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Chapman KM, Richardson FJ, Forster CY, Middleton EJT, White TE, Burke PF, Latty T. Artificial flowers as a tool for investigating multimodal flower choice in wild insects. Ecol Evol 2023; 13:e10687. [PMID: 38020672 PMCID: PMC10659823 DOI: 10.1002/ece3.10687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 10/10/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023] Open
Abstract
Flowers come in a variety of colours, shapes, sizes and odours. Flowers also differ in the quality and quantity of nutritional reward they provide to entice potential pollinators to visit. Given this diversity, generalist flower-visiting insects face the considerable challenge of deciding which flowers to feed on and which to ignore. Working with real flowers poses logistical challenges due to correlations between flower traits, maintenance costs and uncontrolled variables. Here, we overcome this challenge by designing multimodal artificial flowers that varied in visual, olfactory and reward attributes. We used artificial flowers to investigate the impact of seven floral attributes (three visual cues, two olfactory cues and two rewarding attributes) on flower visitation and species richness. We investigated how flower attributes influenced two phases of the decision-making process: the decision to land on a flower, and the decision to feed on a flower. Artificial flowers attracted 890 individual insects representing 15 morphospecies spanning seven arthropod orders. Honeybees were the most common visitors accounting for 46% of visitors. Higher visitation rates were driven by the presence of nectar, the presence of linalool, flower shape and flower colour and was negatively impacted by the presence of citral. Species richness was driven by the presence of nectar, the presence of linalool and flower colour. For hymenopterans, the probability of landing on the artificial flowers was influenced by the presence of nectar or pollen, shape and the presence of citral and/or linalool. The probability of feeding increased when flowers contained nectar. For dipterans, the probability of landing on artificial flowers increased when the flower was yellow and contained linalool. The probability of feeding increased when flowers contained pollen, nectar and linalool. Our results demonstrate the multi-attribute nature of flower preferences and highlight the usefulness of artificial flowers as tools for studying flower visitation in wild insects.
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Affiliation(s)
- Kathryn M. Chapman
- School of Life and Environmental SciencesThe University of SydneySydneyNew South WalesAustralia
| | - Freya J. Richardson
- School of Life and Environmental SciencesThe University of SydneySydneyNew South WalesAustralia
- Sydney Institute of AgricultureThe University of SydneySydneyNew South WalesAustralia
| | - Caitlyn Y. Forster
- School of Life and Environmental SciencesThe University of SydneySydneyNew South WalesAustralia
| | - Eliza J. T. Middleton
- School of Life and Environmental SciencesThe University of SydneySydneyNew South WalesAustralia
| | - Thomas E. White
- School of Life and Environmental SciencesThe University of SydneySydneyNew South WalesAustralia
| | - Paul F. Burke
- UTS Business School and Centre for Business Intelligence and Data AnalyticsUniversity of Technology SydneySydneyNew South WalesAustralia
| | - Tanya Latty
- School of Life and Environmental SciencesThe University of SydneySydneyNew South WalesAustralia
- Sydney Institute of AgricultureThe University of SydneySydneyNew South WalesAustralia
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Xiang G, Jiang Y, Lan J, Huang L, Hao L, Liu Z, Xia J. Different influences of phylogenetically conserved and independent floral traits on plant functional specialization and pollination network structure. Front Plant Sci 2023; 14:1084995. [PMID: 36760631 PMCID: PMC9902514 DOI: 10.3389/fpls.2023.1084995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/03/2023] [Indexed: 06/18/2023]
Abstract
Plant specialization and pollination network structure play important roles in community assembly. Floral traits can mediate plant-pollinator interactions and thus have important impacts on nestedness and modularity of pollination network. When such traits are phylogenetically conserved, therefore, phylogeny and traits should predict network structure to similar degrees. Moreover, conserved network structures were also found attributed to pollination syndrome or pollination system. However, we still know little about the relation between pollination syndrome and pollination network, especially under a phylogenetic framework. Herein, we established a phylogenetic framework including five floral traits (flower density, floral size, floral shape, floral symmetry, and floral color) and five species-level metrics (species strength, weighted closeness, specialization d', nestedness contribution, and modularity contribution) to test how floral traits could directly or indirectly influence species' specialization and network structure in central China. Phylogenetic signals were found in all floral traits except flower density. Structural equation model and phylogenetic structural equation model results showed that both floral size and floral density affected plant specialization and its contribution to network modularity indirectly. However, compared with phylogenetic independent flower density, phylogenetic conserved floral size had much more complexed influences, having a direct influence both on species' specialization and on modularity contribution. In this nested and modular network, abundant species with larger flowers tend to be more central and had larger values of z. Floral shape, symmetry, and color could act as co-flowering filters in pollination sharing and help to shape network modularity. Our results emphasize that phylogenetically conserved traits partially represent pollination syndrome and are important drivers for modular structure of local pollination network. This study may improve the understanding how the evolutionary history and ecological process drive local network structure and dynamics.
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Affiliation(s)
- Ganju Xiang
- Hubei Provincial Key Laboratory for Protection and Application of Special Plant Germplasm in Wuling Area of China, College of Life Sciences, South-Central Minzu University, Wuhan, Hubei, China
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, China
| | - Yunyi Jiang
- Hubei Provincial Key Laboratory for Protection and Application of Special Plant Germplasm in Wuling Area of China, College of Life Sciences, South-Central Minzu University, Wuhan, Hubei, China
| | - Jinmao Lan
- Hubei Provincial Key Laboratory for Protection and Application of Special Plant Germplasm in Wuling Area of China, College of Life Sciences, South-Central Minzu University, Wuhan, Hubei, China
| | - Liuying Huang
- Hubei Provincial Key Laboratory for Protection and Application of Special Plant Germplasm in Wuling Area of China, College of Life Sciences, South-Central Minzu University, Wuhan, Hubei, China
| | - Lijun Hao
- Hubei Provincial Key Laboratory for Protection and Application of Special Plant Germplasm in Wuling Area of China, College of Life Sciences, South-Central Minzu University, Wuhan, Hubei, China
| | - Zhiqian Liu
- Hubei Provincial Key Laboratory for Protection and Application of Special Plant Germplasm in Wuling Area of China, College of Life Sciences, South-Central Minzu University, Wuhan, Hubei, China
| | - Jing Xia
- Hubei Provincial Key Laboratory for Protection and Application of Special Plant Germplasm in Wuling Area of China, College of Life Sciences, South-Central Minzu University, Wuhan, Hubei, China
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Carlson ML, Fulkerson JR. Phenotypic selection on floral traits in the arctic plant
Parrya nudicaulis
(Brassicaceae). Ecol Evol 2022; 12:e8624. [PMID: 35261739 PMCID: PMC8888260 DOI: 10.1002/ece3.8624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 10/20/2021] [Accepted: 10/29/2021] [Indexed: 11/06/2022] Open
Abstract
The evolution of floral traits is often attributed to pollinator‐mediated selection; however, the importance of pollinators as selective agents in arctic environments is poorly resolved. In arctic and subarctic regions that are thought to be pollen limited, selection is expected to either favor floral traits that increase pollinator attraction or promote reproductive assurance through selfing. We quantified phenotypic selection on floral traits in two arctic and two subarctic populations of the self‐compatible, but largely pollinator‐dependent, Parrya nudicaulis. Additionally, we measured selection in plants in both open pollination and pollen augmentation treatments to estimate selection imposed by pollinators in one population. Seed production was found to be limited by pollen availability and strong directional selection on flower number was observed. We did not detect consistently greater magnitudes of selection on floral traits in the arctic relative to the subarctic populations. Directional selection for more pigmented flowers in one arctic population was observed, however. In some populations, selection on flower color was found to interact with other traits. We did not detect consistently stronger selection gradients across all traits for plants exposed to pollinator selection relative to those in the pollen augmentation treatment; however, directional selection tended to be higher for some floral traits in open‐pollinated plants.
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Affiliation(s)
- Matthew L. Carlson
- Alaska Center for Conservation Science University of Alaska Anchorage Anchorage Alaska USA
- Biological Sciences Department University of Alaska Anchorage Anchorage Alaska USA
| | - Justin R. Fulkerson
- Alaska Center for Conservation Science University of Alaska Anchorage Anchorage Alaska USA
- Biological Sciences Department University of Alaska Anchorage Anchorage Alaska USA
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Trunschke J, Lunau K, Pyke GH, Ren ZX, Wang H. Flower Color Evolution and the Evidence of Pollinator-Mediated Selection. Front Plant Sci 2021; 12:617851. [PMID: 34381464 PMCID: PMC8350172 DOI: 10.3389/fpls.2021.617851] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 05/14/2021] [Indexed: 06/01/2023]
Abstract
The evolution of floral traits in animal-pollinated plants involves the interaction between flowers as signal senders and pollinators as signal receivers. Flower colors are very diverse, effect pollinator attraction and flower foraging behavior, and are hypothesized to be shaped through pollinator-mediated selection. However, most of our current understanding of flower color evolution arises from variation between discrete color morphs and completed color shifts accompanying pollinator shifts, while evidence for pollinator-mediated selection on continuous variation in flower colors within populations is still scarce. In this review, we summarize experiments quantifying selection on continuous flower color variation in natural plant populations in the context of pollinator interactions. We found that evidence for significant pollinator-mediated selection is surprisingly limited among existing studies. We propose several possible explanations related to the complexity in the interaction between the colors of flowers and the sensory and cognitive abilities of pollinators as well as pollinator behavioral responses, on the one hand, and the distribution of variation in color phenotypes and fitness, on the other hand. We emphasize currently persisting weaknesses in experimental procedures, and provide some suggestions for how to improve methodology. In conclusion, we encourage future research to bring together plant and animal scientists to jointly forward our understanding of the mechanisms and circumstances of pollinator-mediated selection on flower color.
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Affiliation(s)
- Judith Trunschke
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Klaus Lunau
- Institute of Sensory Ecology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Graham H. Pyke
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- Department of Biological Sciences, Macquarie University, Ryde, NSW, Australia
| | - Zong-Xin Ren
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Hong Wang
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
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Donoso A, Rivas C, Zamorano A, Peña Á, Handford M, Aros D. Understanding Alstroemeria pallida Flower Colour: Links between Phenotype, Anthocyanins and Gene Expression. Plants (Basel) 2020; 10:plants10010055. [PMID: 33383740 PMCID: PMC7824551 DOI: 10.3390/plants10010055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/26/2020] [Accepted: 12/09/2020] [Indexed: 06/12/2023]
Abstract
Flower colour is mainly due to the accumulation of flavonoids, carotenoids and betalains in the petals. Of these pigments, flavonoids are responsible for a wide variety of colours ranging from pale yellow (flavones, flavonols and flavanodiols) to blue-violet (anthocyanins). This character plays a crucial ecological role by attracting and guiding pollinators. Moreover, in the ornamental plants market, colour has been consistently identified as the main feature chosen by consumers when buying flowers. Considering the importance of this character, the aim of this study was to evaluate flower colour in the native Chilean geophyte Alstroemeria pallida, by using three different approaches. Firstly, the phenotype was assessed using both a colour chart and a colourimeter, obtaining CIELab parameters. Secondly, the anthocyanin content of the pigmented tepals was evaluated by high-performance liquid chromatography (HPLC), and finally, the expression of two key flavonoid genes, chalcone synthase (CHS) and anthocyanidin synthase (ANS) was analysed using real-time polymerase chain reaction (PCR). Visual evaluation of A. pallida flower colour identified 5 accessions, ranging from white (Royal Horticultural Society (RHS) N999D) to pink (RHS 68C). Moreover, this visual evaluation of the accessions correlated highly with the CIELab parameters obtained by colourimetry. An anthocyanidin corresponding to a putative 6-hydroxycyanidin was identified, which was least abundant in the white accession (RHS N999D). Although CHS was not expressed differentially between the accessions, the expression of ANS was significantly higher in the accession with pink flowers (RHS 68C). These results suggest a correlation between phenotype, anthocyanin content and ANS expression for determining flower colour of A. pallida, which could be of interest for further studies, especially those related to the breeding of this species with ornamental value.
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Affiliation(s)
- Amanda Donoso
- Faculty of Agricultural Sciences, University of Chile, Santiago 8820808, Chile; (A.D.); (C.R.); (A.Z.); (Á.P.)
| | - Constanza Rivas
- Faculty of Agricultural Sciences, University of Chile, Santiago 8820808, Chile; (A.D.); (C.R.); (A.Z.); (Á.P.)
| | - Alan Zamorano
- Faculty of Agricultural Sciences, University of Chile, Santiago 8820808, Chile; (A.D.); (C.R.); (A.Z.); (Á.P.)
| | - Álvaro Peña
- Faculty of Agricultural Sciences, University of Chile, Santiago 8820808, Chile; (A.D.); (C.R.); (A.Z.); (Á.P.)
| | - Michael Handford
- Department of Biology, Faculty of Sciences, University of Chile, Santiago 7800003, Chile;
| | - Danilo Aros
- Faculty of Agricultural Sciences, University of Chile, Santiago 8820808, Chile; (A.D.); (C.R.); (A.Z.); (Á.P.)
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Christopher DA, Mitchell RJ, Karron JD. Pollination intensity and paternity in flowering plants. Ann Bot 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Paine KC, White TE, Whitney KD. Intraspecific floral color variation as perceived by pollinators and non-pollinators: evidence for pollinator-imposed constraints? Evol Ecol 2019. [DOI: 10.1007/s10682-019-09991-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Souto-Vilarós D, Vuleta A, Jovanović SM, Budečević S, Wang H, Sapir Y, Imbert E. Are pollinators the agents of selection on flower colour and size in irises? OIKOS 2018. [DOI: 10.1111/oik.04501] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Daniel Souto-Vilarós
- ISEM, Univ. de Montpellier, CNRS, IRD, EPHE; Montpellier France
- Faculty of Science, Biology center, Univ. of South Bohemia, Branišovská 1760; CZ-37005 České Budějovice Czech Republic
| | - Ana Vuleta
- Dept of Evolutionary Biology; “Siniša Stanković” Inst. for Biological Research, Univ. of Belgrade; Belgrade Serbia
| | - Sanja Manitašević Jovanović
- Dept of Evolutionary Biology; “Siniša Stanković” Inst. for Biological Research, Univ. of Belgrade; Belgrade Serbia
| | - Sanja Budečević
- Dept of Evolutionary Biology; “Siniša Stanković” Inst. for Biological Research, Univ. of Belgrade; Belgrade Serbia
| | - Hui Wang
- ISEM, Univ. de Montpellier, CNRS, IRD, EPHE; Montpellier France
- College of life sciences, Northwest A&F Univ.; Yangling Shaanxi China
| | - Yuval Sapir
- The Botanical Garden, School of Plant Sciences and Food Security, Tel Aviv Univ.; Ramat Aviv Tel Aviv Israel
| | - Eric Imbert
- ISEM, Univ. de Montpellier, CNRS, IRD, EPHE; Montpellier France
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Eidesen PB, Little L, Müller E, Dickinson KJM, Lord JM. Plant–pollinator interactions affect colonization efficiency: abundance of blue-purple flowers is correlated with species richness of bumblebees in the Arctic. Biol J Linn Soc Lond 2017. [DOI: 10.1093/biolinnean/blw006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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10
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Tang XX, Liu HL, Zhang C, Wang Y, Zhang X, Yi Y. Flower Colour Polymorphism inGeranium nepalense(Geraniaceae): Adaptation to Non-Pollinator Agents. Polish Journal of Ecology 2016. [DOI: 10.3161/15052249pje2016.64.4.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Wang H, Talavera M, Min Y, Flaven E, Imbert E. Neutral processes contribute to patterns of spatial variation for flower colour in the Mediterranean Iris lutescens (Iridaceae). Ann Bot 2016; 117:995-1007. [PMID: 27084922 PMCID: PMC4866319 DOI: 10.1093/aob/mcw036] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 12/28/2015] [Accepted: 01/17/2016] [Indexed: 05/25/2023]
Abstract
BACKGROUND AND AIMS Flower colour polymorphism in plants has been used as a classic model for understanding the importance of neutral processes vs. natural selection in population differentiation. However, current explanations for the maintenance of flower colour polymorphism mainly rely on balancing selection, while neutral processes have seldom been championed. Iris lutescens (Iridaceae) is a widespread species in the northern Mediterranean basin, which shows a stable and striking purple-yellow flower colour polymorphism. To evaluate the roles of neutral processes in the spatial variation for flower colour in this species, patterns of neutral genetic variation across its distribution range were quantified, and phenotypic differentiation was compared with neutral genetic differentiation. METHODS Genetic diversity levels and population genetic structure were investigated through the genotyping of a collection of 1120 individuals in 41 populations ranging from Spain to France, using a set of eight newly developed microsatellite markers. In addition, phenotypic differentiation for flower colour was also quantified by counting colour morph frequency in each population, and measuring the reflectance spectra of sampled individuals. KEY RESULTS Populations in Spain present a sharp colour transition from solely purple to solely yellow. The results provide evidence that genetic drift through limited gene flow is important in the evolution of monomorphic populations. In contrast, most populations in France are polymorphic with both phenotypes, and the colour frequencies vary geographically without any spatial gradients observed. A pattern of isolation by distance is detected in France, and gene flow between adjacent populations seems to be an important factor maintaining populations polymorphic. CONCLUSIONS Overall, neutral processes contribute to patterns of spatial variation for flower colour in I. lutescens, but it cannot be excluded that natural selection is also operating. An interaction between neutral processes and natural selection is suggested to explain the spatial variation for flower colour in I. lutescens.
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Affiliation(s)
- Hui Wang
- Institut des Sciences de l'Évolution de Montpellier (ISEM), UMR 5554, Université de Montpellier, Montpellier, France and
| | - María Talavera
- Institut des Sciences de l'Évolution de Montpellier (ISEM), UMR 5554, Université de Montpellier, Montpellier, France and
| | - Ya Min
- Institut des Sciences de l'Évolution de Montpellier (ISEM), UMR 5554, Université de Montpellier, Montpellier, France and
| | - Elodie Flaven
- Institut des Sciences de l'Évolution de Montpellier (ISEM), UMR 5554, Université de Montpellier, Montpellier, France and
| | - Eric Imbert
- Institut des Sciences de l'Évolution de Montpellier (ISEM), UMR 5554, Université de Montpellier, Montpellier, France and
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Gross K, Sun M, Schiestl FP. Why Do Floral Perfumes Become Different? Region-Specific Selection on Floral Scent in a Terrestrial Orchid. PLoS One 2016; 11:e0147975. [PMID: 26886766 DOI: 10.1371/journal.pone.0147975] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 01/11/2016] [Indexed: 12/01/2022] Open
Abstract
Geographically structured phenotypic selection can lead to adaptive divergence. However, in flowering plants, such divergent selection has rarely been shown, and selection on floral signals is generally little understood. In this study, we measured phenotypic selection on display size, floral color, and floral scent in four lowland and four mountain populations of the nectar-rewarding terrestrial orchid Gymnadenia odoratissima in two years. We also quantified population differences in these traits and pollinator community composition. Our results show positive selection on display size and positive, negative, or absence of selection on different scent compounds and floral color. Selection on the main scent compounds was consistently stronger in the lowlands than in the mountains, and lowland plants emitted higher amounts of most of these compounds. Pollinator community composition also differed between regions, suggesting different pollinators select for differences in floral volatiles. Overall, our study is the first to document consistent regional differences in selection on floral scent, suggesting this pattern of selection is one of the evolutionary forces contributing to regional divergence in floral chemical signaling.
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Carlson JE, Holsinger KE. Extrapolating from local ecological processes to genus-wide patterns in colour polymorphism in South African Protea. Proc Biol Sci 2015; 282:20150583. [PMID: 25876847 PMCID: PMC4426637 DOI: 10.1098/rspb.2015.0583] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 03/20/2015] [Indexed: 11/12/2022] Open
Abstract
Polymorphic traits are central to many fundamental discoveries in evolution, yet why they are found in some species and not others remains poorly understood. We use the African genus Protea-within which more than 40% of species have co-occurring pink and white floral colour morphs-to ask whether convergent evolution and ecological similarity could explain the genus-wide pattern of polymorphism. First, we identified environmental correlates of pink morph frequency across 28 populations of four species. Second, we determined whether the same correlates could predict species-level polymorphism and monomorphism across 31 species. We found that pink morph frequency increased with elevation in Protea repens and three section Exsertae species, increased eastward in P. repens, and increased with seed predation intensity in section Exsertae. For cross-species comparisons, populations of monomorphic pink species occurred at higher elevations than populations of monomorphic white species, and 18 polymorphic species spanned broader elevational gradients than 13 monomorphic species. These results suggest that divergent selection along elevational clines has repeatedly favoured polymorphism, and that more uniform selection in altitudinally restricted species may promote colour monomorphism. Our findings are, to our knowledge, the first to link selection acting within species to the presence and absence of colour polymorphism at broader phylogenetic scales.
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Affiliation(s)
- Jane E Carlson
- Department of Ecology and Evolutionary Biology, University of Connecticut, U-3043, Storrs, CT 06269, USA
| | - Kent E Holsinger
- Department of Ecology and Evolutionary Biology, University of Connecticut, U-3043, Storrs, CT 06269, USA
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McGimpsey VJ, Lord JM. In a world of white, flower colour matters: A white-purple transition signals lack of reward in an alpineEuphrasia. AUSTRAL ECOL 2015. [DOI: 10.1111/aec.12238] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Vicky J. McGimpsey
- Department of Botany; University of Otago; PO Box 56 Dunedin 9054 New Zealand
| | - Janice M. Lord
- Department of Botany; University of Otago; PO Box 56 Dunedin 9054 New Zealand
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15
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Davis SL, Dudle DA, Nawrocki JR, Freestone LM, Konieczny P, Tobin MB, Britton MM. Sexual dimorphism of staminate- and pistillate-phase flowers of Saponaria officinalis (bouncing bet) affects pollinator behavior and seed set. PLoS One 2014; 9:e93615. [PMID: 24690875 PMCID: PMC3972141 DOI: 10.1371/journal.pone.0093615] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 03/07/2014] [Indexed: 01/25/2023] Open
Abstract
The sequential separation of male and female function in flowers of dichogamous species allows for the evolution of differing morphologies that maximize fitness through seed siring and seed set. We examined staminate- and pistillate-phase flowers of protandrous Saponaria officinalis for dimorphism in floral traits and their effects on pollinator attraction and seed set. Pistillate-phase flowers have larger petals, greater mass, and are pinker in color, but due to a shape change, pistillate-phase flowers have smaller corolla diameters than staminate-phase flowers. There was no difference in nectar volume or sugar content one day after anthesis, and minimal evidence for UV nectar guide patterns in staminate- and pistillate-phase flowers. When presented with choice arrays, pollinators discriminated against pistillate-phase flowers based on their pink color. Finally, in an experimental garden, in 2012 there was a negative correlation between seed set of an open-pollinated, emasculated flower and pinkness (as measured by reflectance spectrometry) of a pistillate-phase flower on the same plant in plots covered with shade cloth. In 2013, clones of genotypes chosen from the 2012 plants that produced pinker flowers had lower seed set than those from genotypes with paler flowers. Lower seed set of pink genotypes was found in open-pollinated and hand-pollinated flowers, indicating the lower seed set might be due to other differences between pink and pale genotypes in addition to pollinator discrimination against pink flowers. In conclusion, staminate- and pistillate-phase flowers of S. officinalis are dimorphic in shape and color. Pollinators discriminate among flowers based on these differences, and individuals whose pistillate-phase flowers are most different in color from their staminate-phase flowers make fewer seeds. We suggest morphological studies of the two sex phases in dichogamous, hermaphroditic species can contribute to understanding the evolution of sexual dimorphism in plants without the confounding effects of genetic differences between separate male and female individuals.
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Affiliation(s)
- Sandra L. Davis
- University of Indianapolis, Department of Biology, Indianapolis, Indiana, United States of America
- * E-mail:
| | - Dana A. Dudle
- DePauw University, Department of Biology, Greencastle, Indiana, United States of America
| | - Jenna R. Nawrocki
- University of Indianapolis, Department of Biology, Indianapolis, Indiana, United States of America
| | - Leah M. Freestone
- DePauw University, Department of Biology, Greencastle, Indiana, United States of America
| | - Peter Konieczny
- DePauw University, Department of Biology, Greencastle, Indiana, United States of America
| | - Michael B. Tobin
- DePauw University, Department of Biology, Greencastle, Indiana, United States of America
| | - Michael M. Britton
- DePauw University, Department of Biology, Greencastle, Indiana, United States of America
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Campbell DR, Forster M, Bischoff M. Selection of trait combinations through bee and fly visitation to flowers of Polemonium foliosissimum. J Evol Biol 2013; 27:325-36. [PMID: 24341383 DOI: 10.1111/jeb.12295] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 11/11/2013] [Accepted: 11/11/2013] [Indexed: 11/27/2022]
Abstract
Pollinators are known to exert natural selection on floral traits, but the extent to which combinations of floral traits are subject to correlational selection (nonadditive effects of two traits on fitness) is not well understood. Over two years, we used phenotypic manipulations of plant traits to test for effects of flower colour, flower shape and their interaction on rates of pollinator visitation to Polemonium foliosissimum. We also tested for correlational selection based on weighting visitation by the amount of conspecific pollen delivered per visit by each category of insect visitor. Although bumblebees were the presumed pollinators, solitary bees and flies contributed substantially (42%) to pollination. In manipulations of one trait at a time, insects visited flowers presenting the natural colour and shape over flowers manipulated to present artificial mutants with either paler colour or a more open or more tubular flower. When both colour and shape were manipulated in combination, selection on both traits arose, with bumblebees responding mainly to colour and flies responding mainly to shape. Despite selection on both floral traits, in a year with many bumblebees, we saw no evidence for correlational selection of these traits. In a year when flies predominated, fly visitation showed a pattern of correlational selection, but not favouring the natural phenotype, and correlational selection was still not detected for expected pollen receipt. These results show that flower colour and shape are subject to pollinator-mediated selection and that correlational selection can be generated based on pollinator visitation alone, but provide no evidence for correlational selection specifically for the current phenotype.
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Affiliation(s)
- D R Campbell
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, USA; Rocky Mountain Biological Laboratory, Crested Butte, CO, USA
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Campbell DR, Bischoff M. Selection for a floral trait is not mediated by pollen receipt even though seed set in the population is pollen-limited. Funct Ecol 2013. [DOI: 10.1111/1365-2435.12131] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Diane R. Campbell
- Department of Ecology and Evolutionary Biology; University of California; Irvine; CA; 92697,; USA
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BISCHOFF MASCHA, CAMPBELL DIANER, LORD JANICEM, ROBERTSON ALASTAIRW. The relative importance of solitary bees and syrphid flies as pollinators of two outcrossing plant species in the New Zealand alpine. AUSTRAL ECOL 2012. [DOI: 10.1111/j.1442-9993.2012.02389.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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