Drown Devin M, Levri Edward P, Dybdahl Mark F
School of Biological Sciences, Washington State University Pullman, WA, USA.
Department of Biology Penn State Altoona, Altoona, PA, USA.
Evol Appl. 2011 Jan;4(1):132-43. doi: 10.1111/j.1752-4571.2010.00149.x. Epub 2010 Aug 3.
It is not clear which forms of plasticity in fitness-related traits are associated with invasive species. On one hand, it may be better to have a robust performance across environments. On the other, it may be beneficial to take advantage of limited favorable conditions. We chose to study a worldwide invasive species, Potamopyrgus antipodarum, and compare the plasticity of life-history traits of a sample of invasive genotypes to a sample of ancestral-range genotypes. We examined the responses to salinity in this freshwater snail because it varies spatially and temporally in the introduced range and contributes to variation in fitness in our system. We used a recently developed statistical method that quantifies aspects of differences in the shape among reaction norms. We found that the invasive lineages survived and reproduced with an increased probability at the higher salinities, and were superior to ancestral-range lineages in only two traits related to reproduction. Moreover, we found that in terms of traits related to growth, the invasive lineages have a performance optimum that is shifted to higher salinities than the ancestral-range lineages as well as having a narrower niche breadth. Contrary to the prediction of the general purpose genotype hypothesis, we found that invasive lineages tended to be opportunistic specialists.
尚不清楚与适应性相关的性状中哪些可塑性形式与入侵物种有关。一方面，在各种环境中都具有稳健的表现可能更好。另一方面，利用有限的有利条件可能是有益的。我们选择研究一种全球入侵物种——新西兰泥蜗，并比较入侵基因型样本与原始分布范围基因型样本的生活史性状可塑性。我们研究了这种淡水蜗牛对盐度的反应，因为盐度在引入区域会随空间和时间变化，并且会影响我们研究系统中的适应性差异。我们使用了一种最近开发的统计方法，该方法可以量化反应规范之间形状差异的各个方面。我们发现，入侵谱系在较高盐度下存活和繁殖的概率增加，并且在仅与繁殖相关的两个性状上优于原始分布范围谱系。此外，我们发现，在与生长相关的性状方面，入侵谱系的表现最优值向比原始分布范围谱系更高的盐度转移，并且生态位宽度更窄。与通用基因型假说的预测相反，我们发现入侵谱系倾向于成为机会主义专家。
