CABI Europe-Switzerland, Chemin des Grillons 1, 2800 Delémont, Switzerland.
Ecology. 2011 Apr;92(4):829-35. doi: 10.1890/10-1230.1.
One commonly accepted mechanism for biological invasions is that species, after introduction to a new region, leave behind their natural enemies and therefore increase in distribution and abundance. However, which enemies are escaped remains unclear. Escape from specialist invertebrate herbivores has been examined in detail, but despite the profound effects of generalist herbivores in natural communities their potential to control invasive species is poorly understood. We carried out parallel laboratory feeding bioassays with generalist invertebrate herbivores from the native (Europe) and from the introduced (North America) range using native and nonnative tetraploid populations of the invasive spotted knapweed, Centaurea stoebe. We found that the growth of North American generalist herbivores was far lower when feeding on C. stoebe than the growth of European generalists. In contrast, North American and European generalists grew equally well on European and North American tetraploid C. stoebe plants, lending no support for an evolutionary change in resistance of North American tetraploid C. stoebe populations against generalist herbivores. These results suggest that biogeographical differences in the response of generalist herbivores to novel plant species have the potential to affect plant invasions.
一个被广泛接受的生物入侵机制是，物种在引入一个新的地区后，会摆脱其天敌，从而增加分布和丰度。然而，哪些天敌被逃脱了仍不清楚。已经详细研究了对专门的无脊椎草食动物的逃避，但尽管在自然群落中，一般性草食动物具有深远的影响，但它们对入侵物种的控制潜力仍知之甚少。我们使用来自入侵物种斑点矢车菊（Centaurea stoebe）的本地（欧洲）和引入（北美）种群的一般性无脊椎草食动物，在实验室中进行了平行的饲养生物测定。我们发现，北美草食动物的生长速度远低于欧洲草食动物在食用斑点矢车菊时的生长速度。相比之下，北美和欧洲的草食动物在欧洲和北美的四倍体斑点矢车菊植株上的生长情况相同，这表明北美四倍体斑点矢车菊种群对草食动物的抗性没有发生进化变化。这些结果表明，一般性草食动物对新型植物物种的反应的生物地理差异有可能影响植物的入侵。
