Ambrosia beetles (Coleoptera: Scolytinae) cultivate their fungal symbiont within host substrates as the sole source of nutrition on which the larvae and adults must feed. To investigate a possible role for semiochemicals in this interaction, we characterized electrophysiological and behavioral responses of Xylosandrus germanus to volatiles associated with its fungal symbiont Ambrosiella grosmanniae. During still-air walking bioassays, X. germanus exhibited an arrestment response to volatiles of A. grosmanniae, but not antagonistic fungi Beauveria bassiana, Metarhizium brunneum, Trichoderma harzianum, the plant pathogen Fusarium proliferatum, or malt extract agar. Solid phase microextraction-gas chromatography-mass spectrometry identified 2-ethyl-1-hexanol, 2-phenylethanol, methyl benzoate and 3-methyl-1-butanol in emissions from A. grosmanniae; the latter two compounds were also detected in emissions from B. bassiana. Concentration-responses using electroantennography documented weak depolarizations to A. grosmanniae fungal volatiles, unlike the comparatively strong response to ethanol. When tested singly in walking bioassays, volatiles identified from A. grosmanniae elicited relatively weak arrestment responses, unlike the responses to ethanol. Xylosandrus germanus also exhibited weak or no long-range attraction to the fungal volatiles when tested singly during field trials in 2016–2018. None of the fungal volatiles enhanced attraction of X. germanus to ethanol when tested singly; in contrast, 2-phenylethanol and 3-methyl-1-butanol consistently reduced attraction to ethanol. Volatiles emitted by A. grosmanniae may represent short-range olfactory cues that could aid in distinguishing their nutritional fungal symbiont from other fungi, but these compounds are not likely to be useful as long-range attractants for improving detection or mass trapping tactics.

Ambrosia 甲虫（鞘翅目：Scolytinae）在宿主基质内培养它们的真菌共生体，作为幼虫和成虫必须喂养的唯一营养来源。为了研究化学信息素在这种相互作用中的可能作用，我们表征了Xylosandrus Germanus对其真菌共生菌 Ambrosiella grosmanniae相关挥发物的电生理和行为反应。在静止空气步行生物测定期间，X . Germanus对A. grosmanniae 的挥发物表现出抑制反应，但对拮抗真菌Beauveria bassiana、Metarhizium brunneum、Trichoderma harzianum和植物病原体Fusarium proliferatum 的挥发物没有反应，或麦芽提取物琼脂。固相微萃取-气相色谱-质谱法鉴定了罗汉果排放物中的 2-乙基-1-己醇、2-苯基乙醇、苯甲酸甲酯和 3-甲基-1-丁醇；后两种化合物也在B. bassiana 的排放物中检测到。与对乙醇的相对强烈反应不同，使用触角电图的浓度反应记录了对罗汉果真菌挥发物的弱去极化。当在步行生物测定中单独测试时，从罗汉果中鉴定出的挥发物引起了相对较弱的阻滞反应，这与对乙醇的反应不同。木糖醇在 2016-2018 年的田间试验中单独测试时，也表现出对真菌挥发物的弱或没有远距离吸引力。单独测试时，没有一种真菌挥发物能增强X. Germanus对乙醇的吸引力；相比之下，2-苯基乙醇和3-甲基-1-丁醇始终降低对乙醇的吸引力。A. grosmanniae释放的挥发物可能代表短程嗅觉线索，有助于将它们的营养真菌共生体与其他真菌区分开来，但这些化合物不太可能用作改善检测或大规模诱捕策略的长程引诱剂。