The selection mosaic and diversifying coevolution between crossbills and lodgepole pine
The selection mosaic and diversifying coevolution between crossbills and lodgepole pine
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DOI：
10.1086/303213
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发表时间：
1999-05-01
影响因子：
2.9
通讯作者：
Benkman, CW
中科院分区：
文献类型：
--
作者：
Benkman, CW
不对称竞争决定了两种种子捕食者中的哪一种驱动了扭叶松（Pinus contorta ssp. latifolia）球果的进化。红松鼠（Tamiasciurus hudsonicus）在扭叶松林中是有效的抢先竞争者，以至于红交嘴雀（Loxia curvirostra）不常见，并且来自红松鼠的选择驱动了球果的进化。当没有红松鼠时，交嘴雀数量增加，并在与松树的进化军备竞赛中共同进化。类似地，红松鼠改变了大种子松树的进化轨迹，其中许多大种子松树依靠鸟类（鸦科）传播种子。因此，种群呈现出具有协同进化热点的选择镶嵌体。在协同进化热点地区，对交嘴雀的分歧选择可能导致生殖隔离和物种形成。这导致地理镶嵌体随后减少，但使交嘴雀辐射进化的适应景观多样化。因此，分歧选择是一把双刃剑。分歧选择在形成选择镶嵌体方面至关重要，但当它促进生殖隔离和物种形成时，又会侵蚀选择镶嵌体。
Asymmetrical competition determines which of two seed predators drives the evolution of lodgepole pine (Pinus contorta ssp. latifolia) cones. Red squirrels (Tamiasciurus hudsonicus) are effective preemptive competitors in lodgepole pine forests so that red crossbills (Loxia curvirostra) are uncommon and selection from Tamiasciurus drives cone evolution. When Tamiasciurus are absent, crossbills increase in abundance and coevolve in an evolutionary arms race with pine. Similarly, Tamiasciurus alters the evolutionary trajectories of large-seeded pines, many of which rely on birds (Corvidae) for their seed dispersal. Populations therefore exhibit a selection mosaic with coevolutionary hot spots. In the coevolutionary hot spots, divergent selection on crossbills potentially leads to reproductive isolation and speciation. This results in a subsequent reduction in the geographic mosaic but diversifies the adaptive landscape on which crossbills have radiated. Thus, divergent selection is a double-edged sword. Divergent selection is critical in creating a selection mosaic but erodes the selection mosaic when it promotes reproductive isolation and speciation.