Volatiles are of key importance for host-plant recognition in insects. In the pollination system of Lithophragma flowers and Greya moths, moths are highly specialized on Lithophragma, in which they oviposit and thereby pollinate the flowers. Floral volatiles in Lithophragma are highly variable between species and populations, and moths prefer to oviposit into Lithophragma flowers from populations of the local host species. Here we used gas chromatography coupled with electroantennographic detection (GC-EAD) to test whether Greya moths detect specific key volatiles or respond broadly to many volatiles of Lithophragma flowers. We also addressed whether olfactory detection in Greya moths varies across populations, consistent with a co-evolutionary scenario. We analyzed flower volatile samples from three different species and five populations of Lithophragma occurring across a 1400 km range in the Western USA, and their sympatric female Greya politella moths. We showed that Greya politella detect a broad range of Lithophragma volatiles, with a total of 23 compounds being EAD active. We chemically identified 15 of these, including the chiral 6, 10, 14-trimethylpentadecan-2-one (hexahydrofarnesyl acetone), which was not previously detected in Lithophragma. All investigated Lithophragma species produced the (6R, 10R)-enantiomer of this compound. We showed that Greya moths detected not only volatiles of their local Lithophragma plants, but also those from allopatric populations/species that they not encounter in local populations. In conclusion, the generalized detection of volatiles and a lack of co-divergence between volatiles and olfactory detection may be of selective advantage for moths in tracking hosts with rapidly evolving, chemically diverse floral volatiles.

挥发物对昆虫宿主植物的识别至关重要。在石楠花朵和灰蛾的授粉系统中，飞蛾在石楠上高度专化，它们在卵中产卵，从而使花朵授粉。石斑鱼中的花卉挥发物在物种和种群之间变化很大，飞蛾更喜欢从当地寄主物种的种群中产卵到石斑鱼花中。在这里，我们使用了气相色谱结合电造影检测（GC-EAD）来测试灰蛾是否检测出特定的关键挥发物或对石藻的许多挥发物有广泛的响应花朵。我们还讨论了在灰蛾中嗅觉检测是否随人群而异，这与共同进化的情况一致。我们分析了在美国西部1400公里范围内出现的三个不同物种和五个石斑鱼种群的花卉挥发物样本，以及它们的同胞雌性Greya politella飞蛾。我们表明，Greya politella可检测到广泛的石藻挥发物，共有23种化合物具有EAD活性。我们化学鉴定了其中的15种，包括手性6、10、14-三甲基十五烷-2-酮（六氢法呢基丙酮），这是以前在石棺中未发现的。所有调查过的碎石分子产生了该化合物的（6 R，10 R）-对映体。我们表明，灰蛾不仅检测到其当地石藻植物的挥发物，而且还检测到它们在当地种群中未遇到的异源种群/物种的挥发物。总之，挥发物的普遍检测以及挥发物和嗅觉检测之间缺乏共散性可能对蛾类具有快速发展的，化学上多样化的花卉挥发物的寄主跟踪具有选择性的优势。