Western University BiologyWestern Science

Archived Friday Philosophicals Abstracts - Fall Semester 2012

December 7, 2012

Yani Adamson: Local adaptation in song sparrows

Yani Adamson Philosophical

Supervisor: Dr. Beth Macdougall-Shackleton
Degree: Ph.D. Candidate

The local adaptation hypothesis predicts that subpopulations are better adapted to their local environment than to other environments. In the context of a songbird host-bloodborne parasite system, I hypothesized that host individuals remaining to breed close to where they were born should be better able to defend against the local parasites, relative to hosts immigrating from other populations. To test this, I captured song sparrows from different locations around Eastern Ontario. I used genetic assignment tests to estimate the degree to which individuals breeding in a location were of local origin (“assignment index”), and also assessed blood-borne parasite load. My results support the local adaptation hypothesis and suggest an important role for parasites in restricting host dispersal.

November 30, 2012

Danielle Griffith: Changes in biological nitrogen fixation by cyanobacteria in response to altered environmental conditions

Danielle Griffith Philosophical

Supervisor: Dr. Zoë Lindo
Degree: M.Sc. Candidate

The use of natural model systems, such as the bryosphere, are critical in predicting the response of ecosystem C- and N-budgets to global environmental change. Within the bryosphere, the symbiotic association between cyanobacteria and mosses is known to fix atmospheric nitrogen (N) and supplement ecosystems with bio-available N. However, the impact of global change factors including temperature, N-addition, and CO 2 on the N-fixation process—biological nitrogen fixation (BNF)—remains largely unstudied. The present research explores the response of BNF by the cyanobacterium Nostoc punctiforme to global change factors in laboratory, greenhouse, and field settings. By using a multi-setting approach with a full factorial experimental design, the study aims to predict how environmental changes interact to alter N dynamics within terrestrial ecosystems.

Rajesh Kumar Gupta: Genome Profiling of the Two Strains of Green Alga Chlamydomonas raudensis

Rajesh Kumar Gupta

Supervisors: Dr. Norman Hüner and Dr. Denis Maxwell
Degree: M.Sc. Candidate

Previous studies from the Maxwell/Hüner group has shown that based on Internal Transcribed Spacer sequencing a previously unknown green alga isolated from Antarctica is in fact a strain of Chlamydomonas raudensis. However, unlike the type strain of C. raudensis (SAG 49.72), the Antarctic strain (UWO241) is psychrophilic - that is it has an optimum growth temperature below 15ºC and dies above 20ºC. So, although these two strains are the same species, their growth habit is very different. For my specific project, I have employed a RAPD based approach for genome characterization of these two strains of C. raudensis. In this study I have employed different 13 nucleotide long random primers for genome wide polymorphism survey of UWO & SAG along with 3 closely related strains of Chlamydomonas reinhardtii to see the extent of genomic variation between UWO & SAG in comparison to the model alga C. reinhardtii strains.

November 23, 2012

Scott Colborne: You are what you eat: foraging ecology, sexual selection, invasive species, and sympatric speciation in bluegill (Lepomis macrochirus) and pumpkinseed sunfish (Lepomis gibbosus)

Scott Colborne Philosophical

Supervisor: Dr. Bryan Neff
Degree: Ph.D. Candidate

Understanding the resource use of individuals provides insight not only into food web structure, but also other ecological and evolutionary processes. Using stable isotopes of carbon and nitrogen as a tool to examine resource use my research has covered three main projects. First, resource use and morphology of alternative reproductive tactics of bluegill sunfish (Lepomis macrochirus) was examined to test potential trade-offs between natural and sexual selection. Second, I examined the resource use of pumpkinseed sunfish (Lepomis gibbosus) in freshwater lakes following the invasion of zebra mussels. Finally, the role of resource polymorphisms within populations as a factor in speciation was tested by examining both diet and assortative mating using stable isotopes. The goal of my research is to provide insight into the important roles foraging ecology plays in natural populations.

David Swan

Supervisor: Dr. Liana Zanette
Degree: Ph.D. Candidate

November 16, 2012

Timothy J. A. Hain: The ecology and evolution of kin recognition

Timothy Hain Philosophical

Supervisor: Dr. Bryan Neff
Degree: Ph.D. Candidate

Since Hamilton formally described kin selection theory, biologists have been interested in how animals can recognize their kin. Indeed, over 250 species have been shown to discriminate kin from non-kin. However, the way that an animal’s ecology influences the evolution of its kin recognition mechanism has been largely ignored. In my thesis, I used two species of teleost fish, bluegill (Lepomis macrochirus) and guppies (Poecilia reticulata), to investigate the influence of mating system on the evolution of kin recognition. In both species, the level of promiscuity reliably predicts the recognition mechanism used, revealing the importance of an animal’s ecology on the evolution of kin recognition.

Katie Marshall: The four axes of stress: how intensity, duration, frequency, and period of low temperature exposures interact and impact physiology and fitness in insects

Katie Marshall Philosophical

Supervisor: Dr. Brent Sinclair
Degree: Ph.D. Candidate

Environmental stress interacts with the physiology of individuals to determine an individual’s fitness. While environmental stress is generally characterized by both intensity and duration of that stress, recent work has shown that both physiology and fitness can also be impacted by frequency and period between stress exposures. I used cold tolerance in four different species of Canadian insects with contrasting cold tolerance strategies (the goldenrod gall fly, the eastern spruce budworm, the woolly bear caterpillar, and the fruit fly Drosophila melanogaster) to explore how intensity, duration, frequency, and period of stress all impact and interact in their impacts individual physiology and fitness. I found that in most species, increased frequency of stress tends to reduce fitness even when duration and intensity are controlled.

November 9, 2012

Muna Basahi: Development of common scab suppressive soils using strains from the genus Pseudomonas

Muna Basahi Philosophical

Supervisor: Dr. George Lazarovits
Co-supervisor: Dr. Greg Thorn
Degree: M.Sc. Candidate

Common scab affects potato crops worldwide leading to high economic losses. In 2002 an estimate of $15.3 to $17.3 million is lost due to common scab in Canada. Soils that are suppressive to common scab have been described. In these soils disease does not develop even though inoculum of the pathogen is present. Adding suppressive soils to soils where disease is prevalent negates disease from occurring and this soil also becomes disease suppressive. The most widely studied agents associated with suppressive soils are members of the Pseudomonas fluorescens group and they have not yet been tested for their impact on the scab pathogen. In this study I intend to investigate the use of strain(s) from the genus Pseudomonas in developing suppressive soils to common scab.

Nico Muñoz: Evolutionary potential of thermal tolerance within a population of Chinook salmon

Nico Muñoz Philosophical

Supervisor: Dr. Bryan D. Neff
Degree: M.Sc. Candidate

Evaluating the evolutionary potential of species to adapt to warming temperatures is critical for understanding the biological impacts of climate change. For aquatic ectotherms, such adaptive responses will likely involve adjustments of their optimum temperature (Topt) and their upper critical temperature (Tcrit. We used a quantitative genetic breeding design to evaluate the genetic architecture underlying Topt and Tcrit within a population of Chinook salmon (Oncorhynchus tshawytscha). Additive genetic, non-additive genetic, and maternal effects explained 32%, 19%, and 0% of the phenotypic variance in Topt, respectively, while these effects explained 17%, 0%, and 5% of the variance in Tcrit. These results suggest that adaptation from standing genetic variation for both Topt and Tcrit may be possible in this population as an evolutionary response to changing temperatures.

November 2, 2012

Jace McLaughlin: Bioassays as tools for improved algal bloom screening

Jace McLaughlin Philosophical

Supervisors: Dr. Irena Creed and Dr. Charles Trick
Degree: M.Sc. Candidate

The RTgill-W1 cell line and erythrocyte lysis assays were studied and manipulated in an attempt to develop fast, reliable, low volume, and high throughput screening methods of toxic and noxious freshwater algal compounds. Through the use of various analytical standards and extracts from freshwater cyanobacteria and chrysophyte cultures, both bioassays have been evaluated in terms of their sensitivity to the toxic and noxious compounds commonly produced in Ontario lakes. A number of these compounds have been determined to be appropriate for detection by the bioassays, suggesting that these assays may be appropriate for wide scale use. Successful adaptation of these assay methods will improve the screening efficiency and capacity for investigators of water quality and bloom dynamics.

Lena Vanden Elsen: Factors influencing autumn-winter migration in dabbling ducks in Atlantic, Mississippi and Central Flyways

Lena Vanden Elsen Philosophy

Supervisor: Dr. Scott Petrie
Co-supervisor: Dr. Christopher Guglielmo
Degree: M.Sc. Candidate

Severity of weather necessary to cause southern migration by waterfowl may differ among species. Some species of duck may migrate independently of weather severity, where migration results from endogenous rhythms related to photoperiod. A Weather Severity Index (WSI) was developed for mallards (Anas platyrhynchos; Schummer et al. 2010) and used temperature and snow cover data to explain change in relative abundance of mallards at mid-latitude staging areas during autumn-winter. I aim to investigate the relative contribution of weather and photoperiod cues for other species of dabbling ducks using data from standardized waterfowl surveys conducted throughout eastern North America, September – February. Developed WSIs for each species of duck will be modeled with future climate change scenarios to determine how duck distributions may vary with climate change.

October 26, 2012

Magda Konopka: Impacts of selected veterinary drugs on soil communities

Magda Konopka Philosophical

Supervisor: Dr. Edward Topp
Co-supervisor: Dr. Hugh Henry
Degree: M.Sc. Candidate

The veterinary drugs (antibiotics and antiparasitics) are fed to or injected into livestock animals to increase their growth, prevent outbreaks of disease and treat sick animals in the herd. These compounds and their metabolites are then excreted and are released to the environment through manure application. Once released, they can influence whole soil communities. I will investigate the changes in soil communities due to three drugs, comparing mixture effect vs. single drug effect, two concentrations (high and low dose), and several time points (acute effect, recovery, chronic effect). I will sample the soil in treated microplots and determine the rates of nitrogen transformation: degradation of organic matter, mineralization and nitrification rates; and use molecular techniques to determine abundance of organisms responsible for these processes.

Katelyn Weaver: Habitat selection during the nonbreeding period by Eastern Population Tundra Swans (Cygnus columbianus columbianus)

Katelyn Weaver Philosophical

Supervisor: Dr. Scott Petrie
Co-Supervisor: Dr. Hugh Henry
Degree: M.Sc. Candidate

Around 1970, wetland loss and conversion to agriculture necessitated Eastern Population Tundra Swans (TUSWS) to incorporate waste agricultural grains into their diets in addition to traditional foods. Identifying how TUSWs select wetland and terrestrial habitats in altered landscapes is essential to assess TUSWs’ biological requirements, predict effects of habitat change, test hypotheses underlying ecological processes and enable conservation strategies to ensure adequate foraging habitats are available for swans. I will use satellite telemetry data from 55 Eastern Population TUSWs to investigate seasonal selection of agricultural and wetland habitats during the nonbreeding period. My objective is to determine if habitat selection differs seasonally at the Atlantic Coast, Great Lakes, Prairies, and Northern Boreal Forest and how nutritional requirements, food availability and habitat accessibility influences habitat use..

October 19, 2012

John O’Leary: Population genetic structure in the flesh fly, Fletcherimyia fletcheri, a commensal inhabitant of the northern purple pitcher plant, Sarracenia purpurea

John O'Leary Philosophical

Supervisor: Dr. Nusha Keyghobadi
Degree: M.Sc. Candidate

Communities that occupy container-like habitats, such as the northern purple pitcher plant, are ideal for research on metapopulation and meta-community structure due to co-occurrence of multiple species within spatially well defined habitat patches. The northern purple pitcher plant, Sarracenia purpurea, is the exclusive larval habitat for the flesh fly, Fletcherimyia fletcheri. This study intends to examine the effects of broad scale landscape configurations and composition on the genetic community structure of flesh flies in habitat patches across Algonquin Provincial Park. Through the use of spatially oriented genetic samples we hope to develop a viable system model that will be able to predict rates of gene flow between regions based on least cost pathway analyses of the landscape composition across 15 locations across the park.

Matthew Emrich: Ensemble Structure of Sympatric Insectivorous Bats

Matthew Emrich Philosophical

Supervisor: Dr. Brock Fenton
Degree: M.Sc. Candidate

Bat communities consist of many species with similar diets. A competitive view of niches suggests that bats partition available resources. I placed two microphone arrays in cluttered, edge and open habitats and recorded continuously from sunset to sunrise in the vicinity of Windsor Cave in Jamaica. From these recordings I reconstructed flight paths of bats whose echolocation calls were recorded. I also captured bats including Molossus molossus, Tadarida brasiliensis, Mormoops blainvillii, Pteronotus parnellii, Pteronotus quadridens, Pteronotus macleayi, using mist nets and harp traps and took morphological measurements. Differences in morphology, habitat selection, periods of peak activity and flight speeds emerged from a comparison among the different insectivorous species. I found sympatric bats differed from one another in at least one of the factors I studied.

October 12, 2012

Taylor A. Finger: Factors influencing spring migration chronology of Lesser Scaup (Aythya affinis) and Mallards (Anas platyrhynchos)

Taylor Finger Philosophical

Supervisor: Dr. Scott Petrie
Co-Supervisor: Dr. Irena Creed
Degree: M.Sc. Candidate

Research indicates that the timing of spring migration by lesser scaup is fixed relative to other waterfowl. In contrast, mallards, as habitat generalists may adjust timing of migration based on annual differences in weather. Combined data from lesser scaup and mallards enable us to test hypotheses about the relative contribution of photoperiod and weather metrics on timing of spring migration in birds. I will use satellite tracking data from lesser scaup and annual spring migration surveys to determine the influence of photoperiod and weather metrics on spring migration chronology and peak migration dates of lesser scaup and mallards. My objective is to test the relative influence of photoperiod and developed weather indices hypothesized to influence migration chronology in waterfowl.

Lindsey Clairmont: Pollinator specialization in flower-visiting bats

Lindsey Clairmont Philosophical

Supervisor: Dr. Brock Fenton
Degree: M.Sc. Candidate

Flower-visiting bats are important pollinators of many species of angiosperms. Flower-visiting bats can be generalist or specialist pollinators, where specialists pollinate only a few plant species and generalists pollinate many. Many studies have investigated specialization in pollination systems from the perspective of the plant, by compiling lists of flower visitors and pollinators, however, comparatively few studies have investigated pollinator specialization from the perspective of the flower-visitors. In this study I aim to classify five species of flower-visiting bats in terms of their specialization for pollination using microscopic observations of pollen present in guano to quantify the number of different plant species visited by the bats within one foraging bout and one season.