Western University BiologyWestern Science

Archived Friday Philosophicals Abstracts - Fall Semester 2011

December 2, 2011

Emma Mullen: Uncovering the gene regulatory network for worker sterility in honey bees

Emma Mullen Philosophical

Supervisor: Dr. Graham Thompson
Degree: M.Sc. Candidate

The evolution of reproductive altruism was a substantial challenge to Darwin’s theory of natural selection. How can altruistic castes evolve if they produce few or no offspring? Hamilton resolved Darwin’s dilemma by showing that altruist fitness can be maximized if ‘genes for altruism’ are passed indirectly through reproducing relatives. Despite this understanding from inclusive fitness theory, we do not yet know how these genes function, not even for eusocial honey bees for which whole-genome analyses are possible. In this study I use bioinformatic tools to reconstruct gene networks that describe worker altruism in terms of ovary activation. Specifically, I link candidate gene lists with gene-function information to assemble provisional networks, then test the characteristics of each construct against expectations arising from social gene theory.

Drew Moore: Investigating the relationship between male quality and vocal performance, and testing for morphological constraints on performance, in Song Sparrows

Drew Moore Philosophical

Supervisor: Dr. Beth MacDougall-Shackleton
Degree: M.Sc. Candidate

Birdsong, like many mating signals, has multiple aspects to which receivers can attend. One such aspect is vocal performance, defined as the ability to perform a physically demanding song. While previous studies have shown that female song sparrows (Melospiza melodia) may use song complexity and local song structure when selecting a mate, the role of vocal performance in mate choice remains unknown. I will examine the causes and consequences of variation in vocal performance in song sparrows, by investigating the relationship between vocal performance and male quality, and testing for morphological constraints on performance. If variation in vocal performance is found to reflect male quality and/or influence female mate choice, this would represent an important advance in our understanding of birdsong as a complex signal.

November 25, 2011

Nico Muñoz: Global warming and adaptation in Chinook salmon

Nico Muñoz Philosophical

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

Recently, Pacific salmon (Oncorhynchus spp.) have demonstrated remarkable physiological adaptations to their thermal migratory conditions, with populations’ optimum temperature for aerobic scope (T opt) matching historic temperatures during their spawning migration. However, because ectothermic organisms become thermally limited when their aerobic scope is reduced, these population-specific differences cause some stocks to be particularly vulnerable to warming temperatures. In my proposed research, I am going to examine the genetic and environmental contributions to the T opt of several populations of Chinook salmon (Oncorhynchus tshawytscha) by employing a quantitative genetic breeding design and conducting reciprocal translocation experiments. By describing the heritability and plasticity of T opt , this study will further our understanding of how these iconic fish may be able to respond to natural selection under climate change.

Jasmine Farhan: The reproductive biology of male Western Bean Cutworm (Straicosta albicosta) moths in Southern Ontario

Jasmine Farhan Philosophical

Supervisor: Dr. Jeremy McNeil
Degree: M.Sc. Candidate

Western Bean Cutworm (WBC, Straicosta albicosta), a dry bean and corn pest, is native to Western United States. In recent years this insect has expanded its range eastwardly as far as New York State and northwardly as far as Timiskaming County, Ontario, and parts of Quebec. Although no significant economic damage has yet been reported in Ontario or Quebec, there is fear that this insect might soon be a major pest, causing great economic damage if not controlled properly. To properly control this agricultural pest, its reproductive behaviour needs to be understood. This study will be conducted in both the lab and the field and will follow the reproductive biology of male WBC moths under different biotic and abiotic factors.

November 18, 2011

Joanna Konopka: Effect of climate on the reproductive biology of Western bean cutworm (Striacosta albicosta) females

Joanna Konopka Philosophical

Supervisor: Dr. Jeremy McNeil
Degree: M.Sc. Candidate

The Western bean cutworm (WBC) is an insect pest of corn and dry beans, and is a cause of crop yield loss and quality reduction in areas where it occurs. Until recently this native species has been restricted to the Western United States. However, in the last decade there has been an eastward movement of WBC and significant numbers are now found in Ontario and Quebec, where there are concerns that this species may become a major pest. Very little is known about reproduction of WBC, yet any rational management plan, must be based on a solid understanding of the basic behavioural and chemical ecology of the target pest. This project will investigate effects of biotic and abiotic factors on reproductive biology of WBC females.

Christopher Austin

Christopher Austin Philosophical

Supervisor: Dr. Amanda Moehring
Degree: M.Sc. Candidate

With the current shifts in global climate, it is critical for us to understand how organisms historically have adapted to local climate and their potential future ability to respond to changes, particularly in temperature. Drosophila simulans and D. melanogaster are closely related species that are both found worldwide. I will test the hypothesis that D. simulans is more phenotypically plastic than D. melanogaster, which is thought to be a more genetically adapted species. To do this, I will determine whether populations of D. simulans and D. melanogaster that were sampled from locations across the world have adapted to their local environment by comparing their optimum fitness temperatures at a variety of life stages (eggs, larvae, and adult fecundity). Each experiment will involve subjecting flies to six temperatures (14, 18, 21, 24, 27, and 30°C) and assessing their survival, development, and reproductive success. This study will determine if there is a difference in optimum temperatures, compare these differences to determine the degree of genetic variability among populations, and finally, determine the overall phenotypic plasticity of each species.

November 11, 2011

Angela Marinas: Migration in the true armyworm, Pseudaletia unipuncta

Angela Marinas Philosophical

Supervisors: Dr. Jeremy McNeil and Dr. Chris Guglielmo
Degree: Ph.D. Candidate

Insects migrate in order to escape deteriorating habitats and colonize new ones. According to the ‘oogenesis-flight syndrome’, migration in female insects is physiologically incompatible with reproduction. The vast majority of insect species that emigrate from deteriorating habitats do so as sexually immature (post-teneral and pre-reproductive) individuals, and oogenesis inhibits migratory behaviour. However, a prolonged pre-oviposition period where resources are directed to flight machinery (larger wings, body size and muscles) and fuel (lipids) used during the migratory period could have a negative effect on subsequent reproductive output, even if the migrants succeed in locating a suitable habitat. Using the true armyworm, this study would address differences between migrants and non-migrants to see if adaptations mitigate the costs of migration on future reproduction.

Kristin Jonasson: Migration energetics of silver-haired bats

Kristin Jonasson Philosophical

Supervisor: Dr. Chris Guglielmo
Degree: Ph.D. Candidate

The energetic demands of avian migration have been extensively studied, but considerably less is known about migratory bats. As both birds and bats are flying endotherms, they are subject to similar ecological pressures and their adaptations to migration are predicted to be convergent in many respects. One major difference between birds and bats is the timing of their reproduction with respect to migration. Unlike birds, reproductive activity (i.e. mating, pregnancy) in bats overlaps with the migration period. The aim of my research is to investigate how bats manage their energy budget as they migrate and compare the strategies of males and females. I will use a variety of methods to estimate energy expenditure during non-flight periods and quantify fuel stores in silver-haired bats during migration.

November 4, 2011

Lisa Kennedy: Factors affecting fat and lean mass deposition during stopover in passerines measured by quantitative magnetic resonance

Lisa Kennedy Philosophical

Supervisor: Dr. Chris Guglielmo
Degree: M.Sc. Candidate

Songbirds depend on stopover sites during their annual migration to accumulate sufficient fat and lean mass to fuel long-distance flight. Although it is now recognized that lean mass is an important component of fuel for birds, the factors that determine variation in the deposition of fat and lean mass are very poorly understood. Quantitative magnetic resonance (QMR) is a new non-invasive method that allows quick, accurate and repeated measurement of fat and lean mass of birds in the field. Therefore, to refine our knowledge of changes in body composition, we used QMR to measure fat and lean mass changes and investigated the influence of season, sex and age on fuel accumulation at a stopover site for 30 passerine species in Long Point, Ontario.

Julia Thompson: The influence of environment on the growth and fitness of glyphosate-resistant and -susceptible giant ragweed (Ambrosia trifida L.) plants after treatment with glyphosate

Julia Thompson Philosophical

Supervisors: Dr. Rob Nurse and Dr. Hugh Henry
Degree: M.Sc. Candidate

In 2010 a giant ragweed biotype in Southwestern Ontario was confirmed to be the first plant species in Canada resistant to glyphosate. The goals of my study were to determine if growth environment interacts with herbicide injury, if resistant seedlings could be controlled at early growth stages, and if resistance is associated with a fitness penalty. My results suggest that growth environment did not interact with glyphosate injury and resistant seedlings sprayed with glyphosate survived treatment at all leaf stages and herbicide doses. The results of the fitness experiments are still pending; however, if resistance delays flowering and there are less resources provided to dormancy and viability, there may be an impact on the longevity of giant ragweed seed in the soil seed bank.

October 28, 2011

Melissa Raffoul: Harmful cyanobacterial blooms and cyanotoxins in Lake Naivasha, Kenya

Melissa Raffoul Philosophical

Supervisor: Dr. Charles Trick
Degree: M.Sc. Candidate

With our global population rising, and demands for water increasing, cyanobacterial blooms threaten the world’s freshwater resources. Cyanobacteria can produce cyanotoxins, which can lead to illness or death if ingested. The cyanobacterial community was studied in Lake Naivasha, Kenya, a eutrophic, human-influenced lake. From August 2010 to March 2011, a cyanobacterial bloom, dominated by the toxin-producing genus Microcystis, proliferated on the lake. Average in situ chlorophyll concentrations reached a high of approximately 100 µg/L in March 2011. Preliminary results suggest that the hepatotoxin, microcystin, was present in small amounts. By May 2011, the bloom dissipated, and the algal community was dominated by a small desmid. Examining the lake in these different states will lead to better understanding of the ecosystem dynamics and threat for future blooms.

October 21, 2011

Mélanie F. Guigueno: Sex differences in spatial cognition in brown-headed cowbirds: testing the adaptive specialization hypothesis in a species with sex-role reversal

Mélanie F. Guigueno Philosophical

Supervisors: Dr. David Sherry and Dr. Scott MacDougall-Shackleton
Degree: Ph.D. Candidate

The adaptive specialization hypothesis posits that cognition and the brain are specialized to serve specific ecological functions. Female brown-headed cowbirds search for host nests, whereas males do not. Females have a larger hippocampus than males, a sex difference that is the reverse of that found in many other species. I will measure aspects of spatial memory in female and male cowbirds using touchscreens and a foraging task. The adaptive specialization hypothesis predicts superior female spatial ability. I also expect to find more a pronounced sex difference during breeding, when females have a higher demand for spatial memory. Finally, I will also determine if performance is correlated with hippocampal size and if this size difference varies with breeding condition.

Meghan Gerson: Introduced Chinook salmon in Lake Huron: are they pre-adapted to spawn at the right time?

Meghan Gerson Philosophical

Supervisor: Dr. Yolanda Morbey
Degree: M.Sc. Candidate

The goal of my study was to determine if introduced Chinook salmon in the Sydenham river, Lake Huron, are pre-adapted for spawning timing. In native populations, there is a seasonal decline in reproductive lifespan and a corresponding decline in fat stores, minimizing the probability that later arriving females will reuse nests. Typically, native Chinook salmon spawn 88 - 98% of their eggs. In the Sydenham river however, spawning is occurring early, thus fish are initially experiencing higher than optimal temperatures for spawning. Additionally, no seasonal decline in either reproductive lifespan or fat stores was found and percentage of eggs spawned was 74 ± 11%. These data imply that reproductive timing of Chinook salmon does not appear to be pre-adapted in this system.

October 14, 2011

Matthew Emrich: The Community Structure of Insectivorous Bats in the Region of Windsor Cave, Jamaica

Matthew Emrich Philosophical

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

The question of how bat communities are structured and whether there is inter or intraspecific competition for food remains inconclusive, with some studies supporting competition and other studies showing there is no competition. The purpose of my research is to examine different aspects of the insectivorous bats that occur in the Great Windsor Cave, Jamaica. If competition was the driving factor in the evolution of the bat community in Jamaica, then differences in phenotypic traits, including body size, wing morphology and echolocation calls, should be observed. I will compare inter-species diet, flight patterns during hunting, echolocation call structures, skull and wing morphology and patterns of habitat use, to show that bat communities have reduced competition by exploiting different food resources.

Jace McLaughlin: Developing cell-based assays for the detection of freshwater algal compounds

Jace McLaughlin Philosophical

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

The spatial variability of algal blooms in Ontario’s freshwater lakes provides a challenge for investigators seeking to assess the biological impacts of toxic and noxious bloom events. Several small scale bioassays have been developed for detection of freshwater pollutants, but few attempts have been made to modify these assays for the purpose of freshwater algal compound analysis. The RTgill-W1 cell line and erythrocyte lysis assays will be studied and manipulated in an attempt to develop fast, reliable, low volume, and high throughput screening methods of toxic and noxious freshwater algal compounds. Successful adaptation of these assay methods will improve the screening efficiency and capacity for investigators of water quality and bloom dynamics.