Selection mosaic exerted by specialist and generalist herbivores on chemical and physical defense of Datura stramonium.
Selection mosaic exerted by specialist and generalist herbivores on chemical and physical defense of Datura stramonium.
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DOI：
10.1371/journal.pone.0102478
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Núñez-Farfán J
中科院分区：
文献类型：
--
作者：
Castillo G;Cruz LL;Tapia-López R;Olmedo-Vicente E;Carmona D;Anaya-Lang AL;Fornoni J;Andraca-Gómez G;Valverde PL;Núñez-Farfán J
草食动物的选择是推动植物防御性状进化的主要力量，如叶毛或次生代谢产物。然而，植物的防御表达在不同的种群中是高度不同的，确定这种变异的来源仍然是一个主要的挑战。植物种群通常分布在广泛的地理范围内，并暴露在不同的食草动物群落中，从多面手(以多种植物为食)到专家(以有限的一组植物为食)。我们研究了专家或多面手食草动物经常食用的曼陀罗的8个种群，以检验次生化合物(阿托品和东莨菪碱)和物理防御(毛密度)上的表型选择模式是否可以解释这些性状的地理变异。根据共同进化理论，我们评估了衍生程度更高的生物碱(东莨菪碱)是否比其前体(阿托品)具有更高的适应性益处，以及这种影响在专业草食动物和普通草食动物之间是否有所不同。我们的结果表明，在几乎所有的种群和草食动物中，一致的定向选择降低了阿托品的浓度。衍生最多的生物碱(东莨菪碱)只在一个种群中受到青睐，该种群由一种多面手食草动物主导。总体而言，选择模式支持选择花叶的存在，并解释了先前研究中观察到的阿托品浓度与草食动物对植物的损害之间的正相关。
Selection exerted by herbivores is a major force driving the evolution of plant defensive characters such as leaf trichomes or secondary metabolites. However, plant defense expression is highly variable among populations and identifying the sources of this variation remains a major challenge. Plant populations are often distributed across broad geographic ranges and are exposed to different herbivore communities, ranging from generalists (that feed on diverse plant species) to specialists (that feed on a restricted group of plants). We studied eight populations of the plant Datura stramonium usually eaten by specialist or generalist herbivores, in order to examine whether the pattern of phenotypic selection on secondary compounds (atropine and scopolamine) and a physical defense (trichome density) can explain geographic variation in these traits. Following co-evolutionary theory, we evaluated whether a more derived alkaloid (scopolamine) confers higher fitness benefits than its precursor (atropine), and whether this effect differs between specialist and generalist herbivores. Our results showed consistent directional selection in almost all populations and herbivores to reduce the concentration of atropine. The most derived alkaloid (scopolamine) was favored in only one of the populations, which is dominated by a generalist herbivore. In general, the patterns of selection support the existence of a selection mosaic and accounts for the positive correlation observed between atropine concentration and plant damage by herbivores recorded in previous studies.
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影响因子：
10.7
作者：
Charlesworth, B
通讯作者：
Charlesworth, B
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