Population position along the fast-slow life-history continuum predicts intraspecific variation in actuarial senescence.

Abstract

Patterns of actuarial senescence can be highly variable among species. Previous comparative analyses revealed that both age at the onset of senescence and rates of senescence are linked to position of a species along the fast-slow life-history continuum. As there are few long-term datasets of wild populations with known-age individuals, intraspecific (i.e. between-population) variation in senescence is understudied and limited to comparisons of wild and captive populations of the same species, mostly birds and mammals. In this paper, we examined how population position along the fast-slow life-history continuum affects intraspecific variation in senescence in an amphibian, Bombina variegata. We used capture-recapture data collected in four populations with contrasting life-history strategies. Senescence trajectories were analysed using Bayesian capture-recapture models. We show that in populationswith fast life histories the onset of actuarial senescence was earlier and individuals aged at a faster rate than individuals in populationswith slow life histories. Our study provides one of the few empirical examples of among-population variation in actuarial senescence patterns in the wild and confirms that the fast-slow life-history gradient is associated with both macroevolutionary and microevolutionary patterns of actuarial senescence.