Thom Michael D, Johnson Dominic D P, MacDonald David W
Wildlife Conservation Research Unit, Department of Zoology, South Parks Road, Oxford OX1 3PS, United Kingdom.
Evolution. 2004 Jan;58(1):175-83. doi: 10.1111/j.0014-3820.2004.tb01584.x.
Diapause, the temporary cessation of development at an early life-history stage, is widespread among animals and plants. The range of taxa exhibiting various forms of diapause indicates its enormous ecological significance and highlights its value as a model for examining life-history trait evolution. However, despite the impact of diapause on species ecology, there is little understanding of its adaptive value in many groups. Furthermore, the relative roles of phylogeny and ecology in determining the contemporary expression of the trait remain unresolved. Delayed implantation (DI) is a type of diapause found in several orders of mammals. It is particularly prevalent in the Mustelidae, with mustelids making up more than half of all mammals known to exhibit DI. This taxon is thus ideal for examining life-history predictors of DI and investigating the mode of evolution. Both maximum likelihood and maximum parsimony methods of ancestral state reconstruction indicated DI to be plesiomorphic in the mustelids, although multiple state changes are required to explain its contemporary distribution. After controlling for phylogeny, species with and without DI could be discriminated using just three variables: longevity, maximum latitude of the geographical distribution, and a term describing maternal investment. Our analyses supported the hypothesis that DI is more prevalent in seasonal climates. We also showed that longer-lived species are more likely to exhibit DI, suggesting a time cost to the trait. We found no correlate for the highly variable duration of DI, which remains unexplained. Although ecological factors can predict the distribution of DI in modern mustelids, phylogenetic constraint is likely to play an important role.
滞育是指在生命史早期阶段发育的暂时停止，在动植物中广泛存在。表现出各种滞育形式的分类单元范围表明了其巨大的生态意义，并突出了其作为研究生命史特征进化模型的价值。然而，尽管滞育对物种生态有影响，但在许多类群中对其适应价值的了解却很少。此外，系统发育和生态在决定该特征当代表达中的相对作用仍未得到解决。延迟着床（DI）是在几个哺乳动物目中发现的一种滞育类型。它在鼬科中尤为普遍，鼬科动物占已知表现出DI的所有哺乳动物的一半以上。因此，这个分类单元是研究DI的生命史预测因素和调查进化模式的理想选择。祖先状态重建的最大似然法和最大简约法都表明DI在鼬科中是原始的，尽管需要多次状态变化来解释其当代分布。在控制了系统发育之后，仅使用三个变量就可以区分有DI和没有DI的物种：寿命、地理分布的最大纬度以及一个描述母体投资的术语。我们的分析支持了DI在季节性气候中更普遍的假设。我们还表明，寿命较长的物种更有可能表现出DI，这表明该特征存在时间成本。我们没有发现DI高度可变持续时间的相关因素，这仍然无法解释。虽然生态因素可以预测现代鼬科动物中DI的分布，但系统发育限制可能起着重要作用。
