Host-Parasite Interactions

Plants and animals in their natural environments interact with a wide range of other living organisms. These include both beneficial interactions and damaging encounters with parasites, pathogens and herbivores. The module examines the different kinds of organisms that have evolved a parasitic lifestyle and the ways in which they parasitize their hosts. In parallel, the module will introduce the different strategies that plants and animals use to defend themselves, including the recruitment of other organisms to act as allies. The continuing conflict between hosts and parasites results in a so-called 'evolutionary arms race'.

 Practical work will develop laboratory skills, and assessment will develop skills in data analysis, writing and argument. The module will also examine the evolutionary costs and benefits of defence, and the evidence for short and long-term immunological memory. Since the module is aimed primarily at addressing ecological and physiological questions rather than the biomedical aspects of parasitology, the focus will be on invertebrate rather than vertebrate hosts.

Students will be able to describe a range of subject specific topics, such as the main groups of parasitic organisms and their lifestyles; the structural and behavioural defences against parasites, pathogens and herbivores in plants and animals, and the key features of innate and adaptive immunity in plants and animals. This module will also enhance students’ ability to identify the main selective processes shaping the evolution of host resistance to parasites, along with providing explanations as to why many defence mechanisms are inducible rather than permanently expressed, and how specialist herbivores and parasites have co-evolved with their hosts to overcome resistance.