Sarah Knutie Philipinnes

Sarah Knutie
Graduate Student

(801) 585-9742




I am an invasion biologist interested in the ecology of novel and long-standing host-parasite relationships. I am specifically interested in 1) tolerance and resistance as defense mechanisms in susceptible and reservoir hosts against introduced parasites, and 2) applied control methods of introduced parasites. 


Ecology of novel host-parasite relationships
For my dissertation work, I am studying the effects of an introduced parasite, Philornis downsi, on vulnerable and reservoir hosts in the Galapagos Islands.  Reservoir hosts do not suffer the effects of the parasites and are therefore important in maintaining parasites in a population.  I am currently identifying defense mechanisms that enable the reservoir hosts to deal with the parasite without a cost to fitness. Specifically, I am exploring trade-offs in tolerance and resistance defense mechanisms in both reservoir and vulnerable hosts. I am also attempting to develop a low cost, low labor method for controlling P. downsi within the nest in the Galapagos.

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Host defense mechanisms in long-standing host-parasite relationships
Hosts that have long-standing relationships with their parasites have likely evolved defense mechanisms to deal with their parasites.  I am comparing the effects of native Philornis nest flies on black-faced grassquits and tropical mockingbirds in Tobago.  Both species are phylogentically related and similar ecologically to their congeners in the Galapagos (i.e. Darwin’s finches and Galapagos mockingbirds.  These systems present the opportunity to compare tolerance and resistance mechanisms within novel and long-standing host-parasite relationships.


Malaria and Rock Pigeons
Avian malaria is often found at lower infection intensities in older birds than younger birds. One explanation of this pattern is that younger birds are removed from the population before reaching adulthood, thus removing the highest infection intensities from the population. We tested this hypothesis by experimentally manipulation parasite intensity of Haemoproteus columbae, a malaria parasite, and examining the impact of the parasite on the development and survival of free-living nestling and fledgling rock pigeons (Columba livia).  The field component is a piece of a larger project investigating host-parasite interactions, through laboratory experiments, between rock pigeons, a hippoboscid fly (Pseudolynchia canariensis), and Haemoproteus columbae by fellow graduate student, Jessi Waite. This work has been published in Evolutionary Ecology.

Sarah Knutie

Philippines Biodiversity Survey
In the summer of 2010, I joined a collaborative project between the University of Utah and the University of Kansas to survey vertebrates and their parasites in the Philippines. We focused on several locations throughout the island of Luzon. One of the objectives of this multi-year project is to understand how the loss of biodiversity of vertebrate hosts may reflect on their parasites.



Research and teaching are both important to me as a biologist. I have integrated many high school and undergraduate students and local field assistants into my field collection. I have primarily assisted as a TA in physiology courses, but have also helped with several field courses, including Field Ecology, Ornithology, Mammalogy, and Animal Behavior at Itasca Biological Station run through the University of Minnesota. In the future, I hope to design more field-based courses in parasite ecology.

How to band a bird


During the little spare time I have, I enjoy dancing, biking, birding/bird-banding, backpacking, photography, hiking, traveling, playing soccer, eating bacon, and watching old western movies.  Besides all the money I will make in academia I am here because I have a true passion and curiosity for how the natural world works. Nicknames include: bird nerd and crazy bird lady, but you can call me... Knutie. 



Knutie, S.A., S.M. McNew, A.W. Bartlow, D.A. Vargas, D.H. Clayton. 2014 Darwin’s finches combat introduced nest parasites with fumigated cotton. Current Biology 24(9):R355–R356DOI: PDF

Knutie, S.A., J.A.H. Koop, S.S. French, and D.H. Clayton. In press. Experimental test of the effect of introduced hematophagous flies on corticosterone levels of breeding Darwin’s finches. General and Comparative Endocrinology.

Koop, J.A.H., J.P. Owen, S.A. Knutie, M.A. Aguilar, and D.H. Clayton. 2013. Experimental demonstration of a parasite-induced immune response in wild birds: Darwin’s finches and introduced nest flies. Ecology and Evolution DOI: 10.1002/ece3.651.

Knutie, S.A., J.L. Waite, D.H. Clayton. 2012 Does avian malaria reduce fledging success: An experimental test of the selection hypothesis. Evolutionary Ecology DOI: 10.1007/s10682-012-9578-y.

Knutie, S.A., M.E. Pereyra. 2012. A comparison of winter stress responses in cardueline finches. The Auk 129:479-490.

Brown, C. R., A. T. Moore, V. A. O'Brien, A. Padhi, S. A. Knutie, G. R. Young and N. Komar. 2010. Natural infection of vertebrate hosts by different lineages of Buggy Creek virus (family Togaviridae, genus Alphavirus). Archives of Virology 155:745-749.

Brown, C. R., S. A. Strickler, A. T. Moore, S. A. Knutie, A. Padhi, M. B. Brown, G. R. Young, V. A. O'Brien and N. Komar. 2010. Winter ecology of Buggy Creek virus (Togaviridae, Alphavirus) in the central Great Plains. Vector-Borne and Zoonotic Diseases 10(4):355-363.

Brown, C. R., A. T. Moore, S. A. Knutie and N. Komar. 2009. Overwintering of infectious Buggy Creek virus (Togaviridae, Alphavirus) in Oeciacus vicarius (Cimicidae) in North Dakota. Journal of Medical Entomology 46:391-394.

Henly, S., A. Ostdiek, E. Blackwell, S. Knutie, A. Dunlap and D. Stephens. 2008. The discounting by interruptions hypothesis: model and experiment. Behavioral Ecology 19(1):154-162.

Darwins Finch