Mutualists and antagonists drive among-population variation in selection and evolution of floral display in a perennial herb
Mutualists and antagonists drive among-population variation in selection and evolution of floral display in a perennial herb
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DOI：
10.1073/pnas.1301421110
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发表时间：
2013-11-05
影响因子：
11.1
通讯作者：
Ehrlen, Johan
中科院分区：
文献类型：
--
作者：
Agren, Jon;Hellstrom, Frida;Ehrlen, Johan
选择方向的空间变异驱动了适应性分化的进化。然而，很少有实验研究已经检查了不同的环境因素的选择和自然种群的进化轨迹的变化的相对重要性。在这里，我们结合联合收割机8年的观测数据和田间试验，以评估互惠和拮抗作用的相对重要性的空间变异的选择和短期进化的遗传为基础的花显示二型性的短命多年生草本植物粉报春。该物种的自然种群包括两种花型：长花型植物，其花朵远高于地面;短花型植物，其花朵接近地面。花柄形态的选择方向和幅度在种群间存在差异，短型的频率也存在差异（中位数为19%，范围为0-100%; n = 69个种群）。在四个站点重复的田间试验表明，与食草动物和传粉者的相互作用的强度的变化是负责的两种变体的相对适合度的双种群差异。食草动物施加的选择有利于短花葶的变形，而传粉媒介介导的选择有利于长花葶的变形。此外，在自然种群之间的选择变化与变形频率变化的差异，并在9个网站的实验去除食草动物显着减少了8年以上的短柄变形的频率。结果表明，放牧和授粉强度的空间变化产生选择镶嵌，生物相互作用的变化可以触发自然植物种群的快速遗传变化。
Spatial variation in the direction of selection drives the evolution of adaptive differentiation. However, few experimental studies have examined the relative importance of different environmental factors for variation in selection and evolutionary trajectories in natural populations. Here, we combine 8 y of observational data and field experiments to assess the relative importance of mutualistic and antagonistic interactions for spatial variation in selection and short-term evolution of a genetically based floral display dimorphism in the short-lived perennial herb Primula farinosa. Natural populations of this species include two floral morphs: long-scaped plants that present their flowers well above the ground and short-scaped plants with flowers positioned close to the ground. The direction and magnitude of selection on scape morph varied among populations, and so did the frequency of the short morph (median 19%, range 0-100%; n = 69 populations). A field experiment replicated at four sites demonstrated that variation in the strength of interactions with grazers and pollinators were responsible for among-population differences in relative fitness of the two morphs. Selection exerted by grazers favored the short-scaped morph, whereas pollinator-mediated selection favored the long-scaped morph. Moreover, variation in selection among natural populations was associated with differences in morph frequency change, and the experimental removal of grazers at nine sites significantly reduced the frequency of the short-scaped morph over 8 y. The results demonstrate that spatial variation in intensity of grazing and pollination produces a selection mosaic, and that changes in biotic interactions can trigger rapid genetic changes in natural plant populations.