Thomas Gavin H, Freckleton Robert P, Székely Tamás
Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
Proc Biol Sci. 2006 Jul 7;273(1594):1619-24. doi: 10.1098/rspb.2006.3488.
Phenotypic diversity is not evenly distributed across lineages. Here, we describe and apply a maximum-likelihood phylogenetic comparative method to test for different rates of phenotypic evolution between groups of the avian order Charadriiformes (shorebirds, gulls and alcids) to test the influence of a binary trait (offspring demand; semi-precocial or precocial) on rates of evolution of parental care, mating systems and secondary sexual traits. In semi-precocial species, chicks are reliant on the parents for feeding, but in precocial species the chicks feed themselves. Thus, where the parents are emancipated from feeding the young, we predict that there is an increased potential for brood desertion, and consequently for the divergence of mating systems. In addition, secondary sexual traits are predicted to evolve faster in groups with less demanding young. We found that precocial development not only allows rapid divergence of parental care and mating behaviours, but also promotes the rapid diversification of secondary sexual characters, most notably sexual size dimorphism (SSD) in body mass. Thus, less demanding offspring appear to facilitate rapid evolution of breeding systems and some sexually selected traits.
表型多样性在各谱系中分布并不均匀。在此，我们描述并应用一种最大似然系统发育比较方法，来测试鸻形目（滨鸟、鸥类和海雀）不同类群之间表型进化速率的差异，以检验一个二元性状（后代需求；半早成或早成）对亲代抚育、交配系统和第二性征进化速率的影响。在半早成物种中，雏鸟依赖父母提供食物，但在早成物种中，雏鸟自行觅食。因此，在父母无需喂养幼雏的情况下，我们预测弃巢的可能性会增加，进而导致交配系统的分化。此外，预计在幼雏需求较少的类群中，第二性征的进化会更快。我们发现，早成发育不仅使得亲代抚育和交配行为能够迅速分化，还促进了第二性征的快速多样化，最显著的是体重方面的两性异形（SSD）。因此，需求较少的后代似乎有助于繁殖系统和一些性选择性状的快速进化。
