Proceedings of the Royal Society B · Nov 11, 2026

Age-related shifts in dietary and oviposition preferences and steep costs of modest parental ageing in Drosophila melanogaster

By Barker O, Ivimey-Cook ER, Haerty W et al.

Nutritional requirements vary across sexes and lifetimes and are predicted to influence dietary preferences. Here, we tested the hypothesis that diet preferences vary adaptively with sex, age and life stage. We used the fruit fly Drosophila melanogaster to take independent snapshots of choice for three protein : carbohydrate (P : C) diets in both sexes of young (5 d), mid-aged (15 d) or old (25 d) flies, while simultaneously recording oviposition site choice. We then tested, for mothers of each age, the diet preferences, development and survival on each diet of their larval offspring. Diet choice was sex- and age-specific. Males consistently preferred high carbohydrate, and females high protein (and these preferences became stronger with age). By contrast, oviposition choice was for balanced (1 : 1 P : C) and high carbohydrate diets in young and old females, respectively. Larvae of old, but not young, parents also preferred balanced diets. Young-parent larvae developed faster on balanced diets, with survival differences (highest with high carbohydrate) evident only in mid-aged-parent larvae. Unexpectedly, mid-aged-parent larvae had slower development and higher preadult mortality than young-parent larvae. Thus, diet choices may not be optimized across parents and offspring, and we identify novel effects of modest increases in parental age and offspring diets on offspring fitness.

doi.org/10.1098/rspb.2026.1983Open accessPubMed 43008826Mechanisms