Professor and Chair
Plant Secondary MetabolismResearch Wesbsite
My research program is based on the study of plant secondary metabolites or phytochemicals. I am interested in how plants use phytochemicals to interact with other organisms or defend themselves against environmental factors such as wounding and pathogen attack. We spend a lot of time isolating and analysing phytochemicals using various chromatographic techniques and bioassays. Our research activities can be divided into two categories: 1) Biosynthesis of Suberin and 2) Chemical Ecology of Phytochemicals. Each is briefly described below.
1) Biosynthesis of Suberin
In response to wounding and other environmental stresses, the cells of plants exposed to the stress may be induced to form suberin. Suberin is the name given to a specific cell wall modification deposited in periderm, wound periderm, and endo- and exodermal cells that involves the biosynthesis of a poly(phenolic) domain (SPPD) within the cell wall as well as a poly(aliphatic) domain (SPAD) between the plasma membrane and the cell wall. The structure of suberin has undergone revision as new information about its chemical composition is revealed. We recently proposed a new structural model for potato tuber suberin, based on our studies as well as extensive literature reports. We have also developed a model to help understand the macromolecular assembly of the SPPD and have two current projects testing it. More recently, we have initiated a metabolite profiling project to better understand the changes in both primary and secondary metabolism that occur during suberization.
2) Chemical Ecology of Phytochemicals
Many phytochemicals are biologically active and play a direct role in the interaction between a plant and its environment. In my lab we are investigating the potential of ginsenosides to act as allelochemicals and how different soilborne fungi respond to them in vitro.
Assistant Professor of Environmetrics
Ecological statistics and modellingResearch Wesbsite
Ecological systems are complicated -- that is an understatement. Dynamics in an ecosystem result from the combined effects of processes at the individual, population, and community levels that are each affected by many factors, both internal and external. Studying these systems is further complicated by the fact that direct observations of individuals are often impossible or impractical, so that sophisticated methods are needed to extract information about the system from the data that is collected.
I am jointly appointed between the Department of Statistical and Actuarial Science and the Department of Biology, and my research focuses on developing novel statistical methods for the analysis of data from ecological studies and on working with biologists and wildlife scientists to implement these methods in their own research. In particular, I am interested in hierarchical models for ecological data that are fit in a Bayesian framework using advanced Markov chain Monte Carlo Sampling techniques. My primary area of application is in the analysis of data from mark-recapture studies of wild animal populations to study the basic biology of these animals and to understand the effects of human impacts including habitat disturbance and climate change. Specific projects I have worked on include:
I have also worked recently on complex models to identify factors affecting variability in individual behaviours, like parenting behaviour in songbirds and aggressive behaviours in hermit crabs (Bridger, 2015), and on new methods to study changes in a predators preferences for different prey (Roualdes et al., in preparation).
Canada Research Chair in Environment and Sustainability
Cross-appointed with Earth Sciences and Geography
Ecohydrology, biogeochemistry and wetland ecosystem scienceResearch Wesbsite
Taking an interdisciplinary environmental science approach, Dr. Branfireun and his research group seek to understand the bidirectional nature of hydrological – ecological interactions at a range of scales. They direct their efforts toward ecosystems that are particularly sensitive to the impacts of natural and human-induced environmental change. Dr. Branfireun is involved in projects studying the hydrology, ecology and biogeochemistry of wetland-dominated environments from the Canadian sub-arctic to the sub-tropics of Mexico. Dr. Branfireun's research program is strongly field oriented, using the latest approaches to the measurement of environmental processes. He also directs a modern laboratory facility in the BIOTRON Institute for Experimental Climate Change Research at Western University for the study of speciated trace metals in the environment such as mercury and arsenic.
Brain Metabolism and AgingResearch Wesbsite
Optimizing Brain Metabolism for Successful Aging
The Cumming laboratory studies the changes in brain metabolism and antioxidant defence that occur with age. We are trying to understand how age-dependent alterations in brain metabolism affect memory and contribute to neurodegenerative disorders, including Alzheimer’s disease.
We currently are using a variety of biochemical, genetic, microscopic and neuroimaging techniques to examine aerobic glycolysis and antioxidant response in both cell culture and animal models of aging and neurodegenerative diseases.
Developmental Biology - Extracellular Matrix Remodelling scienceResearch Wesbsite
Extracellular matrix remodelling in Developing Xenopus laevis
Healthy tissue function requires proper cell adhesion, and this adhesion is in part provided by proteins collectively known as the extracellular matrix (ECM). The ECM can be cut and remodelled by proteins called matrix metalloproteinases (MMPs). The function of MMPs is in turn regulated by inhibitors named RECK and TIMPs. Many cell types lose their normal functions when cell-ECM interactions are broken, in a process similar to the transformation of healthy cells into uncontrolled cancer cells. We use the frog, Xenopus laevis, as well as a number of cell lines as model systems to examine how specific ECM remodelling events control cell migration, invasion and ultimately cell fate. Several embryological and microinjection, as well as in vitro and in vivo cell culture techniques are used to investigate expression patterns, cell signalling events, and cytoskeletal rearrangements and how they are related to ECM remodelling events, and diverse processes such as cell proliferation, migration and death.
Currently we are focusing on a membrane bound MMP named MT1-MMP. MT1-MMP appears to be a key lynch-pin in several processes as it is believed to not only regulate ECM remodelling, but also to activate other MMPs, transduce signalling cascades, as well as impact cellular viability. Understanding this regulation would be crucial in our understanding of the roles that these molecules play in development and disease.
Fungal Cell and Molecular BiologyResearch Wesbsite
My research interests centre around fungal cell biology. I have worked on elucidating the structure and function of fungal fimbirae. Analogous to bacterial pili, fimbriae are long flexuous fibrils 7 nm in diameter and up to 20 µm in length. Originally described on the anther smut Microbotryum violaceum, they have been shown to be present on a wide variety of fungi. In addition I have added my expertise to various other projects in the life and material sciences.
Developmental Biology - Extracellular Matrix Remodelling scienceResearch Wesbsite
In the last several years my group has made major strides in the development of Tetranychus urticae (spider mite) as an arthropod herbivore model. T. urticae has a rapid life cycle and feeds on over 1000 plant species. It therefore represents a key pest for greenhouse crops, annual field crops and many horticultural crops. The use of chemical pesticides is the predominant method of controlling spider mites. However, due to their short generation time and high reproduction rate, spider mites have developed resistance to the major pesticide groups, presenting a major challenge to control them. Currently, there are no cultivars resistant to spider mites.
We have led the T. urticae whole genome sequencing project [funded by the USA Department of Energy and Joint Genome Institute (DOE-JGI; https://jgi.doe.gov/why-sequence-the-two-spotted-spider-mite/ )], and established an international collaborative team GAP-M, ( http://www.spidermite.org/?page_id=108), funded by Genome Canada, Ontario Genomics Institute and Ontario Ministry of Research and Innovation, to assemble, annotate and analyse the T. urticae genome. We developed protocols for spider mite rearing, established a normal table of spider mite development, and developed methods for large-scale embryo collections, assay of gene expression (in situ hybridization and antibody staining) and inactivation of genes using RNA interference (RNAi). We are now moving forward with the goal of developing environmentally sound pest control strategies that reduce environmental pollution and energy consumption in agricultureEvolution of developmental mechanisms
We are examining the functions and expression patterns of genes analogous to Drosophila segmentation genes in Copidosoma floridanum, an insect with a radically derived mode of early development. We are using in-situ hybridisation, antibody staining and ds RNAi to determine how the role of these genes may have changed over evolutionary time.Biotechnology
We are using fundamental knowledge gathered in the projects described above to develop novel tools for sustainable agriculture as well as in developing novel materials. To date, two applications are under development:
Arabidopsis Developmental Genetics/ Genomics of plant-pest interaction/ BiotechnologyResearch Wesbsite
Genomics of plant-pest interaction
In order to develop alternative pest control strategies for sustainable agriculture, it is important to understand the interaction between plants and their herbivores. We are using Arabidopsis thaliana, tomato and grapevine as plant models, and the newly established chelicerate model Tetranychus urticae (spider mite) to uncover genomic responses of both organisms during plant-herbivore interaction. This work is part of an international collaborative initiative (GAP-M, Genomics in Agricultural Pest Management) that is funded by Genome Canada and Ontario Genomics Institute, and by Ontario Ministry of Research and Innovation.Arabidopsis developmental genetics
The aim of my research is to understand the molecular mechanisms that govern diversity of plant shoot forms. We are using the reference plant Arabidopsis thaliana for which excellent molecular-genetic resources are available and thousands of wild inbred strains have been collected, including some (e.g. Sy-0) with altered shoot morphology. We initially identified changes in the expression of flowering time genes FLC, FRI and HUA2, as required for the establishment of the Sy-0 phenotype and the lab is now focused on understanding the functions of the HUA2 gene, a putative pre-mRNA processing factor. We are also analyzing natural genetic variations in the floral regulator MAF2 that is a member of the tandemly duplicated cluster of MADS-box containing transcription factors in Arabidopsis thaliana.Biotechnology
The overall goal is to exploit fundamental knowledge to develop novel tools for sustainable agriculture and development of novel materials. To date, two applications are under development:
Animal ecological and evolutionary physiology
I have wide ranging research interests in physiological ecology, and this is reflected in the diversity of lab and field projects attempted (usually successfully) by me, my students and post-docs. Officially, I try to integrate physiology, biochemistry, behaviour, ecology, evolution and conservation biology. Unofficially, my lab group is in a constant state of identity crisis about what we really do. Our work is inherently multi-disciplinary and provides a means to understand how mechanistic processes operate within the larger context of whole organism performance. Physiology, in concert with morphology and behaviour, influences how animals interact with the environment, and understanding its flexibility will help us to predict how species may respond to natural or man-made perturbations.
My current research focuses on the physiology of endurance flight and stopover refueling in migratory birds and bats. We have a wide variety of laboratory and field studies underway using the wind tunnel and other unique capabilities of the Advanced Facility for Avian Research, my mobile Field Laboratory for Integrative Ecological Research (FLIER), and a digital telemetry array that we are installing in Ontario in collaboration with Bird Studies Canada.
Professor; Director, Environmental Sciences Western field station & Associate Chair (Graduate)
Animal ecological and evolutionary physiologyResearch Wesbsite
I am a terrestrial plant ecologist with interests in biogeochemistry, community ecology, physiological plant ecology and global change ecology. I use field experimentation, laboratory methods and theoretical modeling to explore questions ranging from resource acquisition by individual plants to species responses at the community level and nutrient cycling at the ecosystem level. I am particularly interested in winter ecology, and exploring how plants and microorganisms interact to regulate nutrient cycling in both natural and managed systems.
Associate Professor; Cross-appointed to Computer Science and Ophthalmology; Associate Scientist at the Lawson Health Research Institute
Genome organization and integrity
Biological conservation, isotope ecology
Within a theme of adaptations to global change, Hobson’s research is at the interface between applied animal ecology/conservation and Biogeochemistry with particular emphasis on the development and use of naturally occurring stable isotopes and other intrinsic markers to answer otherwise intractable questions. This approach has been applied to a broad range of research questions ranging from the ecology of individuals to communities at local to continental scales. Hobson’s most recent emphasis has been on addressing nutrient allocation strategies in birds and full life-cycle conservation of migratory birds and insects through the development and use of isoscapes. This work seeks to examine how anthropogenic changes are influencing migratory organisms throughout their annual cycles and to identify best conservation practices.
Eukaryotic Cell Division
Eukaryotic cells rely on the dynamic interactions of DNA, RNA, proteins and lipids in order to grow, divide and respond "intelligently" to environmental and/or developmental cues. All of the information necessary to carry out these complex functions must be encoded into the genome in a "self-extracting" form. An understanding of the molecular mechanisms used to extract, express, copy, and protect this information has been, and continues to be, a major goal of biology.
One of the premier organisms used to understand this complexity is the fission yeast, Schizosaccharomyces pombe. This unicellular eukaryote provides tremendous experimental advantages that include the ease of genetic manipulation, the availability of genomics tools, and the capacity to apply advanced biochemistry and fluorescence microscopy. Research in the lab focuses these tools on the regulatory modules governing the successful completion of cytokinesis.
Cytokinesis comprises the stage of the cell cycle in which newly segregated chromosomes are irreversibly separated into independent daughter cells by the mechanical cleavage of the mother cell into two. The successful completion of cytokinesis requires the intricate interplay of gene products that range from signalling molecules to elements of the cytoskeleton. Thus, this experimental system provides an excellent opportunity to increase our understanding of how eukaryotic cells assemble and regulate complex genetic networks. Through the study of cytokinesis in we hope to reveal general themes, or rules of genetic regulation, that are applicable to the control of genetic pathways across all eukaryotes.
Cell Signaling in Vertebrate EmbryosResearch Wesbsite
http://thekellylab.weebly.com (Please acess via WiFi)
The series of events that pattern the vertebrate embryo may be considered a proliferative, almost cancerous-like growth phase goverened by strict developmental guidelines. Many of these events rely on cell-cell communication and the transduction of signals across the plasma membrane of the receiving cell. Thus, disrupting this signaling has dramatic and disastrous effects on many aspects of cell physiology including, but not limited to, cell-cell and cell-substrate interactions, cell polarity, endo- and exocytosis, migration, proliferation, and differentiation. My research specifically deals with the cell-cell signaling events that pattern the developing vertebrate embryo, and particulary how crosstalk generated by Reactive Oxygen Species influence Wnt-beta-catenin, Planar Cell Polarity, and G-Protein Coupled Receptor-linked pathways. The models that I use vary from established tissue culture cells like the mouse F9 embryonal carcinoma line, to the zebrafish (Danio rerio) embryo. The biological phenomenon that piques my interest is the epithelial-to-mesenchymal transition, which is involved in normal embryonic development including extraembryonic endoderm formation, gastrulation and heart formation, as well in human disease conditions such as fibrosis and metastatic cancer.
Molecular ecology, landscape genetics and conservation geneticsResearch Wesbsite
I am a molecular ecologist and research in my lab integrates concepts and methods from population genetics, conservation biology and landscape ecology. We use a combination of field and lab techniques to investigate factors that affect the genetic diversity, and spatial genetic structure, of populations. Applied aspects of our research relate to conservation, habitat fragmentation, and the management of invasive and pest species.
Gene Families and RegulationResearch Wesbsite
I have always been fascinated by the complexity of regulatory processes in organisms. It is amazing to see how organisms are able to sense small changes in the environment or in their own metabolism, and to respond by changing the expression of select genes. This can lead to tissue- and/or cell-specific responses such as those involved in protein reallocation and complex formation, or changes in activity spectra of enzymes. The complexity of these events is often increased as many reactions involve multi gene families encoding proteins that have highly similar but not identical sequences that mediate and fine-tune cellular responses.
To study regulatory events in plants we chose as a model system the arogenate dehydratase family (ADTs) in Arabidopsis thaliana. In Arabidopsis there are six members in the ADT family and these enzymes catalyze the last step in the synthesis of phenylalanine. We believe that these enzymes are catalyzing a key step in the production of phenylalanine and thereby co-ordinating the Shikimate pathway and the many branches of phenylpropanoid biosynthesis. We are interested to understand and characterizing as many of the molecular aspects which relate to this gene family inArabidopsisthaliana. The questions we are asking can be at times as simple as: why does Arabidopsisneed six versions of this enzyme? How do these enzymes differ? Are there post-translational modifications? Do these different members of the ADT family contribute to different protein complexes? Are the enzymes or the encoding genes regulated differentially in response to different internal and environmental cues? We already have found some answers. All six ADTs code for proteins which have similar but not identical enzymatic functions. All six ADTs are expressed in all tissues and developmental stages analyzed, but not at the same levels. The encoded proteins have unique subcellular localization patterns. And just to make it even more fun, the six ADTs form homo- and hetero dimers. We still need to investigate if these dimers are formed in all parts of the plant, if they result in unique compositions of protein complexes and what functional consequences these dimer and/or complex formations may have.
Yeast Systematics, Ecology, and EvolutionResearch Wesbsite
Lachance studies the evolution, biogeography, biodiversity, and systematics of ascomycetous yeasts. Long-term objectives have been to document yeast biodiversity in natural habitats at the interface of insects and plants, the process of species formation in nature, and the underlying causes of the global distribution of yeasts. The habitats have included floricolous insects, particularly Coleoptera.
One focal point is a group of large-spored Metschnikowia species associated with nitidulid beetles that visit flowers of Convolvulacae and other plants that produce short-lived flowers. The biogeography of these yeasts, their mechanisms of reproductive isolation, and the reconstruction of speciation events have been examined in populations whose distribution ranges across the New World and the Australian-Pacific region. Currently these yeasts are being studied at the level of the whole genome. This has allowed us to construct a robust phylogeny and to study the genetic basis for reproductive isolation and other phenomena.
Community ecology, Soil ecologyResearch Wesbsite
Many ecosystems are currently undergoing dramatic changes in biodiversity due to habitat loss and fragmentation associated with land use change, pollution, overexploitation, and climate change. Mitigating these effects requires an understanding of the drivers of biodiversity loss, and the consequences of loss on ecosystem processes and functioning. As there is unequivocal evidence for directly linking the effects of global change, soil biodiversity and nutrient cycling, my research uses a combined aboveground-belowground approach for understanding the regulation and functional significance of biodiversity. My lab uses experiments in the field, greenhouse and laboratory (BIOTRON), and the integration of empirical results with current theoretical perspectives to help identify how to mitigate the impacts of environmental change and maintain ecosystem function in soil systems.
Ecoimmunology and behavioural ecology of migratory birdsResearch Wesbsite
Parasites are taxonomically and geographically widespread, and can have catastrophic effects on host survival and reproduction. As a result, parasites are increasingly recognized as critical drivers of host evolution. Research in my lab seeks to understand how evolutionary processes such as parasite-mediated selection interact with ecological processes such as seasonal migration, natal dispersal, mate choice and immune development to shape patterns of genetic variation within and among songbird populations. Specific projects include evolutionary arms races between songbirds and malarial parasites; geographic variation in parasite assemblages and in immune-related loci such as the major histocompatibility complex (MHC); effects of infectious disease on the timing, distance and success of seasonal migration; ecological immunology of migration and dispersal; and chemical and acoustic signals by which songbirds advertise their genetic makeup at MHC and assess that of potential mates.
Mechanisms of Metal ToleranceResearch Wesbsite
Plants have a remarkable ability to withstand high concentrations of potentially toxic contaminants in their environment. My research aims to better understand the biochemical and physiological mechanisms that permit such tolerance. Much of our work is done at the whole-plant level although individuals projects have ventured into the surrounding soil, including microbes in the rhizosphere; examined tissue-level and sub-cellular compartments in which contaminants accumulate; or into the realm of genes and enzymes. The approaches that we take include: (1) investigate the production and exudation of organic compounds as a mechanism to detoxify metal ions, (2) determine the localization of metal ions and other contaminants at the subcellular level, (3) model the movement of contaminants from the soil into the plant and (4) identify the relationship between phytotoxicity and a number of biochemical pathways that mediate plant stress. Many projects in the lab involve crop plants, but our choice is based on which plant species or cultivar best allows us to test a particular hypothesis, and not on its economic value.
Helen I Battle Professor
Behavioural and Chemical Ecology of InsectsResearch Wesbsite
The main thrust of my research programme is to understand the reproductive strategies of insects that migrate in response to either predictable or unpredictable habitat change. The research is multidisciplinary in nature, looking at the behavioural and ecological aspects, as well as using physiological and molecular approaches to understand the mechanisms controlling the reproductive biology in species where mate location and mate choice are modulated by sex pheromones. I am also interested in different aspects of plant-insect and host-parasitoid interactions that involve chemical cues (infochemicals). I have generally chosen to work on pest species, or their natural enemies, as model research systems. This allows us to not only address basic questions in reproductive biology but also to generate data that may be used in the development of more environmentally rational approaches to insect control.
Marine Ecology and Educational Technology
My work revolves around the interaction between people and the marine environment and aims to promote ocean sustainability by improving management and conservation outcomes. To achieve this goal, I use a diverse array of empirical and observational approaches to study the behavior, movement ecology and population dynamics of marine species, with a strong focus on species that are directly exploited or adversely affected by commercial and recreational fisheries.
I also conduct pedagogical research focused on the use of educational technology to enhance learning outcomes for students. My current work explores the benefits of disseminating assessment feedback through virtual learning environments.
Communicating with sound and vibrationResearch Wesbsite
I am interested in understanding how different animals, particularly invertebrates, perceive sounds and also vibrations. My research uses different experimental techniques like laser vibrometry and 3D uCT imaging, and couples them with physics and mechanics based modelling to understand how these two types of mechanosensory systems function.
My research aims at understanding the different mechanisms used by these sensory systems to adapt to their ecological needs and achieve high sensitivity. An obvious mechanism is structure, both of the sensor itself and also of the whole body that that sensor is embedded in.
I am also particularly interested in a unique physiological mechanism called 'active amplification' that only some mechanosensory systems possess. In insects this process works through the sensory neurons which expend their own energy to actively amplify incoming sounds and the resulting vibrations. This amplification occurs through the activity of motor proteins within these neurons. This is a unique process for many reasons, and not least because it blends the sensory with the motor. As a result, I spend a lot of time thinking about these categories themselves, about whether and when they are useful to consider as separate.
I also occasionally work in sound and vibration production, since much of the experimental and theoretical apparatus is the same. One area of sound production that I am particularly interested in is the use of acoustic tools and objects. I've shown that simple insects like tree crickets can make optimal tools and that optimization is achievable using a small set of rules. In the future, I want to examine this cognitive system further. I also want to explore the possibility that the size of such 'rule-sets' might be a better way to think about the complexity of animal tools and objects.
Genetics of behaviour and species formationResearch Wesbsite
The broad-scale research goals of my laboratory are to understand the genetic and neural bases of variation in behaviour. Two behaviours that are critical for survival and reproduction are aggression and mating behaviour. While these traits have been extensively studied in males, their underlying genetic and neural basis in females is poorly understood. My research group seeks to identify the underlying genetic and neural variation that leads to variation in female mating receptivity and female aggression. We use the model system of Drosophila due to the extensive genetic and molecular tools this species offers. We use a mix of quantitative genetics, molecular genetics, neuroscience, cellular biology, and behavioural assays in order to understand these complex traits.
Behavioural Ecology; Seasonal and life history timingResearch Wesbsite
My research integrates evolutionary theory and empirical studies to study the adaptive timing behaviour of migratory birds and fish. Ongoing projects include sex differences in the stopover behaviour and timing of warblers in southern Ontario, the evolution & ecology of introduced salmon in the Great Lakes, environmental cues of annual migration timing in kokanee salmon, and optimal maturation schedules in lake whitefish. Questions about seasonal timing are critical in this era of climate change, when phenological mismatch with the environment has the potential to impact populations.
Molecular and Behavioural EcologyResearch Wesbsite
My lab’s long-term goal is to provide an understanding of phenotypic diversity in natural populations – why do individuals look and act the way they do – from molecules to organisms living in their natural environment. Understanding the forces that shape and affect our world’s biodiversity is a fundamental objective in biology and is important for pure discovery as well as the conservation of our natural resources. This objective requires scientific research that addresses the genetic basis of behavioural, physiological, and morphological variation. My lab uses genetic and molecular tools to examine questions at the interface of evolution, ecology, and genomics. This approach has the potential to provide a comprehensive understanding of phenotypic diversity including the evolution of genes, gene function, and the interaction between genes and the environment.
We predominately work with fish including bluegill, bullhead, guppy, and salmon. Several of these species are socially and economically important in Canada and represent billions of dollars per year to our economy through the recreational and commercial fisheries as well as the aquaculture industry. Thus, the scientific knowledge that my lab produces is also important for the effective management of our natural resources and for ensuring their sustainability. Our research falls into four areas:
Molecular mechanisms of morphogenesisResearch Wesbsite
For the past two decades, the application of genetic dissection and molecular biology has resulted in an explosion in our knowledge of the mechanisms that control the process of Development. One of the major experimental systems that contributed to this explosion is the model organism Drosophila melanogaster. My laboratory is studying two aspects of the molecular basis of the body plan. The body plan is required for positioning and determining the identity of the various body parts.
The first aspect of the body plan that we study is the role that the protein encoded by the gene fushi tarazu plays in determining the number of segments of Drosophila body plan. Fushi tarazu protein is expressed in every other segment resulting in bands of Fushi tarazu expression across the anterior posterior axis. Without fushi tarazu protein, the embryo develops lacking half of its segments.
The second aspect of the body plan that we study is the role of the proteins encoded by the two genes, proboscipedia and Sex combs reduced, in determining of the identity of four body parts. Both proboscipedia and Sex combs reduced are homeotic genes. Mutant alleles in homeotic genes result in striking phenotypes where one body part is transformed into the likeness of another. Loss-of-Proboscipedia protein results in the transformation of the mouth parts into a pair of first leg tarsi.
Assistant Professor, Departmental Statistical Consultant
Forest ecology, landscape pathology, forest health monitoring, statistical analysis
My main scientific questions are: How much tree mortality is normal in a forest? And, how can we identify places and times where that baseline mortality rate is exceeded? My responsibilities in the Biology Department currently include 1) teaching field biology courses (undergraduate), 2) teaching statistics courses (graduate), and 3) statistical consulting.
I currently offer two field biology courses. Biol 3230F is based on campus with day trips to nearby field sites in early fall. The course emphasizes, study design and field measurement techniques. My other field course, Adirondack Forest Ecology, is offered in collaboration with other Ontario universities (oupfb.ca) and takes place in mid-May at the Newcomb Campus research station in the central Adirondack Mountains, NY, USA. The students and I spend two weeks living at the research station, exploring the flora, fauna, and history of the region, and practicing field sampling methods.
Recent graduate courses have included mixed effects modeling, multivariate statistics, and spatial statistics. I typically teach one graduate statistics course in the winter term. Courses emphasize informed application of analytical techniques using R and based on a comprehensive conceptual understanding of the underlying methodology but not based on formal mathematical derivations.
In addition to teaching these courses I offer statistical consulting to researchers in the Biology Department including faculty, post-docs, graduate & undergraduate honours thesis students. If you are interested in any of these or other help with study design, statistics or R, please email me!
Genetics of Social BehaviorResearch Wesbsite
In my lab, we are interested in determining the neurogenetic mechanisms by which animals respond to the presence of another similar individual. How does an animal decide what to do with the information that another individual is nearby? What are the neurogenetic circuitries underlying social interactions?
Using a now widespread behaviour paradigm designed in my lab, we assess one aspect of the fruit flies’ (Drosphila melanogaster) social behaviour: their preferred social space (space "bubble"). In an undisturbed group, flies will settle a reproducible distance that will depend on their genotype and their environment (social experience, their age and that their parents, or exposure to toxins, synaptic function...). We also quantify another type of response to social cues: flies strongly avoid the volatile substance Drosophila stressed odorant (dSO) emitted by stressed flies. Those paradigms have the advantage of being straightforward to implement, which allow us to pursue several lines of research, falling under two main umbrellas:
Fundamental Behavioural Genetics questions:
We are pursuing the neurogenetic characterization of social space behaviours in Drosophila, determining the neural circuitry underlying the social distance preference. We address these questions using both genetic mutants and biochemical approaches.
Through collaboration with Agriculture Canada, we also are characterizing dSO: its emission, its reception, and its composition (beyond CO2).
Study of candidate genes:
Taking advantage of the simple behavioural paradigms and use them as diagnostic tools to elucidate conserved pathways underlying candidate genes or environmental conditions affecting human behaviours, in order to identify potential targets for drug discovery. Indeed, inappropriate response to others is a shared deficit in many mental disorders, such as schizophrenia and bipolar disorders.
Our work contributes to the mapping of the central brain neural substrate underlying basic (non-sexual and non-aggressive) response to another nearby fly. This work will be relevant not only to studies of Drosophila behaviour, but also to genetics of social behaviour in other organisms. Indeed, as for other behaviours initially dissected in Drosophila – learning and memory, circadian rhythm (Nobel Prize 2017 Physiology and Medicine) - the cellular and molecular basis of social behaviour might be conserved through evolution.
Finally, I deeply enjoy sharing my fascination for the complexity of the biological world with students of all levels. I think that teaching happens beyond the classroom, and in parallel to teaching in the classroom, I have been continuously mentoring undergraduate and graduate students in my research projects.
Insects at Low TemperaturesResearch Wesbsite
Insect thermal biology; Insect-yeast interactions; Polar biology; Arctic spiders; Applied thermal biology; Sterile insect releases; Overwinter biology; Functional genomics.
Genome evolution and genetic diversity of microbial eukaryotesResearch Wesbsite
We study genome architecture, genetic diversity, and the evolutionary forces that fashion genes and chromosomes. We’re interested in how nonadaptive processes shape genomes, including their nucleotide composition, compactness, conformation, chromosome number and telomeres. Much of our research employs protists (microbial eukaryotes). Protists have among the most diverse and eccentric genomes in the biological world, yet they are generally an untapped resource for studying genome evolution. We love weird genomes and trying to understand how they got that way.
Comparative Physiology and BiochemistryResearch Wesbsite
My research program aims to understand how the metabolic systems of animals adapt to environmental challenges. In particular I am interested in the strategies used by endothermic animals to deal with cold environments. When challenged by the cold, most endotherms increase metabolic rate and heat production. We study enzymatic and mitochondrial “futile cycles” in bumblebees and rats as possible mechanisms of non-shivering thermogenesis.
Some small endotherms use an apparently opposite strategy by entering hibernation or torpor during the coldest parts of the year. These states involve profound reductions of body temperature and metabolic rate, allowing for energetic savings at a time when food supplies are typically at their lowest. We study mitochondrial metabolism in hibernation (using ground squirrels) and daily torpor (using dwarf Siberian hamsters) to better understand the mechanisms of metabolic suppression, and potential interactions with temperature and diet.
Microbial Ecology and BioinformaticsResearch Wesbsite
In most environments, microbes thrive and billions live together. Although invisible to us, these billions of microbes perform key biogeochemical functions, such as carbon cycling and primary production, that enable other life to exist. In the Tai lab, we investigate who are these billions of microbes, how do they interact with each other and with other members of the community, what are they doing, and how does their activity shape their environment and their ecosystem. Our research involves community ecology, biogeography, evolution, genomics, and bioinformatics. Most recently, my research has centred around the microbes inhabiting marine beaches and the fascinating symbiotic microbial communities in the hindguts of termites.
Evolution, Ecology and the Biomechanics of Animal Design
My research interests focus primarily on the interface between evolution, ecology, and biomechanics. In general, I am curious about constraints in design that might set the upper limits to performance for such activities as jumping, running, flying and biting. In this context, I have used the decapod claw (crabs and lobsters) as a model system. Decapod claws are exceptionally strong ‘biting’ devices used in the subjugation of hard-shelled prey; although simple in design, they are one of the strongest biting devices observed in any animal group. This is not surprising, considering that durophagous crabs and lobsters have been hunting hard-shelled prey, such as snails and clams, for millions of years. Indeed, this system provides one of the best examples of a coevolutionary arms-race between predator and prey. I have documented ecologically significant variation in claw performance and design among six species of Cancer crabs, which live on the Pacific Northwest coast (Bamfield Marine Station). I have also examined variation in claw performance and design at the population level, documenting rapid shifts in performance attributes in an invasive species. This work was conducted on the invasive green crab, Carcinus maenas, which now has a world-wide distribution and a well-documented invasion history in the Gulf of Maine. My research integrates approaches from diverse fields, including morphometrics, physiology, and development within an evolutionary context, to understand how animals are ‘designed’.
Behavioural Genetics and SociobiologyResearch Wesbsite
My lab studies the biological basis of insect social behaviour; how it evolves, how it is maintained and why some species are social while others are not. Much like human societies, eusocial ants, bees, wasps and termites show bewildering complexity in how their societies are structured. Yet for insects, this complexity is derived from an economically simple division of labour into reproductive and non-reproductive specialists. Studying reproductive division of labour in insects at the level of the gene can provide key insights into how complex social systems evolved from simpler, ancestral ones. Studies on social insects can also help understand how our own societies might naturally mediate conflict, cooperation, altruism and spite. My lab uses natural history information from insects, the theory of social evolution and state-of-the-art gene technology imported from the medical sciences to discover how molecules influence the evolution and expression of social traits. Conversely, we are interested in how sociality itself influences the transmission and expression of genes. Within this theme, my lab tackles four broad questions:
Fungal Ecology and SystematicsResearch Wesbsite
The long-term research goal of the Thorn lab is to explore the relationships between phylogeny and function - evolution and ecology - in the fungi. Fungi are critically important in most terrestrial ecosystems, providing mineral nutrients to vascular plants through mycorrhizal symbioses and decomposing plant remains to recycle both organic and inorganic nutrients through the ecosystem. Fungi form networks of microscopic filamentous cells, and interact with all of the organisms - ranging from bacteria to mammals and plants - that share their physical environment. Although processes, such as nutrient cycling, that are driven by fungi are well recognized, almost nothing is known about which specific organisms are doing the job or how their interactions with other organisms affect the outcome of the process. A hypothesis underlying this work is that species are unique, multiplex organisms which can only be thought of as functionally redundant in terms of their ability to carry out a single biochemical reaction under laboratory conditions. Different species of fungi may indeed share this biochemical capacity, but each has a unique suite of other biochemical capacities and inter-organismal interactions that makes it unique in the natural environment.
Major research areas in Thorn’s lab include phylogeny of fungi inhabiting soil, litter and wood, discovery and description of fungal diversity, and determining the effects of disturbance, including agriculture, climate change and forestry, on fungal diversity and ecosystem function.
Cell Biology and GlycobiologyResearch Wesbsite
The main areas of my research interests include the following: Biological Activity and Functions of Animal and Plant Lectins, Glycobiology, Molecular Mechanisms of Cellular Stress Responses, Cellular Signaling, Reactive Oxygen Species, Redox-Regulation of Cellular Functions, Cancer Biology, Lymphangiogenic Factors, Innate Immunity.
Global change biology, plant physiology and ecologyResearch Wesbsite
My research focuses on physiological responses to high temperatures, drought stress and changes in CO2 concentration, with the goal of determining the mechanisms underpinning plant responses to global change at molecular and biochemical scales and the implications of these responses for the larger community and ecosystem scales.
Professor & Faculty Scholar
Wildlife Population, Conservation, and Behavioural EcologyResearch Wesbsite
We work on fear. Particularly, how the fear of predators alters the brain, behaviour, and physiology of individuals in addition to population dynamics and community structure. We examine how fear applies to conservation, biodiversity and management, and its implications for human mental health including Post-Traumatic Stress Disorder. We conduct manipulations in the field, in semi-natural conditions, and the lab to better understand how fear functions in nature. We work on a variety of mammalian and avian species in Canada and abroad from apex predators (e.g. African lions, cougars, bears) to meso-carnivores (e.g. raccoons, European badgers), herbivores (e.g. impala, deer), small mammals (e.g deermice), and birds. We have published some of the seminal empirical papers on fear effects in wildlife, including the important role that fear of the human ‘super predator’ plays. We have access to excellent infrastructure for fieldwork of all sorts, including field sites in Canada, the U.S., and South Africa, in addition to unparalleled lab resources at the Advanced Facility for Avian Research and our Large Outdoor Aviaries for semi-natural conditions at Western.