Ecology and Evolution Discussions Down Under: Evolutionary Interactions

Invited Panel: Ary Hoffmann, Karyn Johnson, Ben Schwessinger

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Uncovering the determinants of pathogen diversity in nature
Anna-Liisa Laine (University of Zurich)

Pathogens are prevalent across all ecosystems and exert negative effects on their hosts. Hence, there is a pressing need to understand risks of infection and how these evolve. Traditionally, host-pathogen interactions have been largely viewed within the ‘one host-one parasite’ framework although in reality the same host may be attacked by a myriad of pathogenic microbes. However, remarkably little is known about the factors that determine which pathogens co-occur within the same host individual and how they interact. Theoretically the resulting interaction has been proposed to range along a continuum where at the one end we find superinfection with a single strain gaining dominance of the entire host, and at the other end of the continuum we find coinfection. For a long time, the empirical study of disease dynamics under coinfection lagged behind theoretical predictions due to the methodological challenges of directly observing coinfection dynamics. In my talk I will present case studies of within host pathogen strain diversity and species diversity, and what we’ve learned about the determinants of this diversity.

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Do eco-evolutionary feedbacks matter in host-pathogen interactions?
Ben Ashby (University of Bath)

Pathogens play a major role in host ecology and evolution, and vice versa. Understanding fundamental ecological and evolutionary processes – and the interplay between them (“eco-evolutionary feedbacks”) – is crucial not only for managing infectious diseases, but also for explaining a wide range of biological phenomena, including spatial and temporal patterns of diversity such as "Red Queen Dynamics". Eco-evolutionary feedbacks are often difficult to intuit, but mathematical modelling can offer key insights. In this talk, I will discuss how we can approach modelling these effects and how they influence the evolution of traits such as resistance, infectivity, and virulence.