The role of temperature in the distribution of the glacier ice worm, Mesenchytraeus solifugus (Annelida: Oligochaeta: Enchytraeidae)
The role of temperature in the distribution of the glacier ice worm, Mesenchytraeus solifugus (Annelida: Oligochaeta: Enchytraeidae)
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DOI：
10.1657/aaar0015-042
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发表时间：
2016-02-01
影响因子：
2
通讯作者：
Shain, Daniel H.
中科院分区：
文献类型：
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作者：
Dial, Roman J.;Becker, Melissa;Shain, Daniel H.
北美冰川冰虫，Mesenchytraeus solifugus（埃默里，1898年），仅限于沿海冰川在美国太平洋西北部的一个令人费解的400公里的分布差距沿着阿拉斯加-不列颠哥伦比亚边界和几个离散的人口北方分支在南纬度。我们说明了冰虫的行为，丰度和分布的最低温度的作用。该研究包括200个冰川和25个线粒体CO 1单倍型，来自该物种5 x 105 km（2）的地理范围。前一个夏季地表的冬季最低温度似乎决定了：（1）冰蠕虫占据的海拔，（2）能够支持它们的冰川，以及（3）它们栖息的山脉。冰蠕虫不会栖息在前一个夏季表面冬季温度低于-7摄氏度的冰川上。贝氏系统发育中的环节动物分子钟表明冰蠕虫从2.23 Ma的水生祖先分化出来，在1.6-1.7 Ma形成了三个分支。寒冷的敏感性，加上阿拉斯加东南部的地理和过去的气候，可能造成了分布差距，这一假设得到了他们的地理位置的支持。
The North American glacier ice worm, Mesenchytraeus solifugus (Emery, 1898), is restricted to coastal glaciers in the American Pacific Northwest with a puzzling 400 km distribution gap along the Alaska-British Columbia border and several disjunct populations of northern clades in southern latitudes. We illustrate the role of minimum temperatures in ice worm behavior, abundance, and distribution. The study included 200 glaciers and 25 mitochondrial CO1 haplotypes from the species' 5 x 105 km(2) geographic range. Minimum winter temperatures on the previous summer surface appear to determine: (1) the elevations ice worms occupy, (2) the glaciers that can support them, and (3) the mountain ranges they inhabit. Ice worms do not inhabit glaciers with over-winter temperatures below -7 degrees C on the previous summer surface. An annelid molecular clock in a Bayesian phylogeny suggests ice worms diverged from an aquatic ancestor 2.23 Ma, emerging as three clades 1.6-1.7 Ma. Cold sensitivity, together with southeast Alaska's geography and past climate, likely created the distribution gap, a hypothesis supported by their phylogeography.