Overview
Why do parasites vary so much in their host ranges?
Some parasites are highly specialised, infecting single host species, whereas others are highly generalised, able to infect multiple species.
About this opportunity
This ‘host range’ of a parasite determines the overall impact it has on their host community, and the infection risk for newly-introduced species to the community. Given global concerns about parasite emergence, and increasing invasions and (re)introductions of potential host species, understanding the factors that determine parasite host range is crucial for managing disease emergence and impact.
We know a parasite’s host range depends on: (i) the relative densities of host species in the community, (ii) rates of transmission within and between those species, and (iii) how closely related the host species are, which affects how easy it is for parasites to jump between them. However, existing theories about how these factors combine to drive selection towards generalism or specialism remain incomplete, and largely untested.
We have developed two invertebrate host systems (Tribolium beetles and Drosophila flies), with parasites that vary in host range. You will conduct selection experiments to evolve host range under contrasting host availability and relatedness scenarios, and combine these with novel theory to unpick the drivers of host range. Finally, you will apply those principles to a conservation setting, to understand how host community composition influences disease risk associated with species translocations.
Specific objectives
Through this project you will:
- Develop novel theory to assess how host densities, relatedness, and transmission networks drive the evolution of parasite host range.
- Test those predictions through laboratory selection experiments under alternative host community scenarios, quantifying the ecological and phylogenetic drivers underpinning parasite host range.
- Develop empirically-grounded risk characterisation tools that link host range to measurable ecological thresholds, improving prediction and mitigation of disease emergence during species translocations.
Timeliness & Novelty
Increasing concerns about parasite emergence, and the consequences of species’ invasions and introductions, means there is an urgent need to understand how parasites evolve within multihost communities, and the risks they pose to native and introduced species. However, existing theories on the drivers of host range currently lack empirical validation, and the application of those theories to real-world conservation remains poorly exploited.
You will combine novel theory with selection experiments to reveal real-time evolutionary dynamics and test predictions about the evolution of parasite host range. By using those principles to develop risk characterisation tool in the context of species translocations, this project will provide a novel link from fundamental concepts to real-world application, informing how parasites respond to, and impact, changing ecological communities.
What we are looking for, and what training you will receive
This project will suit students interested in both fundamental and applied aspects of infectious disease ecology and evolution, seeking to gain high-level research experience and training in mathematical modeling, experimental design and conservation.
You will join a vibrant and inclusive research environment, supported by experts in theoretical (Fenton) and empirical (Viney; Tyukmaeva) infectious disease biology, and practical conservation (Howe, Natural England CASE partner). In addition to the project-specific skills you will develop, you will be embedded within the ACCE+ Doctoral Landscape Award programme, where you will have access to a range of general and personal skills development activities, as part of a thriving cohort of like-minded environmental science research students.
Project CASE Status
This project is a CASE project. Your project will be co-supervised by the non-academic partner organisation, and you will spend 3-6 months on a placement with your CASE partner in their workplace. You will experience training, facilities and expertise not available in an academic setting, and will build business and research collaborations.