红脂大小蠹入侵机制与化学生态学研究

红脂大小蠹Dendroctonus valens LeConte是近来入侵我国的重大林业害虫,入侵山西后迅速在相邻省份扩展蔓延。文章围绕作者对红脂大小蠹入侵来源地、暴发机制以及红脂大小蠹化学生态学等领域开展的研究工作进展进行了总结。历史资料记载和分子证据均支持红脂大小蠹由北美(美国西海岸)地区传入。松树萜烯类化合物是红脂大小蠹寻找适合寄主的重要信号物质,近期在北美和中国几个地区同时开展的研究,确认了3-蒈烯对红脂大小蠹具有最强引诱作用,该研究结果简化和修正了先前北美一直使用的3组分植物源引诱剂配方;在筛选有效引诱成分的基础上,开展了引诱剂定量缓释载体的研究,该释放载体已经被授权专利,并得到广泛推广应用。红脂大小蠹信息素一直没有得到鉴定,近来通过对红脂大小蠹后肠提取物的分析,分离鉴定了5种电生理和行为上有生物活性的萜烯类氧化物,其中有3个组分对红脂大小蠹植物源引诱剂具有增效作用。在驱避剂方面,研究证实了马鞭草烯酮以及非寄主挥发物对红脂大小蠹具有驱避作用。同时,研究证明,马鞭草烯酮对红脂大小蠹的作用存在剂量效应。目前,作者正开展红脂大小蠹-共生菌-寄主松树三者相互关系以及红脂大小蠹与土著种之间化学通讯等方面的研究,以期阐明红脂大小蠹的入侵性及暴发机制,寻求更有效的控制途径。

Progress on invasion biology and chemical ecology of red turpentine beetle, Dendroctonus valens

The red turpentine beetle, Dendroctonus valens LeConte, native in North America, is a destructive exotic pest of pines in China. Since its first large outbreak in 1999 in Shanxi Province, D. valens has spread rapidly to the adjacent provinces Hebei, Henan and Shaanxi, and has infested over 500 000 hm~2 of Chinese pine stands, killing more than 6 million trees to date. Here, we report the recent progress, principally results of our researches on the D. valens, including the origin of introduction, the response to host monoterpenes, the pheromone identification, the potential repellents, the relationship of the invasion with the fungal symbionts. Historic records and molecular data support the hypothesis that the introduction of D. valens to China was recent and originated from the Pacific North-west of the U.S.A. The studies on the response to host volatiles by native and introduced populations showed that ( )-3-Carene was the most attractive monoterpene for the native and Chinese populations of D. valens, and ( )-3-Carene is thus broadly applicable for monitoring D. valens in both China and North America. Relatively little is known of its pheromone biology. Our recent work, using gas chromatographic and mass spectral (GC-MS) analysis of hindgut volatiles, revealed the presence of Trans-verbenol, Cis-verbenol, Myrtenol, Myrtenal, and Verbenone, and the bioactivity of these oxygenated monoterpenes to D. valens were confirmed. Although the appropriateness of classifying these compounds as pheromones is still uncertain, these compounds clearly have potential for use in management of this important invasive beetle. Verbenone, an antiaggregant for many bark beetles, has been shown to be effective in interrupting the response of D. valens to host volatiles and has a dose-dependent effect in its interruption. All of these results indicate that Verbenone functions as a multipurpose pheromone for D. valens. In the studies of responses of D. valens to non-host volatiles (NHVs), 1-Octen-3-ol, (Z)-3-hexen-1-ol, and (E)-2-hexen-1-ol were the three most effective NHVs, significantly reducing D. valens to kairomone_baited traps. In the development and implementation of a semiochemical_based management programme for D. valens, NHVs and Verbenone may have considerable potential for disrupting the beetle's ability to locate suitable hosts. A novel lure release device, Sun vial, devised and patented in China, was broadly applied in the management on the D. valens. At present, studies on the fungal symbionts of D. valens in both China and North America and the chemical communication relationships of D. valens with native bark beetles are well underway. The aims of these studies are to determine the importance of behavioral chemistry and fungal associates in the invasiveness and aggressiveness of D. valens and to test our hypothesis"What goes around and what comes around".