红皮云杉主要单萜烯对云杉八齿小蠹的毒力及行为调控作用

Toxicity and Behavioral Regulatory Effects of Monoterpenes in Picea koraiensis to the Bark Beetle Ips typographus(Coleoptera:Scolytidae)

【目的】通过分析健康和衰弱红皮云杉树干单萜烯释放量的差异,评价单萜烯对云杉八齿小蠹的熏蒸毒性,测试单萜烯对其聚集信息素的行为增效和抑制作用,在此基础上研发用于云杉八齿小蠹种群调控的高效信息化学物质。【方法】利用动态顶空采样法收集健康和衰弱红皮云杉树干挥发物,利用气相色谱仪对其进行定性和定量分析,进一步利用熏蒸法测定主要单萜烯对云杉八齿小蠹成虫的熏蒸毒力,野外行为测定单萜烯对云杉八齿小蠹及其天敌红胸郭公甲的行为影响。【结果】红皮云杉树干释放的单萜烯主要是S-(–)-α-蒎烯、R-(+)-α-蒎烯、月桂烯、S-(–)-β-蒎烯、3-蒈烯、(–)-柠檬烯和(+)-柠檬烯;健康红皮云杉单萜烯释放总量显著高于衰弱木,但R-(+)-α-蒎烯和(+)-柠檬烯的释放量差异不显著。7种单萜烯对云杉八齿小蠹成虫的致死中浓度LC50值介于3.10~4.50μL·mL^(-1)之间,(+)-柠檬烯的熏蒸毒性最强;7种单萜烯间的熏蒸毒性差异显著,但在雌雄成虫间未表现出显著差异。行为测试发现3-蒈烯、(–)-柠檬烯和(+)-柠檬烯能显著降低聚集信息素对云杉八齿小蠹的诱捕量,S-(–)-β-蒎烯对诱捕量没有显著影响。与(–)-柠檬烯和(+)-柠檬烯相比,3-蒈烯能显著提高聚集信息素对红胸郭公甲的引诱作用。【结论】红皮云杉树干可释放7种主要单萜烯,在适合云杉八齿小蠹定殖的衰弱木上单萜烯释放量低于健康云杉。单萜烯对云杉八齿小蠹具有熏蒸毒性,参与调控红皮云杉―云杉八齿小蠹―红胸郭公甲三级营养关系。柠檬烯可作为驱避剂用于云杉八齿小蠹的生态防控中。

【Objective】In this study,we analyzed the differences in the release of monoterpenes from the trunk of healthy and weak Picea koraiensis,evaluated their fumigation toxicity to adult of Ips typographus,and tested their synergistic and antogonistic effects on aggregation pheromones of the bark beetle.Based on these investigation,we aims to produce efficient semiochemicals for population regulation of I.typographus in the forest.【Method】Dynamic headspace sampling was used to collect the volatiles released from the stem of healthy and weak P.koraiensis.Gas chromatography was used to qualitatively and quantitatively analyze the monoterpenes.The toxicity of the monoterpenes against adult I.typographus was determined by using the headspace fumigation method,and the behavioral effects of the monoterpenes on I.typographus and its natural enemy,Thanasimus substriatus(Coleoptera:Cleridae)were analyzed in the forest.【Result】The major monoterpenes from the trunk of P.koraiensis were identified,including S-(–)-α-pinene,R-(+)-α-pinene,S-(–)-β-pinene,myrcene,3-carene,(–)-limonene,and(+)-limonene.The total amount of monoterpenes in healthy stems was significantly higher than that in weakened stems,while the release amount of R-(+)-α-pinene and(+)-limonene showed no significant difference between healthy and weakened stems.The LC50 values of seven monoterpenes against I.typographus ranged from 3.10–4.50μL·mL^(-1),with(+)-limonene showing the strongest toxicity.There were significant differences in LC50 values among the seven monoterpenes,but not between male and female adult beetles.The field behavioral test showed that 3-carene,(–)-limonene,and(+)-limonene significantly reduced the trap catches of I.typographus by aggregation pheromones,but S-(–)-β-pinene showed no effect on the trap catches.Compared to(–)-limonene and(+)-limonene,3-carene was able to significantly improve the trap catches of the predator T.substriatusby aggregation pheromones.【Conclusion】The trunk of P.koraiensis can release seven major monoterpenes.The weakened spruce,suitable for colonization by I.typographus,releases less monoterpenes than the healthy spruce.These monoterpenes have fumigation toxicity against I.typographus and may be involved in regulating tritrophic relationships between spruce,I.typographus,and T.substriatus.Limonene can be used as a repellent for ecological prevention and control of I.typographus.