Phillips Benjamin L, Brown Gregory P, Webb Jonathan K, Shine Richard
School of Biological Sciences A08, University of Sydney, New South Wales 2006, Australia.
Nature. 2006 Feb 16;439(7078):803. doi: 10.1038/439803a.
Cane toads (Bufo marinus) are large anurans (weighing up to 2 kg) that were introduced to Australia 70 years ago to control insect pests in sugar-cane fields. But the result has been disastrous because the toads are toxic and highly invasive. Here we show that the annual rate of progress of the toad invasion front has increased about fivefold since the toads first arrived; we find that toads with longer legs can not only move faster and are the first to arrive in new areas, but also that those at the front have longer legs than toads in older (long-established) populations. The disaster looks set to turn into an ecological nightmare because of the negative effects invasive species can have on native ecosystems; over many generations, rates of invasion will be accelerated owing to rapid adaptive change in the invader, with continual 'spatial selection' at the expanding front favouring traits that increase the toads' dispersal.
甘蔗蟾蜍（海蟾蜍）是大型无尾目动物（体重可达2千克），70年前被引入澳大利亚以控制甘蔗田中的害虫。但结果是灾难性的，因为这些蟾蜍有毒且极具入侵性。我们在此表明，自蟾蜍首次抵达以来，蟾蜍入侵前沿的年推进速度增加了约五倍；我们发现腿更长的蟾蜍不仅移动速度更快，而且是最先到达新区域的，此外，前沿的蟾蜍比在较老（已长期存在）种群中的蟾蜍腿更长。这场灾难似乎即将演变成一场生态噩梦，因为入侵物种会对本地生态系统产生负面影响；经过许多代之后，由于入侵者的快速适应性变化，入侵速度将会加快，在不断扩张的前沿持续进行的“空间选择”有利于那些增加蟾蜍扩散能力的性状。
