Friday Philosophicals

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Anna Chernyshova: The brain-gut axis of honey bees: testing how microbiota affect individual and collective behavior
Jackson Kusack: Assignment of harvested waterfowl using stable isotopes

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

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
9-Dec-22 Eric Grimm TBA Sam Rycroft TBA
13-Jan-23 Emma Churchman TBA Ala Abdel Rahman TBA
20-Jan-23 Andrew Beauchamp TBA Shyanika Nissanka Pedi Duraylage TBA
27-Jan-23 Rachel Rajsp TBA Trevor Pettit TBA
3-Feb-23 Ryan Conklin TBA Sophie Killam TBA
10-Feb-23 Cailyn McKay TBA Julien Koja TBA Justin To TBA
17-Feb-23 Campbell McKay TBA Scout Thompson TBA
24-Feb-23 Reading Week
3-Mar-23 Cristina Turcu TBA Samantha Hopkins TBA Melina Keurschner TBA
10-Mar-23 Kiana Lee TBA Jessica Stokes-Rees TBA
17-Mar-23 Katarina Kukolj TBA Mehra Balsara TBA
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 thain@uwo.ca 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 (thain@uwo.ca) 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.