Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, P.O. Box 190, SE 234 22, Lomma, Sweden.
Research Institute for Nature and Forest (INBO), Herman Teirlinckgebouw, Havenlaan 88, bus 73, B-1000, Brussels, Belgium.
J Chem Ecol. 2023 Aug;49(7-8):451-464. doi: 10.1007/s10886-023-01405-6. Epub 2023 Jan 31.
Predatory long-legged flies of the genus Medetera are important, but currently understudied, natural enemies of Scolytinae bark beetles such as Ips typographus. Medetera flies lay eggs on beetle-infested trees, where the developing larvae find their prey, but the chemical cues used by Medetera to locate infested trees are currently unknown. To identify odors attracting Medetera signaticornis, a species in Europe, headspace samples were collected at several time-points through different stages of I. typographus attacks on logs of Norway spruce (Picea abies). The headspace samples were analyzed using combined gas chromatography and mass spectrometry (GC-MS), and gas chromatography coupled with electroantennographic detection (GC-EAD) to determine compounds that stimulate M. signaticornis antennae. Antennae of M. signaticornis males and females were found to detect (-)-cis-verbenol, ( +)-trans-verbenol and myrtenol, which are known to be produced by bark beetles. Antennal responses were also observed for verbenene, isoterpinolene, α-pinene oxide, camphor, pinocamphone, terpinene-4-ol, myrtenal, borneol, α-terpineol, geranyl acetone, and verbenone, which are primarily produced by microorganisms, and α-pinene, α-fenchene, β-pinene, camphene, 3-carene, limonene, γ-terpinene, and terpinolene, known spruce tree compounds. In field experiments testing two synthetic blends containing 18 antennal active and two additional compounds 2-methyl-3-buten-2-ol and ipsdienol we observed significant attraction of M. signaticornis within 24 h. These attractive blends can form the basis for development of Medetera monitoring lures for use in future forest and pest management.
掠食性长足虻属长脚蝇是重要的，但目前研究不足的，是星天牛等树皮甲虫的天敌。长足虻在有甲虫的树上产卵，幼虫在那里找到它们的猎物，但目前还不知道长足虻用来定位受感染树木的化学线索。为了确定吸引欧洲物种 signaticornis 的气味，在不同阶段的云杉八齿小蠹对挪威云杉原木的攻击过程中，在几个时间点采集了顶空样本。使用气相色谱和质谱联用 (GC-MS) 以及气相色谱与触角电位检测联用 (GC-EAD) 对顶空样本进行分析，以确定刺激 M. signaticornis 触角的化合物。发现 M. signaticornis 雄蝇和雌蝇的触角可以检测到 (-)-顺式马鞭草烯醇、( +)-反式马鞭草烯醇和桃金娘醇，这些物质已知是由树皮甲虫产生的。触角反应也观察到马鞭烯醇、异松油烯、α-蒎烯氧化物、樟脑、对伞花烃、萜品-4-醇、桃金娘醛、龙脑、α-松油醇、香叶基丙酮和马鞭草烯酮，这些物质主要由微生物产生，以及α-蒎烯、α-葎草烯、β-蒎烯、莰烯、3-蒈烯、柠檬烯、γ-萜品烯和萜品烯-4-醇，这些都是已知的云杉树化合物。在测试两种含有 18 种触角活性化合物和另外两种化合物 2-甲基-3-丁烯-2-醇和 ipsdienol 的合成混合物的田间实验中，我们观察到 M. signaticornis 在 24 小时内有明显的吸引力。这些有吸引力的混合物可以为未来森林和害虫管理中开发 Medetera 监测诱饵奠定基础。
