落叶松八齿小蠹对聚集信息素和寄主挥发性萜烯成分的电生理响应

Olfactory Reception of Conspecific Aggregation Pheromone and Host Volatile Terpenes by Asian Larch Bark Beetle,Ips subelongatus

采用顶空吸附采样法采集落叶松八齿小蠹3种寄主(华北落叶松、兴安落叶松和长白落叶松)树干和针叶的萜烯类挥发物,用正己烷洗脱后经手性气相色谱及质谱进行定性定量分析,同时采用触角电位仪和气相色谱-触角电位仪联用技术分析落叶松八齿小蠹对聚集信息素成分和寄主单萜类成分的选择性和敏感性。共鉴定出12种挥发性单萜烯成分,其中,S-(-)-α-蒎烯、R-(+)-α-蒎烯、3-蒈烯、R-(+)-β-蒎烯和S-(-)-β-蒎烯的含量占80%以上。3-蒈烯,S-(-)-α-蒎烯、(+)-柠檬烯、γ-萜品烯和萜品油烯均表现出EAD活性。另外,对伞花烃也有强烈的EAD信号,但在健康树体挥发物中未检测到该成分。落叶松八齿小蠹雌雄成虫对聚集信息素成分(-)-小蠹烯醇有强烈的EAD活性,但是对(+)-和(-)-小蠹二烯醇表现出不同的EAD响应现象。落叶松八齿小蠹雌雄成虫触角对EAD活性萜烯成分及聚集信息素成分的检测阈值是0.1μg,而不同成分的饱和水平存在差异。最后讨论了寄主萜烯挥发物和小蠹虫聚集信息素之间的相互关系。

Terpenes volatiles from the stem barks and needles of Dahurian larch （Larix gmelinii） , Prince Rupprecht larch （Larix principis-rupprechtii）, and Korean larch （Larix olgensis）, which are common hosts in the range of Ips subelongatus in northeastern China, were entrapped by dynamic headspace collection technique, and then the hexane elution of the volatiles was analyzed by chiral gas chromatography （GC） and GC-mass spectrometry （MS） in order to identify components of the volatiles. Totally 12 monoterpenes was identified, which are mainly consists of S-（ - ）-α- pinene, R-（ ＋ ）-α-pinene, 3-carene, R-（ ＋ ）-β-pinene, and S-（ - ）-β-pinene accounting for more than 80% of the total collected monoterpenes. Furthermore, the olfactory sensitivity and selectivity of I. subelongatus to synthetic host volatiles were assayed by a coupled gas chromatograph-electroantennographic detector （GC-EAD） and electroantennogram （EAG）. The olfactory responsiveness to S-（- ）-α-pinene, 3-carene, （ ＋ ）-limonene, β-terpinene, and terpinolene was assessed in GC-EAD analyses. In addition, β-cymene also elicited a strong EAD response, but it was not detected from the headspace volatile of healthy trees in the chiral GC analyses. As for the aggregation pheromone components, the strongest EAD response was obtained with （ - ）-ipsenol on both female and male antennae, however, different EAD response patterns to （ ＋ ）- and （ - ）-ipsdienol on male and thresholds of EAG responsiveness to synthetic monoterpenes levels of different compounds were different. Finally, we female antennae were observed in the GC-EAD analyses. The and aggregation pheromones were 0. 1μg, but the saturation discussed the relationship of host volatiles and aggregation pheromone of bark beetles.