## 3 Results and Discussion  
### Volatile Emissions of Symbionts  
SPME-GC-MS volatile compositions for individual fungal symbionts of _E. perbrevis_ are presented as the peak area percentages in Table 1. A total of 15 compounds were detected from the emissions of the six symbionts, and the chemical structures of those compounds are illustrated in Figure 1. Notably, the monoterpene hydrocarbons and oxygenated monoterpencoids were the most abundant terpenoid classes emitted by the symbionts. Limonene and _trans-p_-menth-2-en-1-ol were the major constituents in the group of monoterpencoids in five symbionts, while aristolochene and valencene were higher in symbiont AF-8 than in _Acremonium_ sp., AF-6 and _Graphium_ sp. (Figure 2). Regarding the components present in the commercial quercivorol lure [16], _trans-p_-menth-2-en-1-ol was the only volatile detected across all six symbionts. _cis-p_-Menth-2-en-1-ol was detected in the emissions from _Graphium_ sp. and both _Acremonium_ spp. but was absent in the emissions from AF-6, AF-8, and _Fusarium_ sp. nov. \(\alpha\)-Phellandrene was detected in the emissions from _A. murorum_ and _Graphium_ sp., while \(\beta\)-phellandrene was emitted from cultures of _A. murorum_, AF-8, and _Graphium_ sp. Figure 1: Structure of compounds presented in Table 1.  
Figure 2: Percent composition of terpenoid classes in the fungal symbionts of _E. perbrevis_. MH—monoterpene hydrocarbons; OM—oxygenated monoterpenes; SH—sesquiterpene hydrocarbons. The results of principal component analysis (PCA) are indicated by the principal components (PC) score and loading plots (PCA-Biplot). The PCA of volatile components yielded three PCs with eigenvalues \(\geq\) 1, accounting for 97.01% of the total variance across the entire dataset. The first, second, and third PCs contributed 49.41%, 31.30%, and 16.30% of the total variance, respectively (Table 2). Scores and loading plots of the first two PCs obtained from volatile emissions of six symbionts are presented in Figure 3. The PCA showed three different groupings: _A. murorum_ and _Graphium_ sp. are located separately in the upper and lower right quadrants, respectively, while _Acremonium_ sp., AF-6, AF-8 and _Fusarium_ sp. nov. are clustered in the lower left quadrant. Figure 3 displays the variables factor map indicating the discriminating emissions among the symbionts. Compounds **6** (_cis-p_-menth-2-en-1-ol), **9** (terpinen-4-ol), **10** (\(\alpha\)-terpineol), **11** (_trans_-piperitol), **12** (\(\beta\)-elemene) and **15** (\(\beta\)-bazzanene) are grouped in the lower right associated with _Graphium_ sp. ; and compounds **1** (\(\alpha\)-phellandrene), **2** (\(\alpha\)-terpinene), **3** (\(p\)-cymene), **5** (\(\beta\)-phellandrene), **7** (_cis-p_-mentha-2,8-dien-1-ol) and **8** (_trans-p_-menth-2-en-1-ol) are grouped in the upper right corner associated with _A. murorum_. In contrast, compounds **4** (limonene), **13** (aristolochene) and **14** (valencene) are grouped in the lower left associated with _Acremonium_ sp. and the three _Fusarium_ species (AF-6, AF-8 and _Fusarium_ sp. nov). Aristolochene was first isolated from _Aspergillus terreus_, and the headspace profile of _Penicillium roqueforti_ and _P. digitatum_ cultures were found to be rich in (+)-aristolochene (up to 80%) and valencene (11%) [27]. A hierarchical cluster analysis (HCA) dendrogram categorized the symbionts into three main clusters (Figure 4). Cluster I and II represented _A. murorum_ and _Graphium_ sp., respectively. Cluster III grouped _Acremonium_ sp., AF-6, AF-8 and _Fusarium_ sp. nov, confirming the results from PCA. PCA and HCA results revealed that _cis-p_-menth-2-en-1-ol and _trans-p_-menth-2-en-1-ol are the key components for discriminating effect of symbionts. This is the first report to compare chemical profiles of the volatile emissions in the six fungal species studied. \begin{table}