The common grass yellow Eurema mandarina (Pieridae, Coliadinae) widely inhabits Japan, feeds on various fabaceous plants such as silktree (Albizia julibrissin) and uses d‐pinitol, a cyclitol omnipresent in Fabaceae, as a primary oviposition stimulant. However, E. mandarina has a clear host preference within the Fabaceae; for example, white clover (Trifolium repens) is a nonhost despite containing d‐pinitol. The present study aims to identify plant chemicals in white clover that inhibit oviposition of E. mandarina. Females lay very few eggs on T. repens foliage and plastic plant models treated with a methanolic extract of the foliage. The foliage extract is fractionated by successive extraction with chloroform, isobutanol and water. None of these fractions induce egg‐laying responses. The aqueous fraction is further separated into four subfractions (Tr‐3‐1 to Tr‐3‐4) by column chromatography. Among these subfractions, females show high egg‐laying responses to Tr‐3‐1, which is known to contain d‐pinitol. Interestingly, Tr‐3‐2, when mixed with Tr‐3‐1, significantly decreases egg‐laying responses, indicating that it contains oviposition deterrents. Chemical analyses reveal that two cyanogenic glucosides, linamarin and lotaustralin, are the major constituents of Tr‐3‐2. Authentic linamarin does not elicit egg‐laying responses and significantly inhibits female oviposition when mixed with Tr‐3‐1 at the natural concentration. Although these cyanogenic glucosides are reported to synergistically induce oviposition of a coliadine species Colias erate on white clover, we conclude that linamarin acts as an oviposition deterrent for E. mandarina, restricts its host range and regulates their differential host acceptance.

中文翻译：

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三叶草的含氰苷可阻止普通草黄桉树的产卵

常见的草黄色橙花（Pieridae, Coliadinae）广泛栖息在日本，以各种豆科植物为食，如丝科（Albizia julibrissin），并使用豆科植物中普遍存在的环醇d-松醇作为主要的产卵刺激剂。然而，E. mandarina 在豆科植物中具有明显的寄主偏好。例如，白三叶草 (Trifolium repens) 尽管含有 d-松醇，但不是宿主。本研究旨在鉴定白三叶草中抑制 E. mandarina 产卵的植物化学物质。雌性在白杨树叶和用树叶的甲醇提取物处理的塑料植物模型上产卵很少。叶子提取物通过用氯仿、异丁醇和水连续提取进行分级。这些部分都不会引起产卵反应。通过柱色谱法将水性部分进一步分离为四个亚部分（Tr-3-1 至 Tr-3-4）。在这些亚组分中，雌性对已知含有 d-松醇的 Tr-3-1 表现出较高的产卵反应。有趣的是，当 Tr-3-2 与 Tr-3-1 混合时，会显着降低产卵反应，表明它含有排卵威慑剂。化学分析表明，两种氰苷，亚麻苦苷和lotaustralin，是Tr-3-2的主要成分。当与天然浓度的 Tr-3-1 混合时，正宗的亚麻苦苷不会引起产卵反应并显着抑制雌性产卵。尽管据报道这些含氰苷可协同诱导白三叶草上的可丽碱物种 Colias erate 的产卵，但我们得出结论，亚麻苦苷可作为大肠杆菌的产卵威慑剂。