Last Updated: 07/07/2025
Integrating resistance and tolerance to parasitic infection with life-history theory
Objectives
This project has four aims:
- Predict the optimal life-history and defence by adapting and extending a model of ontogenetic growth, which is based on the balance of energy during the host’s development, by letting the host allocate energy to an innate immune system and including the within-host dynamics of the parasite and its by the immune response. Main outputs will be how the parasite’s growth rate and host’s environment affect the patterns of resistance and tolerance;
- Give input to the model with experiments that investigate several of the central aspects of the approach, with questions linking immunity and defence on the one hand with metabolism and energetic utilisation on the other hand.
- What is the impact of diet on immune-competence and on resistance and tolerance?
- How does oxidative stress interact with the defence mechanisms of the mosquito?
- Does stimulation of the immune system affect defence, nutrient levels and oxidative stress?
- Test predictions of model by using experimental evolution to test predictions of the model about the optimal allocation to growth and to defence against parasitic infection.
- Answer whether mosquitoes choose their diet to increase protection against malaria. Sugar-feeding on plants forms an important part of the diet of mosquitoes.
- Do different plants offer different levels of immune-competence and resistance?
- Do mosquitoes shift their preference for plants from those that enhance their longevity when uninfected to those that enhance their defence against malaria when infected?
To minimise a parasite’s impact on health, hosts can attack the parasite developing within them to reduce the parasite load or they can reduce the damage caused by a given parasite load. The distinction between these two defences – resistance and tolerance – is attracting increasing attention by parasitologists and evolutionary biologists. Much of their work deals with genetic correlations between resistance and tolerance, how the environment can shape these correlations, and how these correlations feed into the epidemiological dynamics to shape evolution. Yet disentangling resistance and tolerance, and understanding their implications for the co-evolution of hosts and parasites remains problematic. It is suggested that understanding of resistance and tolerance can be improved by combining physiological and evolutionary approaches in an integrated picture of the host’s life-history and its response to parasitic infection, focusing on how a host allocates its resources to development, reproduction, and defence. Accordingly, the objective is to move ideas about the evolution of host defence from a basis that relies on observed relationships between resistance and tolerance to one that integrates physiological and evolutionary ideas with resource ecology and life-history theory. This project combines theory and experiments with two biological systems: (i) the microsporidian Vavraia culicis and its host, the mosquito Aedes aegypti and (ii) the malaria parasite Plasmodium falciparum and its mosquito vector Anopheles gambiae.
Nov 2016 — Mar 2020
$690,493
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