Abstract # 152:

Scheduled for Friday, June 19, 2015 03:30 PM-03:45 PM: (Cascade E) Oral Presentation


PARENTS FACE A QUANTITY QUALITY TRADEOFF OVER OFFSPRING REPRODUCTION AND LIFESPAN IN ICELAND

R. F. Lynch
University of Missouri, 3009 Crestwood Lane, Columbia, MO 65203, USA
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      life history theory provides a framework for understanding how organisms allocate time, energy, and investment in an effort to maximize reproduction. Fast life history organisms prioritize faster growth and invest in fertility while slow life histories are characterized by slow growth and increased investment in survival. Because the resources are finite, the production of additional offspring necessarily dilutes the resources that parents have available to invest in all other offspring. Therefore, parents will presumably face a dilemma between investing in current offspring vs. investing in additional offspring or, rather, a tradeoff between producing more offspring and higher quality offspring. Although this strategic choice lies at the center of evolutionary biology, testing it in humans has been difficult, in large part due to the long generation time of our species.8 To solve this problem, this study utilized available data spanning approximately 300 years provided by an Icelandic genealogy. We report that with each additional full sibling, 1) an individual’s average lifespan is reduced by almost one year, and 2) their lifetime reproductive success (LRS) is decreased by an average of .07 children. This phenomenon changes significantly over time in response to changing environmental conditions, so that poor environmental conditions exacerbate this trend. Our analysis provides a framework for understanding the ultimate evolutionary consequences of the conflict between the production of and investment in offspring.