Western University BiologyWestern Science

Friday Philosophicals - Fall Semester 2017

Sean McElaney: Contrasting overwinter ecology of Swainson’s Thrush (Catharus ustulatus) in Andean forest and shade coffee plantations and Yanju Ma: Dietary Exposure to Methylmercury Affects Flight Endurance in a Migratory Songbird.

Sean McElaney: Contrasting overwinter ecology of Swainson’s Thrush (Catharus ustulatus) in Andean forest and shade coffee plantations
Yanju Ma: Dietary Exposure to Methylmercury Affects Flight Endurance in a Migratory Songbird

October 6, 2017

Sean McElaney: Contrasting overwinter ecology of Swainson’s Thrush (Catharus ustulatus) in Andean forest and shade coffee plantations

Sean McElaney photoSupervisor: Dr. Keith Hobson

Shade-grown coffee plantations provide wintering Neotropical migrants with an alternative to primary growth forest which has disappeared throughout most of their range. However, it remains unclear whether plantations can provide enough structure to maintain viable wintering populations of many species. We studied Swainson’s Thrush (Catharus ustulatus) wintering in two different sites in the Colombian Andes that consisted of a mixture of montane forest and shade-grown coffee plantation. In comparing the two habitats we looked at several factors that are indicative of habitat quality, such as age/sex hierarchies, and migration timing. We also used stable isotopes (δ13C and δ15N) to better understand dietary differences between habitats. My research aims to determine whether wintering Neotropical migrants benefit from this agroecosystem, and find ways to improve shade-grown coffee practices in the future.

Yanju Ma: Dietary Exposure to Methylmercury Affects Flight Endurance in a Migratory Songbird

Yanju Ma photoSupervisors: Dr. Chris Guglielmo and Dr. Brian Branfireun

Although there has been widely reported that methylmercury (MeHg) exposure can reduce bird fitness, little is known about its effects on migration. Migrating songbirds typically make multiple flights, refueling for short periods between flights. How refueling at MeHg contaminated stopover sites would contribute to MeHg bioaccumulation, and how such exposure could affect subsequent flight performance during migration has not been determined. In a dosing experiment we show that migratory warblers rapidly accumulate dietary MeHg in blood and internal tissues in just 1-2 weeks. And, in two-hour wind tunnel flights, warblers had a greater median number of strikes (landing or losing control), longer strike duration, and shorter flight duration. Also, the number of strikes in the first 30 minutes of exposed warblers was related to blood mercury concentration in a sigmoid, dose-dependent fashion with a threshold of 10.99 ppm. Hyperphagic migratory songbirds rapidly bioaccumulate MeHg, which can decrease endurance flight performance..

September 29, 2017

Devin Roberts: Assessing Predator Naïveté in Columbian Black-tailed Deer

Devin Roberts photoSupervisor: Dr. Liana Zanette

Where predators are lost, prey often become fearless (naïve), exacerbating their negative effects on lower trophic levels. In British Columbia’s Gulf Islands, all large carnivore predators have been extirpated, excepting domestic dogs, and Columbian black-tailed deer (Odocoileus hemionus) have become problematically overabundant in their absence, a problem occurring with deer populations across the globe. However, it is unknown whether these deer have become naïve to their lost predators. I have used an automated behavioural response system to conduct three playback experiments, assaying naïveté on multiple Gulf Islands by testing whether the deer recognize the auditory cues of cougars, wolves, bears, and humans as a threat. I also conducted a cafeteria-style experiment testing the deer’s recognition of olfactory predator cues. I hypothesize that the deer have become naïve to their extirpated predators.

Jordan Kustec: The effect of resource and environmental variability on Collembola community structure

Jordan Kustec photoSupervisor: Dr. Zoë Lindo

Soil food webs are integral, yet understudied components of Earth’s ecosystems. Within belowground systems, resources can vary widely across small spatial scales, which can lead to highly different communities within a common area. Changes in temperature, nutrient availability and predation can create an abundance, loss, or compositional difference of certain functional groups in soil systems. Within these belowground systems Collembola act as an important functional group by grazing on soil microbes, and being an abundant food source for soil predators. My research aims to characterize how predation pressure, resource addition and differentiation within soils affect Collembola community structure. This research will broaden understanding of how communities respond to resource shifts within soil systems.

Friday Philosophicals run every Friday in BGS 3000 in the fall term. Seminars are at 3:30pm - 4:30pm.

Speaker Schedule Fall Term 2017- Winter Term 2018

DATE FIRST SPEAKER SECOND SPEAKER
2017
Oct. 20 Biology Graduate Research Forum
Oct. 27 Dean Evans (E) Andrew Beauchamp (E)
Nov. 3 Renee Howard (E) Spencer Heuchan (E)
Nov. 10 Jackson Kusack (E) Veerta Singh (E)
Nov. 17 Joanna Konopka (E) Mathew Stefan (E)
Nov. 24 Nicole Zathey (E) Christian Therrien (E)
Dec. 1 Badru Mugerwa (E) Michael Dallosch (I)
2018
Jan. 12  Christopher Course (E) Tosha Kelly (E)
Jan. 19 Caitlyn Lyons (I) Kaelyn Bumelis (I)
Jan. 26 Andrew Chaulk (I) Christine Scharf (I)
Feb. 2 Garth Casbourn (I) Robert Martin (I)
Feb. 9 Olivia Colling (I) Aida Parvizi (I)
Feb. 16 Corrine Genier (I) Claire Bottini (I)
Mar. 2 William Laur (I) Lauren Witterick (I)
Mar. 9 Anna Chernyshova (I) Kevin Erratt (I)
Mar. 16 Jennifer Blythe (I) Alannah Mattice (I)
Mar. 23 Kyra Simone (I) Maryam Jangjoo (E)
Mar. 30  Good Friday
Apr. 6 Nicole Zathey (E) Jing Tian (E)
Babak Ataei Mehr (E, maybe)
I = Introductory Seminar, E = Exit Seminar