Benkman Craig W, Parchman Thomas L, Favis Amanda, Siepielski Adam M
Department of Biology, New Mexico State University, Las Cruces, New Mexico, 88003, USA.
Am Nat. 2003 Aug;162(2):182-94. doi: 10.1086/376580. Epub 2003 Jun 25.
Few studies have shown both reciprocal selection and reciprocal adaptations for a coevolving system in the wild. The goal of our study was to determine whether the patterns of selection on Rocky Mountain lodgepole pine (Pinus contorta spp. latifolia) and red crossbills (Loxia curvirostra complex) were concordant with earlier published evidence of reciprocal adaptations in lodgepole pine and crossbills on isolated mountain ranges in the absence of red squirrels (Tamiasciurus hudsonicus). We found that selection (directional) by crossbills on lodgepole pine where Tamiasciurus are absent was divergent from the selection (directional) exerted by Tamiasciurus on lodgepole pine. This resulted in divergent selection between areas with and without Tamiasciurus that was congruent with the geographic patterns of cone variation. In the South Hills, Idaho, where Tamiasciurus are absent and red crossbills are thought to be coevolving with lodgepole pine, crossbills experienced stabilizing selection on bill size, with cone structure as the agent of selection. These results show that crossbills and lodgepole pine exhibit reciprocal adaptations in response to reciprocal selection, and they provide insight into the traits mediating and responding to selection in a coevolutionary arms race.
很少有研究表明在野外共同进化的系统中存在相互选择和相互适应的情况。我们研究的目的是确定落基山黑松（Pinus contorta spp. latifolia）和红交嘴雀（Loxia curvirostra complex）的选择模式是否与先前发表的在没有红松鼠（Tamiasciurus hudsonicus）的孤立山脉上黑松和交嘴雀相互适应的证据一致。我们发现，在没有红松鼠的地方，交嘴雀对黑松的选择（定向）与红松鼠对黑松的选择（定向）不同。这导致了有红松鼠和没有红松鼠的地区之间的选择差异，这与球果变异的地理模式一致。在爱达荷州的南山，那里没有红松鼠，红交嘴雀被认为与黑松共同进化，交嘴雀在喙大小上经历了稳定选择，球果结构作为选择因子。这些结果表明，交嘴雀和黑松表现出相互适应以应对相互选择，并且它们为在共同进化的军备竞赛中介导和响应选择的性状提供了见解。
