Evolutionary Ecology of Black Pineleaf Scale Infestations on Ponderosa Pine

黑松叶鳞虫（Nuculaspis californica Coleman）是西部黄松（Pinus ponderosa Lawson）的寄生虫。这些昆虫相对于它们的寄主来说寿命很短，而且大部分是定居的，它们的种群在与单独的寄主树和同一棵松树内的不同分支之间的极短距离内被细分和遗传分化（Alstad and Corbin, in press）。最近研究得出的三种不同的证据（Alstad and Edmunds 1989， Alstad and Corbin出版，Alstad未发表）推翻了我们早期的观点（Edmunds and Alstad 1978, 1981; Alstad and Edmunds 1983a, 1983b），即规模种群结构反映了规模巢对单个寄主树内在的基因型特征的适应。本研究将对黄松黑松叶蚧虫局部分化机制的新假设进行验证：尺度适应是与外源表型性状相关的选择结果，这些性状(a)是松树基因型与其环境相互作用的产物，(b)在树内和树间都有变化。这些相反的假设代表了植物/草食动物相互作用文献中的主要主题；它们是进化生态学家的基本兴趣，对森林管理具有明确而重要的意义。

The black pineleaf scale insect (Nuculaspis californica Coleman) is a parasite of western yellow pine (Pinus ponderosa Lawson. The insects are shortlived relative to their host and largely sedentary, and their populations are subdivided and genetically differentiated over extraordinarily short distances in association with both individual host trees, and different branches within a single pine (Alstad and Corbin, in press). Three different kinds of evidence resulting from recent research (Alstad and Edmunds 1989, Alstad and Corbin in press, and Alstad unpublished) compromise our earlier view (Edmunds and Alstad 1978, 1981; Alstad and Edmunds 1983a, 1983b) that scale population structure reflects adaptation of the scale demes to intrinsic, genotypic characteristics of individual host trees. The proposed research will test a new hypothesis about the mechanistic causes of local differentiation in black pineleaf scale insects infesting ponderosa pine: that scale adaptation results from selection related to extrinsic phenotypic traits which (a) are the product of interactions between the pine genotype and its environment, and (b) vary both within and between trees. These opposing hypotheses represent major themes in the literature of plant/herbivore interactions; they are of basic interest to evolutionary ecologists and have clear and important implications for forest management.