Reproductive consequences of transient pathogen exposure across host genotypes and generations
María Ordovás-Montañés1, Gail M Preston2, Georgia C Drew1
1Department of Zoology University of Oxford Oxford UK.
Ecology and Evolution
|March 31, 2022
Summary
Host organisms, like nematodes, can delay reproduction when infected by pathogens but recover lifetime offspring production. Genetic differences influence these fitness costs across generations.
Area of Science:
- Evolutionary Biology
- Host-Pathogen Interactions
- Life-History Theory
Background:
- Pathogen infection can impose fitness costs on hosts through immune responses and direct exploitation.
- Understanding how these costs vary by host genotype and across generations is crucial for evolutionary studies.
- Energy reallocation between reproduction and defense is a key strategy for hosts facing infection.
Purpose of the Study:
- To disentangle the fitness costs of pathogen infection in *Caenorhabditis elegans*.
- To differentiate costs arising from immune upregulation versus direct pathogen exploitation.
- To investigate the role of host genotype and maternal effects on fitness costs.
Main Methods:
- Exposure of wild and domesticated *C. elegans* isolates to live and heat-killed *Staphylococcus aureus*.
- Quantification of offspring production delays and lifetime fecundity.
- Analysis of genetic variation in fitness costs and maternal effects on offspring growth.
Main Results:
- Transient exposure to live or heat-killed pathogens caused a short-term delay in nematode reproduction.
- Lifetime fecundity recovered to control levels despite initial exposure.
- Significant genetic variation was observed in cumulative offspring production and fitness cost magnitude.
- A positive correlation was found between parental reproductive delay and offspring population growth costs.
Conclusions:
- Host organisms demonstrate a capacity to recover fecundity following transient pathogen exposure.
- Genetic variation influences the costs associated with pathogen infection and defense.
- Maternal pathogen exposure can have transgenerational effects on offspring fitness.
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