United States Department of Agriculture, Forest Service, Pacific Northwest Research Station, Corvallis, Oregon, United States of America.
PLoS One. 2020 Jul 30;15(7):e0236276. doi: 10.1371/journal.pone.0236276. eCollection 2020.
Red turpentine beetle, Dendroctonus valens (Coleoptera: Curculionidae: Scolytinae) is a non-aggressive pine bark beetle native to North America, and more aggressive invader in China. Dispersing pioneer beetles are attracted to potential host trees by oleoresin monoterpene kairomones, but respond more strongly to those combined with ethanol, a mixture often released from stressed, dying, or recently dead trees. (+)-3-Carene, usually the dominant or co-dominant monoterpene in ponderosa pine, Pinus ponderosa, is a stronger attractant than α-pinene or β-pinene where tested over a large portion of the D. valens range, while (+)-3-carene+ethanol was shown previously to attract twice the beetles of (+)-3-carene. A field test comparing D. valens attraction among the three monoterpenes when all are released with ethanol has never been reported, and was our objective. In three US Pacific Northwestern pine forests, (-)-β-pinene+ethanol lures attracted 1.4 to 1.9 times more beetles than (+)-3-carene+ethanol. (+)- or (±)-α-pinene+ethanol lures were least attractive. A 1:1:1 monoterpene mixture+ethanol lure attracted more beetles than the 1:1:1 lure, but it was not statistically higher. Monoterpenes were dispensed from low density polyethylene bottles and their release rates monitored in laboratory and field tests. Under laboratory conditions (+)-3-carene was released much more rapidly than (+)-α-pinene or (-)-β-pinene when dispensed separately, or in a 1:1:1 mixture. (+)-3-Carene in the 1:1:1 mixture increased the release of both pinenes over their rates when dispensed separately. (-)-β-Pinene+ethanol is currently the strongest kairomone lure for D. valens attraction in US northwest pine forests, and has value for beetle detection, monitoring, research, and management.
红脂大小蠹，Dendroctonus valens（鞘翅目：象甲科：小蠹科）是原产于北美的非攻击性松褐天牛，也是中国更具攻击性的入侵物种。扩散先锋甲虫被松节油单萜信息素吸引到潜在的宿主树上，但对与乙醇结合的信息素反应更强烈，这种混合物通常是从受压力、垂死或最近死亡的树木中释放出来的。在大量的 D. valens 分布范围内，通常是白松、Pinus ponderosa 的主要或共同优势单萜 (+)-3-蒈烯比 α-蒎烯或 β-蒎烯更具吸引力，而 (+)-3-蒈烯+乙醇之前已被证明比 (+)-3-蒈烯吸引两倍的甲虫。在三个美国太平洋西北松林中，从未有报道比较三种单萜化合物在释放乙醇时对 D. valens 的吸引力，这是我们的目标。在 (-)-β-蒎烯+乙醇诱饵中，(-)-β-蒎烯+乙醇诱饵吸引了 1.4 到 1.9 倍的甲虫，而 (+)-3-蒈烯+乙醇诱饵的吸引力最小。(+)或（±）-α-蒎烯+乙醇诱饵的吸引力最小。1:1:1 单萜混合物+乙醇诱饵比 1:1:1 诱饵吸引了更多的甲虫，但没有统计学上的优势。单萜化合物从低密度聚乙烯瓶中分配，并在实验室和野外试验中监测其释放率。在实验室条件下，当单独分配或在 1:1:1 混合物中分配时，(+) -3-蒈烯的释放速度比 (+)-α-蒎烯或 (-)-β-蒎烯快得多。1:1:1 混合物中的 (+)-3-蒈烯增加了两种蒎烯的释放速度，超过了单独分配时的速度。(-)-β-蒎烯+乙醇是目前美国西北松林对 D. valens 吸引力最强的信息素引诱剂，对甲虫的检测、监测、研究和管理具有价值。
