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Zhang HP, Tao ZB, Trunschke J, Shrestha M, Scaccabarozzi D, Wang H, Ren ZX. Reproductive Isolation Among Three Nocturnal Moth-Pollinated Sympatric Habenaria Species (Orchidaceae). FRONTIERS IN PLANT SCIENCE 2022; 13:908852. [PMID: 35812980 PMCID: PMC9257206 DOI: 10.3389/fpls.2022.908852] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/16/2022] [Indexed: 06/15/2023]
Abstract
Comparison and quantification of multiple pre- and post-pollination barriers to interspecific hybridization are important to understand the factors promoting reproductive isolation. Such isolating factors have been studied recently in many flowering plant species which seek after the general roles and relative strengths of different pre- and post-pollination barriers. In this study, we quantified six isolating factors (ecogeographic isolation, phenological isolation, pollinator isolation, pollinia-pistil interactions, fruit production, and seed development) that could possibly be acting as reproductive barriers at different stages among three sympatric Habenaria species (H. limprichtii, H. davidii, and H. delavayi). These three species overlap geographically but occupy different microhabitats varying in soil water content. They were isolated through pollinator interactions both ethologically (pollinator preference) and mechanically (pollinia attachment site), but to a variable degree for different species pairs. Interspecific crosses between H. limprichtii and H. davidii result in high fruit set, and embryo development suggested weak post-pollination barriers, whereas bidirectional crosses of H. delavayi with either of the other two species fail to produce fruits. Our results revealed that pollinators were the most important isolating barrier including both ethological and mechanical mechanisms, to maintain the boundaries among these three sympatric Habenaria species. Our study also highlights the importance of a combination of pre-and post-pollination barriers for species co-existence in Orchidaceae.
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Affiliation(s)
- Hai-Ping Zhang
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhi-Bin Tao
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, China
- CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences (CAS), Wuhan, China
| | - Judith Trunschke
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, China
| | - Mani Shrestha
- Department of Disturbance Ecology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Daniela Scaccabarozzi
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
- School of Molecular and Life Sciences, Curtin University, Bentley, WA, Australia
| | - Hong Wang
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
- Lijiang Forest Biodiversity National Observation and Research Station, Lijiang, China
| | - Zong-Xin Ren
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
- Lijiang Forest Biodiversity National Observation and Research Station, Lijiang, China
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Zhang W, Gao J. Multiple factors contribute to reproductive isolation between two co-existing Habenaria species (Orchidaceae). PLoS One 2017; 12:e0188594. [PMID: 29176771 PMCID: PMC5703478 DOI: 10.1371/journal.pone.0188594] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 11/09/2017] [Indexed: 11/21/2022] Open
Abstract
Reproductive isolation is a key feature that forms barriers to gene flow between distinct plants. In orchids, prezygotic reproductive isolation has been considered to be strong, because their associations with highly specific pollinators. In this study, the reproductive ecology and reproductive isolation of two sympatric Habenaria species, H. davidii and H. fordii, was investigated by floral phenology and morphology, hand-pollination experiments and visitor observation in southwest China. The two species were dependent on insects for pollination and completely self-compatible. A number of factors have been identified to limit gene flow between the two species and achieved full reproductive isolation. Ecogeographic isolation was a weak barrier. H. fordii and H. davidii had completely overlapped flowering periods, and floral morphology plays an important role in floral isolation. The two species shared the same hawkmoth pollinator, Cechenena lineosa, but the pollinaria of the two orchids were attached on different body parts of pollinators. Prezygotic isolation was not complete, but the interspecific pollination treatments of each species resulted in no seed sets, indicating that unlike many other orchid species, in which the postzygotic reproductive isolation is very weak or complete absence, the post-zygotic isolation strongly acted in the stage of seed production between two species. The results illustrate the reproductive isolation between two species involves multiple plant life-history stages and a variety of reproductive barriers can contribute to overall isolation.
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Affiliation(s)
- Wenliu Zhang
- Centre for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jiangyun Gao
- Laboratory of Ecology and Evolutionary Biology, State Key Laboratory for Conservation and Utilization of Bio-resources in Yunnan, Yunnan University, Kunming, Yunnan, China
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Nunes CEP, Wolowski M, Pansarin ER, Gerlach G, Aximoff I, Vereecken NJ, Salvador MJ, Sazima M. More than euglossines: the diverse pollinators and floral scents of Zygopetalinae orchids. Naturwissenschaften 2017; 104:92. [PMID: 29028068 DOI: 10.1007/s00114-017-1511-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 09/25/2017] [Accepted: 09/30/2017] [Indexed: 12/27/2022]
Abstract
Floral volatile organic compounds (VOCs) play important roles in plant-pollinator interactions. We investigated the reproductive ecology and floral VOCs of Zygopetalinae orchids to understand the relationship between floral scents and pollinators. We performed focal observations, phenological censuses and breeding system experiments in eight species in southeast Brazil. Floral scents were collected and analysed using SPME/GC-MS. We performed multivariate analyses to group species according to affinities of their VOCs and define compounds associated to each plant. Dichaea cogniauxiana was pollinated by weevils which use their developing ovules, while D. pendula was pollinated by the same weevils and perfume-collecting male euglossine bees. The other species were deceit-pollinated by bees. Zygopetalum crinitum was pollinated by carpenter bees, while W. warreana, Z. mackayi and Z. maxillare were bumblebee-pollinated. The latter was also pollinated by Centris confusa. Breeding system varied widely with no association to any pollinator group. Most VOCs are common to other floral scents. Zygopetalum crinitum presented an exclusive blend of VOCs, mainly composed of benzenoids. The scents of Pabstia jugosa, Promenaea xanthina and the Zygopetalum spp. were similar. The bumblebee-pollinated species have flowering periods partially overlapped, thus neither phenology nor pollinators constitute hybridization barriers among these species. Euglossines are not the only pollinators of Zygopetalinae. Different VOCs, size and lifespan of flowers are associated with distinct pollinators. A distinctive VOC bouquet may determine specialisation in carpenter bees or male euglossines within bee-pollinated flowers. Finally, visitation of deceit-pollinated flowers by perfume-collecting euglossines allows us to hypothesise how pollination by this group of bees had evolved.
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Affiliation(s)
- Carlos E P Nunes
- Programa de Pós-Graduação em Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, C.P. 6109, Campinas, SP, 13083-970, Brazil.
| | - Marina Wolowski
- Instituto de Ciências da Natureza, Universidade Federal de Alfenas, Alfenas, MG, 37130-001, Brazil
| | - Emerson Ricardo Pansarin
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras, Universidade de São Paulo, Ribeirão Preto, SP, 14040-901, Brazil
| | - Günter Gerlach
- Botanical Garden München-Nymphenburg, Menzinger Str., 65, 80638, Munich, Germany
| | - Izar Aximoff
- Jardim Botânico do Rio de Janeiro, Rua Pacheco Leão 915, Rio de Janeiro, RG, 22460-030, Brazil
| | - Nicolas J Vereecken
- Agroecology & Pollination Group, Landscape Ecology & Plant Production Systems Unit, Free University of Brussels, Boulevard du Triomphe C.P. 264/2, B-1050, Brussels, Belgium
| | - Marcos José Salvador
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, C. P. 6109, Campinas, SP, 13083-970, Brazil
| | - Marlies Sazima
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, C. P. 6109, Campinas, SP, 13083-970, Brazil
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Muth F, Papaj DR, Leonard AS. Multiple rewards have asymmetric effects on learning in bumblebees. Anim Behav 2017. [DOI: 10.1016/j.anbehav.2017.01.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Keller B, de Vos JM, Schmidt‐Lebuhn AN, Thomson JD, Conti E. Both morph- and species-dependent asymmetries affect reproductive barriers between heterostylous species. Ecol Evol 2016; 6:6223-44. [PMID: 27648239 PMCID: PMC5016645 DOI: 10.1002/ece3.2293] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 06/03/2016] [Accepted: 06/07/2016] [Indexed: 12/13/2022] Open
Abstract
The interaction between floral traits and reproductive isolation is crucial to explaining the extraordinary diversity of angiosperms. Heterostyly, a complex floral polymorphism that optimizes outcrossing, evolved repeatedly and has been shown to accelerate diversification in primroses, yet its potential influence on isolating mechanisms remains unexplored. Furthermore, the relative contribution of pre- versus postmating barriers to reproductive isolation is still debated. No experimental study has yet evaluated the possible effects of heterostyly on pre- and postmating reproductive mechanisms. We quantify multiple reproductive barriers between the heterostylous Primula elatior (oxlip) and P. vulgaris (primrose), which readily hybridize when co-occurring, and test whether traits of heterostyly contribute to reproductive barriers in unique ways. We find that premating isolation is key for both species, while postmating isolation is considerable only for P. vulgaris; ecogeographic isolation is crucial for both species, while phenological, seed developmental, and hybrid sterility barriers are also important in P. vulgaris, implicating sympatrically higher gene flow into P. elatior. We document for the first time that, in addition to the aforementioned species-dependent asymmetries, morph-dependent asymmetries affect reproductive barriers between heterostylous species. Indeed, the interspecific decrease of reciprocity between high sexual organs of complementary floral morphs limits interspecific pollen transfer from anthers of short-styled flowers to stigmas of long-styled flowers, while higher reciprocity between low sexual organs favors introgression over isolation from anthers of long-styled flowers to stigmas of short-styled flowers. Finally, intramorph incompatibility persists across species boundaries, but is weakened in long-styled flowers of P. elatior, opening a possible backdoor to gene flow through intramorph pollen transfer between species. Therefore, patterns of gene flow across species boundaries are likely affected by floral morph composition of adjacent populations. To summarize, our study highlights the general importance of premating isolation and newly illustrates that both morph- and species-dependent asymmetries shape boundaries between heterostylous species.
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Affiliation(s)
- Barbara Keller
- Department of Systematic and Evolutionary BotanyUniversity of ZürichZollikerstrasse 1078008ZürichSwitzerland
| | - Jurriaan M. de Vos
- Department of Ecology and Evolutionary BiologyBrown University80 Waterman StreetBox G‐WProvidenceRhode Island02912USA
- Present address: Comparative Plant and Fungal Biology DepartmentRoyal Botanic GardensKewRichmondSurreyTW9 3AE UK
| | | | - James D. Thomson
- Ecology and Evolutionary Biology DepartmentUniversity of Toronto25 Harbord St.TorontoOntarioM5S 3G5Canada
| | - Elena Conti
- Department of Systematic and Evolutionary BotanyUniversity of ZürichZollikerstrasse 1078008ZürichSwitzerland
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Nunes CEP, Amorim FW, Mayer JLS, Sazima M. Pollination ecology of two species of Elleanthus (Orchidaceae): novel mechanisms and underlying adaptations to hummingbird pollination. PLANT BIOLOGY (STUTTGART, GERMANY) 2016; 18:15-25. [PMID: 25678071 DOI: 10.1111/plb.12312] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 02/05/2015] [Indexed: 06/04/2023]
Abstract
Relationships among floral biology, floral micromorphology and pollinator behaviour in bird-pollinated orchids are important issues to understand the evolution of the huge flower diversity within Orchidaceae. We aimed to investigate floral mechanisms underlying the interaction with pollinators in two hummingbird-pollinated orchids occurring in the Atlantic forest. We assessed floral biology, nectar traits, nectary and column micromorphologies, breeding systems and pollinators. In both species, nectar is secreted by lip calli through spaces between the medial lamellar surfaces of epidermal cells. Such a form of floral nectar secretion has not been previously described. Both species present functional protandry and are self-compatible yet pollinator-dependent. Fruit set in hand-pollination experiments was more than twice that under natural conditions, evidencing pollen limitation. The absence of fruit set in interspecific crosses suggests the existence of post-pollination barriers between these sympatric co-flowering species. In Elleanthus brasiliensis, fruits resulting from cross-pollination and natural conditions were heavier than those resulting from self-pollination, suggesting advantages to cross-pollination. Hummingbirds pollinated both species, which share at least one pollinator species. Species differences in floral morphologies led to distinct pollination mechanisms. In E. brasiliensis, attachment of pollinarium to the hummingbird bill occurs through a lever apparatus formed by an appendage in the column, another novelty to our knowledge of orchid pollination. In E. crinipes, pollinarium attachment occurs by simple contact with the bill during insertion into the flower tube, which fits tightly around it. The novelties described here illustrate the overlooked richness in ecology and morphophysiology in Orchidaceae.
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Affiliation(s)
- C E P Nunes
- Programa de Pós-Graduação em Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil
| | - F W Amorim
- Departamento de Botânica, Instituto de Biociências, Universidade Estadual Paulista "Júlio de Mesquita Filho", Botucatu, São Paulo, Brazil
| | - J L S Mayer
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil
| | - M Sazima
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil
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