title: Resource allocation as a driver of senescence: life history tradeoffs produce age patterns of mortality.
abstract: We investigate the effects of optimal time and resource allocation on age patterns of fertility and mortality for a model organism with (1) fixed maximum lifespan, (2) distinct juvenile and adult diets, and (3) reliance on nonrenewable resources for reproduction. We ask when it is optimal to tolerate starvation vs. conserve resources and then examine the effects of these decisions on adult mortality rates. We find that (1) age-related changes in tradeoffs partition the life cycle into as many as four discrete phases with different optimal behavior and mortality patterns, and (2) given a cost of reproduction, terminal investment can produce a signal of actuarial senescence. Also, given limitations imposed by non-replenishable resources, individuals beginning adult life with more replenishable resources do not necessarily live longer, since they can engage in capital breeding and need not defer reproduction to forage; low reproductive overheads and low costs of starvation also encourage capital breeding and may lead to earlier terminal investment and earlier senescence. We conclude that, even for species with qualitatively similar life histories, differences in physiological, behavioral and environmental tradeoffs or constraints may strongly influence optimal allocation schedules and produce variation in mortality patterns and life expectancy.
authors: Department of Biology, Gilbert Hall, Stanford University, Stanford, CA 94305, USA; Max Planck Research Group Modeling the Evolution of Aging, Max Planck Institute for Demographic Research, Konrad-Zuse Str. 1, 18057 Rostock, Germany. Electronic address: razieldavison@gmail.com.
authors: Raziel
authors: R
authors: Davison
authors: Department of Biology, Gilbert Hall, Stanford University, Stanford, CA 94305, USA; Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA. Electronic address: boggscl@mailbox.sc.edu.
authors: Carol L
authors: CL
authors: Boggs
authors: Max Planck Research Group Modeling the Evolution of Aging, Max Planck Institute for Demographic Research, Konrad-Zuse Str. 1, 18057 Rostock, Germany. Electronic address: baudisch@demogr.mpg.de.
authors: Annette
authors: A
authors: Baudisch
mesh_terms: D000367:Age Factors; D000375:Aging / Q000502:physiology*; D003198:Computer Simulation; D004032:Diet; D005298:Fertility / Q000502:physiology*; D008018:Life Cycle Stages / Q000502:physiology*; D008954:Models, Biological; D009026:Mortality; D040841:Resource Allocation; D013045:Species Specificity
keywords: Cost of reproduction; Foraging; Lifespan; Starvation; Terminal investment