Data from: Testing evolutionary explanations for the lifespan benefit of dietary restriction in fruit flies (Drosophila melanogaster)

Dietary restriction (DR), limiting calories or specific nutrients without
malnutrition, extends lifespan across diverse taxa. Traditionally, this
lifespan extension has been explained as a result of diet-mediated changes
in the trade-off between lifespan and reproduction, with survival favoured
when resources are scarce. However, a recently proposed alternative
suggests that the selective benefit of the response to DR is the
maintenance of reproduction. This hypothesis predicts that lifespan
extension is a side effect of benign laboratory conditions, and DR
individuals would be frailer and unable to deal with additional stressors,
and thus lifespan extension should disappear under more stressful
conditions. We tested this by rearing outbred female fruit flies
(Drosophila melanogaster) on 10 different protein:carbohydrate diets.
Flies were either infected with a bacterial pathogen (Pseudomonas
entomophila), injured with a sterile pinprick or unstressed. We monitored
lifespan, fecundity and measures of ageing. DR extended lifespan and
reduced reproduction irrespective of injury and infection. Infected flies
on lower protein diets had particularly poor survival. Exposure to
infection and injury did not substantially alter the relationship between
diet and ageing patterns. These results do not provide support for
lifespan extension under DR being a side effect of benign laboratory
conditions.