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Katie E. Marshall

Assistant Professor of Biology

Ph.D., University of Western Ontario
B.S., Acadia University


kemarshall@ou.edu
405-325-3193 (Phone)
405-325-6202 (Fax)
SH 302

curriculum vitae

Research

The long-term goal of my lab is to understand how stress is experienced through individual-level physiology to shape species abundance and distribution.  To do this, we focus on the physiological effects and ecological outcomes of repeated stress exposure on ectotherms.

While the impacts of single stress events are relatively well-understood, most organisms experience repeated stressors over the course of their lifespan.  In particular, temperature and water availability fluctuate on daily and weekly timescales, causing cycles of damage and opportunities for recovery.  The questions we address include: 1) what is the type of damage that repeated stress incurs? 2) how are repair and preparatory processes entrained? and 3) what are the fitness implications of the energetic costs of preparatory and repair responses?  To answer these questions, we use a broad set of tools on multiple levels of biological organization including gene expression, metabolomics, biochemical assays, survival and reproductive output assays, and species distribution models.  By integrating the results of these tools, we aim to provide both a better understanding of fundamental questions in physiology ecology, as well as better forecasting in applied fields including forensic entomology, and invasive, agricultural, and forest pest management.

Some of our current projects include:

Modelling the impacts of frequency of stress on ectothermic animal distributions: Repeated stress exposure appears to induce trade-offs between stress hardiness and reproductive output, which means that models of species distribution may be sensitive to the effects of stress frequency.  Using dung beetles and the eastern spruce budworm as model organisms, we aim to understand how climate change impacts on the variability of temperature and water availability will impact where species live. 

Physiological responses to repeated desiccation stress: While temperature is an important predictor of species ranges, water availability can also have large impacts.  We aim to understand some of the mechanisms and tradeoffs of resistance to repeated desiccation stress in the model organisms Drosophila melanogaster and Tribolium casteneum.

We are recruiting graduate students starting in Fall 2016!  Please contact Dr. Marshall (kmarshall@zoology.ubc.ca) for further information.

Publications

  • Marshall, K.E., & Sinclair, B. J. The relative importance of number, duration, and intensity of cold stress events in determining survival and energetics of an overwintering insect. (2015) Functional Ecology. 29, 357-366. http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.12328/abstract

  • Marshall, K.E. & Baltzer, J. L. Decreased competitive interactions drive a reverse species richness latitudinal gradient in sub-Arctic forests. (2015) Ecology. 96, 461-470. http://www.esajournals.org/doi/abs/10.1890/14-0717.1

  • Marshall, K.E., Thomas, R. H., Roxin, Á., Chen, E. K.Y., Brown, J.C.L., Gillies, E. R., & Sinclair, B. J. (2014). Seasonal accumulation of acetylated triacylglycerols by a freeze-tolerant insect. Journal of Experimental Biology. 217, 1580-1587. http://jeb.biologists.org/content/217/9/1580.full.pdf

  • Marshall, K.E. & Sinclair, B.J. (2012) The impacts of repeated cold exposure in insects. Journal of Experimental Biology. 215, 1607-1613. http://jeb.biologists.org/content/215/10/1607.full

  • Marshall, K.E. & Sinclair, B.J. (2012) Threshold temperatures mediate the impact of reduced snow cover on overwintering freeze tolerant caterpillars. Naturwissenschaften 99, 33-41. http://www.ncbi.nlm.nih.gov/pubmed/22139093

  • Zhang, J., Marshall, K.E., Westwood, J.T., Clark, M.S. & Sinclair, B.J. (2011). Divergent transcriptomic responses to repeated and single cold exposures in Drosophila melanogaster. Journal of Experimental Biology. 214, 4021-4029. http://www.ncbi.nlm.nih.gov/pubmed/22071194

  • Marshall, K.E. & Sinclair, B.J. (2011) The sub-lethal effects of repeated freezing in the woolly bear caterpillar Pyrrharctia isabella. Journal of Experimental Biology. 214, 1205-1212. http://www.ncbi.nlm.nih.gov/pubmed/21389206

  • Marshall, K.E. & Sinclair, B.J. (2010) Repeated cold exposure results in a survival-reproduction tradeoff in Drosophila melanogaster. Proceedings of the Royal Society B. 277, 963-969. http://rspb.royalsocietypublishing.org/content/277/1683/963