Data from: The effect of diet and time after bacterial infection on fecundity, resistance, and tolerance in Drosophila melanogaster

Mounting and maintaining an effective immune response in the face of
infection can be costly. The outcome of infection depends on two host
immune strategies: resistance and tolerance. Resistance limits pathogen
load, while tolerance reduces the fitness impact of an infection. While
resistance strategies are well studied, tolerance has received less
attention, but is now considered to play a vital role in host–pathogen
interactions in animals. A major challenge in ecoimmunology is to
understand how some hosts maintain their fitness when infected while
others succumb to infection, as well as how extrinsic, environmental
factors, such as diet, affect defense. We tested whether dietary
restriction through yeast (protein) limitation affects resistance,
tolerance, and fecundity in Drosophila melanogaster. We predicted that
protein restriction would reveal costs of infection. Because infectious
diseases are not always lethal, we tested resistance and tolerance using
two bacteria with low lethality: Escherichia coli and Lactococcus lactis.
We then assayed fecundity and characterized bacterial infection pathology
in individual flies at two acute phase time points after infection. As
expected, our four fecundity measures all showed a negative effect of a
low-protein diet, but contrary to predictions, diet did not affect
resistance to either bacteria species. We found evidence for diet-induced
and time-dependent variation in host tolerance to E. coli, but not to L.
lactis. Furthermore, the two bacteria species exhibited remarkably
different infection profiles, and persisted within the flies for at least
7 days postinfection. Our results show that acute phase infections do not
necessarily lead to fecundity costs despite high bacterial loads. The
influence of intrinsic variables such as genotype are the prevailing
factors that have been studied in relation to variation in host tolerance,
but here we show that extrinsic factors should also be considered for
their role in influencing tolerance strategies.