Maternal and paternal sugar consumption interact to modify offspring life history and physiology

Intergenerational effects on offspring phenotypes occur in response to
variation in both maternal and paternal nutrition. Because the combined
maternal and paternal effects are rarely considered together however,
their relative contributions, and the capacity for interactions between
parental diets to shape offspring life history and physiology are not
understood. To address this, we altered sucrose levels of adult fruit
flies (Drosophila melanogaster) prior to mating, across two generations,
producing parent-parent and parent-offspring combinations that were either
matched or mismatched in dietary sucrose. We then measured lifespan,
fecundity, body mass, and triglyceride levels in parents and offspring. We
reveal complex non-additive interactions, that involve diets of each
parent and offspring to shape offspring phenotypes, but the effects were
generally not consistent with an adaptive response to parental diet.
Notably, we find that interacting parental flies (sires and dams) lived
longer when their sucrose treatments were matched, but they produced
shorter-lived offspring.