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Rego JO, Monzón VH, Mesquita-Neto JN. The invasive bumblebee Bombus terrestris (Linnaeus, 1758) disrupts the adaptive function of heteranthery by indiscriminately visiting the pollinating and feeding anthers of Senna arnottiana flowers. PLANT BIOLOGY (STUTTGART, GERMANY) 2024; 26:821-831. [PMID: 38861656 DOI: 10.1111/plb.13673] [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: 02/11/2024] [Accepted: 05/02/2024] [Indexed: 06/13/2024]
Abstract
Heteranthery, the presence of different types of anthers on the same flower, is a floral adaptation that aims to balance the need for pollinators to collect pollen as a food resource while ensuring sufficient pollen for pollination. We investigate the role of heteranthery in the pollination of Senna arnottiana flowers and how it is affected by the behaviour of visiting bee species, with a particular focus on the impact of the invasive bumblebee Bombus terrestris. In three populations of S. arnottiana we measured the size of three sets of anthers and style, stigma-anther separation, pollen quantity and fruit set, and contrasted it with the body size, behaviour, and pollination effectiveness of all floral visitors. Different bee species visited S. arnottiana flowers, and their foraging behaviour varied. Large-bodied native bees, including Centris cineraria, Caupolicana sp. and Cadeguala occidentalis, preferentially visited short anthers, whereas B. terrestris, an exotic bumblebee, foraged from both short and long anthers without distinction. In addition, B. terrestris contacted the stigma at a lower rate than large-bodied native bees. Instead of concentrating its pollen-gathering efforts on the feeding anthers, as predicted by the "division of labor" hypothesis, B. terrestris indiscriminately visited both types of anthers similarly. This behaviour of B. terrestris may disrupt the adaptive significance of heteranthery by mixing the roles of pollination and feeding anthers of S. arnottiana. Therefore, our results highlight the potential disruption of this relationship by exotic pollinators and the need to consider it in conservation efforts.
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Affiliation(s)
- J O Rego
- Jardim Botânico da Fundação de Parques Municipais e Zoobotânica de Belo Horizonte, Avenida Otacílio Negrão de Lima, Belo Horizonte, Brazil
- Laboratorio de Ecología de Abejas, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca, Maule, Chile
| | - V H Monzón
- Laboratorio de Ecología de Abejas, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca, Maule, Chile
| | - J N Mesquita-Neto
- Laboratorio de Ecología de Abejas, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca, Maule, Chile
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Vallejo-Marin M, Russell AL. Harvesting pollen with vibrations: towards an integrative understanding of the proximate and ultimate reasons for buzz pollination. ANNALS OF BOTANY 2024; 133:379-398. [PMID: 38071461 PMCID: PMC11006549 DOI: 10.1093/aob/mcad189] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 12/08/2023] [Indexed: 04/12/2024]
Abstract
Buzz pollination, a type of interaction in which bees use vibrations to extract pollen from certain kinds of flowers, captures a close relationship between thousands of bee and plant species. In the last 120 years, studies of buzz pollination have contributed to our understanding of the natural history of buzz pollination, and basic properties of the vibrations produced by bees and applied to flowers in model systems. Yet, much remains to be done to establish its adaptive significance and the ecological and evolutionary dynamics of buzz pollination across diverse plant and bee systems. Here, we review for bees and plants the proximate (mechanism and ontogeny) and ultimate (adaptive significance and evolution) explanations for buzz pollination, focusing especially on integrating across these levels to synthesize and identify prominent gaps in our knowledge. Throughout, we highlight new technical and modelling approaches and the importance of considering morphology, biomechanics and behaviour in shaping our understanding of the adaptive significance of buzz pollination. We end by discussing the ecological context of buzz pollination and how a multilevel perspective can contribute to explain the proximate and evolutionary reasons for this ancient bee-plant interaction.
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Affiliation(s)
- Mario Vallejo-Marin
- Department of Ecology and Genetics, Uppsala University, Uppsala, 752 36, Sweden
| | - Avery L Russell
- Department of Biology, Missouri State University, Springfield, MO, 65897, USA
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Bochorny T, Bacci LF, Dellinger AS, Michelangeli FA, Goldenberg R, Brito VLG. Connective appendages in Huberia bradeana (Melastomataceae) affect pollen release during buzz pollination. PLANT BIOLOGY (STUTTGART, GERMANY) 2021; 23:556-563. [PMID: 33550673 PMCID: PMC8252584 DOI: 10.1111/plb.13244] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 12/31/2020] [Indexed: 05/03/2023]
Abstract
Floral structures, such as stamen appendages, play crucial roles in pollinator attraction, pollen release dynamics and, ultimately, the reproductive success of plants. The pollen-rewarding, bee buzz-pollinated flowers of Melastomataceae often bear conspicuous staminal appendages. Surprisingly, their functional role in the pollination process remains largely unclear. We use Huberia bradeana Bochorny & R. Goldenb. (Melastomataceae) with conspicuously elongated, twisted stamen appendages to investigate their functional role in the pollination process. We studied the effect of stamen appendages on pollinator behaviour and reproductive success by comparing manipulated flowers (appendages removed) with unmanipulated flowers. To assess bee pollinator behaviour, we measured three properties of buzzes (vibrations) produced by bees on Huberia flowers: frequency, duration and number of buzzes per flower visit. We measured male and female reproductive success by monitoring pollen release and deposition after single bee visits. Finally, we used artificial vibrations and laser vibrometry to assess how flower vibrational properties change with the removal of stamen appendages. Our results show that the absence of staminal appendages does not modify bee buzzing behaviour. Pollen release was higher in unmanipulated flowers, but stigmatic pollen loads differ only marginally between the two treatments. We also detected lower vibration amplitudes in intact flowers as compared to manipulated flowers in artificial vibration experiments. The presence of connective appendages are crucial in transmitting vibrations and assuring optimal pollen release. Therefore, we propose that the high diversity of colours, shapes and sizes of connective appendages in buzz-pollinated flowers may have evolved by selection through male fitness.
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Affiliation(s)
- T. Bochorny
- Programa de Pós‐Graduação em Biologia VegetalDepartamento de Biologia VegetalUniversidade Estadual de CampinasCampinas, São PauloBrazil
| | - L. F. Bacci
- Programa de Pós‐Graduação em Biologia VegetalDepartamento de Biologia VegetalUniversidade Estadual de CampinasCampinas, São PauloBrazil
| | - A. S. Dellinger
- Department of Botany and Biodiversity ResearchUniversity of ViennaViennaAustria
| | | | - R. Goldenberg
- Departamento de BotânicaUniversidade Federal do ParanáCuritiba, ParanáBrazil
| | - V. L. G. Brito
- Instituto de BiologiaUniversidade Federal de UberlândiaUberlândiaMinas GeraisBrazil
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Mesquita-Neto JN, Vieira ALC, Schlindwein C. Minimum size threshold of visiting bees of a buzz-pollinated plant species: consequences for pollination efficiency. AMERICAN JOURNAL OF BOTANY 2021; 108:1006-1015. [PMID: 34114214 DOI: 10.1002/ajb2.1681] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 01/20/2021] [Indexed: 06/12/2023]
Abstract
PREMISE Flowering plants with poricidal anthers are commonly visited by buzzing bees, which vibrate flowers to extract pollen. However, not all flower visitors are in fact pollinators, and features such as body size and duration of flower visits are important factors in determining pollination effectiveness. We tested whether bee-to-flower size relationships predict the pollination effectiveness of flower visitors of a buzz-pollinated species (Chamaecrista ramosa, Fabaceae). METHODS We sorted 13 bee taxa into three groups: smaller than, equivalent to ("fit-size"), and larger than flower herkogamy (spatial separation between anthers and stigma). We expected the latter two groups to touch the stigmas, which would be an indicator of pollination effectiveness, more frequently than the first group. To test this hypothesis, we assessed contact with stigmas, foraging behavior, and duration of visits for the three size groups of bees. RESULTS Our data reveal that small bees scarcely touched the stigmas, while large and fit-size bees were the most efficient pollinators, achieving high stigma-touching rates, conducting much shorter flower visits, and visiting flowers and conspecific plants at high rates during foraging bouts. CONCLUSIONS The results did not show size-matching among bees and flowers, as expected, but rather a minimum size threshold of efficient pollinators. The finding of such a threshold is a nonarbitrary approach to predicting pollination effectiveness of visitors to herkogamous flowers with poricidal anthers.
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Affiliation(s)
- José N Mesquita-Neto
- Centro de Investigación en Estudios Avanzados del Maule, Vicerrectoría de Investigación y Postgrado, Universidad Católica del Maule, Talca, Chile
- Programa de Pós-graduação em Biologia Vegetal, Universidade Federal de Minas Gerais, Grupo Plebeia-Ecologia de Abelhas e da Polinização, Av. Presidente Antônio Carlos, 6627, Caixa Postal 486, Belo Horizonte, Minas Gerais, CEP 31270-901, Brazil
| | - Ana Luísa C Vieira
- Programa de Pós-graduação em Biologia Vegetal, Universidade Federal de Minas Gerais, Grupo Plebeia-Ecologia de Abelhas e da Polinização, Av. Presidente Antônio Carlos, 6627, Caixa Postal 486, Belo Horizonte, Minas Gerais, CEP 31270-901, Brazil
| | - Clemens Schlindwein
- Departamento de Botânica, Grupo Plebeia-Ecologia de Abelhas e da Polinização, Universidade Federal de Minas Gerais, Av. Presidente Antônio Carlos, 6627, Caixa Postal 486, Belo Horizonte, Minas Gerais, CEP 31270-901, Brazil
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Kay KM, Jogesh T, Tataru D, Akiba S. Darwin's vexing contrivance: a new hypothesis for why some flowers have two kinds of anther. Proc Biol Sci 2020. [PMID: 33352073 DOI: 10.1098/rspb.2020.2593rspb20202593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023] Open
Abstract
Heteranthery, the presence of two or more anther types in the same flower, is taxonomically widespread among bee-pollinated angiosperms, yet has puzzled botanists since Darwin. We test two competing hypotheses for its evolution: the long-standing 'division of labour' hypothesis, which posits that some anthers are specialized as food rewards for bees whereas others are specialized for surreptitious pollination, and our new hypothesis that heteranthery is a way to gradually release pollen that maximizes pollen delivery. We examine the evolution of heteranthery and associated traits across the genus Clarkia (Onagraceae) and study plant-pollinator interactions in two heterantherous Clarkia species. Across species, heteranthery is associated with bee pollination, delayed dehiscence and colour crypsis of one anther whorl, and movement of that anther whorl upon dehiscence. Our mechanistic studies in heterantherous species show that bees notice, forage on and export pollen from each anther whorl when it is dehiscing, and that heteranthery promotes pollen export. We find no support for division of labour, but multifarious evidence that heteranthery is a mechanism for gradual pollen presentation that probably evolved through indirect male-male competition for siring success.
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Affiliation(s)
- Kathleen M Kay
- Department of Ecology and Evolutionary Biology, University of California, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Tania Jogesh
- Department of Ecology and Evolutionary Biology, University of California, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Diana Tataru
- Department of Ecology and Evolutionary Biology, University of California, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Sami Akiba
- Department of Ecology and Evolutionary Biology, University of California, 130 McAllister Way, Santa Cruz, CA 95060, USA
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Kay KM, Jogesh T, Tataru D, Akiba S. Darwin's vexing contrivance: a new hypothesis for why some flowers have two kinds of anther. Proc Biol Sci 2020; 287:20202593. [PMID: 33352073 PMCID: PMC7779490 DOI: 10.1098/rspb.2020.2593] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 11/26/2020] [Indexed: 01/26/2023] Open
Abstract
Heteranthery, the presence of two or more anther types in the same flower, is taxonomically widespread among bee-pollinated angiosperms, yet has puzzled botanists since Darwin. We test two competing hypotheses for its evolution: the long-standing 'division of labour' hypothesis, which posits that some anthers are specialized as food rewards for bees whereas others are specialized for surreptitious pollination, and our new hypothesis that heteranthery is a way to gradually release pollen that maximizes pollen delivery. We examine the evolution of heteranthery and associated traits across the genus Clarkia (Onagraceae) and study plant-pollinator interactions in two heterantherous Clarkia species. Across species, heteranthery is associated with bee pollination, delayed dehiscence and colour crypsis of one anther whorl, and movement of that anther whorl upon dehiscence. Our mechanistic studies in heterantherous species show that bees notice, forage on and export pollen from each anther whorl when it is dehiscing, and that heteranthery promotes pollen export. We find no support for division of labour, but multifarious evidence that heteranthery is a mechanism for gradual pollen presentation that probably evolved through indirect male-male competition for siring success.
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Affiliation(s)
- Kathleen M. Kay
- Department of Ecology and Evolutionary Biology, University of California, 130 McAllister Way, Santa Cruz, CA 95060, USA
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Telles FJ, Klunk CL, Maia FRD, de Brito VLG, Varassin IG. Towards a new understanding of the division of labour in heterantherous flowers: the case of Pterolepis glomerata (Melastomataceae). Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa107] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Abstract
Pollen-flowers with heteromorphic stamens have been shown to promote an intrafloral division of labour as a solution to fitness costs arising from pollen consumption by bees, known as the pollen dilemma. Usually, the division is based on morphological differences in anther and pollen traits that correlate with stamen function: pollinating anthers are larger and contain more and higher-quality pollen grains than feeding anthers. Here, we present a new strategy based on a high investment in reward production and thus attraction, in the heterantherous Pterolepis glomerata, to overcome short flower longevity and maintain reproductive success. In P. glomerata small feeding anthers not only produced more pollen grains and more grains with cytoplasmic content, but also released more pollen than pollinating anthers after a single visit. This pattern was consistent until the end of floral anthesis, showing the existence of pollen-dosing mechanisms. Bees equally visited flowers with yellow feeding anthers and pollinating anthers with yellow connective appendages, indicating a visual similarity, as predicted by bee vision modelling. Our results demonstrate that the division of labour might have different outcomes. Instead of the classical expectation of more investment in reproductive pollen in pollinating stamens, P. glomerata invested more in attraction and reward in feeding stamens.
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Affiliation(s)
- Francismeire Jane Telles
- Programa de Pós-Graduação em Ecologia e Conservação de Recursos Naturais, Universidade Federal de Uberlândia, Campus Umuarama, Sala, Uberlândia, MG, Brazil
- Programa de Pós-Graduação em Ecologia e Conservação, Centro Politécnico, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
| | - Cristian Luan Klunk
- Programa de Pós-Graduação em Ecologia e Conservação, Centro Politécnico, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
| | - Fabiano Rodrigo da Maia
- Programa de Pós-Graduação em Botânica, Centro Politécnico, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
| | | | - Isabela Galarda Varassin
- Departamento de Botânica, Centro Politécnico, Universidade Federal do Paraná, Curitiba, PR, Brazil
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Konzmann S, Hilgendorf F, Niester C, Rech AR, Lunau K. Morphological specialization of heterantherous Rhynchanthera grandiflora (Melastomataceae) accommodates pollinator diversity. PLANT BIOLOGY (STUTTGART, GERMANY) 2020; 22:583-590. [PMID: 32112502 DOI: 10.1111/plb.13102] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 02/23/2020] [Indexed: 06/10/2023]
Abstract
The tropical Melastomataceae are characterized by poricidal anthers which constitute a floral filter selecting for buzz-pollinating bees. Stamens are often dimorphic, sometimes with discernible feeding and pollinating functions. Rhynchanthera grandiflora produces nectarless flowers with four short stamens and one long stamen; all anthers feature a narrow elongation with an upwards facing pore. We tested pollen transfer by diverse foraging bees and viability of pollen from both stamen types. The impact of anther morphology on pollen release direction and scattering angle was studied to determine the plant's reproductive strategy. Medium-sized to large bees sonicated flowers in a specific position, and the probability of pollen transfer correlated with bee size even among these legitimate visitors. Small bees acted as pollen thieves or robbers. Anther rostrum and pore morphology serve to direct and focus the pollen jet released by floral sonication towards the pollinator's body. Resulting from the ventral and dorsal positioning of the short and long stamens, respectively, the pollinator's body was widely covered with pollen. This improves the plant's chances of outcrossing, irrespective of which bee body part contacts the stigma. Consequently, R. grandiflora is also able to employ bee species of various sizes as pollen vectors. The strategy of spreading pollen all over the pollinator's body is rather cost-intensive but counterbalanced by ensuring that most of the released pollen is in fact transferred to the bee. Thus, flowers of R. grandiflora illustrate how specialized morphology may serve to improve pollination by a functional group of pollinators.
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Affiliation(s)
- S Konzmann
- Institute of Sensory Ecology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - F Hilgendorf
- Institute of Sensory Ecology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - C Niester
- Institute of Sensory Ecology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - A R Rech
- Licenciatura em Educação do Campo, Faculdade Interdisciplinar em Humanidades, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina-MG, Brazil
| | - K Lunau
- Institute of Sensory Ecology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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Dellinger AS, Chartier M, Fernández‐Fernández D, Penneys DS, Alvear M, Almeda F, Michelangeli FA, Staedler Y, Armbruster WS, Schönenberger J. Beyond buzz-pollination - departures from an adaptive plateau lead to new pollination syndromes. THE NEW PHYTOLOGIST 2019; 221:1136-1149. [PMID: 30368819 PMCID: PMC6492237 DOI: 10.1111/nph.15468] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 08/01/2018] [Indexed: 05/20/2023]
Abstract
Pollination syndromes describe recurring adaptation to selection imposed by distinct pollinators. We tested for pollination syndromes in Merianieae (Melastomataceae), which contain bee- (buzz-), hummingbird-, flowerpiercer-, passerine-, bat- and rodent-pollinated species. Further, we explored trait changes correlated with the repeated shifts away from buzz-pollination, which represents an 'adaptive plateau' in Melastomataceae. We used random forest analyses to identify key traits associated with the different pollinators of 19 Merianieae species and estimated the pollination syndromes of 42 more species. We employed morphospace analyses to compare the morphological diversity (disparity) among syndromes. We identified three pollination syndromes ('buzz-bee', 'mixed-vertebrate' and 'passerine'), characterized by different pollen expulsion mechanisms and reward types, but not by traditional syndrome characters. Further, we found that 'efficiency' rather than 'attraction' traits were important for syndrome circumscription. Contrary to syndrome theory, our study supports the pooling of different pollinators (hummingbirds, bats, rodents and flowerpiercers) into the 'mixed-vertebrate' syndrome, and we found that disparity was highest in the 'buzz-bee' syndrome. We conclude that the highly adaptive buzz-pollination system may have prevented shifts towards classical pollination syndromes, but provided the starting point for the evolution of a novel set of distinct syndromes, all having retained multifunctional stamens that provide pollen expulsion, reward and attraction.
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Affiliation(s)
- Agnes S. Dellinger
- Department of Botany and Biodiversity ResearchUniversity of ViennaRennweg 141030ViennaAustria
| | - Marion Chartier
- Department of Botany and Biodiversity ResearchUniversity of ViennaRennweg 141030ViennaAustria
| | - Diana Fernández‐Fernández
- Herbario Nacional del Ecuador (QCNE)Instituto Nacional de BiodiversidadRío Coca E06‐115 e Isla FernandinaQuitoEcuador
| | - Darin S. Penneys
- Department of Biology and Marine BiologyUniversity of North Carolina Wilmington601 S. College RoadWilmingtonNC28403USA
| | - Marcela Alvear
- Institute of Biodiversity Science and SustainabilityCalifornia Academy of Sciences55 Music Concourse DriveSan FranciscoCA94118‐4503USA
| | - Frank Almeda
- Institute of Biodiversity Science and SustainabilityCalifornia Academy of Sciences55 Music Concourse DriveSan FranciscoCA94118‐4503USA
| | - Fabián A. Michelangeli
- Institute of Systematic BotanyThe New York Botanical Garden2900 Southern BlvdBronxNY10458‐5126USA
| | - Yannick Staedler
- Department of Botany and Biodiversity ResearchUniversity of ViennaRennweg 141030ViennaAustria
| | - W. Scott Armbruster
- School of Biological ScienceUniversity of PortsmouthKing Henry 1 StreetPortsmouthP01 2DYUK
- Institute of Arctic BiologyUniversity of Alaska FairbanksFairbanksAK99775USA
| | - Jürg Schönenberger
- Department of Botany and Biodiversity ResearchUniversity of ViennaRennweg 141030ViennaAustria
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