Wolfe Lorne M
Department of Biology, Georgia Southern University, Statesboro, Georgia 30460, USA.
Am Nat. 2002 Dec;160(6):705-11. doi: 10.1086/343872.
Successful biological invaders often exhibit enhanced performance following introduction to a new region. The traditional explanation for this phenomenon is that natural enemies (e.g., competitors, pathogens, and predators) present in the native range are absent from the introduced range. The purpose of this study was to test the escape-from-enemy hypothesis using the perennial plant Silene latifolia as a model system. This European native was introduced to North America in the 1800s and subsequently spread to a large part of the continent. It is now considered a problematic weed of disturbed habitats and agricultural fields in the United States and Canada. Surveys of 86 populations in the United States and Europe revealed greater levels of attack by generalist enemies (aphids, snails, floral herbivores) in Europe compared with North America. Two specialists (seed predator, anther smut fungus) that had dramatic effects on plant fitness in Europe were either absent or in very low frequency in North America. Overall, plants were 17 times more likely to be damaged in Europe than in North America. Thus, S. latifolia's successful North American invasion can, at least in part, be explained by escape from specialist enemies and lower levels of damage following introduction.
成功的生物入侵者在被引入新区域后往往表现出更强的生长态势。对这一现象的传统解释是，其原生地存在的天敌（如竞争者、病原体和捕食者）在引入地不存在。本研究的目的是使用多年生植物宽叶蝇子草作为模型系统来检验天敌逃逸假说。这种原产于欧洲的植物于19世纪被引入北美，随后扩散到北美大陆的大部分地区。现在它被认为是美国和加拿大受干扰栖息地及农田中的一种有害杂草。对美国和欧洲的86个种群的调查显示，与北美相比，欧洲的广食性天敌（蚜虫、蜗牛、花食草动物）的攻击水平更高。在欧洲对植物适合度有显著影响的两种专食性天敌（种子捕食者、花药黑粉菌）在北美要么不存在，要么频率很低。总体而言，欧洲的植物受到损害的可能性是北美的17倍。因此，宽叶蝇子草在北美的成功入侵至少部分可以解释为逃离了专食性天敌以及引入后较低的损害水平。
