## 4 Discussion
In particular, the exogenous addition of N-acetylglucosamine, a monomer of chitin found in the exoskeleton of insects and fungal cell walls, increased hyphal formation in _O. sinensis_, whereas other fungal QS signals previously described in _C. albicans_, such as farnesol and tyrosol, significantly affected the dimorphism of _O. sinensis_[47]. The promiscuity in the QS receptors towards multiple autoinducers can explain the microbial interspecies communication. However, the specific elicitors produced by entomopathogenic fungi remain unknown. An important contribution of this study was the identification of volatile compounds that may act as chemical signals involved in the lifecycle of _B. bassimana_. For example, we identified 1-octen-3-ol as a part of the aromatic profile of AI2. This compound has been directly involved in conidiogenesis in filamentous fungi such as _Trichoderma atrovitoride_[48], exhibited toxicity against insects [49; 50], and retarded seed germination and growth in _Arabidopsis_ plants [51]. The variation in the contents of terpenes and 3-methylbutanol also caught our attention. Compound 3-methylbutanol was previously identified as the major compound produced by the mycelia of AI2 and AS5 (53.40 and 72.73% of all components, respectively) cultured in the PDA medium, followed by terpenes (11.06 and 2.89%, respectively) [28]. We observed that the terpene content decreased and alcohol content increased as the mycelial phase progressed. Interestingly, this ratio remained consistent regardless of virulence capacity, development, or source of isolation; nevertheless, more studies are needed to validate this observation. Terpenes play various ecological roles [52]. Farnesol is a sesquiterpene alcohol that aids cell-to-cell communication, regulates important virulent traits such as morphogenic transition in _C. albicans_[53], and has shown similar activities in other dimorphic fungi as well [47]. _B. bassimana_ emits different types of terpenes during the yeast phase. However, there are no reports on their participation in dimorphic transitions, despite the evidence of their biological activity in insects. For example, isomers of solienene, elemene, and guaiene have shown strong toxicity and antifeedant activity against the larvae of _Spodoptera_ spp. [54; 55; 56; 57]. The fused alcohol 3-methylbutanol is a bioactive compound that acts as a messenger affecting the female egg-laying behavior in _S. frugiperda_[28], promoting the biomass accumulation in plants via auxin transport and signaling depending on the dose, application method, and plant age [58; 59], and inducing filament formation in other fungi such as _Saccharomyces cerevisiae_ and _C. albicans_[11; 13; 60]. The role of fused alcohols as QS molecules has been previously reported for the dimorphic fungus _O. ulmi_ and the polymorphic fungus _C. albicans_[9; 15]. In _O. ulmi_, the authors identified 2-methylbutanol as the compound representing the major peak in the GC-MS profile, exhibiting activity as a QS molecule, thus influencing the fungal morphology. The compound 2-methylbutanol derives from isoleucine catabolism, which also affects the morphology. The dominant compound produced by _B. bassimana_ is 3-methylbutanol, derived from leucine. We propose that 3-methylbutanol is part of a specific fingerprint of the compounds responsible for the dimorphic transition in _B. bassimana_ and may be considered an autoregulatory QS signaling molecule in this fungus. The exogenous addition of the molecule to the I-plates showed activity as a QS molecule, retarding this phenomenon; the amino acid leucine in hemolymph probably acts as a trigger signal in _B. bassimana_ because the effects of amino acids are associated with the synthesis of fused alcohols [2]. The insect hemolymph is rich in free aminoacids [61; 62]. Thus, the in vivo contribution of these endogenous components for fungal morphogenesis, propagation and disease establishment could be significant. The effectiveness of _B.