Campus Units

Ecology, Evolution and Organismal Biology

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

2016

Journal or Book Title

Proceedings of the National Academy of Sciences

Volume

113

Issue

23

First Page

6502

Last Page

6507

DOI

10.1073/pnas.1600035113

Abstract

Lifespan and aging rates vary considerably across taxa; thus, understanding the factors that lead to this variation is a primary goal in biology and has ramifications for understanding constraints and flexibility in human aging. Theory predicts that senescence—declining reproduction and increasing mortality with advancing age—evolves when selection against harmful mutations is weaker at old ages relative to young ages or when selection favors pleiotropic alleles with beneficial effects early in life despite late-life costs. However, in many long-lived ectotherms, selection is expected to remain strong at old ages because reproductive output typically increases with age, which may lead to the evolution of slow or even negligible senescence. We show that, contrary to current thinking, both reproduction and survival decline with adult age in the painted turtle, Chrysemys picta, based on data spanning >20 y from a wild population. Older females, despite relatively high reproductive output, produced eggs with reduced hatching success. Additionally, age-specific mark–recapture analyses revealed increasing mortality with advancing adult age. These findings of reproductive and mortality senescence challenge the contention that chelonians do not age and more generally provide evidence of reduced fitness at old ages in nonmammalian species that exhibit long chronological lifespans.

Comments

This is a manuscript of an article from Proceedings of the National Academy of Sciences 113 (2016): 6502, doi: 10.1073/pnas.1600035113. Posted with permission.

Copyright Owner

Warner et al.

Language

en

File Format

application/pdf

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