Department of Zoology and Physiology and Program in Ecology, University of Wyoming, Laramie, Wyoming, United States of America.
Department of Biology, University of St. Thomas, St. Paul, Minnesota, United States of America.
PLoS One. 2014 Jan 16;9(1):e85845. doi: 10.1371/journal.pone.0085845. eCollection 2014.
Local adaptation--typically recognized as higher values of fitness-related traits for native vs. non-native individuals when measured in the native environment--is common in natural populations because of pervasive spatial variation in the intensity and type of natural selection. Although local adaptation has been primarily studied in the context of biotic interactions, widespread variation in abiotic characteristics of environments suggests that local adaptation in response to abiotic factors should also be common. Potamopyrgus antipodarum, a freshwater New Zealand snail that is an important model system for invasion biology and the maintenance of sexual reproduction, exhibits local adaptation to parasites and rate of water flow. As an initial step to determining whether P. antipodarum are also locally adapted to phosphorus availability, we examined whether populations differ in their responses to phosphorus limitation. We found that field-collected juvenile P. antipodarum grew at a lower rate and reached an important size threshold more slowly when fed a relatively low vs. a relatively high-phosphorus diet. We also detected significant across-population variation in individual growth rate. A marginally significant population-by-dietary phosphorus interaction along with a two-fold difference across populations in the extent of suppression of growth by low phosphorus suggests that populations of P. antipodarum may differ in their response to phosphorus limitation. Local adaptation may explain this variation, with the implication that snails from lakes with relatively low phosphorus availability should be less severely affected by phosphorus limitation than snails from lakes with higher phosphorus availability.
本地适应——通常被认为是在本地环境中测量时,与非本地个体相比,与适应度相关的特征值更高——在自然种群中很常见,因为自然选择的强度和类型在空间上普遍存在差异。尽管本地适应主要在生物相互作用的背景下进行研究,但环境中广泛存在的非生物特征的变化表明,对非生物因素的本地适应也应该很常见。新西兰淡水蜗牛 Potamopyrgus antipodarum 是入侵生物学和维持有性繁殖的重要模式系统,它对寄生虫和水流速度表现出本地适应。作为确定 Potamopyrgus antipodarum 是否也对磷可用性具有本地适应性的初步步骤,我们研究了种群在对磷限制的反应上是否存在差异。我们发现,野外收集的幼年 Potamopyrgus antipodarum 在喂食相对低磷和相对高磷饮食时,生长速度较慢,达到重要的大小阈值的速度也较慢。我们还检测到个体生长率存在明显的种群间差异。种群与饮食磷之间的边缘显著相互作用,以及低磷对生长的抑制程度在种群之间相差两倍,表明 Potamopyrgus antipodarum 的种群可能对磷限制的反应不同。本地适应可能解释了这种差异,意味着来自磷可用性相对较低的湖泊的蜗牛应该比来自磷可用性较高的湖泊的蜗牛受磷限制的影响较小。