THE EFFECTS OF SELECTION BY CLIMATE ON THE LAND‐SNAIL CEPAEA NEMORALIS (L.)
THE EFFECTS OF SELECTION BY CLIMATE ON THE LAND‐SNAIL CEPAEA NEMORALIS (L.)
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气候选择对陆地蜗牛 CEPAEA NEMORALIS (L.) 的影响
DOI：
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发表时间：
1969
期刊：
影响因子：
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通讯作者：
R. Arnold
中科院分区：
文献类型：
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作者：
R. Arnold
关于气候的某些方面如何选择性地作用于奈马属（Cepaea nemoralis）的外壳颜色和条带多态性的证据越来越多。Lamotte（1951, 1959）认为，在法国的一些地区，这种选择导致了种群与栖息地的轻微差异，并认为黄色和无条纹的蜗牛在温暖和阳光充足的地方更受欢迎，粉红色和有条纹的蜗牛在凉爽、阴凉的地方更受欢迎。他（1959）表明，无带状变形的频率与7月平均温度呈正相关，黄色变形的频率与1月平均温度呈负相关。最近（1966年），他更加强烈地强调了气候的选择性作用。对相变体的电阻和行为与温差的关系的实验总体上与研究结果一致（Lamotte, 1959, 1966; Carter, 1965; sedlair, 1956）。在比利牛斯山脉进行的研究（Arnold, 1968）表明，气候可能在影响菌落表型组成方面起着重要作用。与海拔和地形相关的形态频率分布表明，黄色和非带状在更极端的气候条件下更有利，而粉红色和五带状在较温和的气候条件下更有利。这种唇色在比利牛斯山脉也是多态的。可以区分出两种变体，白唇型，其中完全缺乏来自壁壁的深色色素；黑唇型，其中至少有一些深色色素存在。这些变化似乎也对与海拔和地形有关的气候差异做出了反应，因为黑唇在山区温暖和干燥的地方更频繁，在高海拔地区发生频率较低。在被调查的比利牛斯山脉的一个山谷中，带状形态的频率出现了急剧的阶梯式变化（Arnold, 1968，图6）。对莱里达省塞格雷河上的奥加菲纳镇附近的种群的进一步研究（图1）揭示了气候选择的另一个例子，它显然至少对带状形态频率产生了强烈而非常局部的影响。本文的目的是描述这些观察结果。
Evidence has been accumulating about the way in which certain aspects of climate act selectively on the shell color and banding polymorphism of Cepaea nemoralis. Lamotte (1951, 1959) argued that such selection caused populations to vary slightly with habitat in some districts in France, and suggested that yellow and unbanded snails were favored in warmer and sunnier places, and pink and banded snails in cooler, shady, localities. He showed (1959) that there was a positive correlation between the frequency of the unbanded morph and mean July temperature, and a negative one between the frequency of the yellow morph and mean January temperature. Recently (1966), he has emphasized more strongly the selective action of climate. Experiments on the resistance and behavior of the morphs in relation to temperature differences on the whole concur with the findings (Lamotte, 1959, 1966; Carter, 1965; Sedlmair, 1956). Studies made in the Pyrenees (Arnold, 1968) indicate that climate probably plays an important role there in affecting the phenotypic composition of colonies. Morph frequency distributions in relation to altitude, and also to topography, suggest that yellow and unbanded are favored in more extreme climates, whereas pink and fivebanded are less disadvantageous or favored in milder climatic regimes. The species is polymorphic for lip color as well in the Pyrenees. Two morphs can be distinguished, white-lipped, where dark pigment is completely lacking from the peristome and dark-lipped, where at least some dark pigment is present. These morphs appear also to respond to climatic differences associated with altitude and topography, for dark-lip is more frequent in the warmer and drier parts of the mountains, changing to low frequencies at high altitudes. A cline in the frequencies of the banding morphs in one of the Pyrenean valleys investigated appeared to be sharply stepped (Arnold, 1968, Fig. 6). Further study of populations in the vicinity of the step in frequencies, near the town of Orgafina on the River Segre (Fig. 1) in Lerida province, has revealed another example of climatic selection apparently exerting a strong and very local effect on at least the banding morph frequencies. The purpose of this paper is to describe these observations.