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Rupp T, Oelschlägel B, Berjano R, Mahfoud H, Buono D, Wenke T, Rabitsch K, Bächli G, Stanojlovic V, Cabrele C, Xiong W, Knaden M, Dahl A, Neinhuis C, Wanke S, Dötterl S. Chemical imitation of yeast fermentation by the drosophilid-pollinated deceptive trap-flower Aristolochia baetica (Aristolochiaceae). PHYTOCHEMISTRY 2024; 224:114142. [PMID: 38762152 DOI: 10.1016/j.phytochem.2024.114142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 05/08/2024] [Accepted: 05/12/2024] [Indexed: 05/20/2024]
Abstract
Deceptive flowers, unlike in mutualistic pollination systems, mislead their pollinators by advertising rewards which ultimately are not provided. Although our understanding of deceptive pollination systems increased in recent years, the attractive signals and deceptive strategies in the majority of species remain unknown. This is also true for the genus Aristolochia, famous for its deceptive and fly-pollinated trap flowers. Representatives of this genus were generally assumed to be oviposition-site mimics, imitating vertebrate carrion or mushrooms. However, recent studies found a broader spectrum of strategies, including kleptomyiophily and imitation of invertebrate carrion. A different deceptive strategy is presented here for the western Mediterranean Aristolochia baetica L. We found that this species is mostly pollinated by drosophilid flies (Drosophilidae, mostly Drosophila spp.), which typically feed on fermenting fruit infested by yeasts. The flowers of A. baetica emitted mostly typical yeast volatiles, predominantly the aliphatic compounds acetoin and 2,3-butandiol, and derived acetates, as well as the aromatic compound 2-phenylethanol. Analyses of the absolute configurations of the chiral volatiles revealed weakly (acetoin, 2,3-butanediol) to strongly (mono- and diacetates) biased stereoisomer-ratios. Electrophysiological (GC-EAD) experiments and lab bioassays demonstrated that most of the floral volatiles, although not all stereoisomers of chiral compounds, were physiologically active and attractive in drosophilid pollinators; a synthetic mixture thereof successfully attracted them in field and lab bioassays. We conclude that A. baetica chemically mimics yeast fermentation to deceive its pollinators. This deceptive strategy (scent chemistry, pollinators, trapping function) is also known from more distantly related plants, such as Arum palaestinum Boiss. (Araceae) and Ceropegia spp. (Apocynaceae), suggesting convergent evolution. In contrast to other studies working on floral scents in plants imitating breeding sites, the present study considered the absolute configuration of chiral compounds.
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Affiliation(s)
- Thomas Rupp
- Department of Environment & Biodiversity, Paris-Lodron University of Salzburg, Hellbrunnerstr. 34, 5020, Salzburg, Austria
| | - Birgit Oelschlägel
- Institut für Botanik, Technische Universität Dresden, Zellescher Weg 20b, 01062, Dresden, Germany
| | - Regina Berjano
- Department of Vegetal Biology and Ecology, University of Sevilla, Avenida Reina Mercedes s/n, 41012, Sevilla, Spain
| | - Hafez Mahfoud
- Institut für Botanik, Technische Universität Dresden, Zellescher Weg 20b, 01062, Dresden, Germany
| | - Daniele Buono
- Institut für Botanik, Technische Universität Dresden, Zellescher Weg 20b, 01062, Dresden, Germany
| | - Torsten Wenke
- Institut für Botanik, Technische Universität Dresden, Zellescher Weg 20b, 01062, Dresden, Germany
| | - Katharina Rabitsch
- Department of Environment & Biodiversity, Paris-Lodron University of Salzburg, Hellbrunnerstr. 34, 5020, Salzburg, Austria
| | - Gerhard Bächli
- Institut für Evolutionsbiologie und Umweltforschung, Universität Zürich-Irchel, Winterthurerstrasse 190, 8057, Zürich, Switzerland
| | - Vesna Stanojlovic
- Department of Environment & Biodiversity, Paris-Lodron University of Salzburg, Hellbrunnerstr. 34, 5020, Salzburg, Austria
| | - Chiara Cabrele
- Department of Environment & Biodiversity, Paris-Lodron University of Salzburg, Hellbrunnerstr. 34, 5020, Salzburg, Austria
| | - Wujian Xiong
- Department of Environment & Biodiversity, Paris-Lodron University of Salzburg, Hellbrunnerstr. 34, 5020, Salzburg, Austria; Ecological Security and Protection Key Laboratory of Sichuan Province, Mianyang Normal University, Mianxingxi Road 166, 621000, Mianyang, China
| | - Markus Knaden
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans Knoell Strasse 8, 07745, Jena, Germany
| | - Andreas Dahl
- DRESDEN-Concept Genome Center, Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Fetscherstraße 105, 01307, Dresden, Germany
| | - Christoph Neinhuis
- Institut für Botanik, Technische Universität Dresden, Zellescher Weg 20b, 01062, Dresden, Germany
| | - Stefan Wanke
- Institut für Botanik, Technische Universität Dresden, Zellescher Weg 20b, 01062, Dresden, Germany; Departamento de Botánica, Instituto de Biología, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-367, 04510, Coyoacan, Distrito Federal, Mexico; Institut für Ökologie, Evolution und Diversiät, Goethe-Universität, Max-von-Laue-Straße 13, 60438, Frankfurt am Main, Germany; Abteilung Botanik und molekulare Evolutionsforschung, Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, 60325, Frankfurt am Main, Germany
| | - Stefan Dötterl
- Department of Environment & Biodiversity, Paris-Lodron University of Salzburg, Hellbrunnerstr. 34, 5020, Salzburg, Austria.
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Kidyoo A, Kidyoo M, Ekkaphan P, Blatrix R, McKey D, Proffit M. Specialized pollination by cecidomyiid flies and associated floral traits in Vincetoxicum sangyojarniae (Apocynaceae, Asclepiadoideae). PLANT BIOLOGY (STUTTGART, GERMANY) 2024; 26:166-180. [PMID: 38196297 DOI: 10.1111/plb.13607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 11/27/2023] [Indexed: 01/11/2024]
Abstract
Specialized pollination systems frequently match a particular set of floral characteristics. Vincetoxicum spp. (Apocynaceae, Asclepiadoideae) have disk-shaped flowers with open access to rewards and reproductive organs. Flowers with these traits are usually associated with generalized pollination. However, the highly modified androecium and gynoecium that characterize asclepiads are thought to be associated with specialized pollinators. In V. sangyojarniae, we investigated floral biology, pollination, and the degree of pollinator specialization in two localities in Thailand. We examined floral traits that target legitimate pollinators. Flowers of V. sangyojarniae opened only at night, emitted floral scents containing mainly (E)-β-ocimene, 1-octen-3-ol, (E)-4,8-dimethyl-1,3,7-nonatriene (E-DMNT) and N-(3-methylbutyl)acetamide, and provided sucrose-dominated nectar openly to insect visitors. Assessment of pollinator effectiveness indicated that V. sangyojarniae is functionally specialized for pollination by cecidomyiid flies. Although various insects, particularly cockroaches, frequently visited flowers, they did not carry pollinaria. Our results suggest that V. sangyojarniae attracts its fly pollinators by emitting floral volatiles bearing olfactory notes associated with the presence of fungi or, less likely, of prey captured by predatory arthropods (food sources of its pollinators) but offers a nectar reward upon insect arrival. Hence, there is a mismatch between the advertisement and the actual reward. Our results also suggest that the size of floral parts constitutes a mechanical filter where reciprocal fit between flower and insect structures ensures that only suitable pollinators can extract the pollinaria, a prerequisite for successful pollination.
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Affiliation(s)
- A Kidyoo
- Plants of Thailand Research Unit, Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - M Kidyoo
- Plants of Thailand Research Unit, Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - P Ekkaphan
- Scientific and Technological Research Equipment Centre, Chulalongkorn University, Bangkok, Thailand
| | - R Blatrix
- CEFE, University of Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - D McKey
- CEFE, University of Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - M Proffit
- CEFE, University of Montpellier, CNRS, EPHE, IRD, Montpellier, France
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