PHYLOGENETIC CONTRASTS AND THE EVOLUTION OF MAMMALIAN LIFE-HISTORIES

A recent synthetic model of mammalian life history evolution predicts that alphaM = 3(1-delta0.25), where alphaM is the product of age at maturity and the average adult instantaneous mortality rate, and delta is the ratio of weight at independence to average adult female weight. Previous studies have tested this prediction by fitting a non-linear regression to data collected for several species of mammals. However, this procedure suffers from non-independence of data points and may have led to incorrect estimates of regression parameters. We test the same life history prediction using phylogenetically independent contrasts with a phylogeny and data for 23 species of mammals. The results accord with the predicted relationship. Our study is one of the few examples where phylogenctic information has been used to improve the statistical power of a quantitative, model-based prediction of how life history variables should co-evolve.