Data from: Genetic variation in resistance and fecundity tolerance in a natural host-pathogen interaction

Individuals vary in their ability to defend against pathogens. Determining
how natural selection maintains this variation is often difficult, in part
because there are multiple ways that organisms defend themselves against
pathogens. One important distinction is between mechanisms of resistance
that fight off infection, and mechanisms of tolerance that limit the
impact of infection on host fitness without influencing pathogen growth.
Theory predicts variation among genotypes in resistance, but not
necessarily in tolerance. Here, we study variation among pea aphid
(Acyrthosiphon pisum) genotypes in defense against the fungal pathogen
Pandora neoaphidis. It has been well established that pea aphids can
harbor symbiotic bacteria that protect them from fungal pathogens.
However, it is unclear whether aphid genotypes vary in defense against
Pandora in the absence of protective symbionts. We therefore measured
resistance and tolerance to fungal infection in aphid lines collected
without symbionts, and found variation among lines in survival and in the
percent of individuals that formed a sporulating cadaver. We also found
evidence of variation in tolerance to the effects of pathogen infection on
host fecundity, but no variation in tolerance of pathogen-induced
mortality. We discuss these findings in light of theoretical predictions
about host-pathogen coevolution.