International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya.
Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa.
J Chem Ecol. 2024 Nov;50(11):663-678. doi: 10.1007/s10886-024-01501-1. Epub 2024 May 9.
The zoophytophagous mirid predator Nesidiocoris tenuis and the ectoparasitoid Stenomesius japonicus are important biological control agents for several agricultural pests including the invasive leafminer, Phthorimaea absoluta, a destructive pest of Solanaceous crops especially tomato in sub-Saharan Africa. However, little is known about how feeding by N. tenuis can influence the tritrophic interactions in the tomato plant. Here, we tested the hypothesis that N. tenuis phytophagy would influence the tritrophic olfactory interactions between the host plant tomato and pest, predator, and parasitoid. In olfactometer assays, P. absoluta females and N. tenuis adults were both attracted to constitutive volatiles released by the tomato plant. Whereas females of P. absoluta avoided volatiles released by N. tenuis-infested plants, S. japonicus females and N. tenuis adults were attracted to the induced volatiles. In coupled gas chromatography-electroantennographic detection (GC-EAD) recordings of intact and N. tenuis-infested plant volatiles, antennae of P. absoluta and S. japonicus females both detected eight components, whereas N. tenuis adults detected seven components which were identified by GC-mass spectrometry (GC-MS) as terpenes and green leaf volatiles (GLVs). Dose-response olfactometer bioassays revealed that the responses of P. absoluta, N. tenuis, and S. japonicus varied with the composition and concentration of blends and individual compounds tested from N tenuis-induced volatiles. Females of P. absoluta showed no preference for an eight-component blend formulated from the individual repellents including hexanal, (Z)-3-hexenyl butanoate, and δ-elemene identified in the volatiles. On the other hand, S. japonicus females were attracted to an eight-component blend including the attractants (E)-2-hexenal, (Z)-3-hexenol, methyl salicylate, β-phellandrene, and (E)-caryophyllene. Likewise, N. tenuis adults were attracted to a seven-component blend including the attractants β-phellandrene, δ-elemene, and (E)-caryophyllene identified in the volatiles. Our findings suggest that there is potential for the use of terpenes and GLVs to manage the insects in the tritrophic interaction.
植食性盲蝽象捕食性天敌南美盲蝽和外寄生蜂斯氏钝绥螨是几种农业害虫的重要生物防治剂，包括入侵性潜叶蝇，番茄斑潜蝇，一种破坏撒哈拉以南非洲茄科作物特别是番茄的害虫。然而，人们对南美盲蝽的取食如何影响番茄植株的三营养级相互作用知之甚少。在这里，我们检验了这样一个假设，即南美盲蝽的植食性会影响宿主植物番茄与害虫、捕食者和寄生蜂之间的三营养级嗅觉相互作用。在嗅觉仪试验中，番茄斑潜蝇雌性成虫和南美盲蝽成虫均被番茄植株释放的组成性挥发物所吸引。然而，番茄斑潜蝇雌性成虫避开了受南美盲蝽侵害的植物释放的挥发物，而斯氏钝绥螨雌性成虫和南美盲蝽成虫则被诱导的挥发物所吸引。在对完整和受南美盲蝽侵害的植物挥发物的耦合气相色谱-触角电位检测（GC-EAD）记录中，番茄斑潜蝇和斯氏钝绥螨雌性成虫的触角均检测到八种成分，而南美盲蝽成虫则检测到七种成分，这些成分通过 GC-质谱（GC-MS）鉴定为萜类和绿叶挥发物（GLVs）。剂量反应嗅觉仪生物测定表明，番茄斑潜蝇、南美盲蝽和斯氏钝绥螨的反应随组成和浓度的变化而变化，测试的混合物和单个化合物来自南美盲蝽诱导的挥发物。番茄斑潜蝇雌性成虫对由包括己醛、（Z）-3-己烯基丁酸酯和挥发物中鉴定出的δ-榄香烯在内的八种排斥剂组成的混合物没有表现出偏好。另一方面，斯氏钝绥螨雌性成虫被包括（E）-2-己烯醛、（Z）-3-己烯醇、水杨酸甲酯、β-蒎烯和（E）-石竹烯在内的八种混合物吸引。同样，南美盲蝽成虫也被包括在挥发物中鉴定出的β-蒎烯、δ-榄香烯和（E）-石竹烯在内的七种混合物吸引。我们的研究结果表明，萜类和 GLVs 有可能用于管理三营养级相互作用中的昆虫。
