Evolution and ecology of host-parasite systems
Evolutionary Ecology | Behavioural Ecology | Reproductive strategies | Host-parasite systems | Tropical Ecol & Evol | Conservation | Study Sites
Our research uses molecular techniques to characterise parasite infections; to investigate host-parasite-vector interactions, phylogeography and epidemiology. The main area of focus is avian malaria, a vector-borne disease caused by parasites of the genera Plasmodium and Haemoproteus, transmitted by various Diptera. It has a wide geographic distribution, commonly infecting birds in temperate, tropical and subtropical zones.
The high diversity of hosts, vectors and parasites make avian malaria an ideal system for a range of evolutionary and ecological questions. With the introduction of molecular based screening methods the diversity of avian malaria parasites has increased from what was previously thought: while around 200 species have been defined using morphology, molecular evidence suggests there could be tens of thousands of species.
Adding to the complexity of the system, avian malaria parasites also show a range of different host specificity patterns: some parasites are restricted to one host species and others infect birds from multiple families. As a vector-borne infection, there is also a strong environmental component to this disease system, which can result in interesting spatiotemporal dynamics.
Summaries of current projects follow (more information on individual websites). We welcome enquiries about research in this area.
Current Projects
Malaria infection and host life-history in blue tits Cyanistes caeruleus (Sarah Knowles)
Within a host population there is often considerable variation among individuals in their parasitic infections, for example in terms of parasite genotype and parasite load. This project investigates natural variation of avian malaria infections in a blue tit population, with two major aims: (i) to understand the causes of individual variation in malaria infections, including the effects of natal environment, age-dependent effects and breeding effort and (ii) to explore the consequences of variation in avian malaria infections for host fitness and life-history decisions.
Conservation and evolutionary genetics of avian malaria in South Pacific Islands (Farah Ishtiaq)
This project seeks to understand the distribution, movement and consequences of avian malaria in the south-west Pacific, and to determine the extent to which birds are at risk from introduction of this disease. Members of the silvereye species complex (white-eyes), (Zosterops) (family: Zosteropidae) provide a unique model system to explore this question, as this family contains more successful island colonizers than any other passerine group. Examining the three components of this system (parasite, vector and host), we are investigating: i) malaria prevalence across the region in mainland and endemic island counterparts of silvereyes; ii) the reconstruction of the process of avian colonization of the islands based on their malarial lineages; iii) the spectrum of Host-parasite systemsl parasites in arthropod vectors in relation to potential transmission in avian hosts. We collaborate with Imperial College London on their ongoing detailed study of the population genetics of silvereye populations.
Dispersal, environment and spatial heterogenity of avian malaria in tits (Matt Wood)
Host infection with parasites can vary markedly in space and time, even at a local scale in the case of avian malaria in our tit population. Hosts take their parasites with them wherever they go, so does a site have a high level of disease infection due to the local environment, or because infected individuals have moved there? Using long term data, experimental work and mathematical modeling we will examine individual variation in avian malaria infection in tits, and the role of dispersal in the spatial distribution of infection.
Genetics of parasite host compatibility (Olof Hellgren)
The ability of parasites to infect a host species depends on various factors, including how often the parasite encounters a susceptible host species, and the genetic compatibility between parasite and host. We are investigating how the genetic composition of the host affects the extent to which it becomes infected by parasites, using avian malaria in tits as a model system. Starting by investigating the genetic composition of the innate immune system the long time goal is to do a full genome scan in search for genes affecting the susceptibility or resistance to different parasites.
Collaborations
Our main current external collaborators are:
Molecular Population Biology Lab (Lund University, Sweden)
Prof. Mike Boots (University of Sheffield)
Centre for Ecology and Hyrdrology (Edinburgh)
Javier Pérez-Tris (Universidad Complutense Madrid, Spain)
Laboratory of Parasitology (Institute of Ecology, Vilnius University, Lithuania)
Ecology and Evolution section (Imperial College, London)
Tour du Valat (France)
