1. In US Pacific Northwest ponderosa pine forests the primary attraction order shown previously for red turpentine beetle, Dendroctonus valens (Coleoptera: Curculionidae: Scolytinae), is (−)-β-pinene+ethanol > (+)-3-carene+ethanol > (+)-α-pinene+ethanol. The monoterpenes are bicyclic C₁₀H₁₆ isomers containing one 6-carbon ring with one double bond. Both pinenes have a 4-carbon second ring and differ only by their endocyclic or exocyclic double bond. The (+)-3-carene second ring has 3-carbons; its double bond is endocyclic like (+)-α-pinene.
2. Ring system and double bond influences on primary attraction were evaluated by hydrogenating (+)-3-carene and (+)-α-pinene to cis-carane and cis-pinane, respectively. Field test primary attraction strengths were (−)-β-pinene+ethanol > cis-carane+ethanol > cis-pinane+ethanol > ethanol.
3. In combination with ethanol (i) a double bond is not required in either ring system to attract D. valens, (ii) the cis-carane bicyclic 3, 6-carbon ring system provides stronger beetle attraction than the cis-pinane 4, 6-carbon bicyclic ring system, and likely structural basis for stronger (+)-3-carene attraction over (+)-α-pinene, (iii) adding an exocyclic double bond to the 4, 6-carbon ring system elevates attraction above the 3, 6-carbon ring system with no double bond, and (iv) the 4, 6-carbon ring system is a much stronger attractant with an exocyclic rather than endocyclic double bond.

中文翻译：

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顺式carane、(+)-3-carene、cis-pinane、(+)-α-蒎烯和(-)-β-蒎烯的关键结构特征影响红松节油甲虫与乙醇释放时的主要吸引力

1. 在美国太平洋西北部的黄松林中，先前显示的红松节油甲虫Dendroctonus valens（鞘翅目：仙茅科：Scolytinae）的主要吸引顺序是 (-)-β-蒎烯+乙醇 > (+)-3-蒎烯+乙醇 > ( +)-α-蒎烯+乙醇。单萜是双环C ₁₀ H ₁₆异构体，含有一个带一个双键的6-碳环。两种蒎烯都有一个 4 个碳的第二个环，区别仅在于它们的环内或环外双键。(+)-3-carene 第二个环有 3 个碳；它的双键像 (+)-α-蒎烯一样是内环的。
2. 通过将 (+)-3-蒎烯和 (+)-α-蒎烯分别氢化成顺式蒎烷和顺式蒎烷来评估环系和双键对初级吸引力的影响。现场测试的主要吸引强度是 (-)-β-蒎烯+乙醇 >顺式-carane+乙醇 >顺式蒎烷+乙醇 > 乙醇。
3. 与乙醇结合时 (i) 在任一环系统中都不需要双键来吸引D. valens，(ii)顺式-carane 双环 3, 6-碳环系统提供比顺式蒎烷 4, 6更强的甲虫吸引力-碳双环系统，以及比（+）-α-蒎烯更强的（+）-3-蒎烯吸引力的可能结构基础，（iii）向4、6-碳环系统添加环外双键提高吸引力以上3, 6-碳环系统没有双键，以及 (iv) 4, 6-碳环系统是一种更强的引诱剂，具有环外双键而不是环内双键。