Complex Floral Scent Profile of Neottia ovata (Orchidaceae): General Attractants and Beyond

Understanding the complexity of flower scent-a crucial attractant for pollinators and a key factor in ensuring plant reproduction-is an essential ecological task for highly endangered orchids. To address this issue, we studied the flower volatiles profile of Neottia ovata, a nectar-rewarding orchid known for its generalist pollination strategy. We then compared the chemical composition of N. ovata floral scent with scent data of other orchid species to place our findings in the context of general volatile attractants emitted by nectar-rewarding or food-deceptive species. Our results contribute to understanding the complexity of the N. ovata floral scent profile and provide valuable methodological insights. The scented bouquet of N. ovata comprises 100 compounds with a relatively consistent composition across the analyzed samples. It is rich in terpenes, including linalool and trans-/cis-sabinene hydrate, compounds commonly associated with generalized rewarding or food-deceptive pollination systems. Other terpenes identified include α- and β-pinene, limonene, and β-phellandrene, whose presence underscores the generalized nature of the floral scent. Interestingly, in the studied N. ovata populations, the dominance among terpenes is shifting markedly towards γ-terpinene, α-terpinene, and terpinene-4-ol, commonly found in essential oils and the floral scents of some supergeneralist-pollination plants. Aromatic compounds were less represented in the N. ovata scent profile and those of other orchids studied, though benzyl alcohol and benzaldehyde were noticeably more abundant. Aliphatic compounds composed the least prevalent fraction, showing a marked decreasing trend among nectar-rewarding species with generalized or specialized pollination systems. It is worth emphasizing that the applied methodology revealed an extensive group of low-frequency compounds in the N. ovata floral scent. This finding raises new ecological questions about the intraspecific diversity of floral scent profiles and sheds new light on the factors determining effective reproduction in this species of orchid.

Pollinator diversity of the food-deceptive orchids in southern Italy

The orchid family is renowned for its enormous diversity in pollination biology. Many orchid species use deception to attract pollinators, and the main strategy in terrestrial orchids is food deception. Food-deceptive orchids usually show a low number of pollinator visitations, making field observations of pollinators difficult. In this study visual census, pollinator capture and molecular analysis of pollinaria found on caught insects allowed us to obtain information on species composition of orchid pollinators. A total of 321 insects were caught; most specimens were hymenopterans (Apis mellifera, Bombus ruderatus and Eucera rufa) and coleopterans (Tropinota hirta and T. squalida). The identity of species to which pollinaria found on the insect's body belonged was confirmed by molecular analysis. Moreover, some individuals of Billaea lata (Tachinidae, Diptera) were captured and photographed with the pollinaria on their head. Two new and important results emerged clearly in this work: a dipteran, Billaea lata, pollinator of Anacamptis pyramidalis, and two beetles in the genus Tropinota are pollinators of Orchis italica. Our results confirm that generalized food-deceptive orchids of the genera Orchis and Anacamptis show weak pollinator specificity.

The genome sequence of Tachina fera Linnaeus, 1761, a tachinid fly

We present a genome assembly from an individual female Tachina fera (Arthropoda; Insecta; Diptera; Tachinidae). The genome sequence is 752 megabases in span. The majority of the assembly (99.98%) is scaffolded into 6 chromosomal pseudomolecules, with the X sex chromosome assembled. The complete mitochondrial genome was also assembled and is 17.4 kilobases in length.