Department of Biology, University of Missouri at Saint Louis, Saint Louis, Missouri, USA.
Ecology. 2023 Jan;104(1):e3845. doi: 10.1002/ecy.3845. Epub 2022 Oct 12.
Animal pollinators directly affect plant gene flow by transferring pollen grains between individuals. Pollinators with restricted mobility are predicted to limit gene flow within and among populations, whereas pollinators that fly longer distances are likely to promote genetic cohesion. These predictions, however, remain poorly tested. We examined population genetic structure and fine-scale spatial genetic structure (FSGS) in six perennial understory angiosperms in Andean cloud forests of northwestern Ecuador. Species belong to three families (Gesneriaceae, Melastomataceae, and Rubiaceae), and within each family we paired one insect-pollinated with one hummingbird-pollinated species, predicting that insect-pollinated species have greater population differentiation (as quantified with the F statistic) and stronger FSGS (as quantified with the S statistic) than hummingbird-pollinated species. We confirmed putative pollinators through a literature review and fieldwork, and inferred population genetic parameters with a genome-wide genotyping approach. In two of the three species pairs, insect-pollinated species had much greater (>2-fold) population-level genetic differentiation and correspondingly steeper declines in fine-scale genetic relatedness. In the Gesneriaceae pair, however, F and S values were similar between species and to those of the other hummingbird-pollinated plants. In this pair, the insect pollinators are euglossine bees (as opposed to small bees and flies in the other pairs), which are thought to forage over large areas, and therefore may provide similar levels of gene flow as hummingbirds. Overall, our results shed light on how different animal pollination modes influence the spatial scale of plant gene flow, suggesting that small insects strongly decrease genetic cohesion.
动物传粉者通过在个体之间传递花粉粒直接影响植物基因流。移动能力受限的传粉者预计会限制个体内和种群间的基因流动，而飞行距离较长的传粉者则可能促进遗传凝聚。然而，这些预测仍未得到充分验证。我们在厄瓜多尔西北安第斯云雾林的六种多年生林下被子植物中研究了种群遗传结构和小尺度空间遗传结构（FSGS）。物种属于三个科（玄参科、野牡丹科和茜草科），在每个科中，我们将一个昆虫传粉的物种与一个蜂鸟传粉的物种配对，预测昆虫传粉的物种比蜂鸟传粉的物种具有更大的种群分化（用 F 统计量量化）和更强的 FSGS（用 S 统计量量化）。我们通过文献回顾和野外工作确认了假定的传粉者，并通过全基因组基因分型方法推断了种群遗传参数。在三个物种对中的两个中，昆虫传粉的物种具有更大的（>2 倍）种群遗传分化，相应的小尺度遗传相关性下降更为陡峭。然而，在玄参科对中，F 和 S 值在物种之间以及与其他蜂鸟传粉植物相似。在这一对中，昆虫传粉者是 Euglossine 蜜蜂（与其他对中的小型蜜蜂和苍蝇相反），它们被认为在较大的区域内觅食，因此可能提供与蜂鸟相似的基因流动水平。总的来说，我们的研究结果揭示了不同的动物传粉模式如何影响植物基因流的空间尺度，表明小型昆虫强烈降低遗传凝聚。
