ADAPTIVE COLORATION AND GENE FLOW AS A CONSTRAINT TO LOCAL ADAPTATION IN THE STREAMSIDE SALAMANDER, AMBYSTOMA BARBOURI
ADAPTIVE COLORATION AND GENE FLOW AS A CONSTRAINT TO LOCAL ADAPTATION IN THE STREAMSIDE SALAMANDER, AMBYSTOMA BARBOURI
复制标题
适应性颜色和基因流作为河边蝾螈局部适应的制约因素，AMBYSTOMA BARBOURI
DOI：
10.1111/j.1558-5646.1999.tb05383.x
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发表时间：
1999
期刊：
影响因子：
3.3
通讯作者：
J. Caruso
中科院分区：
文献类型：
--
作者：
Andrew Storfer;Jonra Cross;V. Rush;J. Caruso
捕食是影响动物颜色模式的一种重要的选择性力量。一些河边蜥蜴的幼虫种群，与捕食性鱼类一起栖息在溪流中。其他幼体火蜥蜴也在浅水、短暂的溪流中被发现，这些溪流没有捕食者。定量的黑素细胞计数和身体着色面积百分比的估计表明，幼虫的颜色与溪流类型密切相关。与鱼共存的幼虫往往比来自没有灰烬和短暂的溪流的幼虫更轻。两种方法表明，浅色火蜥蜴幼体在相对固定的溪流中与共同背景更匹配，对鱼类来说不像深色幼体那么显眼。首先，使用基于鱼的光谱敏感性和火蜥蜴的反射特性以及自然溪流背景的模型，我们证明了浅色幼虫的隐蔽性是岩石上深色幼虫的三倍。其次，在捕食者选择实验中，较轻的幼虫在岩石上的存活率高于较深的火蜥蜴。目前还不清楚为什么短暂溪流中的幼虫颜色更深。在季节性干燥之前，短暂溪流中的幼虫应该活跃地取食和快速发育，并达到足够的大小以进行变质。几个假设可以解释为什么幼虫在短暂的溪流中往往更暗，例如温度调节能力增强，(在这些较浅的溪流中)更好地屏蔽紫外线辐射，或者更好地与陆地捕食者的背景匹配。在火蜥蜴幼虫与鱼类共存的种群中，存在相对隐蔽性的差异。来自有鱼的种群和来自短暂种群(幼虫较暗)的相对较高基因流的种群的幼虫往往较暗(有更多的黑素团)，对捕食者来说更明显，而那些来自更多遗传隔离种群的幼虫更轻，更神秘。这些差异说明了基因流动对适应性进化的制约作用。
Predation is an important selective force that influences animal color patterns. Some larval populations of the streamside salamander, Ambystoma barbouri, inhabit streams with fish predators. Other larval salamanders are found in shallow, ephemeral streams that are predator‐free. Quantitative melanophore cell counts and estimates of percent body area pigmented indicated that larval coloration is strongly correlated with stream type. Larvae that coexist with fish tend to be lighter than larvae from streams that are Ashless and ephemeral. Two approaches demonstrated that lightly pigmented salamander larvae better match the common background in relatively permanent streams and are less conspicuous to fish than dark larvae. First, using a model based on the spectral sensitivity of the fish and reflectance properties of salamanders and natural stream backgrounds, we showed that light larvae are three times more cryptic than dark larvae on rocks. Second, lighter larvae had higher survival than darker salamanders on rocks in a predator‐ choice experiment. It is not clear why larvae in ephemeral streams are darker. Larvae in ephemeral streams should be active to feed and develop rapidly and reach sufficient size to metamorphose before seasonal drying. Several hypotheses may explain why larvae tend to be darker in ephemeral streams, such as increased thermoregulatory ability, better screening of ultraviolet radiation (in these shallower streams), or better background matching to terrestrial predators. Among populations where salamander larvae coexist with fish, there are differences in relative crypsis. Larvae from populations with fish and relatively high gene flow from ephemeral populations (where larvae are dark) tend to be darker (with more melanophores) and more conspicuous to predators than those from more genetically isolated populations, where larvae are lighter and more cryptic. These differences illustrate the role of gene flow as a constraint to adaptive evolution.