Campus Units

Ecology, Evolution and Organismal Biology

Document Type

Article

Publication Version

Published Version

Publication Date

4-2021

Journal or Book Title

The American Naturalist

Volume

197

Issue

4

First Page

461

Last Page

472

DOI

10.1086/713174

Abstract

Life-history theory predicts that investment in reproduction should increase as future reproductive potential (i.e., residual reproductive value [RRV]) decreases. Researchers have thus intuitively used age as a proxy for RRV and assume that RRV decreases with age when interpreting age-specific investment. Yet age is an imperfect proxy for RRV and may even be a poor correlate in some systems. We used a 31-year study of the nesting ecology of painted turtles (Chrysemys picta) to assess how age and RRV compare in explaining variation in a risky investment behavior. We predicted that RRV would be a better predictor of risky investment than age because RRV accounts for variation in future reproductive potential across life. We found that RRV was high in early life, slowly decreased until midlife, and then steadily decreased to terminal reproduction. However, age predicted risky behavior better than RRV. This finding suggests that stronger correlates of age (e.g., size) may be more responsible for this behavior in turtles. This study highlights that researchers should not assume that age-specific investment is driven by RRV and that future work should quantify RRV to more directly test this key element of life-history theory.

Comments

This article is published as Delaney, David M., Luke A. Hoekstra, and Fredric J. Janzen. "Age predicts risky investment better than residual reproductive value." The American Naturalist 197, no. 4 (2021): 461-472. doi:10.1086/713174. Posted with permission.

Copyright Owner

The University of Chicago

Language

en

File Format

application/pdf

Available for download on Friday, April 01, 2022

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