欧亚云杉树皮甲虫,Ipstypographus是挪威云杉(Piceaabies)的破坏性害虫。欧洲最近的疫情被归因于全球变暖和其他人为影响。树皮甲虫在其整个生命周期中受到多种复杂嗅觉线索的引导。雄性产生的聚集信息素,包括2-甲基-3-丁烯-2-醇和顺式-马鞭草醇,已被确定为分散物种的最强大的引诱剂。除了宿主树,树皮甲虫与多种生物相互作用,包括共生的蛇类真菌,这可能促进甲虫定殖成功和后代发育。以前,在短距离实验室化验中,我们证明了I.typographus成虫被三种共生真菌产生的挥发性有机化合物(VOCs)所吸引:Grosmanniapenicillata,polonica,和钩藤。此外,丰富的杂醇及其乙酸酯被发现是真菌VOC谱中最有吸引力的气味。在这项研究中,使用长距离场捕获实验,我们分析了真菌VOCs作为引诱剂分散I.typographus的作用。结合诱捕器中的信息素测试了两种类型的真菌诱饵:(1)在马铃薯葡萄糖琼脂(PDA)上生长的真菌的活培养物和(2)含有等比例合成杂醇及其乙酸酯的分配器。随后,分析了活真菌诱饵排放的挥发性有机化合物的组成。我们发现,共生真菌协同增加了田间诱捕器中甲虫对信息素的吸引力,活真菌诱饵的吸引力取决于真菌负荷。当一个培养皿和E.polonica时,当与信息素结合时,协同提高了捕获效率,需要三个带有L.europhioides的培养皿来实现相同的目标。真菌杂醇和乙酸酯的合成混合物仅在较低的测试剂量下就提高了信息素的捕获效率。真菌培养物的VOC分析表明,所有三种真菌都产生杂醇和乙酸酯,但组成和数量可变。总的来说,这项研究的结果表明,除了信息素,树皮甲虫也可能利用其共生真菌的挥发性线索来改善树木的定殖和繁殖成功。
Eurasian spruce bark beetle, Ips typographus is a destructive pest of the Norway spruce (Picea abies). Recent outbreaks in Europe have been attributed to global warming and other anthropogenic impacts. Bark beetles are guided by multiple complex olfactory cues throughout their life cycle. Male-produced aggregation pheromones, comprising 2-methyl-3-buten-2-ol and cis-verbenol, have been identified as the most powerful attractants for dispersing conspecifics. In addition to host trees, bark beetles interact with multiple organisms, including symbiotic ophiostomatoid fungi, which may promote beetle colonization success and offspring development. Previously, in a short-distance laboratory assay, we demonstrated that I. typographus adults are attracted to the volatile organic compounds (VOCs) produced by three symbiotic fungi: Grosmannia penicillata, Endoconidiophora polonica, and Leptographium europhioides. Furthermore, the abundant fusel alcohols and their acetates were found to be the most attractive odorants in the fungal VOC profile. In this study, using a long-distance field-trapping experiment, we analyzed the role of fungal VOCs as attractants for dispersing I. typographus. Two types of fungal lures were tested in combination with pheromones in traps: (1) live cultures of fungi grown on potato dextrose agar (PDA) and (2) dispensers containing synthetic fusel alcohols and their acetates in equal proportions. Subsequently, the composition of VOCs emitted from live fungal lures were analyzed. We found that the symbiotic fungi synergistically increased the attraction of beetles to pheromones in field traps and the attractiveness of live fungal lures depended on the fungal load. While one Petri dish with E. polonica, when combined with pheromones synergistically increased trapping efficiency, three Petri dishes with L. europhioides were required to achieve the same. The synthetic mix of fungal fusel alcohols and acetates improved the catch efficiency of pheromones only at a low tested dose. VOC analysis of fungal cultures revealed that all the three fungi produced fusel alcohols and acetates but in variable composition and amounts. Collectively, the results of this study show that, in addition to pheromones, bark beetles might also use volatile cues from their symbiotic fungi to improve tree colonization and reproductive success in their breeding and feeding sites.