Margo I. Adler
University of New South WalesSchool of BEES
Evolution & Ecology Research Centre
UNSW
Sydney, 2052
Australia
Abstracts (first author)
Why do the well-fed die young? An eco-evolutionary perspective on the effects of dietary restriction
Summary:
The phylogenetically conserved life-history responses to dietary restriction (DR) – lifespan extension and reduced fecundity – have long been thought to reflect an adaptive survival mode whereby resources are redirected from reproduction to somatic maintenance and repair, enabling organisms to weather periods of resource scarcity. We argue that this interpretation of DR’s effects is both inconsistent with recent experimental evidence and at odds with the ecology of natural populations. Laboratory studies have shown that high nutrient intake stimulates nutrient-sensing pathways that enhance reproduction as well as the ability to respond to environmental challenges, but impose latent costs -- increased rates of cellular damage and aging – that reduce survival in the lab. However, relative to laboratory organisms, natural populations subject to high extrinsic mortality rates are far less likely to reap the survival benefits associated with DR, or to pay the fitness costs associated with full-feeding. We suggest that DR’s effects are best understood as the corollary of an ancient and highly-conserved strategy that allows organisms to take advantage of periods of resource abundance.
