Western University BiologyWestern Science

Friday Philosophicals - Fall Semester 2017

Badru Mugerwa: Ecotourism and the ecology of fear in a premier African protected area and Michael Dallosch: Do algal blooms like it hot? A spatial-temporal analysis of the dependence of algal blooms on surface water temperature

Badru Mugerwa: Ecotourism and the ecology of fear in a premier African protected area
Michael Dallosch: Do algal blooms like it hot? A spatial-temporal analysis of the dependence of algal blooms on surface water temperature.

December 1, 2017

Badru Mugerwa: Ecotourism and the ecology of fear in a premier African protected area

Badru Mugerwa photoSupervisor: Dr. Liana Zanette

Protected areas protect wildlife for people from people. Uganda’s Bwindi Impenetrable National Park (Bwindi) protects wildlife for people by substituting gorilla ecotourism for destructive illegal hunting, often with dogs, which extirpated the park’s only apex predator leopard (Panthera pardus). However, ecotourism may be not benign if wildlife perceive ecotourists as predators. Using an automated camera and playback system, I tested if wildlife perceive ecotourists as predators by contrasting wildlife’s behavioural responses to playbacks of ecotourists and known predators (dog and leopard) and a non-threatening control (insect). Bwindi wildlife did not respond to ecotourists as predators which is good news for ecotourism. However, the aversive responses to dogs and leopards suggest that: 1) dogs have greater impacts than previously recognized because they are both lethal and frightening to wildlife, and 2) leopards played a significant role in this system, which may conceivably be restored by their re-introduction..

Michael Dallosch: Do algal blooms like it hot? A spatial-temporal analysis of the dependence of algal blooms on surface water temperature

Michael Dallosch photoSupervisor: Dr. Irena Creed

Climate change has been associated with an increase in the frequency and magnitude of harmful algal blooms. Contributing factors to enhanced algal growth may include increases in temperature, precipitation, and extreme events such as floods and droughts. My hypothesis is that rising temperatures are a major contributor to peak algal biomass increase in lakes from the tropics to the arctic. My research aims to identify the relationship between surface water temperature and chlorophyll-a, a proxy for algal biomass, in lakes along a temperature gradient ranging from the tropics to the arctic using satellite remote sensors. My research will improve the prediction of chlorophyll-a, and thereby help policy makers and environmental managers in planning and decision making related to algal blooms.

November 24, 2017

Joshua Isaacson: Katanin-60’s effect on female rejection of heterospecific males in Drosophila species

Joshua Isaacson photoSupervisor: Dr. Amanda Moehring

An organism’s ability to recognize and mate only with conspecific individuals is vital to maximize their reproductive success and offspring’s fitness. I will study the genetic basis of mate recognition and female rejection behaviours by using two Drosophila species, Drosophila simulans (sim) and Drosophila melanogaster (mel). I will determine if Katanin-60, a microtubule-severing protein, affects female rejection of heterospecifics. I will use the CRISPR/Cas9 system to produce hybrids that lack either the mel or sim allele to see if this results in mel-like or sim-like behavior. I will also use RNAi in conjunction with the UAS/Gal4 system to identify which brain regions contribute to female rejection behaviours. Understanding the genes affecting mate recognition and rejection would give us greater insight into how speciation occurs.

Christian Therrien: The effect of shelter availability on foraging behaviour in Atlantic salmon (Salmo salar)

Christian Therrien photoSupervisors: Drs. Yolanda Morbey and Bryan Neff

Throughout their lifetimes, juvenile Atlantic salmon (Salmo salar) are under constant threat from predators and have thus evolved several anti-predator behaviors, such as utilizing shelters. Despite shelter use being an important behavior against predation, how shelter availability influences the foraging behaviour of fish in the wild is not well documented. My research aims to examine how shelter availability affects the foraging behaviour of Atlantic salmon and to examine if there are population differences in this behavior. To address these knowledge gaps, I measured the feeding and activity of juvenile Atlantic salmon from two populations while they were held in net pens erected in a Lake Ontario tributary that differed in their level of shelter. Overall, the results suggest that high shelter availability is beneficial for Atlantic salmon, although the effect differed among populations. The availability of shelter was also shown to influence when salmon foraged.

November 17, 2017

Joanna Konopka: Trophic and competitive interaction among native and exotic egg parasitoids on invasive stink bug host

Joanna Konopka photoSupervisors: Drs. Jeremy McNeil and Tara Gariepy

Parasitoid wasps play an important ecological role in controlling population dynamics of other organisms, and have received particular attention because of their potential use as biological control agents. Biological control of BMSB ( Halyomorpha halys, brown marmorated stink bug), an invasive pest from East Asia of major concern in North America, using egg parasitoids is promising. However, the potential interaction of BMSB and native North American parasitoids is unknown. To elucidate this interaction, I am employing a combination of behavioural, molecular and imaging techniques to determine: 1) which parasitoids are associated with BMSB in Canada; 2) the native egg parasitoids’ ability to exploit BMSB as a host, and 3) the non-target effects of exotic parasitoids. Combined, the findings of my project can be extended to the implementation of informed biocontrol efforts of BMSB in Canada, through enhanced understanding of host-parasitoid interactions regarding the important factors for successful parasitization of BMSB eggs.

Mathew Stefan: Foraging habitats as a driver for divergent selection in pumpkinseed sunfish Lepomis gibbosus

Mathew Stefan photoSupervisor: Dr. Bryan Neff

Disruptive natural selection related to foraging tactics has been recognized as a key factor to the initial stages of species divergence within populations. Pumpkinseed sunfish (Lepomis gibbosus) provide an excellent study system for disruptive selection, as resource-mediated intraspecific competition has been shown to drive divergence between foraging ecomorphs (subset of individuals within populations that that have distinct ecological diet and morphological features). This variation in feeding ecology may lead the ecomorphs to be exposed to different parasites. In theory, variation in parasite communities in different foraging habitats may drive divergent selection on hosts and may promote speciation. I will use pumpkinseed sunfish to examine the role of parasites on MHC and test whether these differences in parasite communities have caused divergent MHC genotypes between pumpkinseed ecomorphs.

November 10, 2017

Jackson W. Kusack: The effect of agricultural intensity on the diet of Barn Swallow (Hirundo rustica) nestlings

Jackson W. Kusack photoSupervisor: Dr. Keith Hobson

In agricultural environments, declines in breeding bird and insect abundances have been related to increasing agriculturally intense practices (monocropping, pesticides, etc.). For an aerial insectivorous bird species, reducing insect availability can influence fitness through limitations on nestling diet, as nutrition during the nestling stage can affect success. To investigate the effect of agricultural intensity on the diet of nestling aerial insectivores, I sampled nestling Barn Swallows from colonies in southern Ontario. I assessed the effect of agricultural intensity on nestling diet using DNA barcoding of fecal sacs and stable isotopic analysis of feathers (δ13C, δ15N), and compared these measures to landscape composition surrounding breeding colonies. Nestling diet showed a significant landscape level effect as stable isotopic values were enriched with higher proportions of row crop. From these preliminary data it appears that there is a landscape level effect on nestling diet.

Veerta Singh: Growth and Toxicity of geographically-distinct isolates of the fish-killing phytoflagellate, Heterosigma akashiwo

Veerta Singh photoSupervisor: Dr. Charles Trick

Coastal waters throughout Canada and many regions of the world have experienced recurring threats of harmful algal blooms (HABs), often resulting in severe fish mortalities. Heterosigma akashiwo is a prominent marine species that episodically forms HABs. H. akashiwo is a microscopic alga of the class Raphidophyceae, aptly named for causing red tides in coastal waters. It has been indicted for extensive fish mortality and as such, results in major economic losses for commercial fishing and aquaculture industries. Management of H. akashiwo blooms is challenging as the cause of toxicity is unclear. My research aims to compare the growth and toxicity between strains of H. akashiwo, isolated from different geographic locations, under a suite of temperature and salinity regimes. This information will deepen our understanding of how different environmental pressures play a role in regulating the growth and toxicity of this species.

November 3, 2017

Renée Howard: Evaluating wetland restoration success by tracking recovery of plant functional traits

Renée Howard photoSupervisor: Dr. Irena Creed

Wetlands are at risk in many areas of North America due to changes in land use and intensification of human activities on the landscape. Restoration efforts have increased in response to recognition of the ecological role of wetlands for flood mitigation, water purification, and carbon sequestration. Vegetation diversity and community composition are typically used to assess restoration success; however, functional traits may be better indicators of wetland recovery. Our research aims to analyze plant functional traits (PFTs) to understand how ecosystem functions change with time since restoration. PFTs and functional diversity will be evaluated from field-based measurements combined with information from functional trait databases. Further, PFT analysis will be compared with traditional diversity metrics to better understand recovery following wetland restoration. It is anticipated that this research will help determine whether PFTs are effective indicators of wetland function and may help inform policy and wetland management efforts across the country.

Spencer Heuchan: Plant stimuli-responsive biodegradable polymers for the use in timed release fertilizer coatings

Spencer Heuchan photoSupervisors: Dr. Hugh Henry and Dr. Elizabeth Gillies

Asynchronies between fertilizer application and crop nutrient demand have led to over-fertilization and increased soil nitrogen leaching from agricultural fields. The use of stimuli-responsive polymers for the coating of fertilizers offers a more targeted delivery mechanism, which could increase nutrient use efficiency and reduce soil nutrient losses. However, despite reducing the amount of leaching many current controlled release degrade based upon environmental conditions. I have been working with a redefined class of triggerable biodegradable polymers (poly(ethyl glyoxylate)) that are designed to go through end-end depolymerization after the protective end cap on the polymer is cleaved off by a specific stimulus. I aim to develop a fertilizer coating that will degrade based on specific plant-root stimuli, which would allow for controlled and targeted release of fertilizer pellets.

October 27, 2017

Dean Evans: Adult and juvenile Bank Swallow (Riparia riparia) post-fledging movements and departure for autumn migration

Dean Evans photoSupervisor: Dr. Keith Hobson

Due to the difficulty of tracking birds once they leave the nest, the post-fledgling period is often the least understood part of the avian life cycle. Bank Swallows (Riparia riparia) are a threatened long distance neotropical migrant and little is known about their pre-migratory and migratory movements, especially in North America. Using the Motus Wildlife Tracking System we examined the post-fledging movements and autumn migration departure decisions of adult and juvenile Bank Swallows in southern Ontario, Canada. We show that juveniles, on average, travel greater distances (747.13 versus 255.91 kilometers) and depart later (15.81 days) than adults. The most common migratory departure routes across Lake Erie were observed to be from Long Point or Point Peele. These routes suggest birds try to minimize or eliminate large over water flights. This is the first study to examine the post-fledgling movements and departure choices of Bank Swallows in North America.

Andrew Beauchamp: Mechanisms underlying migration timing in the sexes and morphs of the White-throated Sparrow.

Andrew Beauchamp photoSupervisors: Dr. Christopher Guglielmo and Dr. Yolanda Morbey

Seasonal migration is common among North American bird species. Many of these species exhibit differential migration, where the spatial and temporal attributes of migration differ between groups of individuals within the same population. Migration speed, overwintering latitude, and migration initiation date may all play a role in differential migration, however, the contribution and relative importance of these behavioural mechanisms is still uncertain. We studied White-throated Sparrows (Zonotrichia albicolis) during spring migration to examine the behavioural mechanisms underlying migration timing. White-throated Sparrow exhibit a genetically linked behaviour and plumage dimorphism that allows for examination of the behavioural mechanisms underlying migration timing beyond males and females. In this talk, I will be focusing on my examination of stopover refuelling rate using plasma metabolite analysis, and the effect of refuelling rate on migratory stopover duration and migration speed.

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 (δ 13C and δ 15N) 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

Dec. 1 Badru Mugerwa (E) Michael Dallosch (I)
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) No second speaker
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