Short- and long-term advantages of an alternative ontogenetic pathway

We documented hypotheses on the evolution of developmental heterochronies by estimating short- and long-term advantages of alternative morphs. In this respect, we compared food energy intakes and body condition between paedomorphic and metamorphic Alpine newts (Triturus alpestris, Caudata, Amphibia) in four populations. Because we found a strong correlation between fat reserves and body condition, we used this last parameter as an indicator of long-term gains. In all studied sites, paedomorphic females showed higher body condition than metamorphic ones. Paedomorphic males were also at advantage in two populations. Paedomorphs exhibited higher energy intakes than metamorphs in two populations and similar gains in two others. Our results support unifying theories that predict the occurrence of facultative paedomorphosis in varied habitats as paedomorphs exhibited better energy balance than metamorphs. This work shows the need for considering integrative parameters such as body condition in the comparative study of performances when studying developmental heterochronies. (C) 2002 The Linnean Society of London, Biological Journal of the Linnean Society, 2002, 77, 105-112.