Functional investigation of monoterpenes for improved understanding of the relationship between hosts and bark beetle

Spruce bark beetle (Ips typographus L.) is the most destructive insect pest of spruce forest in Eurasia. However, contact toxicity, in vivo metabolism, and ecological functions of host monoterpenes are poorly understood at the spruce–bark beetle–predator tritrophic level. Spruce monoterpenes including S-(–)-α-pinene, R-(+)-α-pinene, and myrcene showed contact toxicity to spruce bark beetle, with LD50 values ranging from 24–36 μg/mg. When topically treated with S-(–)-α-pinene or R-(+)-α-pinene, the amount of volatile metabolites [S-(–)-cis-verbenol, 4S-(+)-/4R-(–)-trans-verbenol, and R-(+)-/S-(–)-verbenone] in the hindgut extract of spruce bark beetle varied significantly between sexes, and their quality varied significantly depending on the chirality of α-pinene. More importantly, S-(–)-α-pinene induced male adults to produce large amounts of S-(–)-cis-verbenol and S-(–)-verbenone. When topically treated with myrcene, the expected semiochemicals such as E-myrcenol, ipsenol, and ipsdieno...

云杉八齿小蠹（Ips typographus L.）是欧亚大陆云杉林最具破坏性的昆虫害虫。然而，宿主单萜类物质的触杀毒性、体内代谢过程及生态功能在云杉-八齿小蠹-天敌三营养级层面的研究仍较为匮乏。云杉源单萜类物质包括S-(-)-α-蒎烯、R-(+)-α-蒎烯及月桂烯，对云杉八齿小蠹具有触杀毒性，其半数致死剂量（LD50）范围为24~36 μg/mg。当以体表涂抹方式施加S-(-)-α-蒎烯或R-(+)-α-蒎烯时，云杉八齿小蠹后肠提取物中的挥发性代谢物[S-(-)-顺式马鞭草烯醇、4S-(+)/4R-(-)-反式马鞭草烯醇及R-(+)/S-(-)-马鞭草烯酮]的含量存在显著的性别差异，且其组成比例显著依赖于α-蒎烯的手性构型。更为关键的是，S-(-)-α-蒎烯可诱导雄性成虫大量合成S-(-)-顺式马鞭草烯醇与S-(-)-马鞭草烯酮。当以体表涂抹方式施加月桂烯时，预期可产生的信息化学物质如E-月桂烯醇、ipsenol及ipsdieno……