Authors
E Cunningham1; 1 Edinburgh University, UK Discussion
Parasites are a ubiquitous component of all animal populations. Some infections may be acute and short-lived but more commonly, individuals experience on-going chronic levels of infection that impact on host life-history traits throughout life. The impact of infection is likely to be particularly acute during reproduction when energetic demands are high for both parents working hard to raise a family and offspring in rapid phases of growth. However, this is also a time when costs may be passed on to different family members, leading to indirect costs of infection on individuals other than the primary host. How this plays out across the family can shape both responses to infection and other key life-history traits across an individual’s life. In this talk, I report on seventeen years of data on the impact of parasitism in a long-term study of seabirds, The European Shag. Both novel techniques to measure natural levels of parasitism and experimental manipulations of parasite burden have demonstrated that responses to parasitism are shaped in early life but can impact on different family members in the longer term in very different ways. Family members also differ in their sensitivity to how responses to parasitism play out across different environmental conditions. Quantifying how these ultimately link to breeding success over both the short and the long term is therefore a major part of understanding how predicted environmental shifts may impact both infection dynamics and their impact on host populations. 
