Friday Philosophicals

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Aaya Aboulnaga: The effect of species reintroduction on the genetic diversity of the mottled duskywing butterfly (Erynnis martialis)
Eileen Reinke:Utilizing cover crop mixtures to promote resilient soil health and potato yields
Pedro Conceicao: Post-glacial patterns of predatory mites across a peatland latitudinal-successional gradient

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 20 minutes in length, followed by up to 5 minutes of questions, answers and 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!


2022-2023 Organizer

Dr. Tim Hain

Schedule for 2022-2023

March 24, 2023

Aaya Aboulnaga: The effect of species reintroduction on the genetic diversity of the mottled duskywing butterfly (Erynnis martialis)

Aaya Aboulnaga photo Supervisor: Dr. Nusha Keyghobadi

When conserving a species, consideration should be given to protecting the underlying genetics, and not just the number of individuals. A project to reintroduce the mottled duskywing butterfly (Erynnis martialis) to a reconstruction of its former habitat is underway in southern Ontario, where individuals are captured from an extant population so that their offspring can be used to establish the new population at the release site. The limited starting size of the new population and the removal of individuals from the source makes both populations of this endangered species vulnerable to loss of genetic diversity, as they are susceptible to genetic drift, loss of evolutionary potential, and at risk of experiencing inbreeding depression. For my MSc, I will use microsatellites to monitor the genetic diversity of both populations over the course of the reintroduction program to see the effects of the translocation of individuals on the populations involved.

Eileen Reinke: Utilizing cover crop mixtures to promote resilient soil health and potato yields

Eileen Reinke photo Supervisors: Dr. Zoë Lindo and Dr. Cameron Wagg

Agricultural soils are depleted of biodiversity limiting the functioning of agroecosystems. Cover crop mixtures can benefit ecosystem services and subsequent cash crop yield; however, cover crop mixtures do not always provide such benefits, highlighting the need to understand the interactions of component plants in mixtures and the mechanisms related to increased cash crop yields. My proposed research will contribute to our understanding of interactions of plants in functionally diverse cover crop mixtures and the mechanisms that support the yield of a subsequent cash crop. My proposed research will also evaluate the potential of cover crop mixtures to restore the soil following intensive potato cash cropping with a focus on soil biota that drive agroecosystem functioning that are often neglected from soil health assessments. This knowledge will contribute to supporting ongoing research to make agricultural production systems more sustainable in Atlantic Canada.

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. My research will explore the structure of mesostigmatid mite communities in Sphagnum peatlands across a latitudinal-successional gradient in Ontario investigating the factors underlying their composition.

March 17, 2023

Katarina Kukolj: Investigating the effects of the Blewit mushroom Lepista nuda on the community composition of its soil environment

Katarina Kukolj photo Supervisor: Dr. Greg Thorn

I’m investigating the effects of the edible Blewit mushroom (Lepista nuda) on the community composition of its soil environment in coastal regions of Newfoundland, Canada. Previous studies on Blewits have discovered their antimicrobial properties in the lab, but there have been no field studies to observe how soil and the organisms in it could be changed by growth of Blewit mycelium in their natural environment. This study includes sampling soil at various time points from known natural Blewit patches and nearby treatment plots inoculated with Blewit mycelium, in comparison to plots without Blewits. Arthropod, nematode, bacterial and fungal members of the soil community will be identified and their relative abundance determined by DNA extraction and metabarcoding analyses. These results will tell us how Blewit mycelium changes soil communities and if potential crop pests/pathogens are significantly reduced, essential for understanding their potential in the agricultural industry as a biopesticide and co-crop.

Mehra Balsara: The response to hunter-induced selection on horn characteristics and coat colour in thinhorn sheep Ovis dalli

Mehra Balsara photo Supervisor: Dr. David Coltman

Selective harvesting through trophy hunting can have serious consequences towards the maintenance of genetically healthy populations. Often this hunting results in a reduction in size for 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 two phenotypic traits (horn growth and horn morphology) 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 created 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 10, 2023

Kiana Lee: The effects of warming on floral traits

Kiana Lee photo Supervisors: Dr. Danielle Way and Dr. Jeremy McNeil

Pollination is an essential ecosystem service that is necessary for the reproduction of flowering plants; however, climate warming could affect floral traits that are essential for pollination. My objective is to investigate how floral traits that are important for pollinator attraction change when cucumber plants are grown at ambient or ambient +4°C temperatures. To address this, I measured the size of UV floral guides (signals to pollinators that are only visible under UV wavelengths of light) using UV-visible photography. I also identified changes in the composition and concentration of floral flavonoids (compounds absorbing UV light). Finally, I correlated changes in key floral traits with flower development and plant growth. From this research I will be able to determine how warming can alter how pollinators are attracted to flowers and thus provide pollination services.

Jessica Stokes-Rees: Early-season cover crops prior to spinach planting provide co-benefits for the soil invertebrate community

Jessica Stokes-Rees photo Supervisors: Dr. Ian Scott and Dr. Hugh Henry

Cover crops are recognized as a best management practice in agriculture because they can reduce the need for tillage, herbicides, and fertilizer. Cover crops also can reduce soil erosion, protect soils from weed invasion and, when terminated, increase soil organic matter. The effect of tillage on soil invertebrate diversity and abundance is well documented; however, few studies have addressed how soil invertebrate diversity and abundance respond to cover crop use. My research has focused on differences in invertebrate abundance in response to different cover crop and tillage practices used for cool-season vegetable production. The abundance of earthworms, a keystone species of soil habitats, was significantly higher in plots with cover crops compared to plots that were tilled. Similarly, cover crops increased the abundance and diversity of arthropods. My results suggest that cover crops increase the abundance of beneficial soil organisms, which can contribute to increased resilience of agroecosystems.

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 cycles and storage as waterlogged, anoxic, acidic and low temperatures limit rates of decomposition by microbial communities. However, these conditions are predicted to change due to climate change, potentially altering decomposition processes such that peatlands become carbon sources. Microbial communities are particularly important for decomposition, and climate change will undoubtedly shift microbial biomass and composition. Measuring microbial biomass using PLFA analysis gives vague functional and taxonomic details and are not optimized for organic-rich soils. Using ambient and experimentally warmed plots, I will quantify differences in microbial biomass and community composition, using quantitative PCR (qPCR) and metabarcode sequencing respectively, and compare qPCR and PLFA to see if they are analogous measures of biomass. This will provide estimates for changes in microbial community composition and biomass and validate qPCR as a measure of microbial biomass in peatlands.

March 3, 2023

Samantha Hopkins: Experimental climate warming on Sphagnum traits and community composition in boreal peatlands

Samantha Hopkins photo Supervisor: Dr. Zoë Lindo

Boreal peatlands store carbon as partially decomposed plant matter (peat), with most plant inputs coming from the Bryophyte genus Sphagnum. Sphagnum are ecosystem engineers, altering the hydrology, chemistry, and topography of boreal peatland landscapes to foster their own growth. Within the Sphagnum genus, trait variation exists among species based on habitat preferences related to factors like temperature. As climate change continues to warm the boreal forest zone, community composition shifts in Sphagnum may occur as certain traits become a disadvantage under increasing temperatures. For my MSc, I will attempt to identify how temperature increases affect species traits and community composition under an experimental warming regime; to do this, I will conduct a growth experiment on three Sphagnum species with different habitat preferences and use community composition data in conjunction with Sphagnum traits from the literature to disentangle the mechanisms driving community shifts.

Melina Kuerschner: The Effects of Forest Fire Smoke on Migratory Bird Respiratory Physiology and Flight Performance

Melina Kuerschner photo Supervisors: Dr. Chris Guglielmo and Dr. Yolanda Morbey

For my PhD entry talk I will present the current plan for my thesis. I have decided to focus my project on the effects of forest fire smoke on migratory bird respiratory physiology and flight performance. Due to climate change, the incidence of wildfires has been rapidly increasing. This can have dire consequences for wildlife, many of which have not yet been studied or even discovered. My hypothesis is that birds exposed to airborne contaminants will exhibit reduced ventilatory capabilities and impeded flight exercise performance when compared with control birds. I will do this for both an acute and a chronic treatment, to simulate a polluted migration stopover site and a polluted breeding site, respectively. To evaluate the acute effects of poor air quality, I will study wild-caught yellow-rumped warblers and for the chronic effects I will use homing pigeons, as warblers do not breed well in captivity.

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

Rachel Rajsp photo Supervisor: Dr. Greg Thorn

American ginseng (Panax quinquefolius) is a perennial plant that has been used for centuries in herbal medicines. Due to the rise in demand of wild ginseng the species became classified as endangered while poaching has increased. Instead, field grown ginseng was used as an alternative cultivation method. In field, a disease arose in new ginseng crops that were planted in the same field that ginseng had been previously cultivated. This phenomenon is referred to as ginseng replant disease (GRD). GRD poses a threat to growers across North America as the field sites that contain uncultivated soil are limited. My project investigates alternative fungal identification methods using a modified DNA extraction protocol customized for sandy-loam soil, primers that provide better species resolution (full ITS and TEF region) and compare the mycobiome across several time points in ginseng cultivation and beyond harvest to be used as a potential diagnostic tool for growers.

February 17, 2023

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

Campbell McKay photo Supervisor: Dr. Jeremy McNeil

For many insects, the quality of the larval diet can have lasting effects that will impact adult mass, morphology, and timing. For their larval hostplant, the monarch butterfly (Danaus plexxipus) exclusively exploits milkweeds (Asclepias spp). While breeding generation diets are well studied, how these different species of milkweed prepare migratory generation monarchs for their flight to Mexico remains understudied. Last summer, I reared monarch butterflies on three local species of milkweed: common milkweed (Asclepias syriaca), swamp milkweed (Asclepias incarnata), and butterfly milkweed (Asclepias tuberosa). By directly measuring larval consumption on measured cuttings of leaves in parallel to monarchs reared directly on plants outdoors, I hoped to compare how adults reared on different diets differed in development time, mass, lipid mass, wing surface area, and wing loading, with a focus on how these traits may prepare them for migratory flight.

Scout Thompson: Random mating in the face of balancing selection at class I of the major histocompatibility complex (MHCI) in Song Sparrows (Melospiza melodia)

Scout Thompson photo Supervisor: Dr. Beth MacDougall-Shackleton

Sexual selection is a major catalyst driving the evolutionary trajectory of certain genes. The major histocompatibility complex (MHC), a set of genes providing the ability to detect pathogens, is no exception to this – with many species demonstrating non-random mating at these loci. In song sparrows, it was shown that birds tend to mate with genetically similar individuals at MHC class II (MHCII), the subset that detects extracellular pathogens. However, whether non-random mating occurs at class I (MHCI), which detect intracellular pathogens, was previously unknown. Despite my prediction that mate pairs would be more genetically dissimilar, due to the positive relationship between fitness and MHCI allele number, my work has instead shown a system of random mating. Curiously, I have also found balancing selection operating at these loci, suggesting that non-random mating would confer a fitness benefit but is not occurring - presumably due to an inability to detect MHCI genotype.

February 10, 2023

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

Cailyn McKay photo Supervisor: Dr. Jeremy McNeil

Insect body temperature is often managed by individuals moving to more suitable microhabitats, an option not possible for the sedentary egg and pupal stages. Consequently, these are at greater risk of heat stress during heatwaves. I used the true armyworm (Mythimna unipuncta) to examine the effects of short-term heat stress during several stages of pupal development on subsequent adult reproduction. Heat stress significantly reduced the number and fertility of eggs, especially when it occurred in early development. In part this was due to a reduction in mating frequency, suggesting that pheromone-mediated communication was affected. I will determine if pupal heat shock affects the production and detection of sex pheromones by both sexes, as well as female calling behaviour. The findings will not only add to our understanding potential impacts of climate change on pheromone mediated communication, but are of practical importance as pheromones are used in many pest management programmes.

Julien Koga: Improved production of erinacine A by North American Hericium species in submerged liquid culture fermentation

Julian Koga photo Supervisor: Dr. Greg Thorn

Hericium erinaceus is a choice edible mushroom that produces a variety of bioactive metabolites. Erinacines, produced in the mycelium, are capable of stimulating nerve growth factor (NGF) synthesis and are being considered as therapeutic treatments in diseases associated with NGF-deficiency such as Alzheimer’s and Parkinson’s Disease. However, there is a significant lack of understanding of the production of erinacines in other species of Hericium, four of which occur in North America. This project will evaluate the production of erinacines by wild-harvested North American Hericium species in submerged liquid culture fermentation and aim to optimize their culture conditions for improved yields of erinacine A and mycelial biomass.

Justin To: Love is in the oil, and it reeks of immunity

Justin To photo Supervisor: Dr. Beth MacDougall-Shackleton

Sexual selection reinforces parasite-mediated natural selection, maintaining genetic diversity in host populations. This was described in the Major Histocompatibility Complex (MHC) immune gene family; and now in the Toll-Like Receptors (TLR) gene family. Individuals can assess variation in MHC through olfaction, this was first described in mammals and more recently in birds. Bird preen oil is the major source of avian body odour, and in song sparrows it was shown to covary with MHC profiles and birds can detect these differences. Recently, non-random mating was observed in TLR genes in song sparrows (Melospiza melodia). Alongside this TLR genes interact with preen gland microbial communities, these factors suggest TLR may also be communicated to conspecifics through preen oil odour. I will be testing this relationship using pairwise matrices of Bray-Curtis dissimilarity to determine if TLR gene variation at 2 different loci correspond with preen oil chemical composition.

February 3, 2023

Ryan Conklin: Slow and steady or fast and productive? The association of migration distance on pace of life in song sparrows

Ryan Conklin photo Supervisor: Dr. Beth MacDougall-Shackleton

Pace of life syndrome is an extension of life history theory that focuses on how trade-offs between reproduction and survival are affected by ecological pressures. Migration is one such pressure and in many species of birds, individuals are known to migrate distinct differences relative to conspecifics. Despite pace of life likely having an association with migration distance, as a consequence of short and long-distance migration having differences in both time and energy expenditure and overwintering conditions, such associations remain poorly understood at the individual level. I will be using a combination of overwinter survival rates and deuterium values collected from claw tissue, a proxy for migration distance, to elucidate individual differences between migration distance and its association with pace of life in a population of song sparrows (Melospiza melodia) in southern Ontario. Initial data analysis indicates individuals do migrate distinct distances and have differing survival rates.

Sophie Killam: The potential for gut microbes to affect honey bee hygienic behaviour

Sophie Killam photo Supervisor: Dr. Graham Thompson

Hygiene is a social behaviour of honey bees that protects the hive against pathogens and parasites: hygienic bees detect dead or diseased brood via olfactory cues and remove them to prevent the spread of infection within the colony. Lowering the response threshold at which nurse bees detect infection would effectively increase hygiene, thereby improving colony health. One mechanism to potentially manipulate the hygienic threshold is the brain-gut axis – a proposed bi-directional pathway that links an organism’s gut to its nervous system, brain, and behaviour. For my MSc, I will use a field experiment to manipulate the gut microbiota of whole living colonies then measure any effect on hygiene. I will also test for brain-gut axis effects on the gut and brain directly by sequencing gut microbe composition and imaging bee brains.

January 27, 2023

Ala Abdel Rahman: Combined use of cover crops and the entomopathogenic fungus Metarhizium brunneum to manage wireworm

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

Wireworms, the larval stage of click beetles (Coleoptera: Elateridae), is a major pest of potatoes and other horticultural and field crops globally. Agricultural practices that promote resilience include the use of cover crops in the rotation since they are effective at suppressing soil pests and disease, retaining soil moisture and nutrients, and contribute to overall soil health. Cover crops plants that release allelochemicals or act as fumigants can reduce the wireworm population. A new biopesticide developed from Metarhizium brunneum an entomopathogenic fungus of wireworms, also shows promise, potentially in combination with insecticides and cover crops.

Trevor Pettit: Carbon flux in soil food webs depends on warming and hydrological changes to boreal peatlands

Trevor Pettit photo Supervisor: Dr. Zoë Lindo

Boreal peatlands play an important role in terrestrial carbon (C) storage. At northern latitudes, soil temperature and moisture conditions under climate change are predicted to become more extreme and more variable. Temperature and hydrology play an important role in regulating decomposition and ecosystem functioning, like C sequestration, in boreal peatlands. The objective of my MSc research is to quantify and model the effects of experimentally imposed temperature and moisture conditions that simulate potential future climate, on peatland soil food webs and soil C fluxes. Preliminary results suggest that increases in temperature may drive increases in total C fluxes and C mineralization, while increases in soil moisture may drive decreases in total C fluxes and C mineralization.

January 20, 2023

Andrew Beauchamp: Migration physiology and behaviour: understanding the interaction between individual and environment

Andrew Beauchamp photo Supervisor: Drs. Chris Guglielmo and Yolanda Morbey

Understanding the linkages between environmental variability, physiology, and movement behaviour is vital for assessing how migratory birds use habitat. Measuring these aspects in free-living songbirds is challenging, leaving critical gaps in our knowledge of how the environment shapes migratory songbird ecology. My PhD research fills these gaps by combining physiological profiling and habitat assessments with advanced radio telemetry and radar technologies to explore how the environment shapes songbird refuelling and migratory movement behaviour. My first data chapter explores how the rate of refuelling and migratory stopover duration are influenced by the interaction between individual characteristics and environmental variability. My second data chapter builds on this though experimental manipulation of food availability. Finally, my third data chapter combines radar and acoustic monitoring to examine how social cues encountered by migrants shape departure timing. Preliminary results suggest that age differences in refuelling can be moderated by resource abundance, but departure from stopover is governed primarily by wind conditions.

Shyanika Nissanka:Investigating the origins, evolution, and function of a reverse transcriptase-like gene (rtl) in the mitochondrial genomes of volvocalean green algae

Shyanika Nissanka photo Supervisor: Dr. David Smith

Volvocines are a fascinating group of algae, which includes the model organism Chlamydomonas reinhardtii. The mitochondrial genome of C. reinhardtii is an intriguing 16 kb linear molecule with few protein-coding genes, overhanging telomeres, and a free-standing ORF that codes for a protein that is similar to reverse transcriptase (the rtl gene). The function of rtl is unclear, however, replication of the linear mtgenome is thought to be one of its functions. My research focuses on the diversity of rtl within the Volvocales group as well as the relationship between rtl and mtgenome conformation (i.e., circular vs. linear). My key dataset includes newly assembled transcriptomes from 55 diverse species/strains of volvocalean algae. They were assessed using a BLAST-based approach. Each transcriptome was converted into a custom BLAST database and was queried using known rtl sequences using nucleotide-to-nucleotide (blastn) and amino-acid-to-amino-acid (tblastx) searches. Extracted rtl sequences were used for furthermore analysis.

January 13, 2023

Emma Churchman: What makes a good dad? Linking the effect of perceived paternity on sunfish behaviour and hormones

Emma Churchman photo Supervisor: Dr. Bryan Neff

Parental care is critical for the survival of many young animals. However, parental care is costly to the individual providing care. To balance this cost, parents will allocate their care to offspring they deem valuable, which is often dependent on if the offspring being related to them. Bluegill (Lepomis macrochirus) are a fish species characterized by uniparental care and high levels of cuckoldry. While this species has been shown to adaptively adjust their care in response to paternity level, the mechanisms for this adjustment are not well understood. Hormones like 11-ketotestosterone and prolactin are associated with parental care behaviours, and have been linked to parental care in many species, including bluegill. In my research, I test the theory that these hormones mediate the adjustment in care provided by bluegill parental males by providing indirect visual cues of nest intrusion or direct paternity manipulation.

December 9, 2022

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. 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. This study will utilize in-situ monitoring of floodplain wetlands to determine if these areas function as ‘hot spots’ of mercury methylation. Further to the field study, laboratory work will examine whether the discharge from the still-operating mill site which previously discharged mercury is still influencing mercury methylation. We will use columns to expose contaminated sediments from the river to the current effluent of the mill to determine if this stimulates mercury methylation.

Samuel Rycroft:Freezing tolerance of herbaceous legumes in the northern temperate zone: evidence for a disproportionate freezing sensitivity?

Samuel Rycroft photo Supervisor: Dr. Hugh Henry

In northern temperate regions, the effects of freezing stress from late fall into early spring can vary substantially among herbaceous (i.e., non-woody) plant species. Anecdotal evidence suggests herbaceous legumes (family: Fabaceae) are more freeze-sensitive than other herbaceous functional groups. As legumes can increase soil nitrogen inputs through symbioses with rhizobia, this may have important implications for ecosystem nitrogen cycling in a changing climate. Though previous investigations have studied the effects of freezing on specific legume species, comparative studies on a variety of leguminous vs. non-leguminous species have been lacking. I have been using a combination of controlled environment (freezing treatments within controlled chambers) and field experiments (increased freezing via snow removal) to investigate the impacts of freezing stress on herbaceous legumes relative to other herbaceous species. Thus far, significant impacts on percent cover, abundance, and biomass have been shown for some of the legumes studied.

December 2, 2022

Anna Chernyshova: The brain-gut axis of honey bees: testing how microbiota affect individual and collective behavior

Anna Chernyshova photo Supervisor: Dr. Graham Thompson

The holobiont theory of evolution depicts individuals as deeply symbiotic with its gut microbes, which influence host behaviour via signalling from the gut to the brain. This gut-brain axis takes on added complexity for social taxa since individual behaviour scales-up to affect entire colonies. I use the Western honey bee to study how gut microbiota composition of individuals influences collective behaviour. Specifically, I measure how antibiotic depletion or probiotic enrichment of worker gut fauna affect a bee's defensive and foraging behaviours. I have so far observed changes in defensive colony-wide behaviour but need to test if these changes are due specifically to gut microbes and their brain-influencing metabolites. I am therefore validating my field trials via 16S rRNA bacterial gene amplicon sequencing and histochemical staining of individual bee brains. My findings advance the brain-gut axis framework from its current focus on individuals into the realm of higher-order social interactions.

Jackson Kusack: Assignment of harvested waterfowl using stable isotopes

Jackson Kusack photo Supervisor: Dr. Keith Hobson

To avoid overexploitation of waterfowl populations, harvest strategies must incorporate accurate information on connectivity between breeding and harvest areas, which necessitates efficient assignment of origin for harvested individuals. Current estimates of breeding metrics rely on wing samples and band returns which are assumed to be representative of a continuous breeding population, but this is unlikely accurate for some species. Stable hydrogen isotopes (δ2H) are naturally occurring intrinsic markers that can be used to infer geographic origin on a continental scale without the need for initial marking. The objective of my thesis was to utilize stable isotopes within feathers to determine probabilistic origin of harvested waterfowl and evaluate current knowledge on connectivity. Specifically, my objectives were to (1) evaluate current calibration relationships for waterfowl, (2) compare harvest derivations using band-return data and stable isotopes, and (3) test the flyover hypothesis in a species of conservation concern, the American Black Duck. Results from this integrative approach will be useful to evaluate and improve conservation efforts for waterfowl populations.

November 25, 2022

Bruce Malloch: Exploring a possible mutualism between crust fungi and microarthropods in Canada's Atlantic perhumid forest

Bruce Malloch photo Supervisor: Dr. Greg Thorn

Soil systems contain vast repositories of the earth’s biodiversity, but many of the interactions that occur between soil organisms remain understudied. This study aims to resolve relationships between soil arthropods and crust fungi, which may represent a mutualistic system where fungi utilize arthropods for spore dispersal in exchange for nutrition. Through network theory, arthropod visitation patterns to fungal fruiting bodies can be used to determine if the system is primarily structured by mutualistic interactions or antagonistic ones. Morphological trait data will be used to supplement interaction patterns by determining if certain species interactions are promoted or limited by compatible trait matches. Finally, metabarcoding of arthropod gut contents will help resolve long standing questions surrounding dietary specialization in hyperdiverse lineages of soil fauna such as the mites. Overall, this study will provide an in-depth first look into the interactions between two highly biodiverse groups of soil organisms.

Paul Wan: Changes in the microbiome during ginseng cultivation

Paul Wan photo Supervisor: Dr. Vera Tai

American ginseng, Panax quinquefolius, is a root-crop used for traditional medicine in Asia. The cultivation of ginseng is inhibited by ginseng replant disease (GRD), a condition that decreases ginseng crop health and yield when planted in a former ginseng garden. Fungal and oomycete pathogens are problematic, however the role of the soil bacterial microbiome in causing GRD is not fully understood. Using metabarcoding, I investigated changes to the soil microbiome over three years of ginseng growth to better understand which members of the bacterial microbial community might contribute to GRD. My findings show that microbial communities differed between ginseng gardens, but more importantly that growing ginseng caused a shift in the soil microbiome compared to control sites. Moreover, the microbial communities changed consistently over the three years of ginseng growth. By identifying the specific microbes that contribute to this consistent change, diagnostic tools can be created to assess soil health by Ontario ginseng farmers.

November 18, 2022

Alica Banwell: At the root of it: The introduction of nursery seedlings and their fungi to conifer forests

Alica Banwell photo Supervisor: Dr. Greg Thorn

Ectomycorrhizal (ECM) fungi are commonly found on tree roots in natural forest stands and are of importance in Canada for their role in supporting boreal tree species and for their production of edible mushrooms such as chanterelles (Cantharellus). In addition to being found on trees in natural forest stands, ECM fungi are also found on tree seedlings growing in nurseries for the purpose of reforestation. Little is known about the effect that ECM fungi established on nursery seedlings have on natural forest stand ECM fungi once the seedlings are planted. My project will investigate whether nursery established ECM fungi continue to persist on seedlings once planted in forests, or if existing ECM fungi in forests form associations with seedlings. This knowledge can be used to inform current reforestation practices in Canada and potentially lead to research to improve these practices by protecting existing, ecologically important ECM fungi in our forests.

November 11, 2022

Holly Deighton: Drivers of soil carbon dynamics in the boreal forest along a soil textural gradient

Holly Deighton photo Supervisor: Dr. Zoe Lindo

The boreal forest has historically been regarded as one of the largest terrestrial carbon (C) sinks. However, increased soil organic matter decomposition (SOM) by microbes due to climate change and silviculture (e.g., harvesting and site preparation) may shift boreal forests from being C sinks to C sources. This research seeks to understand the drivers of SOM decomposition, formation, and stabilization in managed boreal forests, specifically looking at both abiotic and biotic processes that regulate microbial carbon use efficiency (CUE). I will use an established stand-scale, full-replicated, experimental study to identify how silviculture influences C dynamics at three boreal forest sites varying in soil texture in Ontario, Canada. I will use an extensive database of forest floor and mineral soils data to determine how silviculture influences soil C stocks and C storage potential. I will also examine how C is utilized by microbes by sampling mineral soils 20 years post-silviculture treatment. Under controlled conditions, I will identify how microbial CUE changes with various warming scenarios. This research will improve microbial-biogeochemical models by providing accurate estimates of CUE to predict how soil texture and silviculture impact microbial activities such as SOM decomposition and, ultimately, the stabilization of C in the boreal forest.

Speaker Schedule for Friday Philosophical Talks 2022-2023
DATE First Speaker Title Second Speaker Title Third Speaker Title
24-Mar-23 Aaya Aboulnaga TBA Eileen Reinke TBA Pedro Conceicao TBA
31-Mar-23 Sarah Dias dos Santos TBA Richard Nguyen TBA Makayla Lloyd TBA

About the seminars

Instructions for Graduate Students

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.