Evolutionary theories of aging 1. The need to understand the process of natural selection

Background: In a Forum article Le Bourg (1998) criticized recent tests of e volutionary theories of aging and suggested alternative explanations for th e long lifespan of ant queens and the positive relationship between body si ze and lifespan in mammals. Moreover, he attempts to criticize evolutionary theories of aging by showing that explanations other than evolutionary the ories of aging probably account for the variation in human lifespan across countries. Objective: Here we show that the arguments of Le Bourg suffer se veral problems. First, many of the arguments reveal a misunderstanding of t he process of natural selection. Second, some of the arguments reflect a la ck of knowledge of evolutionary theories of aging (e.g. pre-reproductive mo rtality is not predicted to influence lifespan of organisms contrary to wha t is claimed). Finally, his final example on lifespan in humans simply is a straw-man because serious evolutionary biologists are well aware of the im portance of confounding variables and would certainly not make the type of conclusion suggested by Le Bourg, Conclusion: Although a critical discussio n of evolutionary theories of aging is welcome, we believe that the alterna tive explanations proposed by Le Bourg are implausible and reflect a misund erstanding of the process of natural selection. Copyright (C) 1999 S. Karge r AG, Basel.