Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prol. de Carpio y Plan de Ayala. Col. Sto. Tomas, México D. F., 11340, Mexico.
J Chem Ecol. 2012 May;38(5):512-24. doi: 10.1007/s10886-012-0112-z. Epub 2012 Apr 28.
The bark beetle Dendroctonus rhizophagus is endemic to northwestern Mexico where it kills immature pines < 3 m tall. We report the first investigation of the chemical ecology of this pest of forest regeneration. We used GC-EAD to assess olfactory sensitivity of this species to volatile compounds from: resin of a major host, Pinus arizonica; mid/hindguts of single, gallery-initiating females; and mate-paired males within galleries of attacked host trees in the field. Antennae of both sexes responded to monoterpenes α-pinene, β-pinene and 3-carene as well as to the beetle-derived oxygenated monoterpenes fenchyl alcohol, myrtenal, cis-verbenol, trans-verbenol, verbenone, and myrtenol. These monoterpenes were quantified from pre-emerged D. rhizophagus adults forced to attack host tissue in the laboratory, and from individuals dissected from naturally-attacked hosts at different stages of colonization. In both bioassays, myrtenol and trans-verbenol were the most abundant volatiles, and trans-verbenol was the only one produced in significantly greater quantities by females than males in a naturally-colonized host. Two field experiments were performed to evaluate behavioral responses of D. rhizophagus to antennally-active monoterpenes. Results show that 3-carene was significantly attractive either alone or in a ternary (1:1:1) combination with α-pinene and β-pinene, whereas neither α-pinene nor β-pinene alone were attractive. None of the beetle-associated oxygenated monoterpenes enhanced the attractiveness of the ternary mixture of monoterpenes, while verbenone either alone or combined with the other five oxygenated terpenes reduced D. rhizophagus attraction to the ternary mixture. The results suggest that attraction of D. rhizophagus to the host tree P. arizonica is mediated especially by 3-carene. There was no conclusive evidence for an aggregation or sex attractant pheromone.
枝梢小蠹虫（Dendroctonus rhizophagus）是墨西哥西北部的特有种，会杀死高度不超过 3 米的未成熟松树。我们首次报道了这种森林更新害虫的化学生态学研究。我们使用 GC-EAD 评估了该物种对以下挥发物的嗅觉敏感性：主要宿主——辐射松（Pinus arizonica）的树脂；单个产卵启动雌虫的中后肠；以及在野外受攻击的宿主树洞中配对的雄性。雌雄两性的触角都对单萜烯 α-蒎烯、β-蒎烯和 3-蒈烯以及由该种甲虫衍生的含氧单萜烯法呢醇、桃金娘烯醛、顺式马鞭烯醇、反式马鞭烯醇、马鞭烯酮和桃金娘醇有反应。这些单萜烯是从被迫在实验室中攻击宿主组织的预先孵化的 D. rhizophagus 成虫以及从处于不同定植阶段的自然攻击宿主中解剖出来的个体中定量的。在这两种生物测定中，桃金娘醇和反式马鞭烯醇是最丰富的挥发物，而且反式马鞭烯醇是在自然定植的宿主中雌虫比雄虫产生的数量明显更多的唯一一种挥发物。进行了两项野外实验以评估 D. rhizophagus 对触角活性单萜烯的行为反应。结果表明，3-蒈烯单独或与 α-蒎烯和 β-蒎烯以三元（1:1:1）组合的形式具有显著的吸引力，而单独的 α-蒎烯或 β-蒎烯没有吸引力。没有一种与甲虫相关的含氧单萜烯增强了三元混合物的吸引力，而马鞭烯酮单独或以与其他五种含氧萜烯的组合形式降低了 D. rhizophagus 对三元混合物的吸引力。结果表明，D. rhizophagus 对宿主树辐射松的吸引力尤其受到 3-蒈烯的介导。没有确凿的证据表明存在聚集或性引诱信息素。
