EVOLUTION OF ADAPTATION THROUGH ALLOMETRIC SHIFTS IN A MARINE SNAIL
EVOLUTION OF ADAPTATION THROUGH ALLOMETRIC SHIFTS IN A MARINE SNAIL
复制标题
海洋蜗牛异速变化的适应进化
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
K. Johannesson
中科院分区：
文献类型：
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作者：
J. Hollander;D. Adams;K. Johannesson
个体间的个体发育变异可能是物种内形态变异的主要原因。例如，不同生长轨迹的进化可能是对生活在不同环境中的个体的不同生态环境的反应，或者是生命阶段或性别差异的反应。潮间带长春花（Littorina saxatilis）在贝壳形状上具有强烈的多态性。我们比较了生命阶段、当地种群和性别之间的个体发生轨迹，以了解个体发生过程中不同的形态终点是如何达到的，以及可能导致这些差异的原因。应用基于地标的几何形态计量学，我们捕获了该物种的四个瑞典种群的壳形状变化。我们还推导了一种方法来可视化由大小与多变量形状空间的关系描述的个体发生轨迹。我们发现，生长轨迹在不同栖息地的个体之间存在差异，性别和成熟期之间也存在差异。生活在岩石悬崖上的雄性在一生中都是等距生长的，而来自同一栖息地的雌性在幼年时从等距生长转变为成年时的异速生长。相比之下，生活在巨石上的雄性和雌性在幼年时生长异速，但在性成熟时转变为等速生长。因此，在这个物种中，个体发育似乎受到栖息地相关选择以及性别和年龄特定选择的影响。这些不同的选择机制导致四组中三组异速生长的个体发生变化。
Abstract Variation in ontogenetic development among individuals may be a major contributor to morphological variation within species. Evolution of different growth trajectories might, for example, evolve as a response to varying ecological contexts of individuals living in different environments, or by life-stage or gender differences. The intertidal periwinkle Littorina saxatilis is strongly polymorphic in shell shape. We compared ontogenetic trajectories between life stages, local populations, and sexes to understand how different morphological end points are reached during ontogeny and what might cause these differences. Applying landmark-based geometric morphometrics, we captured shell shape variation for four Swedish populations of this species. We also derived a method to visualize ontogenetic trajectories described by the relationship of size to the multivariate shape space. We found that growth trajectories differed between individuals living in different habitats, as well as between sexes and maturity stages. Males living on rocky cliffs grew isometrically throughout life, whereas females from the same habitat switched from isometric growth as juveniles to allometric growth as adults. In contrast, males and females living on boulders grew allometrically as juveniles but changed to isometric growth at sexual maturity. Thus, in this species, ontogenetic growth seems influenced by habitat-associated selection as well as by gender and age-specific selection. These differing selection regimes result in ontogenetic shifts in allometry in three of the four groups examined.