Data from: Repeated intra-specific divergence in lifespan and ageing of African annual fishes along an aridity gradient

Lifespan and ageing are substantially modified by natural selection. Across species, higher extrinsic (environmentally-related) mortality (and hence shorter life expectancy) selects for the evolution of more rapid ageing. However, among populations within species, high extrinsic mortality can lead to extended lifespan and slower ageing as a consequence of condition-dependent survival. Using within-species contrasts of eight natural populations of Nothobranchius fishes in common garden experiments, we demonstrate that populations originating from dry regions (with short life expectancy) had shorter intrinsic lifespans and a greater increase in mortality with age, more pronounced cellular and physiological deterioration (oxidative damage, tumor load), and a faster decline in fertility than populations from wetter regions. This parallel intra-specific divergence in lifespan and ageing was not associated with divergence in early life history (rapid growth, maturation) or pace-of-life syndrome (high metabolic rates, active behavior). Variability across four study species suggests that a combination of different ageing and life history traits conformed with or contradicted the predictions for each species. These findings demonstrate that variation in lifespan and functional decline among natural populations are linked, genetically underpinned, and can evolve relatively rapidly.