Data from: Decoupled post-glacial history in mutualistic plant-insect interactions: insights from the yellow loosestrife (Lysimachia vulgaris) and its associated oil-collecting bees (Macropis europaea and M. fulvipes)

Aim: We take a comparative phylogeographical approach to assess whether three species involved in a specialized oil-rewarding pollination system (i.e. Lysimachia vulgaris and two oil-collecting bees within the genus Macropis) show congruent phylogeographical trajectories during post-glacial colonization processes. Our working hypothesis is that within specialized mutualistic interactions, where each species relies on the co-occurrence of the other for survival and/or reproduction, partners are expected to show congruent evolutionary trajectories, because they are likely to have followed parallel migration routes and to have shared glacial refugia. Location: Western Palaearctic. Methods: Our analysis relies on the extensive sampling of 104 Western Palaearctic populations (totalling 434, 159 and 74 specimens of Lysimachia vulgaris, Macropis europaea and Macropis fulvipes, respectively), genotyped with amplified fragment length polymorphism. Based on this, we evaluated the regional genetic diversity (Shannon diversity and allele rarity index) and genetic structure (assessed using structure, population networks, isolation-by-distance and spatial autocorrelation metrics) of each species. Finally, we compared the general phylogeographical patterns obtained. Results: Contrary to our expectations, the analyses revealed phylogeographical signals suggesting that the investigated organisms demonstrate independent post-glacial trajectories as well as distinct contemporaneous demographic parameters, despite their mutualistic interaction. Main conclusions: The mutualistic partners investigated here are likely to be experiencing distinct and independent evolutionary dynamics because of their contrasting life-history traits (e.g. dispersal abilities), as well as distinct hubs and migration routes. Such conditions would prevent and/or erase any signature of co-structuring of lineages in space and time. As a result, the lack of phylogeographical congruence driven by differences in life-history traits might have arisen irrespective of the three species having shared similar Pleistocene glacial refugia.

研究目的：本研究采用比较谱系生物地理学（comparative phylogeography）方法，旨在评估参与特化油报酬传粉系统的3个物种——即黄连花（Lysimachia vulgaris）及巨蜂属（Macropis）内的2种油采集蜂——在冰期后拓殖过程中是否呈现一致的谱系生物地理学轨迹。我们的工作假说为：在特化互利共生关系中，每个物种的生存和/或繁殖均依赖于另一物种的共存，因此共生伙伴应展现一致的演化轨迹，因为它们大概率遵循了平行的迁移路径并共享冰期避难所。
研究区域：西古北界（Western Palaearctic）。
研究方法：本分析基于对西古北界104个种群的大范围采样（其中黄连花、欧洲巨蜂（Macropis europaea）和褐足巨蜂（Macropis fulvipes）的样本数分别为434、159和74份），采用扩增片段长度多态性（amplified fragment length polymorphism, AFLP）进行基因分型。基于此，我们评估了每个物种的区域遗传多样性（香农多样性指数及等位基因稀有度指数）与遗传结构（通过STRUCTURE软件、种群网络、距离隔离分析及空间自相关指标进行评估）。最后，我们对所得的整体谱系生物地理学模式进行了比较。
研究结果：与我们的预期相反，分析结果显示的谱系生物地理学信号表明，尽管存在互利共生关系，但本次研究的生物类群展现出独立的冰期后拓殖轨迹，以及截然不同的当代种群动态参数。
主要结论：本研究中的互利共生伙伴可能因其生活史特征（如扩散能力）的差异，以及不同的扩散枢纽与迁移路径，正经历截然不同且相互独立的演化动态。此类条件会阻止并/或消除谱系在时空尺度上的共结构特征信号。因此，即便这3个物种共享相似的更新世冰期避难所，由生活史特征差异所驱动的谱系生物地理学一致性缺失仍可能出现。