Sex differences in life span and aging are ubiquitous across the animal kingdom and represent along-standing challenge in evolutionary biology. In most species, including humans, sexes differ notonly in how long they live and when they start to senesce, but also in how they react toenvironmental interventions aimed at prolonging their life span or decelerating the onset of aging.Therefore, sex differences in life span and aging have important implications beyond the questionsposed by fundamental science. Both evolutionary reasons and medical implications of sexdifferences in demographic, reproductive and physiological senescence are and will be crucialtargets of present and future research in the biology of aging. Here I propose a two-step approachthat can provide a significant breakthrough in our understanding of the biological basis of sexdifferences in aging. First, I propose to resolve the age-old conundrum regarding the role of sexspecificmortality rate in sex differences in aging by developing a series of targeted experimentalevolution studies in a novel model organism – the nematode, Caenorhabditis remanei. Second, Iaddress the role of intra-locus sexual conflict in the evolution of aging by combining novelmethodology from nutritional ecology – the Geometric Framework – with artificial selectionapproach using the cricket Teleogryllus commodus and the fruitfly Drosophila melanogaster. I willdirectly test the hypothesis that intra-locus sexual conflict mediates aging by restricting theadaptive evolution of diet choice. By combining techniques from evolutionary biology andnutritional ecology, this proposal will raise EU’s profile in integrative research, and contribute tothe training of young scientists in this rapidly developing field.