Archived Friday Philosophicals - Winter Semester 2014

Supervisor: Dr. Scott Petrie/Dr. Christopher Guglielmo
Degree: MSc
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 previously 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. For my study, I am investigating the relative contribution of weather and photoperiod cues for other species of dabbling ducks. I obtained data from standardized waterfowl surveys conducted throughout eastern North America. 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.

Supervisor: Bryan Neff Climate change is projected to have widespread effects that could threaten the viability of natural populations. The ability of a species to adjust to climate change is modulated by its adaptive capacity, some of which involves an evolutionary response. Here we examine the adaptive capacity of Atlantic salmon, an important aquatic ectotherm. In the face of impending climate change, conservation managers may be faced with augmenting or reintroducing individuals that have high thermal tolerance or those from a population with high thermal tolerance. Indeed, current restoration efforts to produce a self-sustaining Atlantic salmon (Salmo salar) population in Lake Ontario focus on three source populations as candidates for reintroduction. In this study, we investigated underlying cellular and molecular factors that may facilitate tissue oxygen supply and thereby thermal tolerance at individual and family levels. The results of this study provide insight into long-term survival for ongoing restoration efforts of Atlantic salmon as well as more broadly into the thermal adaptive capacity of freshwater fishes.

Supervisor: Dr. Liana Zanette
Degree: MSc
Predator effects on prey populations extend beyond direct killing through changes in physiology and behaviour in response to predation risk that affect prey survival and reproduction. One aspect of this involves changes in courtship and mating behaviours which are conspicuous and increase the prey’s risk of detection by predators. As there is a survival cost associated with reproduction, individuals under predation risk should be expected to engage less in courtship and mating behaviours reducing their reproductive success in order to increase their survivability. I aim to examine the acute and chronic effects of predation risk on courtship and mating behaviour and reproductive success in brown-headed cowbirds (Molothrus ater) by experimentally manipulating predation risk during the breeding season.

Supervisor: Liana Zanette
It is becoming clear that the 'fear' of predators shapes prey ecology, in that the mere presence of a predator can leave lasting effects on prey physiology and reproduction. However, it is unknown whether perceived predation risk alters the avian brain and if there is a 'fear network' which processes predator cues. My goal is to examine behavioural and neurological changes in black-capped chickadees (Poecile atricapillus) in response to playbacks of predator calls and conspecific alarm calls. I will quantify activation in several brain areas using immediate-early gene immunohistochemistry and analyse behaviour in response to predator cues. I aim to better understand the processing of predator stimuli in the avian brain, whether neurobiological changes persist over the long term, and if behavioural changes also result.

Supervisor: Jeremy McNeil

Abstract: Because migratory and non-migratory populations occur within the same species, the true armyworm (Pseudaletia unipuncta) presents a unique opportunity to study the costs of flight on reproduction, and the adaptations that minimize such costs. It is believed that migrant populations establishing in a permanently usable habitat should eventually become non-migratory and thus develop traits investing more in reproduction than in flight.  Such a shift in life history has been observed in the Azorean (non-migratory) population of the true Armyworm. By comparing the Hawaiian (non-migratory) and North-American (migratory) Armyworm populations, I wish to test whether the findings in the Azorean population represent a general trend or an anomaly.

Supervisor: Scott Petrie

Animals often associate human disturbance equivocally to potential predation risk and have associated behavioural responses. In autumn and winter waterfowl are subjected to disturbance (i.e. hunting) which can have local effects on distribution and abundance. The juxtaposition of habitats of varying risk of mortality to waterfowl from hunting at Lake St. Clair, Ontario is ideal to investigate waterfowl movements and foraging strategies in relation to this anthropogenic disturbance. My research will estimate temporal and spatial variation of female mallard habitat selection in relation to potential risk of mortality from hunting. Additionally, I will assess how their habitat selection is subsequently related to their their survival and duration of stay within the region.

Supervisor: Liana Zanette
Predators have profound effects on prey population dynamics that go beyond simply killing prey.  The mere risk of predation elicits both behavioural and physiological changes that can alter prey survival.   Birds have been shown to make changes in physiological condition in response to a heightened risk of predation, which has been assumed to aid in increasing escape flight ability and thus evasion from predators.  My research examines whether brown-headed cowbirds (Molothrus ater) make strategic adjustments in order to improve their flight ability.  By manipulating the level of predation risk, I can examine the resulting effect on their physiological condition and test for any changes in flight ability

Doctoral Candidate
Supervisors: Nusha Keyghobadi, Brock Fenton

We expect parasites to be locally adapted to their hosts. We thus expect the parasite’s phylogeny and genetic structure, and the selection on its traits to be largely driven by its host. Insects in the Cimicidae family (Order: Hemiptera) are ectoparasites of warm-blooded animals, such as bats, birds and humans. There are evidences of host switching in many cimicid species in the genus Cimex between bats and humans. In my doctoral project, I will decipher genetic attributes of host associations to bats or humans in North American Cimex species. I will participate in the collection of samples from human homes and bat colonies throughout Canada. Then, I will analyze the collected samples to attempt to decipher differences between bat specialized and human specialized Cimex lineages.

Understanding whether parasites adapt to local hosts or if hosts adapt to local parasites has important implications for patterns of biodiversity. The objective of my research project is to determine the level of concordance between host red crossbill (Loxia curvirostra) population genetic structuring and that of their haematozoan parasites (genera Leucocytozoon, Haemoproteus and Plasmodium). By revealing the genetic structuring of host-parasite systems, my study will provide a better understanding of how host genetic diversity is influenced by parasites.

Supervisors: Scott A. MacDougall-Shackleton and David F. Sherry
Memory can have profound effects on reproductive success. Indeed, female brown-headed cowbirds (Molothrus ater) are obligate brood parasites and must remember the location of suitable host nests, unassisted by males, to ensure their young survive. Breeding females have a larger hippocampus than males. To examine whether females have more accurate spatial memory than males, we investigated sex differences in the memory of captive cowbirds using: 1) touchscreen and 2) spatial navigation tasks. Movement through the environment was important because females outperformed males on the spatial navigation task only. Spatial memory is adaptively specialized in females for brood parasitism. We are currently examining sex, seasonal, and species differences in hippocampal volume, neuron density, and neurogenesis to provide a strong analysis of specialized brain plasticity.

Supervisor: Beth MacDougall-Shackleton

A compelling candidate gene at which both good-gene and compatible-gene effects on fitness may occur is the major histocompatibility complex (Mhc). Mhc loci play a key role in vertebrate immunity through recognizing non-self peptides and presenting them to T-cells. A greater number of distinct Mhc alleles produce a wider array of antigen-binding proteins. In songbirds, it has been proposed that although assessing the genetic similarity (including Mhc profile) of a potential mate might well be adaptive, it may nonetheless not be possible. I will assess potential methods of communication (i.e. song and olfaction) in song sparrows and see if they relay information of Mhc genotype to the receiver.

PhD Candidate
Supervisor: Kathrin S. Bolstad; J. Mark Hanson. Visiting student from New Zealand, hosted by Louise Milligan

Deep-sea squids of the family Octopoteuthidae have been collected from every ocean except the Arctic, and are an ecologically important group, being both key prey for apex marine predators as well as active predators themselves. However, these squids remain poorly studied due to the taxonomic disarray of the family. To rectify this, a global systematic revision is being undertaken based primarily on morphology, but with support, when available, from molecular techniques. Observations to date suggest the existence of ten octopoteuthid species worldwide, including at least three previously undescribed, distributed between two genera. The considerable size of these undescribed species (> 20 kg, > 50 cm body length) demonstrates the continuing poor state of knowledge on the deep ocean, its inhabitants, and their interactions.

MSc candidate
Superviosor: Bryan Neff

Salmon populations have been steadily decreasing across both the eastern and western coast of North America. There have been recent efforts to reverse these declines through hatchery release programs. Unfortunately, many of these programs have been unsuccessful in reversing population declines. Mortality in juveniles caused by inappropriate responding to predator threats may have an effect on hatchery release programs. Predator recognition is a critical aspect of anti-predator behaviour that is potentially altered by hatchery rearing, due to a lack of exposure to predator cues. I will investigate predator recognition in juvenile Atlantic salmon (salmo salar) across three populations with different captive breeding histories. Understanding differences in predator recognition across these populations will shed light on the effect of captive breeding on anti-predator behaviour.

MSc Candidate
Supervisor: Bryan Neff

Nectar-feeding bats play a crucial role in their environment as pollinators and seed dispersers, but little is known about their social interactions at feeding sites. Knowledge of the group dynamics of bats improves our ability to allocate sufficient land and resources for their conservation. In high traffic feeding areas, communication is essential for preventing collisions and maintaining an effective feeding system. This project will investigate the social implications of echolocation in three species of nectar-feeding bats: Glossophaga soricina, Leptonycteris curasoae and Choeronycteris mexicana. I will explore the interactions among these bats visiting point sources of food, using playback experiments and flight-path analysis, and analyze the responses to different echolocation playbacks in order to determine the social context of these calls.

MSc. Candidate
Supervisor: Greg Thorn

Arbuscular mycorrhizae are important symbiotic associations between arbuscular mycorrhizal fungi (AMF) and the roots of many vascular plants. AMF exchange soil nutrients (such as phosphorus) from nutrient pools that the plants cannot reach themselves in exchange for photosynthetically fixed carbon. Arbuscular mycorrhizae are favoured in grassland ecosystems like Walpole Island. Currently, restoration attempts at Walpole are underway to restore agriculturally disturbed fields back to natural tallgrass prairie. A consequence of agricultural disturbance is the simplification of plant communities and disruption of the mycelial networks of AMF. I will be using Next Generation sequencing to determine the species composition of AMF in areas with different disturbance histories. Understanding how disturbance affects AMF could reveal information on how AMF can be used for restoration of endangered ecosystems.

Supervisor: Liana Zanette
Degree: MSc

Predators effect prey populations beyond directly killing individuals. A growing body of research shows that the “fear” of being preyed upon (i.e. perceived predation risk) can induce costly anti-predator behaviours that are powerful enough to reduce prey reproduction and survival. The majority of this research has dealt with the effects of fear on prey only during the nesting period, but the effect on prey beyond this period is as yet unexplored. I will study how acute threat of predation effects the behaviour of Song Sparrows (Melospiza melodia) after the nesting period. To accomplish this I will manipulate the perceived threat of predation with predator playbacks. During the playback I will record the behaviour of both parents and young and compare to behaviour during control periods.

February 07, 2014

MSc. candidate
Supervisor: Irena Creed
For decades, cyanobacterial harmful algal blooms (cyanoHABs) have been observed frequently in eutrophic, nutrient-rich lake systems. Surprisingly, cyanoHABs have been reported in nutrient poor, oligotrophic waters in recent years. Despite nitrogen and phosphorous as important components in the production of cyanobacterial blooms, another way cyanobacteria can assimilate nutrients is by utilizing siderophores to competitively bind iron. In this laboratory grow-out experiment, it is hypothesized that cyanobacterial hydroxamate and catecholate siderophore production will be heightened when phosphorous and nitrogen are low in induced Fe-limited conditions. Filtered lake water and natural phytoplankton obtained from study sites will be used to emulate real-world conditions, and the experimental manipulations will improve our mechanistic understanding of what is controlling the expansion of cyano HABs in freshwater systems.

MSc Candidate
Supervisor: Dr RG Thorn
Common buckthorn (Rhamnus cathartica), a highly competitive Eurasian woody shrub, is currently invading North America.  Dense monoculture thickets of buckthorn reduce native plant species diversity and may also reduce diversity of soil organisms, including mycorrhizal fungi, negatively impacting surrounding symbiotic flora and facilitating invasional meltdowns.  Current long-term control methods including cutting, physical removal or herbicidal applications, exhaust resources. I will be surveying forested regions in Middlesex County, Ontario, identifying fungi associated with the leaves, bark, and roots of Rhamnus cathartica to identify potential biological controls. I will also perform manipulative experiments to assess the effects of root exudate, leaf litter and drupes, containing allelochemicals, on fungal diversity in previously uninvaded soils and on diversity of arbuscular mycorrhizal fungi associated with sugar maple (Acer saccharum) seedlings.

Supervisor's name: Dr. Nusha Keyghobadi
Degree being sought: M.Sc Candidate

The Rocky Mountain apollo butterfly is an ideal subject to study spatially-structured populations, dispersal, and gene flow because of its patchy distribution in mountain landscapes. Sudden, severe reductions in population size (i.e., ‘collapse) are becoming more common in this species with unfavorable over-wintering conditions resulting from climate change, and could cause a loss of genetic diversity through random drift. Using long-term demographic data and samples collected over several years, I will assess the complex interaction between landscape structure, demographic fluctuations and genetic diversity. I will describe the population genetic response to repeated demographic collapses by genotyping samples collected before and after collapses. I will also quantify the time lag between changes in spatial genetic structure and changes in underlying rates of movement.

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

Fish growth can influence maturation timing, with fast growers maturing at a younger age. Furthermore, a different age at maturity can lead to the adoption of alternative reproductive tactics, such as delayed spawning in younger breeding female salmon. The goal of my project is to understand to what degree growth influences the expression of different reproductive tactics in female Kokanee Salmon (Oncorhynchus nerka). Females return to spawn with either a silver colour or a common red nuptial colour. Silver females were generally younger and smaller than the red ones. To compare the growth rate between two phenotypes, I will reconstruct the fish body size at an early age with an established otolith model

PhD candidate
Supervisor: Christopher G. Guglielmo
Joint-Supervisor: Brian A. Branfireun

Mercury is a global threat to human and environmental health. Anthropogenic emissions of mercury have doubled over the past two centuries. Recent research found that songbirds which feed primary invertebrates often accumulate at ppm level, which can cause negative effects in bird fitness. Many migrants can exposure to mercury on their breeding/wintering grounds, as well as migrating routes. How mercury affect bird migration and over winter is still un-known. I will be looking for what is the mercury level during migration: How mercury affect avian migrating distance? Do birds with higher Hg burden face lower survival rate over wintering period and migrating ability affected by mercury in the wind tunnel as well. Hopefully my study will give insight into mercury effects on songbird migration.

Supervisor: Chris Guglielmo

Endurance flight during migration is an energetically demanding activity for birds to perform. As a result, birds may be faced with trade-offs between migration and other energetically costly processes, such as immune system functioning.  Avian blood parasites consume host resources and diminish the oxygen carrying capacity of blood. This may decrease a bird’s resource pool to the point where both endurance flight and immune defense cannot occur simultaneously, as well as limit the ability of birds to perform strenuous exercise. Using parasite counts, genetic analyses, and measures of immune system functioning, I will examine the naturally occurring levels of blood parasite infection and immune system functioning within a migrating population of yellow-rumped warblers (Setophaga coronata). I will then assess the impact of infection on endurance flight performance and immune system functioning within the laboratory.

Supervisor: Scott MacDougall-Shackleton
M.Sc Candidate

Climate change is affecting an increasing number of natural systems and populations across the globe. Along with rises in temperature and precipitation levels, climate change has also been linked to increasing the latency and severity of storms at nearly all latitudes. Such storms are creating difficult environmental conditions for many species, including birds. I will be studying the long-term stress and behavioural effects that inclement winter weather has on a migrating species, white-throated sparrows (Zonotrichia albicollis). To achieve such results, I will be using a hypobaric climatic wind tunnel to simulate high and low pressure systems which affects temperature and barometric pressure accordingly. The stress and behavioural responses will give an insight into how a migrating songbird is responding to human induced climate change.

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

Soil organisms are an important part of nutrient cycling, converting organic material into nitrate forms accessible to plants. With the increased antibiotic use in farm animals to prevent sickness and increase productivity, increasing amounts of antibiotics and their metabolites are reaching the agricultural fields through animal waste used as manure. Many of these drugs are persistent in the environment and can have negative effects on soil organisms. In this project I looked at the effects of three antibiotics. I examined their persistence in soil, their effects on nutrient cycling (mineralization and nitrification), and abundance of ammonia-oxidizing microorganisms (bacteria and archaea that convert ammonia into nitrate). I will present results on mineralization in soils under different drug treatments.

Supervisor: Dr. Bryan Neff
Degree: Ph.D. Candidate
A major challenge in restoring native biodiversity is restoring extirpated populations. Candidate populations for reintroduction can be selected based on the classic concept of genetic matching (genetic connectivity) and the emerging concept of environment matching (similar environments). Here, I examined the performance of three candidate populations of Atlantic salmon (Salmo salar) being considered for reintroduction into Lake Ontario: Saint-Jean (genetic match), Sebago (environment match), and LaHave (neither a genetic nor environment match). Juvenile salmon were exposed to competition with juvenile non-native salmonids, a known impediment to restoration in Lake Ontario. Sebago salmon appear to have better performance than the other two populations examined, suggesting that there are merits to considering candidate populations that are environment matches to the altered environments of extirpated populations.

Supervisor: Dr. Zoë Lindo
Degree: M.Sc (Biology)
Microinvertebrates are a ubiquitous component of almost all terrestrial soil communities. They play a major role in decomposition, stimulate microbial activity, and contribute to soil formation and turnover. However, the enormous amount of undiscovered diversity among soil fauna and the difficulty of directly observing their activities means new methods must be developed to better understand how these organisms will respond to anthropogenic environmental change and what implications this may have for terrestrial systems. My research applies metrics of community composition and function based on trait and body size distributions and compares these to classic taxonomic species identity approaches. I have used these methods in lab and field experiments to determine the combined and individual effects of environmental variables and nutrient availability on soil microinvertebrate community composition.