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Cullen NP, Fetters AM, Ashman TL. Integrating microbes into pollination. CURRENT OPINION IN INSECT SCIENCE 2021; 44:48-54. [PMID: 33248285 DOI: 10.1016/j.cois.2020.11.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/02/2020] [Accepted: 11/06/2020] [Indexed: 06/12/2023]
Abstract
Microbes (fungi, bacteria and viruses) living within flowers are hypothesized to affect pollination. We evaluate current support for this idea at each stage of the pollination process. Evidence to date is convincing that microbes influence pollinator attraction, but data are heavily weighted toward bumblebees and the effects of nectar yeasts. Effects of microbes on the efficacy of pollinator visits is understudied and variable outcomes from field studies suggest quality of pollinator visits, not only quantity, are likely involved. The effect of microbes on pollen performance is underappreciated. Beyond the effect of pathogenic viruses, the impacts of pollen-transmitted endophytic microbes on pollen viability or tube growth are unknown but could affect the outcome of pollen receipt. Future research integrating microbes into pollination should broaden taxonomic diversity of microbes, pollinators and plants and the processes under study.
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Affiliation(s)
- Nevin P Cullen
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Andrea M Fetters
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Tia-Lynn Ashman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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Koupilová K, Štenc J, Janovský Z. Pollen dispersal is driven by pollinator response to plant disease and plant spatial aggregation. Basic Appl Ecol 2021. [DOI: 10.1016/j.baae.2020.10.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Harder LD, Richards SA, Ågren J, Johnson SD. Mechanisms of Male-Male Interference during Dispersal of Orchid Pollen. Am Nat 2021; 197:250-265. [PMID: 33523780 DOI: 10.1086/712378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractSiring success of flowering plants depends on the fates of male gametophytes, which compete for access to stigmas, stylar resources, and ovules. Although rarely considered, pollen may often compete during dispersal, affecting the processes required for export to stigmas: pollen pickup, transport, and deposition. We quantified dispersal interference by tracking bee-mediated dispersal of stained Anacamptis morio (Orchidaceae) pollen from individual donor flowers and inferred the affected dispersal mechanisms on the basis of the fit of a process-based model. During individual trials, all recipient flowers were either emasculated, precluding interference with donor pollen, or intact, adding potentially interfering pollen to the pollinator. The presence of competing pollinaria on bees reduced pickup of additional pollinaria, doubled the overall proportion of lost donor pollen, and reduced total pollen export by 27%. Interference specifically increased loss of donor pollen between successive flower visits and variation in deposition among trials, and it likely also reduced pollen contact with stigmas and pollen deposition when contact occurred. Thus, by altering pollen removal, transport, and deposition, male-male interference during pollen dispersal can significantly-and perhaps commonly-limit plant-siring success.
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Floral traits are associated with the quality but not quantity of heterospecific stigmatic pollen loads. BMC Ecol 2020; 20:54. [PMID: 33023549 PMCID: PMC7539470 DOI: 10.1186/s12898-020-00323-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 09/23/2020] [Indexed: 11/30/2022] Open
Abstract
Background In flowering communities, plant species commonly share pollinators and therefore plant individuals receive heterospecific pollen (HP). However, the patterns of HP transfers can deviate from patterns of plant-pollinator visitations. Although flower-visitor interactions are known to be mediated by floral traits, e.g. floral size or nectar tube depth, the explanatory power of these traits for HP transfer patterns remains elusive. Here, we have explored pollen transfer patterns at three sites in Southern Germany on three dates (early, mid and late summer). At the plant level, we tested whether flower abundance and floral traits are correlated with HP reception and donation. At the community level, we determined whether flower and bee diversity are correlated with network modularity and whether floral traits explain the module affiliation of plant species. We collected the stigmas of flowering plant species, analysed HP and conspecific pollen (CP) loads and measured floral traits, flower and bee diversity. Results Our results show that the degree and intensity of HP reception or donation at the plant level do not correlate with floral traits, whereas at the community level, the module affiliation of who is sharing pollen with whom is well-explained by floral traits. Additionally, variation in network modularity between communities is better explained by plant diversity and abundance than by bee diversity and abundance. Conclusions Overall, our results indicate that floral traits that are known to mediate flower-visitor interactions can improve our understanding of qualitative HP transfer but only provide limited information about the quantity of HP transfer, which more probably depends on other floral traits, flower-visitor identity or community properties.
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55
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Anderson B, Minnaar C. Illuminating the incredible journey of pollen. AMERICAN JOURNAL OF BOTANY 2020; 107:1323-1326. [PMID: 32965026 DOI: 10.1002/ajb2.1539] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 06/25/2020] [Indexed: 06/11/2023]
Affiliation(s)
- Bruce Anderson
- Department of Botany and Zoology, Stellenbosch University, South Africa
| | - Corneile Minnaar
- Department of Botany and Zoology, Stellenbosch University, South Africa
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Hao K, Tian ZX, Wang ZC, Huang SQ. Pollen grain size associated with pollinator feeding strategy. Proc Biol Sci 2020; 287:20201191. [PMID: 32811305 PMCID: PMC7482274 DOI: 10.1098/rspb.2020.1191] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 07/24/2020] [Indexed: 02/06/2023] Open
Abstract
Angiosperm pollen grain diameter varies greatly from a few microns to over 100, but the selective forces driving the interspecific variation in pollen size remain unclear. Although both pre- and post-pollination hypotheses have been proposed, empirical evidence remains scarce. Here we propose that visits by pollen-foraging pollinators have selected against large pollen grains. An association between pollinator behaviour and pollen grain size was confirmed by field studies of 80 flowering species in natural communities, showing that pollinators positively collected pollen in those species with relatively smaller pollen grains but rarely did so in species with larger ones. Allowing for the confounding effects of pollinator type, flower size or style length and pollen grain number, we found a significant effect of pollen-foraging behaviour on variation in pollen grain size, particularly in bee-pollinated plants. While these results suggest that many plant species whose pollen is collected or consumed by pollinators produce small pollen grains, it remains unclear whether pollen grain size is directly affected by pollinator foraging habit or indirectly mediated by pollen number trade-offs.
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Affiliation(s)
| | | | | | - Shuang-Quan Huang
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan 430079, People's Republic of China
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57
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Theron GL, Grenier F, Anderson BC, Ellis AG, Johnson SD, Midgley JM, van der Niet T. Key long-proboscid fly pollinator overlooked: morphological and molecular analyses reveal a new Prosoeca (Nemestrinidae) species. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Long-proboscid nemestrinid flies are keystone pollinators of dozens of Southern African plants and, consequently, their taxonomic status might have important consequences for insect and plant conservation. We focus on Prosoeca peringueyi, considered to be a single, morphologically variable species, upon which a guild of ~28 plants in the winter rainfall region depends for pollination. We quantified morphological variation and established whether it was associated with genetic variation within and among sites. Phylogenetic analyses of the mitochondrial COI gene revealed two well-supported clades. One clade contains long-proboscid individuals that conform morphologically to the holotype of P. peringueyi. The sister clade contains individuals that frequently occur sympatrically with P. peringueyi and have shorter proboscides, with additional diagnostic characters that set it apart from P. peringueyi. A haplotype analysis based on nuclear ribosomal 28S DNA sequences of a subset of individuals corroborated these results. Based on our results, we propose the recognition of two species: P. peringueyi and Prosoeca torquata sp. nov., which is described here. Future research is required to quantify the interaction networks of these two fly species and the plant guilds with which they interact, to facilitate conservation in the global biodiversity hotspot where they occur.
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Affiliation(s)
- Genevieve L Theron
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, Scottsville, South Africa
| | - Florent Grenier
- Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa
| | - Bruce C Anderson
- Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa
| | - Allan G Ellis
- Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa
| | - Steven D Johnson
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, Scottsville, South Africa
| | - John M Midgley
- Department of Natural Sciences, KwaZulu-Natal Museum, Pietermaritzburg, South Africa
- Department of Zoology and Entomology, Rhodes University, Makhanda, South Africa
| | - Timotheüs van der Niet
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, Scottsville, South Africa
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58
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Streher NS, Bergamo PJ, Ashman TL, Wolowski M, Sazima M. Effect of heterospecific pollen deposition on pollen tube growth depends on the phylogenetic relatedness between donor and recipient. AOB PLANTS 2020; 12:plaa016. [PMID: 32665826 PMCID: PMC7333672 DOI: 10.1093/aobpla/plaa016] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 05/11/2020] [Indexed: 05/30/2023]
Abstract
Co-flowering plant species may interact via pollinators leading to heterospecific pollen transfer with consequences for plant reproduction. What determines the severity of heterospecific pollen effect on conspecific pollen performance is unclear, but it may depend on the phylogenetic relatedness of the interactors (pollen donors and recipient). The heterospecific pollen effect might also depend on the extent to which plants are exposed to heterospecific pollen over ecological or evolutionary timescales. For instance, generalist-pollinated plant species might tolerate heterospecific pollen more than specialists. Here, we tested whether heterospecific pollen effects are stronger between closely related species than phylogenetically distant ones in a tropical highland community. Then, based on these results, we determined whether responses to heterospecific pollen were stronger in generalized vs. specialized plant species. We applied heterospecific pollen from close (congeneric) or distant (different families) donors alone or with conspecific pollen on stigmas of three recipient species (one generalist, Sisyrinchium wettsteinii; and two specialists, Fuchsia campos-portoi and Fuchsia regia) and scored pollen tube performance in styles. In all species, pollen from closely related donors grew pollen tubes to the base of the style indicating a high potential to interfere with seed set. Conversely, distantly related heterospecific pollen had no effect on either specialist Fuchsia species, whereas enhanced performance of conspecific pollen was observed in generalist S. wettsteinii. The strong effect of phylogenetic relatedness of donor and recipient might have obscured the role of pollination specialization, at least for the three species examined here. Therefore, phylogenetic relatedness mediated the effect of heterospecific pollen on post-pollination success, with possible consequences for reproductive trait evolution and community assembly for further studies to explore.
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Affiliation(s)
- Nathália Susin Streher
- Graduate Program in Plant Biology, University of Campinas, Campinas, SP, Brazil
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Tia-Lynn Ashman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Marina Wolowski
- Institute of Natural Sciences, Federal University of Alfenas, Alfenas, MG, Brazil
| | - Marlies Sazima
- Plant Biology Department, Institute of Biology, University of Campinas, Campinas, SP, Brazil
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Kriebel R, Drew B, González-Gallegos JG, Celep F, Heeg L, Mahdjoub MM, Sytsma KJ. Pollinator shifts, contingent evolution, and evolutionary constraint drive floral disparity in Salvia (Lamiaceae): Evidence from morphometrics and phylogenetic comparative methods. Evolution 2020; 74:1335-1355. [PMID: 32484910 DOI: 10.1111/evo.14030] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 05/21/2020] [Indexed: 12/23/2022]
Abstract
Switches in pollinators have been argued to be key drivers of floral evolution in angiosperms. However, few studies have tested the relationship between floral shape evolution and switches in pollination in large clades. In concert with a dated phylogeny, we present a morphometric analysis of corolla, anther connective, and style shape across 44% of nearly 1000 species of Salvia (Lamiaceae) and test four hypotheses of floral evolution. We demonstrate that floral morphospace of New World (NW) Salvia is largely distinct from that of Old World (OW) Salvia and that these differences are pollinator driven; shifts in floral morphology sometimes mirror shifts in pollinators; anther connectives (key constituents of the Salvia staminal lever) and styles co-evolved from curved to linear shapes following shifts from bee to bird pollination; and morphological differences between NW and OW bee flowers are partly the legacy of constraints imposed by an earlier shift to bird pollination in the NW. The distinctive staminal lever in Salvia is a morphologically diverse structure that has evolved in concert with both the corolla and style, under different pollinator pressures, and in contingent fashion.
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Affiliation(s)
- Ricardo Kriebel
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| | - Bryan Drew
- Department of Biology, University of Nebraska at Kearney, Kearney, Nebraska, 68849
| | | | - Ferhat Celep
- Department of Biology, Faculty of Arts and Sciences, Kırıkkale University, Yahşiyan, 71450, Turkey
| | - Luciann Heeg
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| | - Mohamed M Mahdjoub
- Department of Biology, Faculty of Natural and Life Sciences and Earth Sciences, University of Bouira, Bouira, 10000, Algeria
| | - Kenneth J Sytsma
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, 53706
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60
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Ashman TL, Alonso C, Parra-Tabla V, Arceo-Gómez G. Pollen on stigmas as proxies of pollinator competition and facilitation: complexities, caveats and future directions. ANNALS OF BOTANY 2020; 125:1003-1012. [PMID: 31985008 PMCID: PMC7262468 DOI: 10.1093/aob/mcaa012] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 01/10/2020] [Accepted: 01/23/2020] [Indexed: 05/22/2023]
Abstract
BACKGROUND Pollen transfer via animals is necessary for reproduction by ~80 % of flowering plants, and most of these plants live in multispecies communities where they can share pollinators. While diffuse plant-pollinator interactions are increasingly recognized as the rule rather than the exception, their fitness consequences cannot be deduced from flower visitation alone, so other proxies, functionally closer to seed production and amenable for use in a broad variety of diverse communities, are necessary. SCOPE We conceptually summarize how the study of pollen on stigmas of spent flowers can reflect key drivers and functional aspects of the plant-pollinator interaction (e.g. competition, facilitation or commensalism). We critically evaluate how variable visitation rates and other factors (pollinator pool and floral avoidance) can give rise to different relationships between heterospecific pollen and (1) conspecific pollen on the stigma and (2) conspecific tubes/grain in the style, revealing the complexity of potential interpretations. We advise on best practices for using these proxies, noting the assumptions and caveats involved in their use, and explicate what additional data are required to verify interpretation of given patterns. CONCLUSIONS We conclude that characterizing pollen on stigmas of spent flowers provides an attainable indirect measure of pollination interactions, but given the complex processes of pollen transfer that generate patterns of conspecific-heterospecific pollen on stigmas these cannot alone determine whether competition or facilitation are the underlying drivers. Thus, functional tests are also needed to validate these hypotheses.
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Affiliation(s)
- Tia-Lynn Ashman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
- For correspondence. E-mail
| | - Conchita Alonso
- Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (EBD-CSIC), Sevilla, Spain
| | - Victor Parra-Tabla
- Department of Tropical Ecology, University of Yucatan, Mérida, Yucatán, México
| | - Gerardo Arceo-Gómez
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN, USA
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61
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Ashman TL, Arceo-Gómez G, Bennett JM, Knight TM. Is heterospecific pollen receipt the missing link in understanding pollen limitation of plant reproduction? AMERICAN JOURNAL OF BOTANY 2020; 107:845-847. [PMID: 32445398 DOI: 10.1002/ajb2.1477] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 02/25/2020] [Indexed: 06/11/2023]
Affiliation(s)
- Tia-Lynn Ashman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Gerardo Arceo-Gómez
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN, USA
| | - Joanne M Bennett
- Institute of Biology, Martin Luther University Halle-Wittenberg, Am Kirchtor 1, 06108, Halle (Saale), Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany
| | - Tiffany M Knight
- Institute of Biology, Martin Luther University Halle-Wittenberg, Am Kirchtor 1, 06108, Halle (Saale), Germany
- Department of Community Ecology, Helmholtz Centre for Environmental Research - UFZ, Theodor-Lieser-Straße 4, 06120, Halle(Saale), Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany
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62
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Baranzelli MC, Benitez-Vieyra S, Glinos E, Trenchi A, Córdoba S, Camina J, Ashworth L, Sérsic AN, Cocucci AA, Fornoni J. Daily fluctuations in pollination effectiveness explain higher efficiency of native over exotic bees in Lepechinia floribunda (Lamiaceae). ANNALS OF BOTANY 2020; 125:509-520. [PMID: 31745546 PMCID: PMC7061175 DOI: 10.1093/aob/mcz187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 11/18/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Despite Stebbins' principle of the most efficient pollinator being proposed decades ago, the most important pollinators are still mainly identified using the frequency of visits to flowers. This shortcoming results in a gap between the characterization of the flower visitors of a plant species and a reliable estimation of the plant fitness consequences of the mutualistic interaction. The performance of a mutualistic visitor depends on its abundance, behaviour, effectiveness (pollen removal and deposition per unit time) and efficiency (seed set per unit time) conditioned by the temporal matching between pollinator activity and temporal patterns of maturation of the sexual functions of flowers. Although there have been recent attempts to provide a conceptual and methodological framework to characterize pollinators' performance, few have combined all key elements of visitors and plants to provide an accurate estimation of pollinators' performance under natural conditions. METHODS We complement information on the flower biology and mating system of the sub-shrub Lepechinia floribunda (Lamiaceae) to provide a daily quantitative estimation of performance (effectiveness and efficiency) of the more abundant pollinators, i.e. native bumble-bees (Bombus spp.) and leafcutter bees (Megachile sp.), and the exotic honey-bee (Apis mellifera). KEY RESULTS Unlike honey-bees or leafcutter bees, native bumble-bees matched the daily pattern of nectar production and stigma receptivity, and showed higher effectiveness and efficiency. Despite the overabundance of honey-bees, visits occurred mainly when stigmas were not receptive, thus reducing the honey-bees' overall performance. CONCLUSIONS Bumble-bees appear to be the most important pollinators and potential historical mediators of reproductive trait evolution in L. floribunda. Because the production of seeds by bumble-bees involved fewer pollen grains for plants and less investment in floral display than honey-bees, contemporary and expected changes in pollinator abundance may affect future L. floribunda floral evolution. If bumble-bees were to be further displaced by anthropogenic disturbance or by competition with honey-bees, their lower efficiency will select for a larger floral display increasing reproductive costs. This scenario may also impose selection to reduce dichogamy to match honey-bee foraging activity.
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Affiliation(s)
- Matias Cristian Baranzelli
- Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, México
- Instituto Multidisciplinario de Biología Vegetal, Universidad Nacional de Córdoba, CONICET, FCEFyN, Córdoba, Argentina
| | - Santiago Benitez-Vieyra
- Instituto Multidisciplinario de Biología Vegetal, Universidad Nacional de Córdoba, CONICET, FCEFyN, Córdoba, Argentina
| | - Evangelina Glinos
- Instituto Multidisciplinario de Biología Vegetal, Universidad Nacional de Córdoba, CONICET, FCEFyN, Córdoba, Argentina
| | - Alejandra Trenchi
- Instituto Multidisciplinario de Biología Vegetal, Universidad Nacional de Córdoba, CONICET, FCEFyN, Córdoba, Argentina
| | - Silvina Córdoba
- Instituto Multidisciplinario de Biología Vegetal, Universidad Nacional de Córdoba, CONICET, FCEFyN, Córdoba, Argentina
| | - Julia Camina
- Instituto Multidisciplinario de Biología Vegetal, Universidad Nacional de Córdoba, CONICET, FCEFyN, Córdoba, Argentina
| | - Lorena Ashworth
- Instituto Multidisciplinario de Biología Vegetal, Universidad Nacional de Córdoba, CONICET, FCEFyN, Córdoba, Argentina
| | - Alicia Noemi Sérsic
- Instituto Multidisciplinario de Biología Vegetal, Universidad Nacional de Córdoba, CONICET, FCEFyN, Córdoba, Argentina
| | - Andrea Aristides Cocucci
- Instituto Multidisciplinario de Biología Vegetal, Universidad Nacional de Córdoba, CONICET, FCEFyN, Córdoba, Argentina
| | - Juan Fornoni
- Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, México
- Instituto Multidisciplinario de Biología Vegetal, Universidad Nacional de Córdoba, CONICET, FCEFyN, Córdoba, Argentina
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Lynn A, Piotter E, Harrison E, Galen C. Sexual and natural selection on pollen morphology in Taraxacum. AMERICAN JOURNAL OF BOTANY 2020; 107:364-374. [PMID: 32052420 DOI: 10.1002/ajb2.1428] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 10/10/2019] [Indexed: 05/22/2023]
Abstract
PREMISE Spiny pollen has evolved independently in multiple entomophilous lineages. Sexual selection may act on exine traits that facilitate male mating success by influencing the transfer of pollen from the anther to the body of the pollinator, while natural selection acts to increase pollen survival. We postulated that relative to sexual congeners, apomictic dandelions undergo relaxed selection on traits associated with male mating success. METHODS We explored sexual selection on exine traits by measuring the propensity for Taraxacum spp. pollen to attach to hairs of flower-visiting bumblebees (Bombus spp.) or flies (Diptera: Syrphidae and Muscoidea) and assessed natural selection by testing whether pollen traits defend against consumption. RESULTS Pollen picked up by bumblebees exhibited a narrower subset of spine-spacing phenotypes, consistent with stabilizing selection. Flies picked up larger pollen from flowers than expected at random. Surveys of corbiculae (pollen basket) contents from foraging bumblebees and feces of flies showed that pollen grains consumed by both kinds of visitors are similar in spine characteristics and size to those produced by the donor. When bees visit inflorescences of apomictic T. officinale, they pick up pollen with spine-spacing phenotypes above the mean and shifted toward those of sexual T. ceratophorum. CONCLUSIONS We demonstrate that traits under sexual selection during pollen pickup vary among pollinators, while natural selection for pollen defense is nil in T. ceratophorum. In hybrid zones between apomictic and sexual dandelions, pollen traits place apomictic donors at a dispersal disadvantage, potentially reinforcing reproductive isolation.
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Affiliation(s)
- Austin Lynn
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65202, USA
| | - Emelyn Piotter
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65202, USA
| | - Ellie Harrison
- Warner College of Natural Resources, Colorado State University, Fort Collins, CO, 80523, USA
| | - Candace Galen
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65202, USA
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Trunschke J, Sletvold N, Ågren J. Manipulation of trait expression and pollination regime reveals the adaptive significance of spur length. Evolution 2020; 74:597-609. [PMID: 31944284 DOI: 10.1111/evo.13927] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 12/21/2019] [Accepted: 01/07/2020] [Indexed: 12/13/2022]
Abstract
Understanding the mechanisms of adaptive population differentiation requires that both the functional and adaptive significance of divergent traits are characterized in contrasting environments. Here, we (a) determined the effects of floral spur length on pollen removal and receipt using plants with artificial spurs representing the species-wide variation in length, and (b) quantified pollinator-mediated selection on spur length and three traits contributing to floral display in two populations each of the short-spurred and the long-spurred ecotype of the orchid Platanthera bifolia. Both pollen receipt and removal reached a maximum at 28-29 mm long spurs in a short-spurred population visited by short-tongued moths. In contrast, pollen receipt increased linearly across the tested range (4-52 mm) and pollen removal was unrelated to spur length in a long-spurred population predominantly visited by a long-tongued moth. The experimentally documented effects on pollen transfer were not reflected in pollinator-mediated selection through female fitness or pollen removal indicating that the natural within-population variation in spur length was insufficient to result in detectable variation in pollen limitation. Our study illustrates how combining trait manipulation with analysis of causes and strength of phenotypic selection can illuminate the functional and adaptive significance of trait expression when trait variation is limited.
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Affiliation(s)
- Judith Trunschke
- Plant Ecology and Evolution, Department of Ecology and Genetics, EBC, Uppsala University, SE-752 36, Uppsala, Sweden.,Current Address: Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, P. R. China
| | - Nina Sletvold
- Plant Ecology and Evolution, Department of Ecology and Genetics, EBC, Uppsala University, SE-752 36, Uppsala, Sweden
| | - Jon Ågren
- Plant Ecology and Evolution, Department of Ecology and Genetics, EBC, Uppsala University, SE-752 36, Uppsala, Sweden
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65
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Newman E, Anderson B. Character displacement drives floral variation in Pelargonium (Geraniaceae) communities. Evolution 2020; 74:283-296. [PMID: 31883274 DOI: 10.1111/evo.13908] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 11/01/2019] [Accepted: 11/26/2019] [Indexed: 11/30/2022]
Abstract
Interactions between plant community members are an underexplored driver of angiosperm floral variation. We investigate character displacement as a potential contributor to floral variation in Pelargonium communities. Pelargoniums all place pollen on the ventral sides of their pollinators, potentially leading to interspecific pollen transfer (IPT) in sympatry. We show that the positions of pollen placement and receipt are determined by anther and style exsertion lengths. Using field experiments, we demonstrate that heterospecific species experience higher IPT if they have similar style lengths than when they have greater style length differences. Using crosses, we show that IPT has negative consequences on seed set. In combination, these results suggest that character displacement in style length is likely to reduce IPT and increase female fitness in sympatry. Patterns of style length variation across 29 different Pelargonium communities suggest that character displacement has occurred in multiple communities. Furthermore, analyses using a wide-ranging species pair show that style lengths are more different between sympatric populations than they are between allopatric populations. In addition to pollinators as agents of floral divergence, this study suggests that variation in Pelargonium community structure has driven style length variation through character displacement.
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Affiliation(s)
- Ethan Newman
- Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, 7602, South Africa
| | - Bruce Anderson
- Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, 7602, South Africa
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Christopher DA, Mitchell RJ, Karron JD. Pollination intensity and paternity in flowering plants. ANNALS OF BOTANY 2020; 125:1-9. [PMID: 31586397 PMCID: PMC6948204 DOI: 10.1093/aob/mcz159] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 09/06/2019] [Accepted: 10/01/2019] [Indexed: 05/10/2023]
Abstract
BACKGROUND Siring success plays a key role in plant evolution and reproductive ecology, and variation among individuals creates an opportunity for selection to act. Differences in male reproductive success can be caused by processes that occur during two stages, the pollination and post-pollination phases of reproduction. In the pollination phase, heritable variation in floral traits and floral display affect pollinator visitation patterns, which in turn affect variation among plants in the amount of pollen exported and deposited on recipient stigmas. In the post-pollination phase, differences among individuals in pollen grain germination success and pollen tube growth may cause realized paternity to differ from patterns of pollen receipt. The maternal plant can also preferentially provision some developing seeds or fruits to further alter variation in siring success. SCOPE In this review, we describe studies that advance our understanding of the dynamics of the pollination and post-pollination phases, focusing on how variation in male fitness changes in response to pollen limitation. We then explore the interplay between pollination and post-pollination success, and how these processes respond to ecological factors such as pollination intensity. We also identify pressing questions at the intersection of pollination and paternity and describe novel experimental approaches to elucidate the relative importance of pollination and post-pollination factors in determining male reproductive success. CONCLUSIONS The relative contribution of pollination and post-pollination processes to variation in male reproductive success may not be constant, but rather may vary with pollination intensity. Studies that quantify the effects of pollination and post-pollination phases in concert will be especially valuable as they will enable researchers to more fully understand the ecological conditions influencing male reproductive success.
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Affiliation(s)
- Dorothy A Christopher
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | | | - Jeffrey D Karron
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
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Jacquemart AL, Buyens C, Hérent MF, Quetin-Leclercq J, Lognay G, Hance T, Quinet M. Male flowers of Aconitum compensate for toxic pollen with increased floral signals and rewards for pollinators. Sci Rep 2019; 9:16498. [PMID: 31712605 PMCID: PMC6848206 DOI: 10.1038/s41598-019-53355-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 10/26/2019] [Indexed: 01/25/2023] Open
Abstract
Many plants require animal pollinators for successful reproduction; these plants provide pollinator resources in pollen and nectar (rewards) and attract pollinators by specific cues (signals). In a seeming contradiction, some plants produce toxins such as alkaloids in their pollen and nectar, protecting their resources from ineffective pollinators. We investigated signals and rewards in the toxic, protandrous bee-pollinated plant Aconitum napellus, hypothesizing that male-phase flower reproductive success is pollinator-limited, which should favour higher levels of signals (odours) and rewards (nectar and pollen) compared with female-phase flowers. Furthermore, we expected insect visitors to forage only for nectar, due to the toxicity of pollen. We demonstrated that male-phase flowers emitted more volatile molecules and produced higher volumes of nectar than female-phase flowers. Alkaloids in pollen functioned as chemical defences, and were more diverse and more concentrated compared to the alkaloids in nectar. Visitors actively collected little pollen for larval food but consumed more of the less-toxic nectar. Toxic pollen remaining on the bee bodies promoted pollen transfer efficiency, facilitating pollination.
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Affiliation(s)
- A-L Jacquemart
- Earth and Life Institute- Agronomy - Université catholique de Louvain, Croix du Sud 2, Box L7.05.14, B-1348, Louvain-la-Neuve, Belgium.
| | - C Buyens
- Earth and Life Institute- Agronomy - Université catholique de Louvain, Croix du Sud 2, Box L7.05.14, B-1348, Louvain-la-Neuve, Belgium
| | - M-F Hérent
- Louvain Drug Research Institute, Pharmacognosy Research Group - Université catholique de Louvain, Avenue E. Mounier, 72, B-1200, Brussels, Belgium
| | - J Quetin-Leclercq
- Louvain Drug Research Institute, Pharmacognosy Research Group - Université catholique de Louvain, Avenue E. Mounier, 72, B-1200, Brussels, Belgium
| | - G Lognay
- Analytical Chemistry, Gembloux Agro-Bio Tech, Université de Liège, Passage des Déportés 2, B-5030, Gembloux, Belgium
| | - T Hance
- Earth and Life Institute - Biodiversity - Université catholique de Louvain, Croix du Sud 4, Box L7.07.04, B-1348, Louvain-la-Neuve, Belgium
| | - M Quinet
- Earth and Life Institute- Agronomy - Université catholique de Louvain, Croix du Sud 2, Box L7.05.14, B-1348, Louvain-la-Neuve, Belgium
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Parra-Tabla V, Angulo-Pérez D, Albor C, Campos-Navarrete MJ, Tun-Garrido J, Sosenski P, Alonso C, Ashman TL, Arceo-Gómez G. The role of alien species on plant-floral visitor network structure in invaded communities. PLoS One 2019; 14:e0218227. [PMID: 31703061 PMCID: PMC6839871 DOI: 10.1371/journal.pone.0218227] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 10/23/2019] [Indexed: 11/18/2022] Open
Abstract
The interactions between pairs of native and alien plants via shared use of pollinators have been widely studied. Community level studies however, are necessary in order to fully understand the factors and mechanisms that facilitate successful plant invasion, but these are still scarce. Specifically, few community level studies have considered how differences in invasion level (alien flower abundance), and degree of floral trait similarity between native and invasive species, mediate effects on native plant-pollinator communities. Here, we evaluated the role of alien species on overall plant-floral visitor network structure, and on species-level network parameters, across nine invaded coastal communities distributed along 205 km in Yucatán, México that vary in alien species richness and flower abundance. We further assessed the potential the role of alien plant species on plant-floral visitor network structure and robustness via computational simulation of native and invasive plant extinction scenarios. We did not find significant differences between native and alien species in their functional floral phenotypes or in their visitation rate and pollinator community composition in these invaded sites. Variation in the proportion of alien plant species and flower abundance across sites did not influence plant-pollinator network structure. Species-level network parameters (i.e., normalized degree and nestedness contribution) did not differ between native and alien species. Furthermore, our simulation analyses revealed that alien species are functionally equivalent to native species and contribute equally to network structure and robustness. Overall, our results suggest that high levels of floral trait similarity and pollinator use overlap may help facilitate the integration of alien species into native plant-pollinator networks. As a result, alien species may also play a similar role than that of natives in the structure and stability of native plant and pollinator communities in the studied coastal sand dune ecosystem.
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Affiliation(s)
- Víctor Parra-Tabla
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán,Mérida, Yucatán, México
- * E-mail:
| | - Diego Angulo-Pérez
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán,Mérida, Yucatán, México
| | - Cristopher Albor
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán,Mérida, Yucatán, México
| | - María José Campos-Navarrete
- División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Tizimín, Tecnológico Nacional de México,Tizimín, Yucatán, México
| | - Juan Tun-Garrido
- Departamento de Botánica, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
| | - Paula Sosenski
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán,Mérida, Yucatán, México
| | - Conchita Alonso
- Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), Avda, Sevilla, Spain
| | - Tia-Lynn Ashman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Gerardo Arceo-Gómez
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN, United States of America
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Moreira-Hernández JI, Muchhala N. Importance of Pollinator-Mediated Interspecific Pollen Transfer for Angiosperm Evolution. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2019. [DOI: 10.1146/annurev-ecolsys-110218-024804] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Understanding how pollen moves between species is critical to understanding speciation, diversification, and evolution of flowering plants. For co-flowering species that share pollinators, competition through interspecific pollen transfer (IPT) can profoundly impact floral evolution, decreasing female fitness via heterospecific pollen deposition on stigmas and male fitness via pollen misplacement during visits to heterospecific flowers. The pollination literature demonstrates that such reproductive interference frequently selects for reproductive character displacement in floral traits linked to pollinator attraction, pollen placement, and mating systems and has also revealed that IPT between given pairs of species is typically asymmetric. More recent work is starting to elucidate its importance to the speciation process, clarifying the link between IPT and current and historical patterns of hybridization, the evolution of phenotypic novelty through adaptive introgression, and the rise of reproductive isolation. Our review aims to stimulate further research on IPT as a ubiquitous mechanism that plays a central role in angiosperm diversification.
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Affiliation(s)
- Juan Isaac Moreira-Hernández
- Department of Biology and Whitney R. Harris World Ecology Center, University of Missouri–St. Louis, St. Louis, Missouri 63121, USA;,
| | - Nathan Muchhala
- Department of Biology and Whitney R. Harris World Ecology Center, University of Missouri–St. Louis, St. Louis, Missouri 63121, USA;,
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Page ML, Ison JL, Bewley AL, Holsinger KM, Kaul AD, Koch KE, Kolis KM, Wagenius S. Pollinator effectiveness in a composite: a specialist bee pollinates more florets but does not move pollen farther than other visitors. AMERICAN JOURNAL OF BOTANY 2019; 106:1487-1498. [PMID: 31713237 DOI: 10.1002/ajb2.1383] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 09/23/2019] [Indexed: 06/10/2023]
Abstract
PREMISE Variation in pollinator effectiveness may contribute to pollen limitation in fragmented plant populations. In plants with multiovulate ovaries, the number of conspecific pollen grains per stigma often predicts seed set and is used to quantify pollinator effectiveness. In the Asteraceae, however, florets are uniovulate, which suggests that the total amount of pollen deposited per floret may not measure pollinator effectiveness. We examined two aspects of pollinator effectiveness-effective pollen deposition and effective pollen movement-for insects visiting Echinacea angustifolia, a composite that is pollen limited in small, isolated populations. METHODS We filmed insect visits to Echinacea in two prairie restorations and used these videos to quantify behavior that might predict effectiveness. To quantify effective pollen deposition, we used the number of styles shriveled per visit. To quantify effective pollen movement, we conducted paternity analysis on a subset of offspring and measured the pollen movement distance between mates. RESULTS Effective pollen deposition varied among taxa. Andrena helianthiformis, a Heliantheae oligolege, was the most effective taxon, shriveling more than twice the proportion of styles as all other visitors. Differences in visitor behavior on a flowering head did not explain variation in effective pollen deposition, nor did flowering phenology. On average, visitors moved pollen 16 m between plants, and this distance did not vary among taxa. CONCLUSIONS Andrena helianthiformis is an important pollinator of Echinacea. Variation in reproductive fitness of Echinacea in fragmented habitat may result, in part, from the abundance of this species.
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Affiliation(s)
- Maureen L Page
- Department of Entomology and Nematology, University of California-Davis, One Shields Avenue, Davis, California, 95616, USA
- Biology Department, Scripps College, 1030 Columbia Avenue, Claremont, California, 91711, USA
| | - Jennifer L Ison
- Biology Department, College of Wooster, 1189 Beall Avenue, Wooster, Ohio, 44691, USA
| | - Alison L Bewley
- Biology Department, Wittenberg University, 200 W. Ward Street, Springfield, Ohio, 45504, USA
| | - Keaton M Holsinger
- Biology Department, Wabash College, 301 West Wabash Avenue, Crawfordsville, Indiana, 47933, USA
| | - Andrew D Kaul
- Biology Department, St. Olaf College, 1520 St. Olaf Avenue, Northfield, Minnesota, 55057, USA
| | - Katie E Koch
- Biology Department, Lakeland University, W3718 South Drive, Plymouth, Wisconsin, 53073, USA
| | - Kory M Kolis
- Biology Department, Gustavus Adolphus College, 800 West College Avenue, Saint Peter, Minnesota, 56082, USA
| | - Stuart Wagenius
- Division of Plant Biology and Conservation, Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, Illinois, 60022, USA
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Minnaar C, de Jager ML, Anderson B. Intraspecific divergence in floral-tube length promotes asymmetric pollen movement and reproductive isolation. THE NEW PHYTOLOGIST 2019; 224:1160-1170. [PMID: 31148172 DOI: 10.1111/nph.15971] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 05/14/2019] [Indexed: 06/09/2023]
Abstract
The causative link between phenotypic divergence and reproductive isolation is an important but poorly understood part of ecological speciation. We studied the effects of floral-tube length variation on pollen placement/receipt positions and reproductive isolation. In a population of Lapeirousia anceps (Iridaceae) with bimodal floral-tube lengths, we labelled pollen of short- and long-tubed flowers with different colour fluorescent nanoparticles (quantum dots). This enabled us to map pollen placement by long- and short-tubed flowers on the only floral visitor, a long-proboscid fly. Furthermore, it allowed us to quantify pollen movement within and between short- and long-tubed flowers. Short- and long-tubed flowers placed pollen on different parts of the pollinator, and long-tubed flowers placed more pollen per visit than short-tubed flowers. This resulted in assortative pollen receipt (most pollen received comes from the same phenotype) and strong but asymmetric reproductive isolation, where short-tubed plants are more reproductively isolated than long-tubed plants. These results suggest that floral-tube length divergence can promote mechanical isolation in plants through divergence in pollen placement sites on pollinators. Consequently, in concert with other reproductive isolation mechanisms, selection for differences in floral-tube length can play an important role in ecological speciation of plants.
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Affiliation(s)
- Corneile Minnaar
- Department of Botany & Zoology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Marinus L de Jager
- Department of Botany & Zoology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Bruce Anderson
- Department of Botany & Zoology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
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Xiong YZ, Jia LB, Zhang C, Huang SQ. Color-matching between pollen and corolla: hiding pollen via visual crypsis? THE NEW PHYTOLOGIST 2019; 224:1142-1150. [PMID: 31225909 DOI: 10.1111/nph.16012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 06/14/2019] [Indexed: 06/09/2023]
Abstract
Visual signals attractive to friends may also attract enemies. The bright colors of anthers and pollen have generally been thought to attract pollinators. We hypothesize that visual crypsis of anthers, and particularly pollen, should be favored in flowering plants because protection from pollen collectors reduces the loss of male gametes. To understand adaptive strategies relating to the color of pollen, we measured the color of pollen, undehisced anther sacs, and their background, the corolla, with a spectrometer for 104 insect-pollinated flowering species from a natural community in Hengduan Mountains, southwest China. The colors of anthers, pollen and corollas were diverse in these species. The color diversity of exposed pollen was significantly higher than that of concealed pollen (i.e. where anthers are enclosed or shielded by corollas). The color contrast between pollen and corolla was significantly smaller in species with exposed pollen than in those with concealed pollen. Unlike anther color, exposed pollen color tended to match its background corolla color. Our phylogenetic comparative analysis showed contrasting effects of pollen color patterns between flowers with exposed pollen and those with concealed pollen, revealing a strategy of hiding pollen from pollen thieves via visual crypsis.
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Affiliation(s)
- Ying-Ze Xiong
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan, New England Biolabs, 430079, China
| | - Li-Bing Jia
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan, New England Biolabs, 430079, China
| | - Chuan Zhang
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan, New England Biolabs, 430079, China
| | - Shuang-Quan Huang
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan, New England Biolabs, 430079, China
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Christopher DA, Mitchell RJ, Trapnell DW, Smallwood PA, Semski WR, Karron JD. Hermaphroditism promotes mate diversity in flowering plants. AMERICAN JOURNAL OF BOTANY 2019; 106:1131-1136. [PMID: 31403705 PMCID: PMC6852098 DOI: 10.1002/ajb2.1336] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 06/04/2019] [Indexed: 05/12/2023]
Abstract
PREMISE Genetically diverse sibships are thought to increase parental fitness through a reduction in the intensity of sib competition, and through increased opportunities for seedling establishment in spatially or temporally heterogeneous environments. Nearly all research on mate diversity in flowering plants has focused on the number of fathers siring seeds within a fruit or on a maternal plant. Yet as hermaphrodites, plants can also accrue mate diversity by siring offspring on several pollen recipients in a population. Here we explore whether mate composition overlaps between the dual sex functions, and discuss the implications for plant reproductive success. METHODS We established an experimental population of 49 Mimulus ringens (monkeyflower) plants, each trimmed to a single flower. Following pollination by wild bees, we quantified mate composition for each flower through both paternal and maternal function. Parentage was successfully assigned to 240 progeny, 98% of the sampled seeds. RESULTS Comparison of mate composition between male and female function revealed high mate diversity, with almost no outcross mates shared between the two sexual functions of the same flower. CONCLUSIONS Dual sex roles contribute to a near doubling of mate diversity in our experimental population of Mimulus ringens. This finding may help explain the maintenance of hermaphroditism under conditions that would otherwise favor the evolution of separate sexes.
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Affiliation(s)
- Dorothy A. Christopher
- Department of Biological SciencesUniversity of Wisconsin – Milwaukee3209 N. Maryland AveMilwaukeeWisconsin53211USA
| | | | - Dorset W. Trapnell
- Department of Plant BiologyUniversity of Georgia120 Carlton StAthensGeorgia30602USA
| | - Patrick A. Smallwood
- Department of Plant BiologyUniversity of Georgia120 Carlton StAthensGeorgia30602USA
| | - Wendy R. Semski
- Department of Biological SciencesUniversity of Wisconsin – Milwaukee3209 N. Maryland AveMilwaukeeWisconsin53211USA
| | - Jeffrey D. Karron
- Department of Biological SciencesUniversity of Wisconsin – Milwaukee3209 N. Maryland AveMilwaukeeWisconsin53211USA
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Dellinger AS, Scheer LM, Artuso S, Fernández-Fernández D, Sornoza F, Penneys DS, Tenhaken R, Dötterl S, Schönenberger J. Bimodal Pollination Systems in Andean Melastomataceae Involving Birds, Bats, and Rodents. Am Nat 2019; 194:104-116. [DOI: 10.1086/703517] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Tonnabel J, David P, Pannell JR. Do metrics of sexual selection conform to Bateman's principles in a wind-pollinated plant? Proc Biol Sci 2019; 286:20190532. [PMID: 31213181 PMCID: PMC6599987 DOI: 10.1098/rspb.2019.0532] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Bateman's principles posit that male fitness varies more, and relies more on mate acquisition, than female fitness. While Bateman's principles should apply to any organism producing gametes of variable sizes, their application to plants is potentially complicated by the high levels of polyandry suspected for plants, and by variation in the spatial distribution of prospective mates. Here we quantify the intensity of sexual selection by classical Bateman metrics using two common gardens of the wind-pollinated dioecious plant Mercurialis annua. Consistent with Bateman's principles, males displayed significantly positive Bateman gradients (a regression of fitness on mate number), whereas the reproductive success of females was independent of their ability to access mates. A large part of male fitness was explained by their mate number, which in turn was associated with males' abilities to disperse pollen. Our results suggest that sexual selection can act in plant species in much the same way as in many animals, increasing the number of mates through traits that promote pollen dispersal.
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Affiliation(s)
- Jeanne Tonnabel
- 1 Department of Ecology and Evolution, University of Lausanne , CH-1015 Lausanne , Switzerland
| | - Patrice David
- 2 Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR 5175, CNRS, UM, Université Paul Valéry Montpellier, EPHE , 1919 route de Mende, 34293 Montpellier Cedex 5 , France
| | - John R Pannell
- 1 Department of Ecology and Evolution, University of Lausanne , CH-1015 Lausanne , Switzerland
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Minnaar C, Anderson B. Using quantum dots as pollen labels to track the fates of individual pollen grains. Methods Ecol Evol 2019. [DOI: 10.1111/2041-210x.13155] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Corneile Minnaar
- Department of Botany and Zoology; Stellenbosch University; Matieland South Africa
| | - Bruce Anderson
- Department of Botany and Zoology; Stellenbosch University; Matieland South Africa
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