Dungey H S, Potts B M, Whitham T G, Li H F
Cooperative Research Centre for Sustainable Production Forestry and School of Plant Science, University of Tasmania, Hobart, Australia.
Evolution. 2000 Dec;54(6):1938-46. doi: 10.1111/j.0014-3820.2000.tb01238.x.
To examine how genetic variation in a plant population affects arthropod community richness and composition, we quantified the arthropod communities on a synthetic population of Eucalyptus amygdalina, E. risdonii, and their F1 and advanced-generation hybrids. Five major patterns emerged. First, the pure species and hybrid populations supported significantly different communities. Second, species richness was significantly greatest on hybrids (F1 > F2 > E. amygdalina > E. risdonii). These results are similar to those from a wild population of the same species and represent the first case in which both synthetic and wild population studies confirm a genetic component to community structure. Hybrids also acted as centers of biodiversity by accumulating both the common and specialist taxa of both parental species (100% in the wild and 80% in the synthetic population). Third, species richness was significantly greater on F1s than the single F2 family, suggesting that the increased insect abundance on hybrids may not be caused by the breakup of coadapted gene complexes. Fourth, specialist arthropod taxa were most likely to show a dominance response to F1 hybrids, whereas generalist taxa exhibited a susceptible response. Fifth, in an analysis of 31 leaf terpenoids that are thought to play a role in plant defense, hybrids were generally intermediate to the parental chemotypes. Within the single F2 family, we found significant associations between the communities of individual trees and five individual oil components, including oil yield, demonstrating that there is a genetic effect on plant defensive chemistry that, in turn, may affect community structure. These studies argue that hybridization has important community-level consequences and that the genetic variation present in hybrid zones can be used to explore the genetic-based mechanisms that structure communities.
为了研究植物种群中的遗传变异如何影响节肢动物群落的丰富度和组成，我们对杏仁桉、里斯登桉及其F1代和高代杂种的合成种群上的节肢动物群落进行了量化。出现了五种主要模式。第一，纯种和杂种种群支持显著不同的群落。第二，杂种上的物种丰富度显著最高（F1>F2>杏仁桉>里斯登桉）。这些结果与同一物种野生种群的结果相似，并且代表了合成种群和野生种群研究均证实群落结构存在遗传成分的首个案例。杂种还通过积累两个亲本物种的常见和特化类群而成为生物多样性中心（在野生种群中为100%，在合成种群中为80%）。第三，F1代的物种丰富度显著高于单个F2家族，这表明杂种上昆虫数量的增加可能不是由共适应基因复合体的解体引起的。第四，特化节肢动物类群最有可能对F1杂种表现出优势反应，而广食性类群则表现出易感反应。第五，在对31种被认为在植物防御中起作用的叶萜类化合物的分析中，杂种通常处于亲本化学类型的中间状态。在单个F2家族中，我们发现单株树木的群落与五种单株油成分（包括油产量）之间存在显著关联，这表明对植物防御化学存在遗传效应，进而可能影响群落结构。这些研究表明杂交具有重要的群落水平后果，并且杂交区域中存在的遗传变异可用于探索构建群落的基于遗传的机制。
