Background: Parasites are ubiquitous in natural systems, and although they can have significant negative effects on host fitness, their observed impacts are often weak or undetectable. This suggests that they can usefully be viewed as ‘passengers’ rather than ‘drivers’ of host demography—for many parasites, host demography and environmental conditions may act as the dominant controls on their dynamics in space and time. Understanding how such factors individually, and in interaction with each other, determine parasite community structure is a major challenge. Metacommunity theory provides a framework to address this question. However, simple metacommunity models currently ignore important structuring processes such as host demographic variation, environmental stochasticity, and seasonality.
Objectives: The aim of this project is investigate the extent to which host demography and variation in the environment can explain observed patterns of (co)variation in parasite prevalence across multiple parasite species with different transmission modes and life histories. The project will focus on parasites in wild wood mouse (Apodemus sylvaticus) populations in the UK. The objectives are:
(1) Determine how environmental factors impact on host reproduction and mortality
(2) Parameterise a demographically structured population model of wild wood mice
(3) Estimate the seasonal force of infection of key parasites
(4) Quantify patterns of parasite (co)variation explained by host and environmental factors
Novelty: Quantifying the processes that drive community assembly and structure are vital for understanding the determinants of biodiversity and community stability. Recent advances in theoretical and conceptual tools can help us understand those processes, but they are still very much in their infancy, and have rarely been tested with data from wild systems. This project will develop and test new ways of understanding the demographic and environmental drivers of parasite communities in wild mammals, enabling deeper insight into the key processes driving their structure and dynamics.
Timeliness: Over the past 10 years, Pedersen and Fenton have established a wild mouse – parasite community system to investigate the ecological and immunological controls on parasite communities. They have accumulated longitudinal data of wild rodents and their parasites (nematodes, cestodes, protozoa, viruses, bacteria) at fine temporal scales (every 2-4 weeks) under spatially-hierarchical sampling (traps within grids within woodlands). These long-term data are now sufficiently long to provide a unique resource to explore the stochastic population dynamics of hosts and their parasite communities.
The project is appropriate for a biology graduate with interests in developing their quantitative skills, as well as candidates with an engineering, mathematics or statistics background who wish to make the transition to mathematical biology. Potential candidates are strongly encouraged to email Dr Dylan Childs ([email protected]
) with informal enquiries before submitting an application.
Science Graduate School
As a PhD student in one of the science departments at the University of Sheffield, you’ll be part of the Science Graduate School. You’ll get access to training opportunities designed to support your career development by helping you gain professional skills that are essential in all areas of science. You’ll be able to learn how to recognise good research and research behaviour, improve your communication abilities and experience the breadth of technologies that are used in academia, industry and many related careers. Visit http://www.sheffield.ac.uk/sgs
to learn more.
Fully funded studentships cover: (i) a stipend at the UKRI rate (£15,009 per annum for 2019-2020), (ii) research costs, and (iii) tuition fees. Studentship(s) are available to UK and EU students who meet the UK residency requirements.
This PhD project is part of the NERC funded Doctoral Training Partnership “ACCE” (Adapting to the Challenges of a Changing Environment View Website. ACCE is a partnership between the Universities of Sheffield, Liverpool, York, CEH, and NHM.
Shortlisted applicants will be invited for an interview to take place in the w/c 10th February 2020.