Upon damage by herbivores, plants release herbivory-induced plant volatiles (HIPVs). To find their prey, the pest’s natural enemies need to be fine-tuned to the composition of these volatiles. Whereas standard methods can be used in the identification and quantitation of HIPVs, more recently introduced techniques such as PTR-ToF–MS provide temporal patterns of the volatile release and detect additional compounds. In this study, we compared the volatile profile of apple trees infested with two aphid species, the green apple aphid Aphis pomi, and the rosy apple aphid Dysaphis plantaginea, by CLSA-GC–MS complemented by PTR-ToF–MS. Compounds commonly released in conjunction with both species include nonanal, decanal, methyl salicylate, geranyl acetone, (Z)-3-hexenyl acetate, (Z)-3-hexenyl butanoate, (Z)-3-hexenyl 2-methyl-butanoate, (E)-β-caryophyllene, β-bourbonene and (Z)-3-hexenyl benzoate. In addition, benzaldehyde and (E)-β-farnesene were exclusively associated with A. pomi, whereas linalool, (E)-4,8-dimethyl-1,3,7-nonatriene were exclusively associated with D. plantaginea. PTR-ToF–MS additionally detected acetic acid (AA) and 2-phenylethanol (PET) in the blends of both trees attacked by aphid species. In the wind tunnel, the aphid predator, Chrysoperla carnea (Stephens), responded strongly to a blend of AA and PET, much stronger than to AA or PET alone. The addition of common and species-specific HIPVs did not increase the response to the binary blend of AA and PET. In our setup, two host-associated volatiles AA + PET appeared sufficient in the attraction of C. carnea. Our results also show the importance of combining complementary methods to decipher the odor profile associated with plants under pest attack and identify behaviourally active components for predators.

在被食草动物破坏后，植物会释放食草诱导的植物挥发物 (HIPV)。为了找到猎物，害虫的天敌需要根据这些挥发物的成分进行微调。虽然标准方法可用于 HIPV 的识别和定量，但最近引入的技术（如 PTR-ToF-MS）可提供挥发性释放的时间模式并检测其他化合物。在这项研究中，我们通过 CLSA-GC-MS 和 PTR-ToF-MS比较了感染了两种蚜虫，青苹果蚜Aphis pomi和玫瑰苹果蚜Dysaphis plantaginea的苹果树的挥发性特征。通常与这两种物质一起释放的化合物包括壬醛、癸醛、水杨酸甲酯、香叶基丙酮（Z）-3-己烯基乙酸酯，（Ž）-3-己烯基丁酸乙酯，（Ž）-3-己烯基2-甲基-丁酸甲酯，（ê）-β-石竹烯，β-bourbonene和（Ž）-3-己烯基苯甲酸酯。此外，苯甲醛和 ( E )-β-法呢烯仅与A. pomi相关，而芳樟醇、( E) -4,8-​​二甲基-1,3,7-壬三烯仅与车前草相关。PTR-ToF-MS 还在受蚜虫侵袭的两种树木的混合物中检测到乙酸 (AA) 和 2-苯基乙醇 (PET)。在风洞里，蚜虫捕食者Chrysoperla carnea(Stephens) 对 AA 和 PET 的混合物反应强烈，比单独的 AA 或 PET 强得多。添加常见的和特定物种的 HIPV 并没有增加对 AA 和 PET 的二元混合物的反应。在我们的设置中，两种宿主相关的挥发物 AA + PET 似乎足以吸引C. carnea。我们的研究结果还表明，结合互补方法来破译与受到害虫侵袭的植物相关的气味特征并识别捕食者的行为活跃成分的重要性。