Project Details
Projekt
Parasite life history trade-offs and the evolution of virulence – a test of the trade-off hypothesis
Applicant
Charlotte Rafaluk-Mohr, Ph.D.
Subject Area
Evolution, Anthropology
Term
since 2024
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 425876005
The hypothesis that trade-offs among virulence, transmission and recovery rate drive the evolution of virulence provides the framework for our current understanding of how virulence evolves. These relationships form the basis of the trade-off hypothesis of virulence evolution that predicts that virulence will optimise at an intermediate level, as high virulence can result in host death before maximal transmission opportunities have been achieved and low virulence can result in recovery before transmission is possible. Despite its prominence, explicit tests of the hypothesis are surprisingly rare. Furthermore, trade-offs impacting growth rate and thus often virulence, are likely not limited to just to those with transmission and recovery rate. In spore forming fungi, growth rate is separated into two stages, vegetative growth, and spore production, each of which contribute differently to transmission and virulence, potentially leading to life history trade-offs which impact virulence. Virulence is also impacted by the host microbiota, meaning that trajectories of virulence evolution and trade-off constants are likely to be closely linked to microbial state of the host. In this project we will explore these questions empirically and mathematically using Tribolium casaneum as a host and the entomopathogenic fungus, Metarhizium spp. as a parasite. This project will use a combination of approaches to test the relationship between virulence and parasite life history traits and the impact of the presence or absence of microbiota on virulence evolution. These approaches include testing the relationships between the traits in natural isolates, experimental selection for a range of virulence levels with either intact or disrupted host microbiota, whole genome sequencing and mathematical modeling to understand how the relationships between vegetative growth, spore production and microbial state impact virulence evolution. Through this combination of approaches, we aim to gain a deeper understanding of the trade-offs and ecological factors influencing the evolution of virulence including and beyond the relationship between virulence, transmission and recovery rate.
DFG Programme
Research Units
