Ribera I, Barraclough T G, Vogler A P
Department of Entomology, The Natural History Museum, London, SW7 5BD, UK.
Mol Ecol. 2001 Mar;10(3):721-35. doi: 10.1046/j.1365-294x.2001.01218.x.
Most aquatic beetles in the family Dytiscidae are tightly associated either with running (lotic) or stagnant (lentic) water bodies. The range size of lotic species is known to be, on average, much smaller than that of lentic species, presumably as a result of differences in dispersal strategies in each habitat type. We explored possible effects of these differences on clade evolution and speciation rates by comparing species-level phylogenies based on cytochrome oxidase I (COI) and 16S rRNA mitochondrial genes for two genera, the lentic Ilybius and the lotic Deronectes. The expectation that species turnover is higher in lotic lineages due to their lower dispersal propensity compared to lentic species was not strongly supported. Deronectes displays a higher frequency of recent splits than Ilybius, consistent with the hypothesis, but the difference was not significant compared to expected patterns under a constant speciation rate null model. Similarly, when the degree of sympatry was plotted against relative node age, more allopatric splits were evident in the lentic Deronectes, suggesting a slower rate of range movement since speciation, but the differences were not significant. We discuss two explanations for our failure to detect differences between the two clades. First, current methods for analysing species-level phylogenies may be sensitive to taxonomic and sampling artefacts. Second, lentic and lotic clades may indeed display similar levels of species turnover despite occupying very different habitats at different spatial scales. More work is needed to investigate the effects of population level processes and spatial scale on macroevolutionary dynamics.
龙虱科的大多数水生甲虫与流水（激流）或静水（湖泊）水体紧密相关。已知激流物种的分布范围平均比静水物种小得多，这可能是由于每种栖息地类型的扩散策略不同所致。我们通过比较基于细胞色素氧化酶I（COI）和16S rRNA线粒体基因的两个属（静水的伊利比乌斯属和激流的德龙内克属）的物种水平系统发育，探讨了这些差异对进化枝进化和物种形成速率的可能影响。与静水物种相比，由于激流谱系的扩散倾向较低，因此预期其物种更替率更高，但这一预期并未得到有力支持。德龙内克属显示出比伊利比乌斯属更高的近期分裂频率，这与假设一致，但与恒定物种形成速率零模型下的预期模式相比，差异并不显著。同样，当将同域程度与相对节点年龄作图时，在静水的德龙内克属中，更多的异域分裂更为明显，这表明自物种形成以来范围移动的速率较慢，但差异并不显著。我们讨论了未能检测到两个进化枝之间差异的两种解释。第一，当前分析物种水平系统发育的方法可能对分类和采样假象敏感。第二，尽管在不同空间尺度上占据非常不同的栖息地，但静水和激流进化枝可能确实显示出相似的物种更替水平。需要更多的工作来研究种群水平过程和空间尺度对宏观进化动态的影响。
