Improvement of starvation resistance via periodic fasting is genetically variable in Drosophila melanogaster

Organisms subjected to periodic nutrient limitation early in life exhibit improvements in aspects of survival, including resistance to some environmental stressors. Recent findings indicate that forms of periodic fasting, such as intermittent fasting and time-restricted feeding, can improve starvation resistance. However, it remains unclear to what extent this survival improvement persists across different genetic backgrounds. In this study, we examine fasting-induced starvation resistance across a broad survey of wild-derived lineages and document genetic variation within this trait. We adopt a standard dietary intervention and show improvement in starvation resistance within a common laboratory lineage, replicating previous results. Next, we examine fasting-induced starvation resistance across isofemale lines collected across latitudes and in different seasons, and among inbred lines derived from flies collected on different continents. We discover genetic variation of fasting-induced starvation resistance and show that fasting improved starvation resistance as often as it worsened starvation resistance. Fasted flies generally showed reduced fat concentration, and their starvation survival varied with sex, season of collection and geographic origin. While specific lineages common to the laboratory can show a specific fasting-induced phenotype, we show that this result is not consistent across genetic backgrounds, reinforcing the idea that phenotypes observed in historic laboratory strains may not be conserved across a species.