Sarah Knowles

NERC Post Doctoral Researcher

Institute of Evolutionary Biology
University of Edinburgh

Office: Room 411, Ashworth Laboratory
Telephone: +44 (0) 31 650 8685
Email: sarah.knowles(at)
2009-present: Post Doctoral Researcher, University of Edinburgh, UK
PhD University of Oxford
BA Biological Sciences, University of Oxford

Research interests

I am a wildlife disease ecologist, broadly interested in how parasites affect host fitness in natural populations, and their role in shaping host evolution.

My PhD work investigated the epidemiology of avian malaria in wild birds, and how these parasite affected host fitness and reproductive decisions. My current research focuses on the causes and consequences of co-infection in nature, using wild wood mice and their parasites as a model system.

Although most host-parasite studies consider disease systems in a single host-single parasite framework, in reality hosts harbour a community of micro-organisms, both commensal and parasitic. Increasing evidence suggests that interactions between members of this community, and between this community and the host, play a critical role in immune development and function, host health and parasite transmission. My research aims to study parasites and their effects on hosts within this complex reality, and determine the importance of this broader perspective for understanding health and disease.

Specifically, I am working on a NERC-funded project in which we are using large-scale field medication experiments on wood mice (
Apodemus sylvaticus) to address the questions:

(1) To what extent do co-infecting parasites interact within hosts, and by what mechanisms?
(2) What are the effects of targeted parasite removal on the remaining community of parasites and commensal bacteria?
(3) How do within-host interactions between parasites affect host fitness and the outcome of disease interventions?


Knowles, S. C. L. (2011) The effect of helminth co-infection on malaria in mice: a meta-analysis. International Journal for Parasitology 41: 1041-1051.

Lachish, S.,
Knowles, S. C. L., Alves, R. Wood, M. J. & Sheldon, B. (2011) Infection dynamics of endemic malaria in a wild bird population: parasite species-dependent drivers of spatial and temporal variation in transmission rates. Journal of Animal Ecology (in press)

Lachish, S.,
Knowles, S. C. L., Alves, R. Wood, M. J. & Sheldon, B. (2011) Fitness effects of endemic malaria infections in a wild bird population: the importance of ecological structure. Journal of Animal Ecology

Knowles, S. C. L., Wood, M.J., Alves, R., Wilkin, T.A. & Sheldon, B. (2011) Molecular epidemiology of malaria prevalence and parasitaemia in a wild bird population. Molecular Ecology 20: 1062-1076

Knowles, S. C. L., Palinauskas, V. & Sheldon, B. (2010). Chronic malaria infections increase family inequalities and reduce parental fitness: experimental evidence from a wild bird population. Journal of Evolutionary Biology 23: 557-569.

Knowles, S. C. L., Wood, M. J. & Sheldon, B. C. (2010). Context-dependent effects of parental effort on malaria infection in a wild bird population, and their role in reproductive trade-offs. Oecologia, 164: 87-97.

Knowles, S. C. L., Nakagawa, S., Sheldon, B. C. (2009). Elevated reproductive effort increases blood parasitaemia and decreases immune function in birds: a meta-regression approach. Functional Ecology 23: 405-415

Liedvogel, M., Szulkin, M.,
Knowles, S.C.L., Wood, M., Sheldon, B.C. (2009). Phenotypic correlates of variation at the Clock gene in a wild blue tit population: evidence for a role in seasonal timing of reproduction. Molecular Ecology 18, 2444-2456.

Raihani, N. J., Ridley A. R., Browning, L. E., Nelson-Flower M. J. &
Knowles, S. (2008). Juvenile female aggression in cooperatively breeding pied babblers: causes and contexts. Ethology 114, 452–458.

Wood, M.J., Cosgrove, C.L., Wilkin, T.A.,
Knowles, S.C.L., Day, K.P., & Sheldon, B.C. (2007). Within-population variation in prevalence and lineage distribution of avian malaria in blue tits Cyanistes caeruleus. Molecular Ecology 16, 3263-3273.

Cosgrove C. L.,
Knowles S. C. L., Day K. P. & Sheldon, B. C. (2006). No evidence for malaria infection during the nestling phase in a passerine bird. Journal of Parasitology 96 (6): 1302-1304


Knowles, S. C. L. & Sheldon, B.C. (2008) Evolutionary biology: parasite, know thyself. Current Biology 18: R655-R657.

Knowles, S. C. L. & Sheldon, B. C. (2007).
Sex Ratios: Human Twins and Fraternal Effects. Current Biology 17, R801-804.