The critical role of dietary metal ions in lifespan and reproduction of Drosophila melanogaster

My thesis investigates how dietary metal ions shape lifespan–reproduction trade-offs in Drosophila melanogaster. Using chemically defined diets, I show that zinc and magnesium play distinct roles in lifespan-reproduction outcomes. Dietary zinc availability is unique amongst metal ions in that it dictates resource re-allocation between these traits. Surprisingly, lifespan is long and reproduction reduced when zinc is limiting, revealing that this micronutrient has an equally powerful effect over life-history trait trade-offs as the commonly studied macronutrients. In contrast, Mg deficiency reduces both lifespan and fecundity, causes abdominal bloating and gut–renal dysfunction, and is not rescued by mid-life Mg resupply. These results show that micronutrient state determines whether dietary restriction–like benefits are possible, with Zn enabling resource reallocation and Mg acting as an essential substrate to sustain life.