Taft Spencer, Najar Ahmed, Erbilgin Nadir
Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada.
J Chem Ecol. 2015 Jun;41(6):540-9. doi: 10.1007/s10886-015-0590-x. Epub 2015 May 27.
The secondary chemistry of host plants can have cascading impacts on the establishment of new insect herbivore populations, their long-term population dynamics, and their invasion potential in novel habitats. Mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae) has recently expanded its range into forests of jack pine, Pinus banksiana Lamb., in western Canada. We investigated whether variations in jack pine monoterpenes affect beetle pheromone production, as the primary components of the beetle's aggregation pheromone, (-)-trans-verbenol and anti-aggregation pheromone (-)-verbenone, are biosynthesized from the host monoterpene α-pinene. Jack pine bolts were collected from five Canadian provinces east of the beetle's current range, live D. ponderosae were introduced into them, and their monoterpene compositions were characterized. Production of (-)-trans-verbenol and (-)-verbenone emitted by beetles was measured to determine whether pheromone production varies with monoterpene composition of jack pines. Depending on particular ratios of major monoterpenes in host phloem, jack pine could be classified into three monoterpenoid groups characterized by high amounts of (+)-α-pinene, 3-carene, or a more moderate blend of monoterpenes, and beetle pheromone production varied among these groups. Specifically, beetles reared in trees characterized by high (+)-α-pinene produced the most (-)-trans-verbenol and (-)-verbenone, while beetles in trees characterized by high 3-carene produced the least. Our results indicate that pheromone production by D. ponderosae will remain a significant aspect and important predictor of its survival and persistence in the boreal forest.
寄主植物的次生化学物质会对新的食草昆虫种群的建立、其长期种群动态以及它们在新栖息地的入侵潜力产生连锁影响。山松甲虫，即西松大小蠹（Dendroctonus ponderosae Hopkins，鞘翅目：象甲科），最近已将其活动范围扩展到加拿大西部的短叶松林（Pinus banksiana Lamb.）。我们研究了短叶松单萜的变化是否会影响甲虫信息素的产生，因为甲虫聚集信息素的主要成分（-）-反式马鞭草烯醇和抗聚集信息素（-）-马鞭草烯酮是由寄主单萜α-蒎烯生物合成的。从甲虫当前分布范围以东的五个加拿大省份采集了短叶松原木，将活的西松大小蠹引入其中，并对它们的单萜成分进行了表征。测量了甲虫释放的（-）-反式马鞭草烯醇和（-）-马鞭草烯酮的产量，以确定信息素产量是否随短叶松的单萜成分而变化。根据寄主韧皮部中主要单萜的特定比例，短叶松可分为三个单萜类组，其特征分别是含有大量的（+）-α-蒎烯、3-蒈烯或单萜的更适度混合，并且甲虫信息素产量在这些组之间有所不同。具体而言，在以高含量（+）-α-蒎烯为特征的树木中饲养的甲虫产生的（-）-反式马鞭草烯醇和（-）-马鞭草烯酮最多，而在以高含量3-蒈烯为特征的树木中饲养的甲虫产生的最少。我们的结果表明，西松大小蠹产生信息素仍将是其在北方森林中生存和持续存在的一个重要方面和重要预测指标。
