Ecology and Evolutionary Biology Commons^™

Food Caching Decisions In Canada Jays (Perisoreus Canadensis), Robert J. Martin

Electronic Thesis and Dissertation Repository

Food scarce periods pose serious challenges for birds, particularly when those periods coincide with demanding life history stages such as overwintering. For resident birds in the Northern hemisphere, resource scarcity typically occurs simultaneously with winter conditions. In order to combat these compounded stressors, some species cache food to ensure a reliable supply of resources. Food caching is the storing of food items for subsequent retrieval and consumption after some delay. Canada Jays (Perisoreus canadensis) are year-round residents of the North American boreal forest and some high elevation areas in the United States, and cache food to combat resource …

Population And Evolution Dynamics In Predator-Prey Systems With Anti-Predation Responses, Yang Wang

Electronic Thesis and Dissertation Repository

This thesis studies the impact of anti-predation strategy on the population dynamics of predator-prey interactions. This work includes three research projects.

In the first project, we study a system of delay differential equations by considering both benefit and cost of anti-predation response, as well as a time delay in the transfer of biomass from the prey to the predator after predation. We reveal some insights on how the anti-predation response level and the biomass transfer delay jointly affect the population dynamics; we also show how the nonlinearity in the predation term mediated by the fear effect affects the long term …

Effects Of Gene-Environment Interactions On The Evolution Of Social Behaviours, Vonica J. Flear

Electronic Thesis and Dissertation Repository

Inclusive fitness models in sociobiology emphasize the importance of relatedness, R, and synergy, S when exploring the evolution of social behaviours. Very few models explicitly consider ‘role’, or environmental stimuli, influencing the expression of behaviours, and none consider genetic-environment interactions where genotype predisposes individuals to certain roles. I propose a third key variable for inclusive fitness models, Q, which describes the overlooked potential bias in the genetic composition of individuals exposed to an environmental stimulus – here referred to as ‘role’. I describe a model built from Price’s formula which can be presented in a ‘Hamilton’s Rule’ format. …

An Investigation Of Epiphytic Diatom Substrate Specificity And Its Use In Paleolimnology, David Rawn Zilkey

Electronic Thesis and Dissertation Repository

Submerged macrophyte communities are an important component of lake ecosystems that can be altered by anthropogenic disturbances. In the absence of direct monitoring, it is difficult to know how these communities respond to such disturbance. This thesis investigated the potential of epiphytic diatoms preserved in lake sediments to record submerged macrophyte community composition. Epiphytic diatoms from Chara sp., Myriophyllum spicatum and Potamogeton robbinsii were sampled from Gilmour Bay, Ontario, Canada to assess whether submerged macrophyte species were characterized by distinct diatom communities. Principal components analysis indicated overlap, but analysis of similarity suggested there were differences in diatom community composition. A …

Genetic Basis Of Hybrid Sterility Between Drosophila Pseudoobscura And D. Persimilis, Alannah J.P. Mattice

Electronic Thesis and Dissertation Repository

Speciation is the underlying process that leads to formation of new species, and therefore is the basis of biodiversity. Genes involved in each stage of speciation, such as those involved in interspecies sterility, remain elusive. Male hybrid sterility and postzygotic isolation between Drosophila pseudoobscura and D. persimilis was examined in this study through backcrossing of female hybrids into each parental line (introgression), selecting for a sterile sperm phenotype, needle-eye sperm. Sperm phenotypes did not separate through backcrossing; instead, males presented with multiple sperm phenotypes. A relationship between the phenotypes observed and the potential genes involved was examined through whole genome …

Characterizing The Diversity Of The Eukaryotic Microbiome In Marine Crustacean Zooplankton., Rose-Lynne Savage

Electronic Thesis and Dissertation Repository

Understanding zooplankton productivity is critical for modeling marine food web function, of which one poorly known factor is the influence of zooplankton symbionts. Zooplankton protist symbiont diversity is underestimated due to the limited surveys and techniques previously used. Using 18S V4 metabarcoding, I characterized the eukaryotic microbiomes associated with crustacean zooplankton from the northern Strait of Georgia, BC. Apostome ciliates were most abundant in all hosts except for cyclopoid copepods, which were dominated by Syndiniales. Most symbiont lineages were more abundant in one or two hosts, suggesting some degree of host preference. Microbiome data also provided information on diet, confirming …

Mathematical Modelling Of Prophage Dynamics, Tyler Pattenden

Electronic Thesis and Dissertation Repository

We use mathematical models to study prophages, viral genetic sequences carried by bacterial genomes. In this work, we first examine the role that plasmid prophage play in the survival of de novo beneficial mutations for the associated temperate bacteriophage. Through the use of a life-history model, we determine that mutations first occurring in a plasmid prophage are far more likely to survive drift than those first occurring in a free phage. We then analyse the equilibria and stability of a system of ordinary differential equations that describe temperate phage-host dynamics. We elucidate conditions on dimensionless parameters to determine a parameter …

Spatial And Temporal Variation Of Nutrients In The Great Lakes-St. Lawrence Basin: Implications For Primary Production In Stream Ecosystems, Nolan Pearce

Electronic Thesis and Dissertation Repository

Growing human populations and associated land use activities has increased the amount of nutrients delivered to surface waters. Eutrophication from the over-enrichment of nitrogen and phosphorus has degraded ecosystem conditions in streams, lakes, and coastal areas worldwide. Thus, the management of anthropogenic nutrient loading is a global concern. This thesis employed a combination of field and experimental research to provide watershed managers with information on the spatial and temporal patterns in stream nutrient enrichment, and the associated ecological effects of anthropogenic nutrient loading in the Great Lakes-St. Lawrence basin. Four studies were completed to address this research goal. First, I …

Amount And Sources Of Population Variability In The Metabolome Of A Crayfish Species, Cora Bilhorn

Electronic Thesis and Dissertation Repository

My study investigated the amount of variation associated with region and stream scales in the metabolomes of northern crayfish (Faxonius virilis), collected from seven streams distributed across three ecoregions in Western Canada. Additionally, my study measured metabolomes of crayfish from the same seven streams after experiencing a common laboratory environment to separate the effects of environmental and genetic variation. Region and stream scales were found to be poor predictors of metabolomic variation among crayfish sampled in the field but exhibited increased predictive ability among crayfish exposed to the common environment, indicating crayfish from separate populations responded differently to …

Contraction Analysis Of Functional Competitive Lotka-Volterra Systems: Understanding Competition Between Modified Bacteria And Plasmodium Within Mosquitoes., Nickolas Goncharenko

Electronic Thesis and Dissertation Repository

We propose and analyze an extension to the classic Competitive Lotka-Volterra (CLV) model. The goal is to model competition between species, with a response from the environment. This response is a function of the population of all species and can represent numerous physical phenomena including resource limitation and immune response of a host due to infection. We name this new system a Functional Competitive Lotka-Volterra (FCLV) model. We mainly use the construction of contraction metrics, to determine global properties of the model. We use this result to analyze the competition between Plasmodium sp. and genetically engineered bacteria within the midgut …

Chemical Communication In Songbirds, Leanne A. Grieves

Electronic Thesis and Dissertation Repository

Avian chemical communication has been understudied due to the misconception that olfaction is unimportant or even lacking in birds. Early work focused on the olfactory foraging capabilities of seabirds because of their ecology (open ocean foraging) and large olfactory bulbs. In contrast, olfaction in passerine birds, comprising over half of all extant avian taxa, was long overlooked due to their relatively small olfactory bulbs. It is now well established that passerines can smell, and their olfactory acuity is comparable to that of macrosmatic mammals such as rats. Much of our theory on communication and mate choice has involved studying visual …

Differential Effects Of Freezing On The Drought Tolerance Of Herbaceous Plants At The Species, Community And Ecosystem Scales, Ricky S. Kong

Electronic Thesis and Dissertation Repository

Both freezing and drought cause cellular dehydration and elicit similar physiological responses in plants, where similar protective compounds are upregulated, including soluble sugars and proteins that help reduce cellular damage. Drought-freeze cross acclimation occurs when drought exposure enhances the freezing tolerance of plants. However, few studies had investigated the reciprocal effects of freezing on drought tolerance, and it was unknown if these interactions could impact plant productivity. Therefore, I examined the effects of freezing on the drought tolerance of individual species and assessed the implications of freeze-drought interactions in an old field community. Poa pratensis was exposed to fall or …

Phage-Bacteria Interaction And Prophage Sequences In Bacterial Genomes, Amjad Khan

Electronic Thesis and Dissertation Repository

In this investigation, we examined the interaction of phages and bacteria in bacterial biofilm colonies, the evolution of prophages (viral genetic material inserted into the bacterial genome) and their genetic repertoire. To study the synergistic effects of lytic phages and antibiotics on bacterial biofilm colonies, we have developed a mathematical model of ordinary differential equations (ODEs). We have also presented a mathematical model consisting of a partial differential equation (PDEs), to study evolutionary forces acting on prophages. We fitted the PDE model to three publicly available databases and were able to show that induction is the prominent fate of intact …

Niche Segregation Among Three Sympatric Species Of Swallows In Southern Ontario, Kaelyn H. Bumelis

Electronic Thesis and Dissertation Repository

Barn Swallows (Hirundo rustica), Cliff Swallows (Petrochelidon pyrrhonota) and Tree Swallows (Tachycineta bicolor) breed sympatrically in southern Ontario but it is unclear how these species differ ecologically, and their coexistence implies niche segregation. I investigated potential interspecific differences in nestling diet and post-fledging movements. Using DNA barcoding of nestling feces and stable isotope analysis (δ¹³C, δ¹⁵N, δ²H) of nestling feathers, I found evidence of differences in dietary sources of provisioned young. Barn Swallows showed evidence of provisioning more terrestrial-based prey, Cliff Swallows provisioned an intermediate diet, and Tree …

Effects Of Dietary Thiaminase On Reproductive Traits In Three Populations Of Atlantic Salmon Targeted For Reintroduction Into Lake Ontario, Kimberly T. Mitchell

Electronic Thesis and Dissertation Repository

The fitness of reintroduced salmonids in Lake Ontario can be reduced by high levels of thiaminase in exotic prey consumed at the adult stage. If sensitivity to dietary thiaminase differs among the three Atlantic salmon populations targeted for reintroduction into Lake Ontario, this could significantly influence their performance. I quantified the effects of experimental diets that contained high or low (control) levels of thiaminase on thiamine concentrations, survival, growth rate, and reproductive traits (sperm and egg quality) in Atlantic salmon from the three candidate source populations. Fish that consumed the high-thiaminase diet had comparable growth rates, but lower survival and …

Diet Composition And Mercury Exposure In Bank Swallows (Riparia Riparia) Breeding At Lakeshore And Aggregate Pits, Corrine S. V. Génier

Electronic Thesis and Dissertation Repository

Bank Swallows (Riparia riparia), a threatened species in Ontario, breed primarily in banks at lakeshores and in artificial aggregate pits. Inland pits may be ecological traps for this species, but the relative tradeoffs between these two nesting habitats are unknown. Availability of aquatic emergent insects at lakeshores may have associated nutritional benefits (e.g. Omega-3 fatty acids) and contaminants (e.g. mercury) that can directly influence juvenile growth. This study compares these breeding habitats to evaluate dietary differences as revealed by fatty acids, stable isotopes (δ¹³C, δ¹⁵N, δ²H), fecal DNA barcoding, and mercury. Lakeshore-nesting …

The Stability Of Temperate Lakes Under The Changing Climate, Aleksey Paltsev

Electronic Thesis and Dissertation Repository

There is a collective prediction among ecologists that climate change will enhance phytoplankton biomass in temperate lakes. Yet there is noteworthy variation in the structure and regulating functions of lakes to make this statement challengeable and, perhaps, inaccurate. To generate a common understanding on the trophic transition of lakes, I examined the interactive effects of climate change and landscape properties on phytoplankton biomass in 12,644 lakes located in relatively intact forested landscapes. Chlorophyll-a (Chl-a) concentration was used as a proxy for phytoplankton biomass. Chl-a concentration was obtained via analyzing Landsat satellite imagery data over a 28-year period (1984-2011) and using …

Above- And Belowground Community Linkages In Boreal Peatlands And Climate Warming Implications, Caitlyn Lyons

Electronic Thesis and Dissertation Repository

Aboveground plants provide resources to the belowground microbial community via plant litter and, in turn, the belowground microbial community provides nutrients for plant uptake, linking the two systems. My aim was to characterize and describe differences in plant community composition, plant litter quality and microbial community composition between two boreal peatlands in northern Ontario. These peatlands have contrasting plant and microbial communities, the Sphagnum moss-dominated peatland harboring a higher fungi to bacteria ratio compared to the Carex sedge-dominated peatland. Clear open top chambers were installed at both sites to simulate warming. Higher temperatures decreased Sphagnum moss in the Sphagnum-dominated …

The Cost Of Protection: Frost Avoidance And Competition In Herbaceous Plants, Frederick Curtis Lubbe

Electronic Thesis and Dissertation Repository

Perennial herbaceous plants in regions that experience winter freezing must survive using belowground structures that can tolerate or avoid frost stress. Soil and plant litter can insulate plant structures from frost exposure, but plants must invest into growth to penetrate through these layers to reach the surface in the spring. The overall goal of my thesis was to test the hypothesis that the protection of overwintering clonal structures by soil or plant litter (frost avoidance) comes at the expense of subsequent reduced growth and competitive ability in absence of freezing stress. I first explored this trade-off with a suite of …

Comparison Of Cyanobacteria Phenotypes With Distinctive Photosynthetic Pigment Compositions To Simulated Lake Browning, Camille Chemali

Electronic Thesis and Dissertation Repository

Browning of inland waters has been noted over large parts of the Northern hemisphere and is a phenomenon with both ecological and societal consequences. The increase in water color is generally ascribed to increasing concentrations of dissolved organic matter (cDOM) of terrestrial origin. Changes in water color will have profound effects on the phytoplankton composition in freshwater systems. Here, I examined the effect of changes in water color associated with coloured DOM (cDOM) on red and green phenotypes of the cyanobacterium, Pseudanabaena, which emerged to surface blooms in Dickson Lake (Algonquin Provincial Park, Ontario) in the summer of 2014. …

Major Histocompatibility Complex Does Not Affect Mating Patterns In Bluegill Sunfish (Lepomis Macrochirus), Lucas Silveira

Electronic Thesis and Dissertation Repository

In many species, individuals prefer mates that are genetically dissimilar at the major histocompatibility complex (MHC). This is likely because it improves offspring resistance to pathogens. Here I provide the first genotypic characterization of the MHC class II peptide binding region in bluegill (Lepomis macrochirus), a species of sunfish, and examine its effect on mating patterns. I hypothesized females would choose to mate with MHC dissimilar males leading to an increase in the resulting offspring’s fitness. I captured females and males during spawning and sequenced the DNA of these fish at the MHC class II putative peptide binding …

The Fruitless Gene Influences Female Mate Preference In Drosophila, Tabashir A. Chowdhury

Electronic Thesis and Dissertation Repository

Species can arise as a result of reproductive barriers that prevent gene flow between diverging populations that force them to remain isolated from one another. Behavioural isolation is one of the earliest acting reproductive barriers determined by the evolution of mating preferences that prevent inter-specific matings. Several traits have been identified that contribute to behavioural isolation, but the genetic basis of interspecific female preference is yet to be determined. I used genetic mapping techniques to identify and confirm that the fruitless gene is affecting species-specific female rejection of interspecies males, contributing to the behavioural isolation between Drosophila melanogaster and D. …

Analyzing Avian Incubation With A Computer Algorithm, Tanya T. Shoot

Electronic Thesis and Dissertation Repository

A stable nest environment is necessary for incubation and development of offspring. Birds vary behaviour to regulate temperature for successful hatchlings. I used a hidden Markov model (HMM) to test how environmental conditions affect incubation behaviour. I examined nest temperatures and behaviours collected from Zebra finches that incubated at 30 °C or 14 °C, then incubated in the same or opposite condition for a second clutch. Data loggers and cameras recorded nest temperature and number of parents on nest. The HMM inferred behaviour from recorded behaviours and temperatures. Temperature and offspring success affected incubation duration. Birds that had successful offspring …

Carbon Cycling In Northern Fen Peatlands – Implications For Climate-Driven Changes Of Ecosystem Carbon Fluxes, Jing Tian

Electronic Thesis and Dissertation Repository

Northern peatlands are important long-term carbon (C) sinks with one-third of northern hemisphere soil organic carbon being stored there. Cool and wet environments at higher latitudes promote C accumulation in northern peatlands by limiting the C loss from decomposition. Northern latitudes are anticipated to experience disproportionately faster climate warming in the future, putting the vast C stores in northern peatlands at risk. There is a concern that northern peatlands are becoming net C sources and further accelerate climate warming. Using both laboratory and field experiments, this doctoral research aimed to explore the potential response of C cycling in northern peatlands …

Contrasting Non-Breeding Ecology Of Swainson’S Thrush (Catharus Ustulatus) In Andean Forest And Shade-Grown Coffee Plantations, Sean Mcelaney

Electronic Thesis and Dissertation Repository

Shade-grown coffee plantations provide Neotropical migratory birds an alternative to primary growth forest which is disappearing throughout their non-breeding range. However, it remains unclear whether plantations can provide enough structure to maintain viable non-breeding populations of many species. I studied Swainson’s Thrush (Catharus ustulatus) in the Colombian Andes in a mixture of montane forest and shade-grown coffee plantation. In comparing the two habitats I looked at factors indicative of habitat quality, such as age/sex hierarchies, area of concentrated use, density, diet, and migration timing. My research aimed to determine whether Neotropical migrants benefit from this agroecosystem, and to …

Top-Down And Bottom-Up Effects On Collembola Communities In Soil Food Webs, Jordan Kustec

Electronic Thesis and Dissertation Repository

Anthropogenic changes are causing shifts within soil food web communities, which may alter ecosystem processes such as nutrient cycling, carbon storage and decomposition. I quantified ecological stressor effects on the abundance, richness, community composition and body size of a soil-dwelling microarthropod (Collembola: Hexapoda). I quantified the effects of warming and nitrogen deposition in two separate field studies and demonstrated that warming shifts Collembola community structure and decreases community body size. I quantified the interactive effects of top-down and bottom-up forces mediated by warming as ecological stressors in Collembola communities. I found that bottom-up effects of nutrient addition did not affect …

Landscape-Level Effects Of Agricultural Intensification On The Condition And Diet Of Nestling Barn Swallows (Hirundo Rustica), Jackson W. Kusack

Electronic Thesis and Dissertation Repository

Farmland bird populations have experienced declines with increasing agricultural intensification for which the leading hypothesis is a reduction of prey insects. This may be especially relevant for aerial insectivores whose primary diet is aerial insects. For this thesis, I examined nestling body condition and used stable isotopes (δ¹³C, δ¹⁵N) and fecal DNA barcoding to determine the diet of a farmland breeding aerial insectivore, the Barn Swallow (Hirundo rustica), within an agro-ecosystem in Southern Ontario, Canada. Nestling body condition was positively affected by agricultural intensification, but all benefits were lost by the pre-fledging stage and …

Hitchhiker's Guide To Migration: Effects Of Experimental Parasitic Infection And Other Immune Challenges On Migratory Traits Of Sparrows, Tosha R. Kelly

Electronic Thesis and Dissertation Repository

Seasonal migration exposes animals to a variety of habitats and parasites, and if infected migratory birds migrate successfully there is great potential for birds to transport infectious diseases long distances. Our current understanding of whether birds contribute to the spread of disease relies upon observational field studies that are limited in their ability to discern cause from effect. Using captive and field-based experiments for my doctoral research, I answered three research questions: (1) are nocturnal migratory restlessness (Zugunruhe) and body condition affected by mounting an acute phase immune response during migration; (2) what are the impacts of parasitic …

Spatial And Temporal Patterns Of Neutral And Adaptive Genetic Variation In The Alpine Butterfly, Parnassius Smintheus, Maryam Jangjoo

Electronic Thesis and Dissertation Repository

Understanding how much genetic diversity exists in populations, and the processes that maintain that diversity, has been a central focus of population genetics. The evolutionary processes that determine patterns of genetic diversity depend on underlying ecological processes such as dispersal and changes in population size. In this thesis, I examine the influence of dispersal and population dynamics on neutral and adaptive genetic variation in a naturally occurring network of populations of the alpine butterfly, Parnassius smintheus.

My first objective was to determine the combined consequences of demographic bottlenecks and dispersal on neutral genetic variation within and among populations. Using …

Patterns And Drivers Of Stream Benthic Macroinvertebrate Community Taxonomy And Function In Agroecosystems, Edward M. Krynak

Electronic Thesis and Dissertation Repository

Anthropogenic activities continue to expand and intensify resulting in vast areas of the globe being dominated by human land uses. Effective land management and conservation decisions depend on our ability to understand and predict biological response to further disturbance in already stressed ecosystems. Moreover, insight into biological response to ecological stressors may be advanced by using trait and functional community measures in combination with taxonomy. My dissertation goal was to describe patterns and drivers of variation in benthic macroinvertebrate communities (BMIC) taxonomic composition and function in streams in an agriculturally dominated landscape. I achieved my goal by conducting three related …