# Complex Floral Scent Profile of _Neottia ovata_ (Orchidaceae): General Attractants and Beyond
## 4 Discussion
All the mentioned terpenes are found in the scent profiles of the considered orchid species that lure with the promise of real or false reward, although in the flower scent of _N. ovata_, dominance visibly shifted towards \(\gamma\)-terpinene, \(\alpha\)-terpinene, and terpinen-4-ol. These terpenes were reported with high concentrations in the essential oils and flower scent of supergeneralist pollination species from the Apiaceae family, specifically in the flower scent of _Aegopaium podagaria_, _Anthriscus sylvestris_, and _Heracleum sibiricum_[63], [PERSON] et al. [64] noted the dominance of terpinolone and \(\gamma\)-terpinene, combined with linalool in some fly-pollinated plants, where this mixture constituted a \"sweet scent\" that elicitedthe response of sapromyophilus houseflies. \(\gamma\)-terpinene is also a dominant component in thyme essential oil, which is, in this case, strictly linked with antioxidant and antibacterial properties [65]. The vital role of terpene alcohols, including \(\alpha\)-terpineol, terpinene-4-ol, and linalool, in the antagonistic relationships of plants with other organisms is often emphasized [56]. However, in the case of the Orchidaceae family, these compounds appear to gain a contrary function, luring the potential pollinators [9]. Terpinen-4-ol is, for example, one of the dominant compounds in the intensely floral fragment flowers of the tropical orchids _Prosthechea vespa_ and _P. fragrans_[66]. Known for attracting to its flowers many taxonomically disparate insect visitors are the species of umbellifer _Angelica sylvestris_, with the domination of \(\alpha\)-pinen, \(\beta\)-phellandrene [67] and \(\beta\)-myrcene, benzaldehyde, and phenylethanol in the flower volatiles [68]. Those two last aromatics, together with benzeneacetaldehyde, benzyl alcohol, and methyl benzoate ester, were iterative components in the flower sent profiles of nectar-rewarding and food-deceptive orchids considered here. Relatively rich pools of aromatic compounds were present in the analyzed orchid scent profiles. The dominant compounds varied, but those mentioned above appeared with noticeably higher frequency and often in a significant proportion within the profile, which can also indicate their role as general attractants. The aromatic ester methyl benzoate, found in generalized-pollination, nectar-rewarding species like _Disa fragrans_, _Schizochilus flexuous_, and _Dactylorhiza viridis_, is also emphasized as a compound connected with the scent of nectar [50], causing EAD activity in pollinators of several orchids [69]. Also among iterative components in the flower scent of nectar-rewarding and food-deceptive orchids were aromatic alcohols, such as benzyl alcohol, 2-phenylethanol, and aromatic aldehydes, mainly benzeneacetaldehyde and benzaldehyde. The last three we found in the _N. ovata_ scent as not dominant compounds, but constant ones. The aliphatic compounds were the least represented floral volatile group in the profiles of the studied orchids. Aliphatics, specifically alkanes and alkenes, play a vital role in the pollination of sexually deceptive orchids, and in such cases, they can dominate or be the scarcer elements of the fragrance composition [70]. In the analyzed group of orchids, the more frequent occurrence of two aliphatic compounds, specifically aldehyde nonanal and ketone 6-methyl-5-hepten-2-one, is noticeable. Nonanal is found in the scent of _N. ovata_ in small quantities. In contrast, the flower scent of other orchids, such as _Platanthera obtusata_ or _Malaxis monophyllos_, is nonanal-rich, which is strongly connected with luring mosquitoes as pollinators [71; 72]. A similar activity attracting mosquitoes is reported for 6-methyl-5-hepten-2-one [9], which was also noted in the flower scent of sexually deceptive _Ophrys insectifera_[73]. The highly sensitive SPME method, which is a selective method, provided us with a compound-rich, complex picture of the scent profile of _N. ovata_ flowers, which might be still incomplete.