Sexual dimorphism in nutrient intake and life span is mediated by mating in Drosophila melanogaster

Mating elicits dramatic changes in behaviour and physiology related to reproduction in female Drosophila melanogaster, but little is known about how mating affects nutrient intake and preferences in this model organism. Postmating switches in reproductive activity and feeding are likely to alter life span because both reproduction and nutrition are closely linked to survival. To explore these possibilities, we compared the intake patterns of protein (P) and carbohydrate (C) preferred by male, mated female and virgin female adults of D. melanogaster and their life span responses under varying dietary P:C balances (0:1, 1:1 and 4:1). Despite sex differences, the patterns of both macronutrient intake and life span were remarkably similar between males and virgin females. Compared to unmated virgins, mated females consumed ca. 2.7 times more nutrients and preferred a diet that was significantly more protein-rich (mated versus virgin females: P:C 1:1.5 versus 1:4). Surprisingly, females that had experienced mating in early adulthood lived longer than those that remained virgin, and this life span-extending effect of mating in females was most profound on a diet that was equally balanced (P:C 1:1). Our results indicate that mating is an important modulator that regulates sex-specific nutrient preference, which in turn alters longevity in D. melanogaster.