Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3JT, UK.
Mol Ecol. 2012 Sep;21(18):4605-17. doi: 10.1111/j.1365-294X.2012.05700.x. Epub 2012 Aug 14.
Little is known about the stability of trophic relationships in complex natural communities over evolutionary timescales. Here, we use sequence data from 18 nuclear loci to reconstruct and compare the intraspecific histories of major Pleistocene refugial populations in the Middle East, the Balkans and Iberia in a guild of four Chalcid parasitoids (Cecidostiba fungosa, Cecidostiba semifascia, Hobbya stenonota and Mesopolobus amaenus) all attacking Cynipid oak galls. We develop a likelihood method to numerically estimate models of divergence between three populations from multilocus data. We investigate the power of this framework on simulated data, and-using triplet alignments of intronic loci-quantify the support for all possible divergence relationships between refugial populations in the four parasitoids. Although an East to West order of population divergence has highest support in all but one species, we cannot rule out alternative population tree topologies. Comparing the estimated times of population splits between species, we find that one species, M. amaenus, has a significantly older history than the rest of the guild and must have arrived in central Europe at least one glacial cycle prior to other guild members. This suggests that although all four species may share a common origin in the East, they expanded westwards into Europe at different times.
关于在进化时间尺度上复杂自然群落中营养关系的稳定性，我们知之甚少。在这里，我们使用来自 18 个核基因座的序列数据，重建并比较了中东、巴尔干半岛和伊比利亚半岛四个拟寄生物种（Cecidostiba fungosa、Cecidostiba semifascia、Hobbya stenonota 和 Mesopolobus amaenus）的主要更新世避难种群的种内历史，这些种都攻击栎瘿蜂属栎瘿。我们开发了一种似然方法，从多基因座数据中数值估计三种群之间分歧的模型。我们在模拟数据上检验了这个框架的能力，并使用内含子基因座的三联体比对，量化了在四个拟寄生物种的避难种群之间所有可能的分歧关系的支持程度。尽管在除一种之外的所有物种中，种群分歧的东向西顺序都有最高的支持度，但我们不能排除其他种群树拓扑的可能性。比较物种间种群分裂的估计时间，我们发现一种物种 M. amaenus 的历史明显比其他物种古老，它必须在其他成员之前至少一个冰川周期到达中欧。这表明，尽管所有四个物种可能在东部有一个共同的起源，但它们在不同的时间向欧洲西部扩张。
