Division of Biological Sciences, University of Montana, Missoula, Montana 59812, USA.
Am Nat. 2012 Oct;180(4):529-33. doi: 10.1086/667585. Epub 2012 Aug 7.
Over the past 3 centuries, many species have been dispersed beyond their natural geographic limits by humans, but to our knowledge, reproductive isolation has not been demonstrated for such neo-allopatric species. We grew seeds from three species of Centaurea (Centaurea solstitialis, Centaurea calcitrapa, and Centaurea sulphurea) that are native to Spain and have been introduced into California, and we tested to what extent seed production was affected by pollen source. Compared with within-population crosses, seed production decreased by 52% and 44%, respectively, when C. solstitialis and C. sulphurea from California were pollinated with conspecific pollen from native populations in Spain. This implies rapid evolution of reproductive isolation between populations in their native and nonnative ranges. Whether reproductive isolation has evolved following the introduction of other species is unknown, but additional cases are likely, considering the large number of neo-allopatric species.
在过去的 3 个世纪中，许多物种已经被人类传播到其自然地理范围之外，但据我们所知，这种新的地理隔离物种尚未表现出生殖隔离。我们从原产于西班牙并已引入加利福尼亚的三种矢车菊（Centaurea solstitialis、Centaurea calcitrapa 和 Centaurea sulphurea）中培育了种子，并测试了花粉源对种子产量的影响。与种群内杂交相比，当来自加利福尼亚的 C. solstitialis 和 C. sulphurea 被来自西班牙本地种群的同种花粉授粉时，种子产量分别下降了 52%和 44%。这意味着种群在其自然和非自然分布范围内的生殖隔离迅速进化。引入其他物种后是否已经进化出生殖隔离尚不清楚，但考虑到大量的新地理隔离物种，可能还会出现更多的情况。
