University of Colorado Museum and Department of E.P.O. Biology, University of Colorado, Campus Box 334, 80309, Boulder, Colorado.
J Chem Ecol. 1992 Jun;18(6):817-31. doi: 10.1007/BF00988322.
The buckeye butterfly,Junonia coenia (Lepidoptera: Nymphalidae), specializes on plants that contain iridoid glycosides. To determine the fate of these compounds in larvae, pupae, and adults of this species, we reared larvae on artificial diets with and without iridoid glycosides, and on leaves of a host plant,Plantago lanceolata (Plantaginaceae). Quantification by gas chromatography showed that newly molted third-, fourth-, and fifth-instar larvae reared on leaves ofP. lanceolata contained means of 5.13, 2.88, and 6.83% dry weight iridoid glycoside. In contrast, the mean iridoid glycoside concentration of actively feeding fifth-instar larvae was 0.28% dry weight, that of pupae was 0.19% dry weight iridoids, and adults contained no detectable iridoids. Feeding experiments suggested that this reduction in actively feeding larvae was due to the metabolism of iridoid glycosides.P. lanceolata leaves in these experiments contained a mean of 1.00% dry weight iridoid glycoside, with a 2:1 ratio of aucubin to catalpol. Calculation of iridoid consumption and utilization indices showed that larvae fed artificial diets consumed, digested, and sequestered aucubin and catalpol in similar ways. When these indices were calculated for larvae fed leaves ofP. lanceolata, catalpol was sequestered twice as efficiently as aucubin.
美洲眼蝶（Junonia coenia）（鳞翅目：蛱蝶科）专门以含有环烯醚萜苷的植物为食。为了确定该物种幼虫、蛹和成虫体内这些化合物的命运，我们在含有和不含有环烯醚萜苷的人工饲料以及车前草（车前科）的叶子上饲养幼虫。通过气相色谱定量分析表明，在车前草叶子上饲养的新蜕皮的三、四、五龄幼虫分别含有 5.13%、2.88%和 6.83%的干重环烯醚萜苷。相比之下，积极取食的五龄幼虫的环烯醚萜苷平均浓度为 0.28%干重，蛹的环烯醚萜苷平均浓度为 0.19%干重，成虫体内则检测不到环烯醚萜苷。喂食实验表明，这种积极取食幼虫数量的减少是由于环烯醚萜苷的代谢。在这些实验中，车前草叶片含有 1.00%的干重环烯醚萜苷，其中桃叶珊瑚苷和梓醇的比例为 2:1。环烯醚萜苷消耗和利用率指数的计算表明，以人工饲料为食的幼虫以相似的方式消耗、消化和螯合桃叶珊瑚苷和梓醇。当这些指数被用于以车前草叶片为食的幼虫时，梓醇的螯合效率是桃叶珊瑚苷的两倍。
