# Complex Floral Scent Profile of _Neottia ovata_ (Orchidaceae): General Attractants and Beyond
## 1 Introduction  
Orchids are renowned for their diverse pollination systems, which involve a variety of attraction mechanisms, including floral scents [1]. As the most complex floral signal,scent is undoubtedly a trait of significant importance in plants' adaptive potential within intricate pollininators' networks [2; 3; 4; 5; 6]. Floral scents are mixtures of organic compounds that vary in chemical properties, molecular weight, polarity, and oxidation state, produced through anabolic and catabolic processes of various biosynthetic pathways [7; 8]. These floral volatiles can be categorized into three main groups: terpenoids, phenylpropanoids/benzenoids (aromatic compounds), and fatty acid derivatives (aliphatic compounds) [9]. Approximately 1700 volatile compounds emitted by flowers have been identified till now, with about 50% originating from orchid taxa [10; 11]. Recent advancements in analytical methods have significantly improved techniques for capturing volatiles, enhancing both the sensitivity of research and the reproducibility of analyses. These developments have accelerated the growth of knowledge about floral scent chemistry and provided new insights into the immense complexity of volatile biochemical signals [9; 12; 13; 14]. An ever-expanding body of data confirms the substantial variation in this floral trait, with notable differences in scent composition even within the same species [15; 16; 17; 18]. Studies have documented that the quality and quantity of final scent composition are influenced by biotic and abiotic environmental factors [18; 19; 20; 21; 22]. Among these factors, the pollination system is one of the most significant drivers of scent diversification [21; 23]. Pollination systems in orchids, a model group for studying plant-pollinator coevolution, are renowned for their specialization toward specific pollinator groups, primarily due to distinct floral morphology (e.g., the shape of the corolla or the structure of the gynostemium). In contrast, generalist pollination, an ancestral system among plants, typically involves multiple functional groups of pollinators [24]. Orchids that occupy the generalist end of the generalization-specialization continuum of pollination systems are relatively rare [25; 26; 27; 28; 29; 30; 31]. These orchids often have phenotypically specialized flowers that can be pollinated by a wide range of floral visitors, varying in size, mouthparts, and food preferences [16]. In this context, the scent profiles of generalist plants tend to be more complex than those of plants with specialist pollination systems, as they must appeal to the preferences of diverse insect species. Some general scent attractants, particularly those associated with nectar feeding, are present in food-rewarding and food-deceptive orchid species--two common pollination strategies among orchids [32]. However, due to stabilizing selection, the scent bouquets of food-rewarding species appear less variable than those of species employing deceptive pollination strategies [33]. Functionally specialized flowers with general attractants are known in various orchid taxa. One example is _Neottia ovata_ ([PERSON], which has open nectaries and accessible nectar, adapted to the exploratory behavior of insects from distinct functional groups. Its floral traits, such as the lip adapted for landing and feeding insects and a longitudinal groove containing accessible nectar, facilitate these interactions [34]. On the other hand, the sepals and petals of _N. ovata_ form a hood-like structure around the gynostemium, with nectar accumulating at the base of the lip. This configuration might be considered a specialized floral adaptation [35]. _Neottia ovata_ produces several dozen yellow-greenish flowers per infloresc. Despite this, the plant is inconspicuous and poorly visible within the surrounding greenery. Consequently, olfactory attraction is central in drawing a broad spectrum of _N. ovata_ pollinators [26; 34]. [PERSON] [26] reported that nearly 300 insect species visit _N.