Vilà Montserrat, Maron John L, Marco Laia
Centre de Recerca Ecològica i Aplicacions Forestals, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
Oecologia. 2005 Jan;142(3):474-9. doi: 10.1007/s00442-004-1731-z. Epub 2004 Nov 3.
The enemy release hypothesis (ERH), which has been the theoretical basis for classic biological control, predicts that the success of invaders in the introduced range is due to their release from co-evolved natural enemies (i.e. herbivores, pathogens and predators) left behind in the native range. We tested this prediction by comparing herbivore pressure on native European and introduced North American populations of Hypericum perforatum (St John's Wort). We found that introduced populations occur at larger densities, are less damaged by insect herbivory and suffer less mortality than populations in the native range. However, overall population size was not significantly different between ranges. Moreover, on average plants were significantly smaller in the introduced range than in the native range. Our survey supports the contention that plants from the introduced range experience less herbivore damage than plants from the native range. While this may lead to denser populations, it does not result in larger plant size in the introduced versus native range as postulated by the ERH.
敌害释放假说（ERH）一直是经典生物防治的理论基础，该假说预测外来物种在引入地的成功是由于它们摆脱了在原生地共同进化的天敌（即食草动物、病原体和捕食者）。我们通过比较欧洲本土和引入北美的贯叶连翘（圣约翰草）种群所受的食草动物压力，对这一预测进行了检验。我们发现，引入种群的密度更大，受昆虫食草作用的损害更小，死亡率也低于原生地的种群。然而，两个区域的总体种群规模并无显著差异。此外，引入区域的植物平均而言比原生区域的植物小得多。我们的调查支持了这样一种观点，即引入区域的植物比原生区域的植物遭受的食草动物损害更少。虽然这可能导致种群密度更大，但正如敌害释放假说所假定的那样，在引入区域与原生区域相比，这并不会使植物长得更大。
