There Goes the Neighborhood: Complex Interactions Between Squirrels, Crossbills and Conifers

有人认为，群落中物种之间相互作用的复杂性限制了结对共同进化的可能性。然而，很少有研究测试关于其他物种的相互作用如何影响特定物种对之间的共同进化的具体假设。红松鼠和红十字鸟在争夺松子。研究人员将通过检查松树种子和球果的形态特征来测试红松鼠是否阻碍了红十字松树和松树之间的共同进化相互作用，其中有一个竞争对手存在(或两个竞争对手都存在)。这项研究将通过确定间接相互作用的进化意义来扩展对复杂物种相互作用的研究。其次，它将区分为什么结对共同进化可能不常见的几种可能的解释。第三，它将区分不同的共同进化假说。这项研究将有助于了解不同的种子捕食者对重要的商业松种--樟子松地理变异的影响，并有助于阐明不同的种子捕食者对松树进化和多样性的重要性。其次，它将为理解为什么群落中没有物种会导致这些群落中剩余物种的快速进化变化提供基础。其影响是，引入以前没有的物种可能会导致引入的物种增加到成为害虫的程度，可能导致独特物种的局部灭绝，并可能导致以前独特的群落同质化。

It has been argued that the complexity of interactions among species in communities limits the potential for pair-wise coevolution. There are, however, few studies that have tested specific hypotheses of how other species' interactions influence coevolution between particular species pairs. Red squirrels and red crossbills compete for pine seeds. The investigator will test whether the red squirrels impede the coevolutionary interaction between red crossbills and pines by examining characteristics of seed and cone morphology of lodgepole pine where one or both competitors are present (or absent). This research will extend studies of complex species interactions by determining the evolutionary significance of indirect interactions. Second, it will distinguish among several potential explanations for why pair-wise coevolution may be uncommon. Third, it will distinguish between alternative hypotheses of coevolution. This study will provide an understanding of the impact of various seed predators on geographic variation in an important commercial pine species, lodgepole pine, and will help elucidate the importance of different seed predators on pine evolution and diversity. Second, it will provide the basis for understanding why the absence of species from communities can lead to rapid evolutionary change in the remaining species in these communities. The implications are that introductions of formerly absent species may result in increases of the introduced species to the point where they become pests, may lead to local extinctions of unique species, and may result in the homogenization of formerly unique communities.