Seasonal Variation in Host Plant Chemistry Drives Sequestration in a Specialist Caterpillar
Seasonal Variation in Host Plant Chemistry Drives Sequestration in a Specialist Caterpillar
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DOI：
10.1007/s10886-021-01321-7
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发表时间：
2021-11
影响因子：
2.3
通讯作者：
Adrian L. Carper;Leif L. Richardson;Rebecca E. Irwin;M. Bowers
中科院分区：
文献类型：
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作者：
Adrian L. Carper;Leif L. Richardson;Rebecca E. Irwin;M. Bowers
植食动物对植物次生代谢物的吸收在寄主植物物候和植食动物个体发生过程中都会发生变化，但很少有研究探讨它们如何同时在野外发生变化。我们探索了白龟头（Chelone glabra）中环烯醚萜苷浓度和组成的变化，以及其专业食草动物巴尔的摩斑蝶（Euphydryas phaeton）在食草动物和寄主植物发育过程中对环烯醚萜苷的吸收。2012年，我们对植物进行了采样，以描述两种环烯醚萜苷、桃红素和梓醇浓度的季节性变化。2017年，我们在整个生长季节对寄主植物和毛虫进行了采样，探索了植物化学与食草动物封存之间的关系。我们还比较了有草食和没有草食的植物环烯醚萜苷浓度，以深入了解次生化合物的水平是否受到草食的影响。我们发现，植物环烯醚萜苷总含量随季节变化而变化，毛虫体内的环烯醚萜苷总含量与植物体内的环烯醚萜苷浓度模式密切相关。但在不同比例的桃红素和梓醇中，毛虫的固存量为寄主植物的2 ~ 20倍。此外，草食植物的环烯醚萜苷浓度低于非草食植物，尽管这种差异随着时间的推移而改变。这些结果表明，虽然寄主植物次生代谢物的变化可能是驱动寄主植物吸收的主要因素，但其他生态因子可能会减轻寄主植物化学与草食吸收之间的关系。
Sequestration of plant secondary metabolites by herbivores can vary across both host plant phenology and herbivore ontogeny, but few studies have explored how they concurrently change in the field. We explored variation in iridoid glycoside concentration and composition in white turtlehead,Chelone glabra, as well as sequestration of iridoid glycosides by its specialist herbivore, the Baltimore checkerspot,Euphydryas phaeton, across the development of both herbivore and host plant. In 2012 we sampled plants to describe seasonal variation in the concentrations of two iridoid glycosides, aucubin and catalpol. In 2017, we sampled both host plants and caterpillars over an entire growing season and explored the relationship between plant chemistry and herbivore sequestration. We also compared iridoid glycoside concentrations of plants with and without herbivory to gain insight into whether levels of secondary compounds were impacted by herbivory. We found that total plant iridoid glycosides varied across the season and that total sequestered iridoid glycosides in caterpillars closely mirrored concentration patterns in plants. However, the magnitude of sequestration by caterpillars ranged from 2 to 20 times the concentrations in host plants, with different proportions of aucubin and catalpol. In addition, plants with herbivory had lower iridoid glycoside concentrations than plants without herbivory, although this difference changed over time. These results suggest that while variation in host plant secondary metabolites may be a dominant factor driving sequestration, other ecological factors may mitigate the relationship between host plant chemistry and herbivore sequestration.