The impact of parasitism on host populations in response to a changing environment

This project investigates why individuals differ in how they respond to infection and how changes in the environment may influence the impact of disease on animal populations.
Project background: Climate change is expected to have a widespread impact on levels of parasitism and disease in wild populations with both ecological and economic consequences. However, the actual response of populations to such changes are often a complex mix of factors such as changing levels of exposure, individual differences in resistance and tolerance and interactions with other environmental stressors operating in the environment. We are interested in how environmental conditions in early life can shape an individual's response to infection and how current conditions limit their ability to deal with disease. We have shown that successful breeding in a long-lived, threatened seabird, the European shag Phalacrocorax aristotelis, is constrained by parasitism, particularly in years of low breeding success. However, these effects vary throughout the breeding season, are often sex specific with different consequences for sons and daughters and differ between members of a brood. The proximate mechanisms underlying these different host responses remain unclear. Are these effects driven by seasonal changes in parasite level, do individuals vary in their susceptibility to infection over time or are these effects simply a consequence of seasonal changes in the composition of breeders that differ in their overall ability to deal with parasitism? It is important to establish the relative importance of these different potential explanations if we are to understand and predict how changes in the host's environment will impact on overall population success.

Key research questions: This project will examine how early life conditions and current environmental conditions impact on an individual's levels of infection and how this impacts individual behaviour and traits related to fitness. There is substantial scope to expand these questions in line with the students own interests. Possibilities include how do early life conditions impact on adult responses to infection? How important is the social environment in determining patterns of infection in individuals? What are the population level effects of parasitism under different environmental scenarios? With major shifts in breeding dates being widely reported the need to establish the relative importance of these different types of mechanisms has become more urgent.