Olfactory signals are critical for soil inhabitants to communicate and respond to the environment. In addition to the well-documented volatile cues from herbivores and herbivory-induced plants, attraction of both entomopathogenic nematodes (EPNs) and insect prey was recently shown to be induced by a saprophytic fungus Fusarium solani. Here, we used headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS), to identify two volatile organic compounds (VOCs), 1-pentanol and 1-octen-3-ol (octenol), from F. solani. In olfactometer bioassays, the infective juvenile stage of the EPN Steinernema diaprepesi was attracted to both VOCs. Although octenol was highly attractive to fungivorous Drosophila melanogaster fruit fly larvae, the non-fungivorous Diaprepes abbreviatus root weevil larvae were repelled by the compound. In soil microcosms, the VOCs delayed the infection of root weevil larvae by S. diaprepesi but facilitated S. diaprepesi infection of fly larvae. Presumably octenol attracted the flies and EPNs to a common locale, while provoking greater separation of EPNs and root weevils than occurred in the absence of the chemical. EPNs may have evolved to exploit these VOCs as a means of encountering fungivorous insects, whereas non-fungivorous arthropods may have evolved to avoid the compounds.

嗅觉信号对于土壤居民沟通和响应环境至关重要。除了食草动物和食草动物引起的挥发性证据外，最近还显示腐生真菌真菌茄镰孢（Fusarium solani）诱导了昆虫病原线虫（EPN）和昆虫的猎物。在这里，我们使用顶空固相微萃取（HS-SPME）结合气相色谱-质谱（GC-MS）来鉴定两种挥发性有机化合物（VOC），分别是1-戊醇和1-辛烯-3-醇（辛烯醇），来自F. solani。在嗅觉仪生物测定中，EPN Steinernema diaprepesi的感染性少年阶段被两种VOC吸引。尽管辛烯醇对真菌很有吸引力果蝇的果蝇幼虫，非真菌性双歧双歧根root象甲幼虫被该化合物驱除。在土壤的微观世界中，挥发性有机化合物会延缓根除双歧杆菌对根象鼻幼虫的感染，但会促进蝇对幼虫的双歧杆菌的感染。大概辛烯醇将果蝇和EPNs吸引到一个共同的地方，而与没有化学药品的情况相比，EPNs和根象鼻虫的分离更大。EPNs可能已经进化为利用这些VOC作为遇到真菌昆虫的手段，而非真菌节肢动物可能已经进化为避免该化合物。