present their research in a collegial environment. All talks are 10-30 minutes in length, followed by up to 5 minutes of questions, with open discussion from the floor. Typically, two speakers will present on a given day. The Friday Philosophicals is an excellent opportunity to learn the rough and tumble of giving scientific talks, gain feedback from faculty and peers – give feedback to your fellow presenters – and, above all, learn about science, biology and effective science communication.

Friday Philosophicals run most Fridays in Kresge Building K106 (check the schedule). Seminars start at 3:30 pm and are expected to end by 4:20 pm.

For incoming students, the Friday Phils provides an excellent forum to present your proposed research in the form of hypotheses, experimental design and intended use of a field, lab or analytical techniques. For outgoing students, the forum is ideal for summarizing your key findings and explaining their broader significance.

Attendance is required of graduate students in the E&E stream, and guests are welcome, including visitors to the department and aspiring undergraduates. The seminar series represents Part 2 (Communication) of BIO 9100y/9150y. Although occasional absences are expected, consistent absence is considered poor form and may result in a grade of ‘Unsatisfactory’ with implications for funding eligibility. Should you go? Yes! Your fellow grad students will appreciate your support – as you will theirs. Besides, it's just fun!


2023-2024 Organizer

Dr. Tim Hain

April 12, 2024

William Laur: Exploring representations of and attitudes towards snakes in online media: an ethnozoological approach

William Laur photo Supervisors: Dr. Hugh Henry, Dr. Scott MacDougall-Shackleton and Dr. Ruth Martin

Attentional biases towards snake visual cues can affect fear acquisition through vicarious learning; it is important to consider how sensationalized depictions of snakes across various forms of media may impact the potential for human hostility and conservation resistance or acceptance. Effectively communicating conservation information related to threatened snake populations to the public may be obstructed by public perceptions of, and attitudes towards, snakes. We collected online media to assess animal-specific themes and representations, and how these depictions may influence human acceptance of snake conservation. We consider the topics published by scientists, themes observed when scientists communicate within their topics of interest, and the attitudes and themes observed on social media. By conducting an exploratory topical and qualitative document analysis of sampled online media, we can identify snake-specific representations and thematic patterns so as to synthesize a description of snake-specific human attitudes for the purpose of informing conservation strategists.

Matheus Sanita Lima: Using third-generation RNA-Sequencing data to exploring organelle noncoding transcriptomes

Matheus Sanita Lima photo Supervisor: Dr. David Smith

Mitochondria and chloroplasts are information processing hubs with genomes inherited from prokaryotic ancestors. Despite billions of years of reductive evolution, organelle genomes exhibit a remarkable diversity in size, content, and structure. Just as convoluted, organelle transcriptomes can be seen as hybrid system - a prokaryotic relic entombed in a eukaryotic vessel. I have demonstrated that organelle genomes are pervasively transcribed by using Illumina data. The essence of these transcriptomes was hard to dissect because of the nature of short Illumina reads. As public repositories now have 3rd-generation RNA-Seq data, I can investigate organelle transcriptomes in a detail not possible before. I have (re)annotated the noncoding portion of ~ 36K organelle genomes and found hundreds of potential ncRNA genes of various sizes. I am now tapping onto long RNA data to validate these ncRNAs (and sORFs). I hypothesize that organelle genomes and transcriptomes are a treasure trove of regulatory elements.

March 22, 2024

Ryan Conklin: Annual survivorship varies between the sexes, but not with overwinter latitude, in song sparrows

Ryan Conklin photo Supervisor: Dr. Beth MacDougall-Shackleton

Many animals display differential migration, where individuals breed at the same site but overwinter at different sites. Assessing how overwinter latitude relates to survival has been difficult to study since only individuals surviving and returning to breed can be sampled. We used stable isotope analysis of winter-grown claw tissue (δ2Hc) as a proxy to examine the relationship between survival and overwinter latitude in differentially-migrating song sparrows (Melospiza melodia). We constructed encounter histories for 551 individuals from ten years of breeding-site capture records and fit a modified Cormack-Jolly-Seber model incorporating a hierarchical model of δ2Hc. Analysis was conducted in the Bayesian framework via MCMC sampling, estimating distributions of missing δ2Hc data based on the individual’s previous values, to assess how survival varies with δ2Hc. Survival and capture probability varied by sex, but δ2Hc was not linked to survival. Such findings help to infer how differential migration is maintained in this population.

Sophie Killam: The Potential to Manipulate the Brain-Gut Axis of Honey Bees to Promote Hygienic Behaviour

Sophie Killam photo Supervisor: Dr. Graham Thompson

Honey bees live in densely populated colonies that are susceptible to communicable disease. To mitigate the spread of infection, colonies can detect and remove diseased brood from their hive, but maintaining this trait within apiaries is challenging. One approach to promoting hygiene is to heighten the sensitivity of bees to diseased brood cues, which may be possible through strategic manipulation of the gut-brain axis. In this study, I delivered a controlled dose of living bacteria that have previously been implicated in the production of olfactory-associated neurotransmitters. I found that, despite a high level of baseline variability, colonies showed an improvement in hygienic ability, suggesting some potential for microbial therapeutics within the beekeeping industry. The response was, however, short-lived despite subsequent treatments, and changes to the gut microbiome itself were likewise transient. My results help clarify the link between the bee gut microbiome and a colony-wide response to disease.

March 22, 2024

Richard Nguyen: Effects of N-heterocyclic carbene-enhanced coatings on microbial corrosion of steel

Richard Nguyen photo Supervisor: Dr. Vera Tai

Corrosion-related expenses cost the global economy 2.5 trillion USD annually, with microbial-influenced corrosion accounting for 20% of total costs. While corrosion-resistant coatings are effective, they are susceptible to disbondment. N-heterocyclic carbenes (NHC) can enhance adhesion of corrosion-resistant coatings like epoxy to metal surfaces. To test the effectiveness of NHC, epoxy and epoxy-NHC-coated steel coupons were exposed to E. coli ATCC 25922. Corrosion levels were evaluated through dissolved iron concentrations in the media, metal oxidation levels and visual analysis using scanning electron and optical microscopy. After two weeks of exposure, all epoxy coatings were damaged, with coupons exposed to E. coli showing increased surface oxidation compared to the control. However, no oxidation and metal discolouration differences existed between epoxy and epoxy-NHC-coated coupons. While NHC did not reduce corrosion by E. coli, NHC may prevent corrosion under less corrosive experimental conditions, with a different epoxy coating, or with environmentally relevant bacteria.

Justin To:Birds reek of immunity, both innate and adaptive?

Justin To photo Supervisor: Dr. Beth MacDougall-Shackleton

Birds can smell and use these chemical signals in the form of odour to communicate and make decisions. Research on the effects of adaptive immune receptor gene variation on body odour and its relation to mate choice has been done extensively. But less is known about how innate immunity affects this odour and related behavior. I examined patterns of correlation between genetic diversity at innate immune receptor genes (toll-like receptors) and song sparrow body odour inferred from preen oil chemical composition. Results showed that pairwise differences in genetic variation at both toll-like receptor3 (viral interacting) and toll-like receptor4 (non-viral interacting) were significantly correlated to pairwise differences at preen oil chemical composition between sparrows. This suggests that innate immune genes may be communicated to conspecifics in the same manner as adaptive immune genes. And provides insights into patterns of immunity evolution and the influence of host behavior in these patterns.

Eric Grimm: Environmental Controls on Mercury Methylation in the English-Wabigoon River System

Eric Grimm photo Supervisor: Dr. Brian Branfireun

Methylmercury is a potent neurotoxin which biomagnifies up trophic levels and is readily formed in aquatic environments under certain biogeochemical conditions. Understanding the environmental controls on methylmercury formation is critical to preventing possible harm to fish consumers. The English - Wabigoon River system has been historically polluted with mercury from a point source discharge within the city of Dryden in Northwestern Ontario. While discharges of mercury have ceased, sediment and fish concentrations remain among the highest in the province. My research has worked to characterize in-situ mercury methylation within riparian wetlands along the river to determine whether these areas are ‘hot-spots’ of methylmercury production. I have also sought to experimentally assess the impact of sulphate and organic matter at different treatment concentrations upon mercury methylation within contaminated sediments under controlled conditions. Preliminary results suggest that sulphate could be a principal control of mercury methylation in riparian wetland sediments.

March 15, 2024

Aaya Aboulnaga: Effects of species reintroduction on the population genetics of the mottled duskywing butterfly (Erynnis martialis)

Aaya Aboulnaga photo Supervisor: Dr. Nusha Keyghobadi

Since 2021, the mottled duskywing (Erynnis martialis) has been undergoing species reintroduction into Pinery Provincial Park. Genetic monitoring of the reintroduction was needed to gauge the success of the reintroduction protocol, as many past animal reintroductions have failed to produce self-sustaining populations due to the effects of low genetic variability. For my project, DNA microsatellites were used to track the genetic diversity of the reintroduced population over time, as well as the genetic effects of removing, captively rearing, and returning individuals to the source population for the reintroduction. The genetic diversity of the reintroduced population was found to be relatively low, but increasing over time, and the source population was not found to be experiencing adverse effects from its role in the reintroduction process. This suggests that the protocol is successful, and the species reintroduction can continue as it is.

Samantha Hopkins: Experimental climate warming changes Sphagnum community composition and reduces diversity in a boreal peatland

Samantha Hopkins photo Supervisor: Dr. Zoë Lindo

The bryophyte genus Sphagnum is an ecologically significant group of mosses that sequester large amounts of carbon (C) within peatlands. Species in the Sphagnum community have varying preferences for temperature and moisture, allowing many species to co-exist along the variable temperature and moisture gradients found in peatlands. In my research, I quantified how the Sphagnum community had changed in warmed vs control plots after 7 years of experimental warming and how these changes were related to plot-level environmental variables. In the warmed plots I found significantly less species diversity, lower abundance of the moisture-dependent species Sphagnum angustifolium, and higher frequency of total Sphagnum die-back compared to the control. Multivariate analysis demonstrated that changes in community composition were driven by the variable’s moisture, shade, and treatment. As climate change alters the composition of the Sphagnum community this creates uncertainty as to how peatland carbon sequestration and storage could be affected long-term.

Melina Kuerschner: The effect of mercury exposure on torpor, migration and fuel stores in silver-haired bats

Melina Kuerschner photo Supervisor: Dr. Chris Guglielmo

Bats frequently use torpor, which is defined as a profound reduction of metabolic rate and therefore, body temperature, to conserve energy. Torpor is especially important for migratory species during stopovers, as migration is extremely energy costly. Methylmercury (MeHg) is a heavy metal that elicits many neurotoxic effects in organisms such as restlessness, hyperactivity, spatial cognition and behavioral deficits including feeding behaviors, motor coordination and balance. Bats may be exposed to high levels of MeHg as it readily bioaccumulates in their prey. This could negatively affect their ability to enter and stay in torpor, potentially induce changes in their migration and activity patterns, and fuel stores. To investigate this, I used previously collected fur samples from silver-haired bats, in conjunction with respirometry, body composition, and radiotelemetry data from previous studies. So far, the results suggest that there is a correlation between the mass of a bat and the mercury load.

March 8, 2024

Pedro Conceicao: Post-glacial patterns of predatory mites across a peatland latitudinal-successional gradient

Pedro Conceicao photo Supervisor: Dr. Zoë Lindo

In Earth’s 4.5-billion-year history the last century has proved an unprecedented period of rapid change driven by multiple and co-occurring anthropogenic-induced climate change factors. These rapid changes are anticipated to have broad and significant impacts on many species and the processes that structure ecological communities. Peatlands are often used to examine patterns of glacial retreat as they form ‘relic’ landscapes across a wide ice retreat gradient and are also habitat for species rich communities of soil-dwelling arthropods, such as mites. The predatory mites (Class Mesostigmata) are small, wingless arthropods very understudied in peatland systems. For my research I have been exploring the structure of mesostigmatid mite communities in Sphagnum peatlands across a latitudinal-successional gradient in Ontario investigating the factors underlying their composition.

Julien Koga: An improved phylogeny of Hericium and production of erinacine A

Julien Koga photo Supervisor: Dr.Greg Thorn

Hericium erinaceus is a choice edible mushroom and a rich source of bioactive secondary metabolites. Among the compounds produced by H. erinaceus, erinacine A is of particular research interest in the treatment of neurodegenerative diseases for its stimulating effects on nerve growth factor synthesis. However, little attention has been given to the production of erinacine A in other species of Hericium partly due to the confusion surrounding the systematics of the genus. A multi-locus analysis was conducted to resolve the phylogeny of Hericium, uncovering interspecific relationships and leading to the description of two novel species. Analyzing the mycelial extracts of several Hericium species, erinacine A was detected in four species. Should erinacine A continue to be of medical and economic interest, these findings suggest that Hericium species other than the commercially produced H. erinaceus may be sources for this compound.

March 1, 2024

Makayla Lloyd:Bioprospecting: Investigating the toxin droplets of Pleurotus species

Makayla Lloyd photo Supervisor: Dr. Greg Thorn

Several genera of carnivorous fungi have been shown to possess diverse mechanisms which trap and digest microfauna as a means of nutrient supplementation. Of these fungi, Pleurotus—commonly known as the oyster mushroom—possesses the unique ability to paralyze nematodes through the production of toxic secondary metabolites contained within liquid microdroplets on aerial hyphae. Although historic and recent attempts have been made to identify this toxin in primary literature, the identity of Pleurotus toxin has not yet been confirmed. Similarly, research focusing on the regulation of this droplet production and their effects on nematodes has been conducted predominantly on one species, P. ostreatus. My research aims to understand the toxin droplet production between twenty-two strains of Pleurotus, as well as uncover the chemical composition of toxin droplets using GC-MS headspace and liquid sampling.

Cristina Turcu: Microbial community response to experimental warming in boreal peatlands

Cristina Turcu photo Supervisor: Dr. Vera Tai

Boreal peatlands are essential in global carbon storage as microbial decomposition is limited by abiotic conditions, however, climate change is predicted to alter microbial communities and biomass, impacting how carbon is stored in peatlands. Thus, to quantify differences in microbial biomass and community composition, quantitative PCR (qPCR) and metabarcode sequencing was used respectively in experimentally warmed plots compared to ambient plots in two fens. Initial results show insignificant changes for bacterial composition and biomass between ambient and experimentally warmed plots but confirm previously known fungal:bacterial ratios at the two fens. This suggests that bacterial communities may not be significantly affected by warming treatments, but further characterization of how fungi and protist respond is essential for a comprehensive understanding of the system. Overall, my research quantifies microbial responses to warming, validates the use of qPCR to estimate biomass, and contribute to carbon cycling models amid climate change.

February 16, 2024

Brendon Samuels: Experimental studies of bird-safe glass

Brendon Samuels photo Supervisor: Dr. Scott MacDougall-Shackleton

Preventing bird-window collisions is an emerging priority for conservation management. Under bird friendly development policies and updated migratory bird regulations, there is growing need for material solutions that provide protection at new and existing buildings. Bird collision deterrents (e.g., glazing with patterns of visual markers) are evaluated using animal experiments that provide indices of effectiveness. However, existing methods involve untested assumptions about the effects of ambient lighting and “visual contrast” on performance of tested materials. In this study, we implemented a choice test procedure using an experimental flight arena. We carried out trials with House Sparrows (Passer domesticus) to compare birds’ choice responses to different glass technologies under manipulated illumination conditions. Preliminary analyses show the visibility and performance of tested glass is related to qualities of ambient lighting. I interpret these findings to recommend improvements to existing glass testing protocols, greater scrutiny of test results and education for architects.

Emad Hazboun: Origins of Mourning Doves recruited into the Fall southern Ontario and continental hunt

Emad Hazboun photo Supervisor: Dr. Keith Hobson

A requirement for managing hunted species is establishing general migratory connectivity between breeding, wintering, and stopover sites and identifying regions of productivity where juveniles are recruited into the fall harvest. Stable isotope methods will be used to evaluate the composition of the fall harvest of Mourning Dove in Ontario and the Central Flyway of North America. The first objective is to establish a Mourning Dove feather δ2Hf isoscape and evaluate the composition of the southern Ontario harvest. Using the derived Mourning Dove feather H isoscape, the second objective is to assign feathers from hunter-killed birds throughout the U.S. flyway to their natal or breeding origin to determine the continental structure of take in the Fall hunt. Identifying these production regions locally and at a continental scale allows conservation efforts to focus on factors limiting recruitment and protection of the most productive regions and is essential to sustainable management.

February 9, 2024

Corrine Genier: Evaluating the role of aquatically derived fatty acids in aerial insectivorous birds

Corrine Genier photo Supervisor: Dr. Keith A. Hobson

In North America, declines in aerial insectivorous songbirds can be attributed to habitat loss and changes in climate, but the quality of insect prey may also be a contributing factor. Fatty acids, the building blocks of fat, are important for the development, growth, and health of young birds. Insects emerging from waterbodies supply more beneficial fatty acids (ie. omega-3 fatty acids) than terrestrial insects. Some birds may also be able to synthesize long-chain fatty acids from readily available short-chain fatty acids. Using bulk stable isotopes measurements of tail feathers, fatty acid profiles of blood plasma, and compound-specific stable isotope measurements of livers, we evaluated how aerial insectivores acquire key fatty acids through their diet or internal synthesis. We found that both wild barn swallows (Hirundo rustica) and purple martins (Progne subis) can synthesize their own long-chain fatty acids at a higher efficiency than previously reported tree swallows. Fatty acid conversion can be a way to compensate or supplement for a lacking diet.

Parker Van Belleghem: Artificial light at night and the migratory stopover behaviour of thrushes

Parker Van Belleghem photo Supervisor: Dr. Yolanda Morbey

Exposure to artificial light at night (ALAN) is becoming an increasing issue as long-term exposure to ALAN can cause serious physiological, psychological, and ecological effects. Migrating songbirds are especially sensitive to ALAN, which can advance migration phenology and act as an attractant. However, the nuances of these effects vary between species, and the underlying mechanisms are not well understood. In this study, I will explore how ALAN may act as an ecological trap for two thrush species, Catharus ustulatus and Catharus guttatus. Focusing on a stopover site in Long Point, ON, I will use automated radio telemetry (i.e. the Motus system) and a sky quality metre to explore the relationships between sky brightness and three key measures of migration traffic and behavioural patterns: the departure time of thrushes leaving the site, the number of thrushes arriving to the site, and the nocturnal activity of thrushes roosting at the site.

February 2, 2024

Pilar Caicedo: Identifying important stopover sites in northern Colombia for long-distance migratory birds

Pilar Caicedo photo Supervisor: Dr. Keith A. Hobson

Despite the emerging picture of stopover use, the distribution, and ecological characteristics of stopover sites for songbirds migrating through Central America and northern South America are still poorly understood. Representations of migratory species’ geographical ranges and identification of factors driving these distributions during migration are important to understand ecological systems and make smart decisions for management and conservation. Unfortunately, collecting high-quality data, especially in the tropics, sometimes poses a challenge due to resources and time availability. Occupancy models provide probably one of the best cost- and time-efficient options to make inferences about habitat suitability for a species, based on spatial variation in occupied sites while accounting for imperfect detection. I used a combination of occupancy analysis and on-the-ground field studies to identify important stopover sites and the factors driving their selection, by long-distance migratory songbirds during spring and fall migration across northern Colombia.

Julia Lacika: Exploiting queen-microbe relationships to boost health and performance of honey bee colonies

Julia Lacika photo Supervisor: Dr. Graham Thompson

Honey bees are difficult to manage in the face of environmental stress, particularly upon exposure to disease. Antibiotics are traditionally used to treat and prevent infection but have become unpopular due to sterilizing effects on the bee's gut microbiome. Probiotics are an eco-friendly alternative, which have so far been shown to increase immunocompetency in worker bees and larvae. However, no study has delivered probiotics directly to the guts of queen bees despite their central role in the hive. In this study, I will first examine if select strains of lactic acid bacteria can survive in an edible medium ('bee candy') long enough and in sufficient dose to deliver to queen bees at the start of their reproductive life. After demonstrating feasibility of this approach in the lab, I will then test the effects of queen probiotic supplementation on small field colonies.

January 26, 2024

Liam Carter: Telomere Dynamics in a Population of Long-Lived Marine Mammal

Liam Carter photo Supervisor: Dr. David Coltman

Telomere length has long been used as a biomarker of aging, generally getting shorter with each cellular division, with the rate of erosion affected by both endogenous and exogenous factors. While there exists a fair amount of literature detailing telomere dynamics and their relationship to life history phenotypes, there has been very little detailing the relationship within long-lived individuals. Sable Island, Nova Scotia, host to the largest Grey Seal population in the world, allows us the opportunity to explore this relationship as a long-lived iteroparous mammal with documented cohorts surveyed annually since the early 1960s. Using existing tissue samples from uniquely branded individuals with complete life history data, I aim to determine how the average length of telomeres at birth has changed in response to environmental stress as the population density increases, as well as determine how telomere dynamics within individuals differ with respect to life history.

Natalie Tateishi: Antibiotic potential of pleurotin and erinacines derived from Hohenbuehelia and Hericium species

Natalie Tateishi photo Supervisor: Dr. Greg Thorn

Antibiotic resistance has become a growing concern of public health. Because of this phenomenon, pharmaceutical companies are less inclined to invest in the development of novel antibiotics as these products will be held in reserve until absolutely needed, thus limiting profits. However, the development of new antibiotics and novel targets are ways to combat this public health crisis. Fungi are a natural source to investigate novel antibiotics, given their previous success from compounds such as penicillin. Hericium and Hohenbuehelia species produce erinacines and pleurotin, respectively, which have demonstrated antibiotic potential. However, there is a lack of research in the variety of Hericium and Hohenbuehelia species studied, and limited research on antibiotic potential of these compounds. This project will extract erinacines and pleurotin from their producing species and determine their antibiotic effects. Extracts will be tested to see if they can reduce the growth of clinically relevant Gram-negative and Gram-positive pathogens.

Tessa Fortnum: Determining the Migratory Patterns of North American Hoverflies (Diptera: Syrphidae) through Stable Isotope Analysis

Tessa Fortnum photo Supervisor: Dr. Keith Hobson

Hoverflies (Diptera: Syrphidae) are globally important pollinators and pest managers, yet their life history is largely unexamined. Stable isotope analysis (δ2H) of inert tissues can be used to approximate latitude of origin, and thus allow us to see if specimens are local to a collection site or migrants from different latitudes. I aim to determine the migratory patterns of six hoverfly species found in southern Ontario and investigate possible correlations between supercooling points, morphology (wing loading and body mass), and migration. In addition to determining migratory patterns, I seek to determine associations between hoverfly and floral species using iNaturalist observations and DNA metabarcoding of pollen. Migratory insects have the ability to move pollen long distances, increasing gene flow between plant populations and increasing genetic diversity; Understanding the floral associations of migratory hoverflies will expand our knowledge of the ecosystem services they provide.

January 19, 2024

Kevin Adeli: Thiamine concentration and heart morphology of alternative reproductive life histories in Chinook salmon (Oncorhynchus tshawytscha)

Kevin Adeli photo Supervisor: Dr. Bryan Neff

Chinook salmon (Oncorhynchus tshawytscha) are a focal point of stocking initiatives in the Laurentian Great Lakes largely due to their efficacy in controlling invasive populations of alewife (Alosa pseudoharengus). Male Chinook salmon have two alternative reproductive life histories that differ in their dietary niche. In Lake Ontario, the larger hooknose males occupy a more pelagic niche than precocial jack males, indicating that hooknose males likely consume more alewife. A challenge for Chinook salmon conservation in Lake Ontario is thiamine (vitamin B1) deficiency, which can arise from the consumption of alewife. Thiamine deficiency has a plethora of negative effects including recruitment failure and cardiovascular constraints. However, no research to date has investigated how the effects of thiamine deficiency may differ across alternative reproductive life histories of Chinook salmon. My project will compare thiamine concentrations between Chinook salmon alternative reproductive life histories with a focus on its potential cardiovascular effects.

Emelie Obi: Scaling down and doubling up: Downsizing and parthenogenesis as ecological responses to climate change in soil microarthropods

Emeli Obi photo Supervisor: Dr. Zoë Lindo

Global warming and other climate-related changes are anticipated to affect ecological communities with consequences for ecosystem function. For instance, increases in soil temperature and decreases in soil moisture – through increased evapotranspiration rates – are predicted to shift the structure and composition of soil biotic communities in ways that may enhance the release of soil carbon back to the atmosphere, especially in boreal peatland systems that are significant global carbon stores. Using both field and controlled lab experiments, I aim to determine if the reduction in community body size (community downsizing) and shift towards parthenogenetic species are responses of oribatid mites – one of the most abundant peatland biotic communities – to climate change. My research will also determine if the observed responses are driven by warming, drying or a combination of both factors.

January 12, 2024

Alexander Niski: Legacy effects of a long-term global change experiment on soil carbon and the soil microbiome

Alexander Niski photo Supervisor: Dr. Hugh Henry

Numerous field experiments have been conducted to examine the effects of global change factors like climate change and altered nutrient cycles on ecosystems, however most of them have been short-term projects (e.g., a decade or less). These shorter study periods often see clear changes in factors like plant composition, but changes in long-term carbon storage can take much longer to become evident. However, the Jasper Ridge Global Change Experiment (JRGCE) presents a unique opportunity to study these global change factors. The JRGCE exposed plots in a California annual grassland to elevated nitrogen, precipitation, carbon dioxide, and warming treatments for 20 years, a period long enough to have measurable impacts on soil carbon sequestration. My objective is to use the JRGCE to examine the legacy effects of global change on soil carbon quantity, quality, and the soil microbiome.

Amedeo Cortese:Fear as a management tool: Scaring predators with predators to protect shorebird nests

Amedeo Cortese photo Supervisor: Dr. Liana Zanette

Throughout Florida’s panhandle, nest predation by medium-sized carnivores has been identified as a main driver of population declines in four species of shorebird. Our goal is to assess whether fear of predators could deter medium-sized carnivores from entering shorebird nesting habitat thereby preventing predation on nests. First, we conducted a 3-month long field manipulation and found that in Florida medium-sized carnivores were up to six times more likely to flee after hearing human vocalizations compared to dogs and non-threatening control sounds. Having established that humans are most feared, speakers broadcasting human and control sounds were placed at pinch-points leading to shorebird nesting habitat. Incursions onto shorebird nesting habitat were documented and data on shorebird nest survival were simultaneously collected. Our results will determine if this ‘predator proof fence’ made entirely of sound is an effective management tool to be adopted for the protection of threatened prey species from their predators.

December 8, 2023

Eva Visscher: Establishing dietary niches and maternal investment in colonial waterbirds on the Laurentian Great Lakes using stable isotope (δ13C and δ15N) analysis of chick blood and temporal trends in egg volume

Eva Visscher photo Supervisor: Dr. Keith Hobson

The Laurentian Great Lakes face numerous threats such as increases in contaminant loads, invasive species, overfishing, loss of habitat, and climate change, which has led to changes in food webs and detrimental impacts on the health of many species. Stable isotope analyses (δ13C and δ15N) of consumer tissues and their prey provide a valuable tool to examine diet, relative trophic position, and the contribution of benthic vs. pelagic nutrients. Egg volume, indicative of energy content and maternal investment in each offspring, has important fitness implications and has been previously correlated with stable isotope dietary markers. This information can be used to better evaluate the effects of current and predicted environmental perturbations. My project will examine the sources of nutrients, trophic ecology, and egg volume trends of two colonial waterbirds, the double-crested cormorant (Nannopterum auritum) and ring-billed gull (Larus delawarensis), from data collected across the Great Lakes in 2022 and 2023.

Tian Yang:The role of root architecture in driving tradeoffs or shared benefits for nutrient acquisition, water acquisition and resistance to soil frost

Tian Yang photo Supervisor: Dr. Hugh Henry

Plants can modulate their root architecture to maximize soil water and nutrient capture in different environments. The two main root architecture categories, taproot and adventitious root systems, are characterized by contrasting patterns in root branching and distribution, which influence resource acquisition. For over-wintering plants, variation in root architecture can have important implications for frost exposure and sensitivity to frost. I will first examine the differences of these root architectures within Plantago lanceolata, a model tap-rooted species, in driving trade-offs or shared benefits for responses to nutrient limitation, water limitation and soil frost using a novel root injury technique that can produce an adventitious rooted phenotype. I will examine the responses of this species both alone in pots and in competition with other species in the field. Thereafter, I will extend the root injury technique and analyses to a greater range of species to expand the generality of my findings.

December 1, 2023

Sarah Santos: Genomic insights into the evolution of North American wild sheep (Ovis spp.)

Sarah Santos photo Supervisor: Dr. David Coltman

The sheer amount of whole-genome sequences (WGS) becoming available allows us to better understand the evolution of different wild species. Here, we sequenced high-quality long-read assemblies of three wild sheep (bighorn, Ovis canadensis; thinhorn: Dall, O. dalli dalli and Stone, O. d. stonei) and short-read sequences of sheep-like fossils. We analyzed the demographic history of extant bighorn and thinhorn individuals by mapping WGS to these high-quality assemblies. The demographic histories of Dall and Stone presented differences, and distinguishing between these subspecies is crucial as Stone also shares ancient hybridization patterns with bighorn. Moreover, we also mapped extant and extinct sheep WGS to the domestic sheep reference genome. We observed a striking result: a fossil from the Natural Trap Cave/USA presents similarities to both extant bighorn and thinhorn sheep. Our findings illustrate the power of WGS in detecting ancient genomic signatures and unravelling the evolutionary history of North American wild sheep.

Will Van Hemessen: Macrofungi of Norfolk County, Brant County, and Waterloo Region, Ontario

Will Van Hemessen photo Supervisor: Dr. Greg Thorn

The largest and most conspicuous fungi, the macrofungi, include many species of ecological and human significance because of their roles in nutrient cycling, mycorrhizal associations with plants, and medicinal and culinary values. Despite their global significance, relatively little is known about the biogeography and conservation needs of macrofungi compared to vascular plants and wildlife. This lack of knowledge is particularly striking in Ontario’s Carolinian Zone, which is one of the most biologically diverse and densely populated regions in Canada. To address this knowledge gap, Dr. Greg Thorn’s lab is undertaking a study of the systematics and biogeography of the Carolinian mushroom fungi (Agaricomycetes). My project focuses on the composition of the macrofungus communities of three municipalities in this region using a combination of historical collection data, field collections, and citizen science. The objectives are to prepare inventories of the macrofungi of each municipality and begin to assess their conservation needs.

Novemeber 24, 2023

Tommy Galfano: Genomic consequences of genetic rescue in a small, inbred population of bighorn sheep (Ovis canadensis)

Tommy Galfano photo Supervisor: Dr. David Coltman

Introducing outbred individuals into smaller, inbred populations, termed genetic rescue, is a commonly proposed method for alleviating populations of the stresses associated with inbreeding depression. An inbred population of bighorn sheep that was isolated for over 60 years underwent a series of three introductions aiming to relieve the population of inbreeding depression. These admixture events led to the development of a robust herd in good health with increased genetic diversity, relative to diversity measures before the translocations, as well as a 2-week shift in breeding dates. But, in 2016, an outbreak of Mycoplasma ovipneumoniae swept through the population, causing an 85% decrease in population size in less than one year. Despite good health and high levels of genetic diversity in this population, it experienced severe mortality from this outbreak. This project will investigate the long-term genomic effects of this genetic rescue, specifically on phenology and epizootic pneumonia survival.

Cailyn McKay: Heat stress experienced during metamorphosis: Impacts on subsequent pheromone-mediated mating in the true armyworm (Mythimna unipuncta)

Cailyn McKay photo Supervisor: Dr. Jeremy McNeil

The sedentary stages (i.e., egg and pupa) of insects may suffer more negative effects following heatwaves, and previously I showed that heat stress during pupal development reduces mating frequency in the true armyworm (Mythimna unipuncta). This suggests the pheromone-mediated communication system was affected. I compared the calling behaviour of females heat stressed during pupal development with controls but found no significant differences. I also compared the content of male hairpencils using gas chromatography and found that heat stress increased the average fluctuating asymmetry of male hairpencils. Future experiments will quantify female pheromone production, as well as the ability of the antennae of both sexes to detect conspecific pheromone using electroantennography. The findings will add to our understanding of the impacts of climate change on pheromone-mediated communication, which could have considerable importance with respect to the use of pheromone traps in pest management programs.

The Philosophicals:
As part of your degree, you are asked to give seminars on your research (this is the second part of Bio 9100y/9150y: Communications). Giving seminars is a good thing. The idea here is to get feedback from a wide range of people to help you along in your research, and to get you feeling comfortable with public speaking. The environment is friendly, thus this is the perfect place to practice that very important Proposal Assessment talk, or the talk you plan to give at an upcoming conference.

A brief outline of what is expected: 
MSc students give one 10-20 minute talk in the first year of their degree, and a 20 minute talk in their second year. PhD students give one 20 minute talk during the second year of their degree and then a 30 minute talk near the end of their degree. A ‘before’ and ‘after’, if you will.

When it is your turn to present: 
Please send an e-mail by 5 pm of the Friday prior to your talk. Your email should include:

1. Your name
2. Your supervisor's name
3. Degree being sought
4. The title of your talk
5. A single-spaced abstract of up to 150 words. 
6. One digital photo as a jpg file, for posting on the website.

Here is an example of a title and abstract for your seminar:

The identification of genes differentially expressed in sterile and reproductive honey bee workers (Apis mellifera)

A fundamental issue of sociobiology is to understand how social insect females regulate their individual reproduction to maximize inclusive fitness. In general, honey bee (Apis mellifera) workers remain sterile throughout their short lives, while they function as helpers to the queen, who is the sole egg-layer of the colony. The environmental cues controlling this behaviour are understood, but the underlying gene regulatory networks are not. In this study, we have manipulated the pheromonal cues that regulate reproduction and have analyzed the gene expression differences between sterile and reproductive workers using oligonucleotide microarrays. Preliminary analysis shows two distinct sets of co-regulated genes: one set associated with sterility, and a second set associated with egg-laying. I interpret these gene expression patterns in the context of social theory.

What to do before your talk:

Talks will be presented in Kresge Building 106. Please consult with the coordinator ( one week in advance to discuss some presentation tips.

A Brief History of Friday Philosophicals

by Paul Handford and Jack Millar

The origins of today’s Ecology-Evolution “Friday Philosophicals” stretch back at least to the early-mid 1970s; maybe there was something even before that, but nearly forty years is as far back as Jack Millar can remember.

Back then, there were two weekly Collip events, which have since become crunched into the one that now happens on Fridays. The Friday event (the “Philosophical”) was simply an end-of-week beer-in-the-fridge session; it originally took place in Collip 104 (since migrating to 208, then to 112 – where we also had a dart board!), with supply duties rotating weekly among the lab groups. Anyone wanting a beer and a chat on a Friday afternoon was welcome, and the custodians were among the regulars. Eventually, it had to become more secretive as the university tightened up its campus beer policy.

Then there were the “Wednesday-Niters”; these were sessions permitting the informal discussion of grad students’ research projects, and they took place in the homes of faculty, around the town. The grad-of-the-day arrived with notes, overheads, a stand-up screen and a two-four or two and made a presentation of their ideas, data, conclusions etc., as appropriate to their stage. The discussions were spirited and great fun, often lasting well into the night: presenters learned the rough & tumble business of presenting and defending their views on their feet, and the rest honed their thinking & questioning skills. All agreed they were a grand institution, and they formed a truly distinctive part of Western’s E&E group experience. On top of being an excellent tool in professional and intellectual development, they comprised a very important piece of the group's social furniture, generating great esprit de corps. But eventually, faculty retired and/or moved out of town until by the later 80s-early 90s we had only 2 locations for most of the winter, early fall and late spring sessions being held at out of town locations.

Eventually it was suggested that the two weekly events be merged. Thus was born the modern Friday Phils format: seminars plus weekly brews in a single Collip location starting off in Collip 208, since migrating to 112, where the last sessions took place in spring 2010. Our swelling graduate ranks have since forced a move from the Collip spaces, so Fall 2010 sees the Friday Phils take their next steps. Let’s hope that its future unrolling will continue to generate a fruitful and fun experience for all.