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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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Yan W, Li Y, Louis EJ, Kyriacou CP, Hu Y, Cordell RL, Xie X. Quantitative genetic analysis of attractiveness of yeast products to Drosophila. Genetics 2024; 227:iyae048. [PMID: 38560786 PMCID: PMC11151935 DOI: 10.1093/genetics/iyae048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 02/19/2024] [Accepted: 02/20/2024] [Indexed: 04/04/2024] Open
Abstract
An attractive perfume is a complex mixture of compounds, some of which may be unpleasant on their own. This is also true for the volatile combinations from yeast fermentation products in vineyards and orchards when assessed by Drosophila. Here, we used crosses between a yeast strain with an attractive fermentation profile and another strain with a repulsive one and tested fly responses using a T-maze. QTL analysis reveals allelic variation in four yeast genes, namely PTC6, SAT4, YFL040W, and ARI1, that modulated expression levels of volatile compounds [assessed by gas chromatography-mass spectrometry (GC-MS)] and in different combinations, generated various levels of attractiveness. The parent strain that is more attractive to Drosophila has repulsive alleles at two of the loci, while the least attractive parent has attractive alleles. Behavioral assays using artificial mixtures mimicking the composition of odors from fermentation validated the results of GC-MS and QTL mapping, thereby directly connecting genetic variation in yeast to attractiveness in flies. This study can be used as a basis for dissecting the combination of olfactory receptors that mediate the attractiveness/repulsion of flies to yeast volatiles and may also serve as a model for testing the attractiveness of pest species such as Drosophila suzukii to their host fruit.
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Affiliation(s)
- Weiru Yan
- Institute of Genetics, School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
- Department of Genetics & Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Yishen Li
- Department of Genetics & Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Edward J Louis
- Department of Genetics & Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | | | - Yue Hu
- Department of Genetics & Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Rebecca L Cordell
- School of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Xiaodong Xie
- Institute of Genetics, School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
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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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Suetsugu K. A novel nursery pollination system between a mycoheterotrophic orchid and mushroom-feeding flies. Ecology 2023; 104:e4152. [PMID: 37610832 DOI: 10.1002/ecy.4152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/25/2023] [Accepted: 07/17/2023] [Indexed: 08/25/2023]
Affiliation(s)
- Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
- Institute for Advanced Research, Kobe University, Kobe, Japan
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Mochizuki K, Okamoto T, Chen KH, Wang CN, Evans M, Kramer AT, Kawakita A. Adaptation to pollination by fungus gnats underlies the evolution of pollination syndrome in the genus Euonymus. ANNALS OF BOTANY 2023; 132:319-333. [PMID: 37610846 PMCID: PMC10583214 DOI: 10.1093/aob/mcad081] [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: 01/22/2023] [Accepted: 07/04/2023] [Indexed: 08/25/2023]
Abstract
BACKGROUND AND AIMS Dipteran insects are known pollinators of many angiosperms, but knowledge on how flies affect floral evolution is relatively scarce. Some plants pollinated by fungus gnats share a unique set of floral characters (dark red display, flat shape and short stamens), which differs from any known pollination syndromes. We tested whether this set of floral characters is a pollination syndrome associated with pollination by fungus gnats, using the genus Euonymus as a model. METHODS The pollinator and floral colour, morphology and scent profile were investigated for ten Euonymus species and Tripterygium regelii as an outgroup. The flower colour was evaluated using bee and fly colour vision models. The evolutionary association between fungus gnat pollination and each plant character was tested using a phylogenetically independent contrast. The ancestral state reconstruction was performed on flower colour, which is associated with fungus gnat pollination, to infer the evolution of pollination in the genus Euonymus. KEY RESULTS The red-flowered Euonymus species were pollinated predominantly by fungus gnats, whereas the white-flowered species were pollinated by bees, beetles and brachyceran flies. The colour vision analysis suggested that red and white flowers are perceived as different colours by both bees and flies. The floral scents of the fungus gnat-pollinated species were characterized by acetoin, which made up >90 % of the total scent in three species. Phylogenetically independent contrast showed that the evolution of fungus gnat pollination is associated with acquisition of red flowers, short stamens and acetoin emission. CONCLUSIONS Our results suggest that the observed combination of floral characters is a pollination syndrome associated with the parallel evolution of pollination by fungus gnats. Although the role of the red floral display and acetoin in pollinator attraction remains to be elucidated, our finding underscores the importance of fungus gnats as potential contributors to floral diversification.
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Affiliation(s)
- Ko Mochizuki
- Botanical Gardens, Graduate School of Science, The University of Tokyo, 3-7-1 Hakusan, Bunkyo-ku, Tokyo, Japan
| | - Tomoko Okamoto
- Faculty of Applied Biological Sciences, Gifu University, Yanagido 1-1, Gifu, Japan
| | - Kai-Hsiu Chen
- Department of Ecology and Evolution, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Chun-Neng Wang
- Department of Life Science, Institute of Ecology and Evolutionary Biology, National Taiwan University, Taipei 10617, Taiwan
| | - Matthew Evans
- Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL 60022, USA
| | - Andrea T Kramer
- Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL 60022, USA
| | - Atsushi Kawakita
- Botanical Gardens, Graduate School of Science, The University of Tokyo, 3-7-1 Hakusan, Bunkyo-ku, Tokyo, Japan
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Cardoso JCF, Johnson SD, Rezende UC, Oliveira PE. The lady's 'slippery' orchid: functions of the floral trap and aphid mimicry in a hoverfly-pollinated Phragmipedium species in Brazil. ANNALS OF BOTANY 2023; 131:275-286. [PMID: 36479901 PMCID: PMC9993062 DOI: 10.1093/aob/mcac140] [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: 07/12/2022] [Accepted: 11/20/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND AIMS Trap flowers are fascinating cases of adaptation, often linked to oviposition-site mimicry systems. Some trap flowers do not imprison pollinators for a pre-determined period, but rather force them to move through a specific path, manipulating their movements in a way that culminates in pollen transfer, often as they leave through a secondary opening. METHODS We investigated the previously unknown pollination system of the lady's slipper orchid Phragmipedium vittatum and assessed the function of micro-morphological traits of its trap flowers. KEY RESULTS Our observations revealed that P. vittatum is pollinated by females of two hoverfly species (Syrphidae). Eggs laid by flies on or near raised black spots on the flowers indicate that the orchid mimics aphids which serve as food for their aphidophagous larvae. Dark, elevated aphid-like spots appear to attract the attention of hoverflies to a slipping zone. This region has downward projecting papillate cells and mucilage secretion that promote slipperiness, causing potential pollinators to fall into the labellum. They then follow a specific upward route towards inner aphid-like spots by holding onto upward oriented hairs that aid their grip. As hoverflies are funnelled by the lateral constriction of the labellum, they pass the stigma, depositing pollen they may be carrying. Later, they squeeze under one of the articulated anthers which places pollen smears onto their upper thorax. Then, they depart through one of the narrow lateral holes by holding onto hairs projecting from the petals. CONCLUSIONS This study confirms the system of aphid mimicry in Phragmipedium and highlights the sophisticated micro-morphological traits used by trap flowers in pollinator attraction, trapping, guidance and release, thus promoting precise pollen transfer.
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Affiliation(s)
| | - Steven D Johnson
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa
| | - Uiara C Rezende
- Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil
| | - Paulo E Oliveira
- Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil
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Perkins J, Hayashi T, Peakall R, Flematti GR, Bohman B. The volatile chemistry of orchid pollination. Nat Prod Rep 2023; 40:819-839. [PMID: 36691832 DOI: 10.1039/d2np00060a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Covering: up to September 2022Orchids are renowned not only for their diversity of floral forms, but also for their many and often highly specialised pollination strategies. Volatile semiochemicals play a crucial role in the attraction of a wide variety of insect pollinators of orchids. The compounds produced by orchid flowers are as diverse as the pollinators they attract, and here we summarise some of the chemical diversity found across orchid taxa and pollination strategies. We focus on compounds that have been experimentally demonstrated to underpin pollinator attraction. We also highlight the structural elucidation and synthesis of a select subset of important orchid pollinator attractants, and discuss the ecological significance of the discoveries, the gaps in our current knowledge of orchid pollination chemistry, and some opportunities for future research in this field.
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Affiliation(s)
- James Perkins
- Research School of Biology, The Australian National University, Australia
| | - Tobias Hayashi
- Research School of Biology, The Australian National University, Australia
| | - Rod Peakall
- Research School of Biology, The Australian National University, Australia.,School of Molecular Sciences, The University of Western Australia, Australia
| | - Gavin R Flematti
- School of Molecular Sciences, The University of Western Australia, Australia
| | - Björn Bohman
- Research School of Biology, The Australian National University, Australia.,School of Molecular Sciences, The University of Western Australia, Australia.,Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Sweden.
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Suetsugu K, Fukushima K, Makino T, Ikematsu S, Sakamoto T, Kimura S. Transcriptomic heterochrony and completely cleistogamous flower development in the mycoheterotrophic orchid Gastrodia. THE NEW PHYTOLOGIST 2023; 237:323-338. [PMID: 36110047 DOI: 10.1111/nph.18495] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 09/09/2022] [Indexed: 06/15/2023]
Abstract
Cleistogamy, in which plants can reproduce via self-fertilization within permanently closed flowers, has evolved in > 30 angiosperm lineages; however, consistent with Darwin's doubts about its existence, complete cleistogamy - the production of only cleistogamous flowers - has rarely been recognized. Thus far, the achlorophyllous orchid genus, Gastrodia, is the only known genus with several plausible completely cleistogamous species. Here, we analyzed the floral developmental transcriptomes of two recently evolved, completely cleistogamous Gastrodia species and their chasmogamous sister species to elucidate the possible changes involved in producing common cleistogamous traits. The ABBA-BABA test did not support introgression and protein sequence convergence as evolutionary mechanisms leading to cleistogamy, leaving convergence in gene expression as a plausible mechanism. Regarding transcriptomic differentiation, the two cleistogamous species had common modifications in the expression of developmental regulators, exhibiting a gene family-wide signature of convergent expression changes in MADS-box genes. Our transcriptomic pseudotime analysis revealed a prolonged juvenile state and eventual maturation, a heterochronic pattern consistent with partial neoteny, in cleistogamous flower development. These findings indicate that transcriptomic partial neoteny, arising from changes in the expression of conserved developmental regulators, might have contributed to the rapid and repeated evolution of cleistogamous flowers in Gastrodia.
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Affiliation(s)
- Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501, Japan
| | - Kenji Fukushima
- Institute for Molecular Plant Physiology and Biophysics, University of Würzburg, Julius-von-Sachs Platz 2, 97082, Würzburg, Germany
| | - Takashi Makino
- Graduate School of Life Sciences, Tohoku University, 6-3, Aramaki Aza Aoba, Aoba-ku, Sendai, 980-8578, Japan
| | - Shuka Ikematsu
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
- Center for Plant Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
| | - Tomoaki Sakamoto
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
- Center for Plant Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
| | - Seisuke Kimura
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
- Center for Plant Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
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Newman EL, Khoury KL, van Niekerk SE, Peter CI. Structural anther mimics improve reproductive success through dishonest signaling that enhances both attraction and the morphological fit of pollinators with flowers. Evolution 2022; 76:1749-1761. [PMID: 35706136 PMCID: PMC9546043 DOI: 10.1111/evo.14540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 03/05/2022] [Accepted: 03/28/2022] [Indexed: 01/22/2023]
Abstract
Numerous studies have identified traits associated with anther mimicry; however, the processes underlying floral deception remain poorly documented for these structures. We studied the importance of pollinator attraction and mechanical fit of anther mimics in Tritonia laxifolia (Iridaceae) and their relative contributions to reproductive success. To determine anther mimics role in attraction, we offered bees' binary choices to flowers painted with UV-absorbent and UV-reflecting paints. We also conducted preference experiments between flowers with excised anther mimics and unmanipulated controls, from which mechanical fit was assessed by allowing single visits. Anther mimics' effects on female reproductive success were determined using similar treatments, but on rooted plants. Bees preferred UV-absorbent over UV-reflecting anther mimics. Bees did not discriminate between flowers with and without three-dimensional anther mimics. Single visits resulted in more pollen deposition on unmanipulated controls over flowers with their anther mimics excised, which was directly linked to pollen-collecting behavior. Controls with unmanipulated anther mimics had higher seed set than those with their anther mimics excised. This study provides insights into pollinator-mediated selection on deceptive floral signals and shows that three-dimensional anther mimics increases reproductive success through both attraction and pollen-collecting behaviors.
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Affiliation(s)
- Ethan L. Newman
- Department of BotanyRhodes UniversityGrahamstown6140South Africa
| | | | | | - Craig I. Peter
- Department of BotanyRhodes UniversityGrahamstown6140South Africa
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Suetsugu K, Okada H, Hirota SK, Suyama Y. Evolutionary history of mycorrhizal associations between Japanese Oxygyne (Thismiaceae) species and Glomeraceae fungi. THE NEW PHYTOLOGIST 2022; 235:836-841. [PMID: 35445414 DOI: 10.1111/nph.18163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 04/07/2022] [Indexed: 06/14/2023]
Affiliation(s)
- Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, Kobe, 657-8501, Hyogo, Japan
| | - Hidehito Okada
- Department of Biology, Graduate School of Science, Kobe University, Kobe, 657-8501, Hyogo, Japan
| | - Shun K Hirota
- Field Science Center, Graduate School of Agricultural Science, Tohoku University, 232-3 Yomogida, Naruko-onsen, Osaki, Miyagi, 989-6711, Japan
| | - Yoshihisa Suyama
- Field Science Center, Graduate School of Agricultural Science, Tohoku University, 232-3 Yomogida, Naruko-onsen, Osaki, Miyagi, 989-6711, Japan
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11
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The Floral Signals of the Inconspicuous Orchid Malaxis monophyllos: How to Lure Small Pollinators in an Abundant Environment. BIOLOGY 2022; 11:biology11050640. [PMID: 35625368 PMCID: PMC9137910 DOI: 10.3390/biology11050640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/01/2022] [Accepted: 04/14/2022] [Indexed: 12/04/2022]
Abstract
Simple Summary Malaxis monophyllos is an ephemeral orchid with very small, greenish flowers, whose pollination system remains vague. Therefore, the authors aimed to identify the flower’s features, including its anatomical micro and ultrastructure as well as scent biochemistry, which are involved in attracting pollinators. In this paper, the authors established the variety of emissions of M. monophyllos volatile compounds, with a high proportion of aldehydes and aliphatic alcohols, listed as chemicals that induce a pronounced reaction in Diptera. Second, the entire M. monophyllos labellum exhibits metabolic and secretory activity, which can be related to both emission of volatiles and visual attractants but also to the nutritional reward for pollinators. All these flower features indicated that its pollination system is dedicated to dipterans, with few signaling modalities corresponding to deceptive species (brood site and food decoy) but also referring to rewarding ones (nutritional secretion, fungus/microbe reward). This research reveals a few new issues in M. monophyllos pollination biology that provides new scientific areas for in-depth insights in the future. Abstract Many orchid species have evolved complex floral signals to ensure pollination efficiency. Here, the authors combined analyses of anatomical flower structure with analyses of the volatile composition and flower-visiting insects’ behaviour, as well as characterised features that can attract pollinators of the inconspicuous orchid Malaxis monophyllos. During field observations, the authors found that only small Diptera (e.g., mosquitos, drosophilids, fungus gnats) visit and are interested in the flowers of M. monophyllos, which was reflected in the characterised flower features that combine well with the pollination system, which engages dipterans. Analyses of the M. monophyllos floral scent revealed substantial concentrations of aliphatic compounds, e.g., 1-octen-3-ol and 1-octanol, which condition the mushroom-like scent and a substantial fraction of alkanes, some of which have been previously described as sex mimicry and aggregation pheromones in orchids’ deceptive systems. The labellum anatomical structure exhibits a highly diverse cell cuticle surface and pronounced metabolic and secretory activity of the epidermal and subepidermal cells from all parts of the labellum. Moreover, our study provides evidence for the subsequent decoys of M. monophyllos flowers, including visual signals, such as raphides located on the labellum margin and the rewarding ones connected with lipid secretion limited to the area behind the column. Taking an integrative approach to studying M. monophyllos pollination biology, the authors provide new insight into its previously vague pollination strategies and provide evidence for complex floral signal operation in luring potential pollinators. The synergistic effect of M. monophyllos flowers’ volatile and visual signals, together with additional rewarding for nectar/fungus/microbe-feeding pollinators, requires further detailed investigation that will be invaluable in explaining the evolution of Diptera-specific pollination systems in orchids.
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Thöming G. Behavior Matters-Future Need for Insect Studies on Odor-Mediated Host Plant Recognition with the Aim of Making Use of Allelochemicals for Plant Protection. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:10469-10479. [PMID: 34482687 DOI: 10.1021/acs.jafc.1c03593] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Allelochemicals, chemical cues that, among other things, mediate insect-plant interactions, such as host plant recognition, have attracted notable interest as tools for ecological control of pest insects. Advances have recently been made in methods for sampling and analyzing volatile compounds and technology for tracking insects in their natural habitat. However, progress in odor-mediated behavioral bioassays of insects has been relatively slow. This perspective highlights this odor-mediated insect behavior, particularly in a natural setting and considering the whole behavioral sequence involved in the host location, which is the key to understanding the mechanisms underlying host plant recognition. There is thus a need to focus on elaborate behavioral bioassays in future studies, particularly if the goal is to use allelochemicals in pest control. Future directions for research are discussed.
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Affiliation(s)
- Gunda Thöming
- Division of Biotechnology and Plant Health, Norwegian Institute of Bioeconomy Research, Høgskoleveien 7, NO-1433 Ås, Norway
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Fly Pollination of Kettle Trap Flowers of Riocreuxiatorulosa (Ceropegieae-Anisotominae): A Generalized System of Floral Deception. PLANTS 2021; 10:plants10081564. [PMID: 34451609 PMCID: PMC8398993 DOI: 10.3390/plants10081564] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 07/12/2021] [Accepted: 07/12/2021] [Indexed: 11/16/2022]
Abstract
Elaborated kettle trap flowers to temporarily detain pollinators evolved independently in several angiosperm lineages. Intensive research on species of Aristolochia and Ceropegia recently illuminated how these specialized trap flowers attract particular pollinators through chemical deception. Morphologically similar trap flowers evolved in Riocreuxia; however, no data about floral rewards, pollinators, and chemical ecology were available for this plant group. Here we provide data on pollination ecology and floral chemistry of R. torulosa. Specifically, we determined flower visitors and pollinators, assessed pollen transfer efficiency, and analysed floral scent chemistry. R. torulosa flowers are myiophilous and predominantly pollinated by Nematocera. Pollinating Diptera included, in order of decreasing abundance, male and female Sciaridae, Ceratopogonidae, Scatopsidae, Chloropidae, and Phoridae. Approximately 16% of pollen removed from flowers was successfully exported to conspecific stigmas. The flowers emitted mainly ubiquitous terpenoids, most abundantly linalool, furanoid (Z)-linalool oxide, and (E)-β-ocimene—compounds typical of rewarding flowers and fruits. R. torulosa can be considered to use generalized food (and possibly also brood-site) deception to lure small nematocerous Diptera into their flowers. These results suggest that R. torulosa has a less specific pollination system than previously reported for other kettle trap flowers but is nevertheless specialized at the level of Diptera suborder Nematocera.
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Capó M, Borràs J, Perelló-Suau S, Rita J, Cursach J. Ecological factors affecting the fitness of the threatened orchid Anacamptis robusta (Orchidaceae): Habitat disturbance, interactions with a co-flowering rewarding orchid and hybridization events. PLANT BIOLOGY (STUTTGART, GERMANY) 2021; 23:121-129. [PMID: 32896978 DOI: 10.1111/plb.13179] [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: 07/16/2020] [Accepted: 08/24/2020] [Indexed: 06/11/2023]
Abstract
The food-deceptive species Anacamptis robusta is threatened in the Balearic Islands, and its habitat has recently been transformed through human disturbance. This study investigated how human disturbance affects the reproductive output of A. robusta and how its fitness is affected by competition with rewarding relatives, fungal infections and hybridization processes. To evaluate the impact of habitat loss on plant fitness, data on reproductive measures were obtained in two well-conserved subpopulations and the unique disturbed subpopulation. Photo-trapping cameras were installed to determine the floral visitation rate. All flowering individuals in 2019 were georeferenced using differential GPS to examine the influence of geospatial patterns on the reproductive success of A. robusta. In addition, hand-pollination treatments were performed to evaluate the hybridization between A. coriophora and A. robusta and the origin of A. × albuferensis. The human-disturbed subpopulation of A. robusta had a lower fruit set success than the subpopulations in well-conserved areas. The presence of A. coriophora is negatively affecting the reproductive output of A. robusta. Moreover, A. robusta can only act as the pollen donor during hybridization. The complexity of the ecological system, which is enhanced by the strong pollinator dependence of the threatened species, must be considered when making conservation decisions. Although human disturbance directly affects plant population stability, other ecological issues must be considered, such as pollinator interaction, interspecific competition for pollinators, fungal infection and hybridization events.
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Affiliation(s)
- M Capó
- Laboratory of Botany, Research Group on Plant Biology under Mediterranean Conditions, Department of Biology, University of Balearic Islands, Palma, Spain
| | - J Borràs
- Laboratory of Botany, Research Group on Plant Biology under Mediterranean Conditions, Department of Biology, University of Balearic Islands, Palma, Spain
| | - S Perelló-Suau
- Laboratory of Botany, Research Group on Plant Biology under Mediterranean Conditions, Department of Biology, University of Balearic Islands, Palma, Spain
| | - J Rita
- Laboratory of Botany, Research Group on Plant Biology under Mediterranean Conditions, Department of Biology, University of Balearic Islands, Palma, Spain
| | - J Cursach
- Laboratory of Botany, Research Group on Plant Biology under Mediterranean Conditions, Department of Biology, University of Balearic Islands, Palma, Spain
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Phillips RD, Reiter N, Peakall R. Orchid conservation: from theory to practice. ANNALS OF BOTANY 2020; 126:345-362. [PMID: 32407498 PMCID: PMC7424752 DOI: 10.1093/aob/mcaa093] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 05/07/2020] [Indexed: 05/21/2023]
Abstract
BACKGROUND Given the exceptional diversity of orchids (26 000+ species), improving strategies for the conservation of orchids will benefit a vast number of taxa. Furthermore, with rapidly increasing numbers of endangered orchids and low success rates in orchid conservation translocation programmes worldwide, it is evident that our progress in understanding the biology of orchids is not yet translating into widespread effective conservation. SCOPE We highlight unusual aspects of the reproductive biology of orchids that can have important consequences for conservation programmes, such as specialization of pollination systems, low fruit set but high seed production, and the potential for long-distance seed dispersal. Further, we discuss the importance of their reliance on mycorrhizal fungi for germination, including quantifying the incidence of specialized versus generalized mycorrhizal associations in orchids. In light of leading conservation theory and the biology of orchids, we provide recommendations for improving population management and translocation programmes. CONCLUSIONS Major gains in orchid conservation can be achieved by incorporating knowledge of ecological interactions, for both generalist and specialist species. For example, habitat management can be tailored to maintain pollinator populations and conservation translocation sites selected based on confirmed availability of pollinators. Similarly, use of efficacious mycorrhizal fungi in propagation will increase the value of ex situ collections and likely increase the success of conservation translocations. Given the low genetic differentiation between populations of many orchids, experimental genetic mixing is an option to increase fitness of small populations, although caution is needed where cytotypes or floral ecotypes are present. Combining demographic data and field experiments will provide knowledge to enhance management and translocation success. Finally, high per-fruit fecundity means that orchids offer powerful but overlooked opportunities to propagate plants for experiments aimed at improving conservation outcomes. Given the predictions of ongoing environmental change, experimental approaches also offer effective ways to build more resilient populations.
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Affiliation(s)
- Ryan D Phillips
- Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, Victoria, Australia
- Kings Park Science, Department of Biodiversity Conservation and Attractions, Kings Park, WA, Australia
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Noushka Reiter
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
- Royal Botanic Gardens Victoria, Corner of Ballarto Road and Botanic Drive, Cranbourne, VIC, Australia
| | - Rod Peakall
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
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Jiang H, Kong JJ, Chen HC, Xiang ZY, Zhang WP, Han ZD, Liao PC, Lee YI. Cypripedium subtropicum (Orchidaceae) employs aphid colony mimicry to attract hoverfly (Syrphidae) pollinators. THE NEW PHYTOLOGIST 2020; 227:1213-1221. [PMID: 32337728 DOI: 10.1111/nph.16623] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 04/09/2020] [Indexed: 06/11/2023]
Abstract
In Orchidaceae, pollination is mostly animal-mediated, and one-third of species have evolved a deceptive pollination mechanism without rewards. Cypripedium is a representative lineage of nonrewarding orchids restricted to temperate regions. Cypripedium subtropicum flowers are pollinated by hoverflies and have hairy tufts that visually resemble an aphid colony covered with honey dew. We recorded the behavior of hoverflies on the flowers, determined the breeding system of the species and the structure of hairy tufts, and investigated the roles of hairy tufts and floral volatiles in this specialized pollination by using pollination experiments, scanning electron microscopy, bioassays and chemical analyses. The white hairy tufts covering the sidelobes of the labellum provide edible rewards and serve as crucial visual lures for hoverflies. The flowers emit primarily (E)-β-farnesene and a smaller amount of β-pinene that were found to attract hoverflies. Our results suggest that C. subtropicum uses both visual mimicry of an aphid-colonized labellum with a reward and chemical mimicry of aphid alarm pheromones to attract hoverflies for pollination. This is the first described example of a rewarding mimicry system in plants, where the models are animals with their secretions and the reward is similar in nutrients to that of the model mimicked.
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Affiliation(s)
- Hong Jiang
- Yunnan Laboratory for Conservation of Rare, Endangered & Endemic Forest Plants, National Forestry and Grassland Administration, Yunnan Academy of Forestry and Grassland, Kunming, 650201, Yunnan, China
| | - Ji-Jun Kong
- Yunnan Laboratory for Conservation of Rare, Endangered & Endemic Forest Plants, National Forestry and Grassland Administration, Yunnan Academy of Forestry and Grassland, Kunming, 650201, Yunnan, China
| | - Hsin-Chun Chen
- Department of Cosmeceutics, China Medical University, Taichung, 40453, Taiwan
| | - Zhen-Yong Xiang
- Yunnan Laboratory for Conservation of Rare, Endangered & Endemic Forest Plants, National Forestry and Grassland Administration, Yunnan Academy of Forestry and Grassland, Kunming, 650201, Yunnan, China
| | - Wei-Ping Zhang
- Yunnan Laboratory for Conservation of Rare, Endangered & Endemic Forest Plants, National Forestry and Grassland Administration, Yunnan Academy of Forestry and Grassland, Kunming, 650201, Yunnan, China
| | - Zhou-Dong Han
- Yunnan Laboratory for Conservation of Rare, Endangered & Endemic Forest Plants, National Forestry and Grassland Administration, Yunnan Academy of Forestry and Grassland, Kunming, 650201, Yunnan, China
| | - Pei-Chun Liao
- Department of Life Science, National Taiwan Normal University, 116, Taipei, Taiwan
| | - Yung-I Lee
- Department of Biology, National Museum of Natural Science, 40453, Taichung, Taiwan
- Department of Life Sciences, National Chung Hsing University, 40227, Taichung, Taiwan
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Phillips RD, Bohman B, Brown GR, Tomlinson S, Peakall R. A specialised pollination system using nectar-seeking thynnine wasps in Caladenia nobilis (Orchidaceae). PLANT BIOLOGY (STUTTGART, GERMANY) 2020; 22:157-166. [PMID: 31705712 DOI: 10.1111/plb.13069] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 10/01/2019] [Indexed: 05/26/2023]
Abstract
Caladenia is a diverse Australian genus that is exceptional among orchids in having both species pollinated by food-seeking and sexually deceived insects. Here, we investigated the pollination of Caladenia nobilis, a species predicted to be food-deceptive due to its large, cream-coloured and apparently nectarless flowers. Pollinator observations were made using experimental clumps of flowers. Measurements of floral colour were undertaken with a spectrometer, nectar was tested using GC-MS, and reproductive success was quantified for 2 years. While C. nobilis attracted nine species of insect, only males of the thynnine wasp Rhagigaster discrepans exhibited the correct size and behaviour to remove and deposit pollen. Male R. discrepans attempted to feed from the surface of the labellum, often crawling to multiple flowers, but showed no evidence of sexual attraction. Most flowers produced little or no nectar, although some may provide enough sucrose to act as a meagre reward to pollinators. Floral colouration was similar to a related Caladenia species pollinated by sexual deception, although the sexually deceptive species had a dull-red labellum. Reproductive success was generally low and highly variable between sites and years. In addition to most visitors being of inappropriate size for pollinia removal, the lack of response to the orchid by several co-occurring species of thynnine wasp suggests filtering of potential pollinators at the attraction phase. Our discovery of a pollination strategy that may be intermediate between food deception and food reward raises the question, how many putatively rewardless orchids actually produce meagre amounts of nectar?
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Affiliation(s)
- R D Phillips
- Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, VIC, Australia
- Kings Park Science, Department of Biodiversity Conservation and Attractions, Kings Park, Perth, WA, Australia
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - B Bohman
- School of Molecular Sciences, The University of Western Australia, Crawley, WA, Australia
| | - G R Brown
- Museum and Art Gallery of the Northern Territory, Darwin, NT, Australia
- CSIRO Land and Water, Winnellie, NT, Australia
- Research Institute for Environment and Livelihoods, Charles Darwin University, Darwin, NT, Australia
| | - S Tomlinson
- Kings Park Science, Department of Biodiversity Conservation and Attractions, Kings Park, Perth, WA, Australia
- School of Molecular & Life Sciences, Curtin University Bentley, Perth, Western Australia, Australia
| | - R Peakall
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
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Bohman B, Tan MMY, Phillips RD, Scaffidi A, Sobolev AN, Moggach SA, Flematti GR, Peakall R. A Specific Blend of Drakolide and Hydroxymethylpyrazines: An Unusual Pollinator Sexual Attractant Used by the Endangered Orchid
Drakaea micrantha. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201911636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Björn Bohman
- School of Molecular Sciences The University of Western Australia Crawley WA 6009 Australia
- Research School of Biology Australian National University Canberra ACT 2600 Australia
| | - Monica M. Y. Tan
- School of Molecular Sciences The University of Western Australia Crawley WA 6009 Australia
| | - Ryan D. Phillips
- Research School of Biology Australian National University Canberra ACT 2600 Australia
- Department of Biodiversity Conservation and Attractions Kings Park Science, 1 Kattidj Close West Perth WA 6005 Australia
- Department of Ecology Environment and Evolution La Trobe University Melbourne Melbourne Victoria 3086 Australia
| | - Adrian Scaffidi
- School of Molecular Sciences The University of Western Australia Crawley WA 6009 Australia
| | - Alexandre N. Sobolev
- School of Molecular Sciences The University of Western Australia Crawley WA 6009 Australia
| | - Stephen A. Moggach
- School of Molecular Sciences The University of Western Australia Crawley WA 6009 Australia
| | - Gavin R. Flematti
- School of Molecular Sciences The University of Western Australia Crawley WA 6009 Australia
| | - Rod Peakall
- School of Molecular Sciences The University of Western Australia Crawley WA 6009 Australia
- Research School of Biology Australian National University Canberra ACT 2600 Australia
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Bohman B, Tan MMY, Phillips RD, Scaffidi A, Sobolev AN, Moggach SA, Flematti GR, Peakall R. A Specific Blend of Drakolide and Hydroxymethylpyrazines: An Unusual Pollinator Sexual Attractant Used by the Endangered Orchid
Drakaea micrantha. Angew Chem Int Ed Engl 2019; 59:1124-1128. [DOI: 10.1002/anie.201911636] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/31/2019] [Indexed: 01/22/2023]
Affiliation(s)
- Björn Bohman
- School of Molecular Sciences The University of Western Australia Crawley WA 6009 Australia
- Research School of Biology Australian National University Canberra ACT 2600 Australia
| | - Monica M. Y. Tan
- School of Molecular Sciences The University of Western Australia Crawley WA 6009 Australia
| | - Ryan D. Phillips
- Research School of Biology Australian National University Canberra ACT 2600 Australia
- Department of Biodiversity Conservation and Attractions Kings Park Science, 1 Kattidj Close West Perth WA 6005 Australia
- Department of Ecology Environment and Evolution La Trobe University Melbourne Melbourne Victoria 3086 Australia
| | - Adrian Scaffidi
- School of Molecular Sciences The University of Western Australia Crawley WA 6009 Australia
| | - Alexandre N. Sobolev
- School of Molecular Sciences The University of Western Australia Crawley WA 6009 Australia
| | - Stephen A. Moggach
- School of Molecular Sciences The University of Western Australia Crawley WA 6009 Australia
| | - Gavin R. Flematti
- School of Molecular Sciences The University of Western Australia Crawley WA 6009 Australia
| | - Rod Peakall
- School of Molecular Sciences The University of Western Australia Crawley WA 6009 Australia
- Research School of Biology Australian National University Canberra ACT 2600 Australia
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Hawkmoth pollination of the orchid Habenaria clavata: mechanical wing guides, floral scent and electroantennography. Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Floral morphology can play a key role in mechanically guiding pollinators towards reproductive structures, particularly when visibility is limited at night, but the functional significance of morphological traits has seldom been considered in this context. Here we describe a remarkably intricate pollination mechanism in the hawkmoth-pollinated African grassland orchid Habenaria clavata, and also document aspects of the reproductive success and chemical ecology of this pollination system. The flowers are pollinated by several short-tongued hawkmoths, particularly Basiothia schenki, which was the most frequent visitor and occurred at all sites. Moths are probably attracted by the strong scent, which was dominated by several oxygenated aromatics that also elicited strong electrophysiological responses from antennae of B. schenki. Apart from the white rostellum lobes and stigma, which serve as a visual guide to the spur entrance, the flower parts are entirely green and indistinguishable from leaves in terms of spectral information. Using motion-activated video cameras we established that the leading edges of the forewings of foraging hawkmoths contact the two upwardly curving petal lobes, and that hawkmoths are then apparently mechanically guided down onto the reproductive structures. Pollinaria are attached in an unusual place – among hairs on the ventral surface of the thorax, between the middle legs – and are brushed over the protruding stigma lobes when the proboscis is fully inserted in the 41-mm-long spur. These results highlight how multiple traits (morphology, spectral reflectance and scent) can act synergistically to ensure transfer of pollen among flowers.
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Kishikawa K, Suetsugu K, Kyogoku D, Ogaki K, Iga D, Shutoh K, Isagi Y, Kaneko S. Development of microsatellite markers for the completely cleistogamous species Gastrodia takeshimensis (Orchidaceae) that are transferable to its chasmogamous sister G. nipponica. Genes Genet Syst 2019; 94:95-98. [PMID: 30956254 DOI: 10.1266/ggs.18-00057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We developed microsatellite markers to compare the genetic variation between the putatively cleistogamous Gastrodia takeshimensis (Orchidaceae) and its chasmogamous sister species G. nipponica. We expected low genetic variation in G. takeshimensis in view of its hypothesized cleistogamy. Eighteen primer pairs were developed from a G. takeshimensis genomic DNA library, and their characteristics were tested for G. takeshimensis and G. nipponica. Seven loci were polymorphic in G. nipponica, whereas all loci showed no polymorphism in G. takeshimensis. Genetic diversity was thus not detected in G. takeshimensis, and it seems to have been lost by repeated selfing in the completely closed flower. The 18 markers described here will be useful for investigating the genetic variation between a cleistogamous species and its chasmogamous sister species.
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Affiliation(s)
- Keiju Kishikawa
- Graduate School of Symbiotic Systems Science and Technology, Fukushima University
| | - Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University
| | - Daisuke Kyogoku
- Present affiliation: Graduate School of Life Sciences, Tohoku University.,Graduate School of Agriculture, Kyoto University
| | - Kenji Ogaki
- Graduate School of Symbiotic Systems Science and Technology, Fukushima University
| | - Daisuke Iga
- Faculty of Symbiotic Systems Science, Fukushima University
| | - Kohtaroh Shutoh
- Graduate School of Symbiotic Systems Science and Technology, Fukushima University.,Faculty of Education, Niigata University
| | - Yuji Isagi
- Graduate School of Agriculture, Kyoto University
| | - Shingo Kaneko
- Faculty of Symbiotic Systems Science, Fukushima University
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23
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Suetsugu K. Social wasps, crickets and cockroaches contribute to pollination of the holoparasitic plant Mitrastemon yamamotoi (Mitrastemonaceae) in southern Japan. PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21:176-182. [PMID: 30098096 DOI: 10.1111/plb.12889] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 08/06/2018] [Indexed: 06/08/2023]
Abstract
Mitrastemon yamamotoi is completely embedded within the tissues of its hosts, except during the reproductive stage, when aboveground parts emerge from host tissues. Its highly modified appearance has attracted attention of many botanists, but very little is known about the reproductive system. Floral visitors to M. yamamotoi were observed in southern Japan. Pollination experiments were conducted to determine the plant's self-compatibility and pollen limitation, as well as the contribution of diurnal and nocturnal visitors to fruit set and outcrossing. Mitrastemon yamamotoi is mainly pollinated by social wasps, but previously unnoticed pollinators (i.e. crickets and cockroaches) are also important, based on visitation frequency and pollen loads. Results of the pollination experiments suggest that nocturnal visitors, such as crickets and cockroaches, contribute to geitonogamous pollination, whereas diurnal visitors, such as social wasps, facilitate outcrossing. The unexpected pollinator assemblage of M. yamamotoi might be influenced by multiple factors, including the highly modified flowers that are produced close to the ground in dark understorey environments, the species' winter-flowering habit and the location of the study site (i.e. near the northern limit of the species' range). Considering that M. yamamotoi occurs widely in subtropical and tropical forests in Asia, additional studies are needed to assess pollinator assemblages of M. yamamotoi at other locations.
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Affiliation(s)
- K Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
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Scaccabarozzi D, Cozzolino S, Guzzetti L, Galimberti A, Milne L, Dixon KW, Phillips RD. Masquerading as pea plants: behavioural and morphological evidence for mimicry of multiple models in an Australian orchid. ANNALS OF BOTANY 2018; 122:1061-1073. [PMID: 30184161 PMCID: PMC6266105 DOI: 10.1093/aob/mcy166] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/12/2018] [Indexed: 05/03/2023]
Abstract
Background and Aims While there is increasing recognition of Batesian floral mimicry in plants, there are few confirmed cases where mimicry involves more than one model species. Here, we test for pollination by mimicry in Diuris (Orchidaceae), a genus hypothesized to attract pollinators via mimicry of a range of co-occurring pea plants (Faboideae). Methods Observations of pollinator behaviour were made for Diuris brumalis using arrays of orchid flowers. An analysis of floral traits in the co-flowering community and spectral reflectance measurements were undertaken to test if Di. brumalis and the pea plants showed strong similarity and were likely to be perceived as the same by bees. Pollen removal and fruit-set were recorded at 18 sites over two years to test if fitness of Di. brumalis increased with the abundance of the model species. Key Results Diuris brumalis shares the pollinator species Trichococolletes capillosus and T. leucogenys (Hymenoptera: Colletidae) with co-flowering Faboideae from the genus Daviesia. On Di. brumalis, Trichocolletes exhibited the same stereotyped food-foraging and mate-patrolling behaviour that they exhibit on Daviesia. Diuris and pea plants showed strong morphological similarity compared to the co-flowering plant community, while the spectral reflectance of Diuris was similar to that of Daviesia spp. Fruit-set and pollen removal of Di. brumalis was highest at sites with a greater number of Daviesia flowers. Conclusions Diuris brumalis is pollinated by mimicry of co-occurring congeneric Faboideae species. Evidence for mimicry of multiple models, all of which share pollinator species, suggests that this may represent a guild mimicry system. Interestingly, Di. brumalis belongs to a complex of species with similar floral traits, suggesting that this represents a useful system for investigating speciation in lineages that employ mimicry of food plants.
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Affiliation(s)
- Daniela Scaccabarozzi
- Department of Environment and Agriculture, Curtin University, Bentley, WA, Australia
- Department of Biology, University of Naples Federico II, Complesso Universitario MSA, Naples, Italy
- Kings Park and Botanic Garden, The Botanic Garden and Parks Authority, West Perth, WA, Australia
| | - Salvatore Cozzolino
- Department of Biology, University of Naples Federico II, Complesso Universitario MSA, Naples, Italy
| | - Lorenzo Guzzetti
- Università degli Studi di Milano-Bicocca, ZooPlantLab, Dipartimento di Biotecnologie e Bioscienze, Piazza della Scienza, Milano, Italy
| | - Andrea Galimberti
- Università degli Studi di Milano-Bicocca, ZooPlantLab, Dipartimento di Biotecnologie e Bioscienze, Piazza della Scienza, Milano, Italy
| | - Lynne Milne
- School of Earth and Planetary Sciences, Curtin University, Bentley, WA, Australia
| | - Kingsley W Dixon
- Department of Environment and Agriculture, Curtin University, Bentley, WA, Australia
| | - Ryan D Phillips
- Kings Park and Botanic Garden, The Botanic Garden and Parks Authority, West Perth, WA, Australia
- Evolution, Ecology and Genetics, Research School of Biology, The Australian National University, Canberra, ACT, Australia
- Department of Ecology, Environment and Evolution, La Trobe University, Vic., Australia
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Suetsugu K, Sueyoshi M. Specialized pollination by fungus gnats in the introduced population of Aspidistra elatior. JOURNAL OF PLANT RESEARCH 2018; 131:497-503. [PMID: 29318535 DOI: 10.1007/s10265-017-1007-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 12/18/2017] [Indexed: 06/07/2023]
Abstract
The monocot genus Aspidistra comprises rhizomatous perennials that are distributed in tropical to warm temperate regions of Asia. Little is known about the pollinators of almost all the species, probably due to the inconspicuous nature of Aspidistra flowers. Nevertheless, the unusual floral morphology suggests biotic pollination, since pollen grains are hidden under each flower's stigma. Aspidistra elatior has been suspected to have a very peculiar pollination ecology. So far, pollination by mollusks, crustaceans, or collembolans has been suspected. However, a recent study showed that A. elatior is mainly pollinated by species of fungus gnats in Kuroshima Island, southern Japan, which is its natural habitat. Here, we investigated the pollination ecology of A. elatior in Shiga Prefecture, central Japan, which is the introduced population, to reveal whether fungus gnats are also the main pollinator in the introduced population. Our study confirmed fungus gnats pollination in the investigated pollination. Furthermore, the main pollinators (i.e., Cordyla sixi and Bradysia sp.) are the same in both Kuroshima and Shiga Prefecture. Therefore, A. elatior mainly depends on a narrow taxonomic group of fungus gnats for pollination. In contrast, we failed to document any terrestrial amphipods visiting the A. elatior flowers, in spite of a relatively high fruit set in natural conditions. This fact will refute the amphipod pollination hypothesis proposed by previous studies. We consider that A. elatior is pollinated by fungus gnats through fungal mimicry, due to its superficial similarity to mushroom fruiting bodies and strong, musky floral scent.
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Affiliation(s)
- Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501, Japan.
| | - Masahiro Sueyoshi
- Forest Zoology Group, Kyushu Research Center, Forestry and Forest Products Research Institute, 4-11-16 Kurokami, Kumamoto, 860-0862, Japan
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26
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Suetsugu K. Achlorophyllous orchid can utilize fungi not only for nutritional demands but also pollinator attraction. Ecology 2018; 99:1498-1500. [PMID: 29574702 DOI: 10.1002/ecy.2170] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 01/18/2018] [Accepted: 01/22/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501, Japan
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27
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Goodrich KR, Jürgens A. Pollination systems involving floral mimicry of fruit: aspects of their ecology and evolution. THE NEW PHYTOLOGIST 2018; 217:74-81. [PMID: 28980704 DOI: 10.1111/nph.14821] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 08/29/2017] [Indexed: 06/07/2023]
Abstract
Floral mimicry of nonfloral resources is found across many angiosperm families, with mimicry of varied models including carrion, dung, fungi, insects and fruit. These systems provide excellent models to investigate the role of visual and olfactory cues for the ecology and evolution of plant-animal interactions. Interestingly, floral mimicry of fruit is least documented in the literature, although ripe or rotting fruits play an important role as a food or brood site in many insect groups such as Diptera, Hymenoptera and Coleoptera, and frugivorous vertebrates such as bats and birds. In ecosystems where fruit represents a frequent, reliable resource (e.g. tropical forests), this form of floral mimicry could represent a common mimicry class with specialization possible along multiple axes such as fruit of different species, stages of ripeness and microbial colonization. In this review, we summarize current research on floral mimicry of fruit. We place this review in the context of floral mimicry of a broader spectrum of nonfloral resources, and we discuss conceptual frameworks of mimicry vs generalized food deception or pre-existing sensory bias. Finally, we briefly review the specificity and complexity of fruit-insect ecological interactions, and we summarize important considerations and questions for moving forward in this field.
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Affiliation(s)
| | - Andreas Jürgens
- Technische Universität Darmstadt, Schnittspahnstrasse 10, Darmstadt, 64287, Germany
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28
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Suetsugu K. Independent recruitment of a novel seed dispersal system by camel crickets in achlorophyllous plants. THE NEW PHYTOLOGIST 2018; 217:828-835. [PMID: 29120037 DOI: 10.1111/nph.14859] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 09/23/2017] [Indexed: 05/26/2023]
Abstract
The seeds of most heterotrophic plants, commonly referred to as dust seeds, are typically dispersed in the air like dust particles. Therefore, little attention has been paid to how seeds of heterotrophic plants are dispersed, owing to the notion that wind dispersal is the dominant strategy. However, inconspicuous but fleshy, indehiscent fruit can be observed in distantly related plants that have independently evolved full heterotrophy. Here I investigated the seed dispersal system in three unrelated fully heterotrophic plants with fleshy, indehiscent fruits (Yoania amagiensis, Monotropastrum humile and Phacellanthus tubiflorus) by direct observation, a differential exclusion experiment of fruit feeders and investigation on seed viability through the digestive tract. The present study revealed that camel crickets are the major seed disperser in three achlorophyllous plants in the study population. This represents the first evidence of seed dispersal by camel crickets in any angiosperm species. These heterotrophic plants grow in the understorey of densely vegetated forests where wind is probably an ineffective seed dispersal agent. Life-history traits of the achlorophyllous plants associated with heterotrophic lifestyles, such as colonization of dark understorey habitats and dust seeds, could facilitate independent recruitment of the novel endozoochorous seed dispersal system by camel crickets.
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Affiliation(s)
- Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501, Japan
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29
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Wong DCJ, Pichersky E, Peakall R. The Biosynthesis of Unusual Floral Volatiles and Blends Involved in Orchid Pollination by Deception: Current Progress and Future Prospects. FRONTIERS IN PLANT SCIENCE 2017; 8:1955. [PMID: 29181016 PMCID: PMC5693887 DOI: 10.3389/fpls.2017.01955] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 10/30/2017] [Indexed: 05/23/2023]
Abstract
Flowers have evolved diverse strategies to attract animal pollinators, with visual and olfactory floral cues often crucial for pollinator attraction. While most plants provide reward (e.g., nectar, pollen) in return for the service of pollination, 1000s of plant species, particularly in the orchid family, offer no apparent reward. Instead, they exploit their often specific pollinators (one or few) by mimicking signals of female insects, food source, and oviposition sites, among others. A full understanding of how these deceptive pollination strategies evolve and persist remains an open question. Nonetheless, there is growing evidence that unique blends that often contain unusual compounds in floral volatile constituents are often employed to secure pollination by deception. Thus, the ability of plants to rapidly evolve new pathways for synthesizing floral volatiles may hold the key to the widespread evolution of deceptive pollination. Yet, until now the biosynthesis of these volatile compounds has been largely neglected. While elucidating the biosynthesis in non-model systems is challenging, nonetheless, these cases may also offer untapped potential for biosynthetic breakthroughs given that some of the compounds can be exclusive or dominant components of the floral scent and production is often tissue-specific. In this perspective article, we first highlight the chemical diversity underpinning some of the more widespread deceptive orchid pollination strategies. Next, we explore the potential metabolic pathways and biosynthetic steps that might be involved. Finally, we offer recommendations to accelerate the discovery of the biochemical pathways in these challenging but intriguing systems.
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Affiliation(s)
- Darren C. J. Wong
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Eran Pichersky
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Rod Peakall
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
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30
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Phillips RD, Brown GR, Dixon KW, Hayes C, Linde CC, Peakall R. Evolutionary relationships among pollinators and repeated pollinator sharing in sexually deceptive orchids. J Evol Biol 2017; 30:1674-1691. [DOI: 10.1111/jeb.13125] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 05/26/2017] [Indexed: 01/31/2023]
Affiliation(s)
- R. D. Phillips
- Ecology and Evolution; Research School of Biology; The Australian National University; Canberra ACT Australia
- Kings Park and Botanic Garden; The Botanic Garden and Parks Authority; West Perth WA Australia
- School of Plant Biology; The University of Western Australia; Nedlands WA Australia
| | - G. R. Brown
- Museum and Art Gallery of Northern Territory; Darwin NT Australia
- Research Institute for Environment and Livelihoods; Charles Darwin University; Darwin NT Australia
| | - K. W. Dixon
- Kings Park and Botanic Garden; The Botanic Garden and Parks Authority; West Perth WA Australia
- School of Plant Biology; The University of Western Australia; Nedlands WA Australia
- Department of Agriculture and Environment; Curtin University; Perth WA Australia
| | - C. Hayes
- Ecology and Evolution; Research School of Biology; The Australian National University; Canberra ACT Australia
| | - C. C. Linde
- Ecology and Evolution; Research School of Biology; The Australian National University; Canberra ACT Australia
| | - R. Peakall
- Ecology and Evolution; Research School of Biology; The Australian National University; Canberra ACT Australia
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31
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The Spider Orchid
Caladenia crebra
Produces Sulfurous Pheromone Mimics to Attract its Male Wasp Pollinator. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201702864] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Bohman B, Phillips RD, Flematti GR, Barrow RA, Peakall R. The Spider Orchid Caladenia crebra Produces Sulfurous Pheromone Mimics to Attract its Male Wasp Pollinator. Angew Chem Int Ed Engl 2017; 56:8455-8458. [PMID: 28470835 DOI: 10.1002/anie.201702864] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Indexed: 11/06/2022]
Abstract
One of the most intriguing natural observations is the pollination of orchids by sexual deception. Chemicals underpin this interaction between the orchid and its sexually attracted male insect pollinator, with the signaling compounds involved, called semiochemicals, predicted to mimic the chemical composition of the sex pheromone. We identified floral semiochemicals from Caladenia (spider orchids) for the first time. We further demonstrate that C. crebra attracts its single pollinator species with a unique system of (methylthio)phenols, three of which are new natural products. Furthermore, as predicted, the same compounds constitute the sex pheromone of the pollinator, the thynnine wasp Campylothynnus flavopictus, representing the first occurrence of sulfurous sex pheromones in Hymenoptera.
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Affiliation(s)
- Björn Bohman
- School of Molecular Sciences, The University of Western Australia, Crawley, WA, 6009, Australia.,Research School of Biology, Australian National University, Acton, ACT, 2601, Australia.,Research School of Chemistry, Australian National University, Acton, ACT, 2601, Australia
| | - Ryan D Phillips
- Research School of Biology, Australian National University, Acton, ACT, 2601, Australia.,Kings Park and Botanic Garden, The Botanic Gardens and Park Authority, West Perth, WA, 6005, Australia.,School of Plant Biology, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Gavin R Flematti
- School of Molecular Sciences, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Russell A Barrow
- Research School of Chemistry, Australian National University, Acton, ACT, 2601, Australia
| | - Rod Peakall
- School of Molecular Sciences, The University of Western Australia, Crawley, WA, 6009, Australia.,Research School of Biology, Australian National University, Acton, ACT, 2601, Australia
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33
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Borges RM. On the Air: Broadcasting and Reception of Volatile Messages in Brood-Site Pollination Mutualisms. SIGNALING AND COMMUNICATION IN PLANTS 2016. [DOI: 10.1007/978-3-319-33498-1_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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