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Qin H, Yi X. Mast seeding is stronger in taller plants. FRONTIERS IN PLANT SCIENCE 2024; 15:1382824. [PMID: 39045592 PMCID: PMC11264343 DOI: 10.3389/fpls.2024.1382824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 06/11/2024] [Indexed: 07/25/2024]
Abstract
Introduction Two economies of scale, predator satiation and pollination efficiency, have been proposed to explain the evolutionary mechanisms of mast seeding adopted by some long-lived plants. Plant height is strongly selected by pollination vectors and may also provide economies of scale; however, it remains unknown whether there is a close relationship between adult plant height and mast seeding intensity. Methods Here, we analyzed mast seeding intensity of 158 plant species to test if adult plant height can select for mast seeding. Results We show that mast seeding intensities are higher in taller plant species irrespective of phylogeny, life form, pollination vector, and type of Spermatophytes. We also show that anemophily rather than entomophily selects for taller plant species and higher mast seeding intensities. Discussion The linear correlations and evolutionary links between adult plant height and mast seeding intensity provide evidence that mast seeding could have evolved as an adaptation to taller strategy of perennial plant species.
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Wróblewska A, Ostrowiecka B, Kotowicz J, Jermakowicz E, Tałałaj I, Szefer P. What are the drivers of female success in food-deceptive orchids? Ecol Evol 2024; 14:e11233. [PMID: 38646005 PMCID: PMC11026981 DOI: 10.1002/ece3.11233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 03/05/2024] [Accepted: 03/20/2024] [Indexed: 04/23/2024] Open
Abstract
A large suite of floral signals, and environmental and biotic characteristics influence the behavior of pollinators, affecting the female success of food-deceptive orchids. In this study, we examined the many factors shaping the reproductive output of three orchid taxa: Dactylorhiza majalis, D. incarnata var. incarnata, and D. fuchsii. We applied a statistical model to correlate female success (number of fruit sets) with individual characteristics (plant and inflorescence height, number of flowers, and spur length), number of pollinaria removed, flowering time, and density of floral units of co-flowering rewarding plants. Our findings suggested that the broad spectrum of variations in Dactylorhiza's morphological traits, floral display, and flowering phenology within different environmental contexts has a significant impact on their reproductive success. The number of fruits increased with an increase in the number of pollinaria removed in the studied Dactylorhiza taxa. In contrast, a higher number of flowers per inflorescence and higher inflorescences in relation to individual height always decreased fruit set. We observed that low number of co-flowering rewarding plants in populations could affect the Dactylorhiza reproductive output as magnets and competitor plants. The synchronization of flowering, or lack thereof, between Dactylorhiza and rewarding plants can limit reproductive success. This demonstrates that the food deception strategy is multidirectional, and reproductive output can vary considerably both spatially and temporally within the context of this strategy.
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Affiliation(s)
- Ada Wróblewska
- Faculty of BiologyUniversity of BialystokBiałystokPoland
| | | | | | | | | | - Piotr Szefer
- Faculty of ScienceUniversity of South BohemiaČeské BudějoviceCzech Republic
- Biology Centre, Institute of EntomologyCzech Academy of SciencesČeské BudějoviceCzech Republic
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Pontarp M, Runemark A, Friberg M, Opedal ØH, Persson AS, Wang L, Smith HG. Evolutionary plant-pollinator responses to anthropogenic land-use change: impacts on ecosystem services. Biol Rev Camb Philos Soc 2024; 99:372-389. [PMID: 37866400 DOI: 10.1111/brv.13026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 10/06/2023] [Accepted: 10/09/2023] [Indexed: 10/24/2023]
Abstract
Agricultural intensification at field and landscape scales, including increased use of agrochemicals and loss of semi-natural habitats, is a major driver of insect declines and other community changes. Efforts to understand and mitigate these effects have traditionally focused on ecological responses. At the same time, adaptations to pesticide use and habitat fragmentation in both insects and flowering plants show the potential for rapid evolution. Yet we lack an understanding of how such evolutionary responses may propagate within and between trophic levels with ensuing consequences for conservation of species and ecological functions in agroecosystems. Here, we review the literature on the consequences of agricultural intensification on plant and animal evolutionary responses and interactions. We present a novel conceptualization of evolutionary change induced by agricultural intensification at field and landscape scales and emphasize direct and indirect effects of rapid evolution on ecosystem services. We exemplify by focusing on economically and ecologically important interactions between plants and pollinators. We showcase available eco-evolutionary theory and plant-pollinator modelling that can improve predictions of how agricultural intensification affects interaction networks, and highlight available genetic and trait-focused methodological approaches. Specifically, we focus on how spatial genetic structure affects the probability of propagated responses, and how the structure of interaction networks modulates effects of evolutionary change in individual species. Thereby, we highlight how combined trait-based eco-evolutionary modelling, functionally explicit quantitative genetics, and genomic analyses may shed light on conditions where evolutionary responses impact important ecosystem services.
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Affiliation(s)
- Mikael Pontarp
- Department of Biology, Lund University, Sölvegatan 37, Lund, 22362, Sweden
| | - Anna Runemark
- Department of Biology, Lund University, Sölvegatan 37, Lund, 22362, Sweden
| | - Magne Friberg
- Department of Biology, Lund University, Sölvegatan 37, Lund, 22362, Sweden
| | - Øystein H Opedal
- Department of Biology, Lund University, Sölvegatan 37, Lund, 22362, Sweden
| | - Anna S Persson
- Centre for Environmental and Climate Science (CEC), Lund University, Sölvegatan 37, Lund, 22362, Sweden
| | - Lingzi Wang
- Centre for Environmental and Climate Science (CEC), Lund University, Sölvegatan 37, Lund, 22362, Sweden
- School of Mathematical Sciences, University of Southampton, 58 Salisbury Rd, Southampton, SO17 1BJ, UK
| | - Henrik G Smith
- Department of Biology, Lund University, Sölvegatan 37, Lund, 22362, Sweden
- Centre for Environmental and Climate Science (CEC), Lund University, Sölvegatan 37, Lund, 22362, Sweden
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Surina B, Balant M, Glasnović P, Gogala A, Fišer Ž, Satovic Z, Liber Z, Radosavljević I, Classen-Bockhoff R. Lack of pollinators selects for increased selfing, restricted gene flow and resource allocation in the rare Mediterranean sage Salvia brachyodon. Sci Rep 2024; 14:5017. [PMID: 38424151 PMCID: PMC10904396 DOI: 10.1038/s41598-024-55344-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 02/22/2024] [Indexed: 03/02/2024] Open
Abstract
Range contraction and habitat fragmentation can cause biodiversity loss by creating conditions that directly or indirectly affect the survival of plant populations. Fragmented habitats can alter pollinator guilds and impact their behavior, which may result in pollen/pollinator limitation and selection for increased selfing as a mechanism for reproductive assurance. We used Salvia brachyodon, a narrowly distributed and endangered sage from eastern Adriatic, to test the consequences of range contraction and habitat fragmentation. Molecular data indicate a severe and relatively recent species range reduction. While one population is reproductively almost completely isolated, moderate gene flow has been detected between the remaining two populations. The high pollen-to-ovule ratio and the results of controlled hand pollination indicate that S. brachyodon has a mixed mating system. Quantitative and qualitative differences in the community and behaviour of flower visitors resulted in limited pollination services in one population where no effective pollinator other than pollen and nectar robbers were observed. In this population, self-pollination predominated over cross-pollination. Various environmental factors, in which plant-pollinator interactions play a pivotal role, have likely created selection pressures that have led to genetic and phenotypic differentiation and different resource allocation strategies among populations.
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Affiliation(s)
- Boštjan Surina
- Natural History Museum Rijeka, Lorenzov Prolaz 1, 51000, Rijeka, Croatia.
- Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Glagoljaška 8, 6000, Koper, Slovenia.
| | - Manica Balant
- Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Glagoljaška 8, 6000, Koper, Slovenia
- Institut Botànic de Barcelona (IBB, CSIC-Ajuntament de Barcelona), Passeig del Migdia S.N., Parc de Montjuïc, 08038, Barcelona, Spain
| | - Peter Glasnović
- Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Glagoljaška 8, 6000, Koper, Slovenia
| | - Andrej Gogala
- Slovenian Museum of Natural History, Prešernova cesta 20, P.O. Box 290, 1001, Ljubljana, Slovenia
| | - Živa Fišer
- Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Glagoljaška 8, 6000, Koper, Slovenia
| | - Zlatko Satovic
- Department of Plant Biodiversity, University of Zagreb, Faculty of Agriculture, Svetošimunska Cesta 25, 10000, Zagreb, Croatia
- Centre of Excellence for Biodiversity and Molecular Plant Breeding, Svetošimunska Cesta 25, 10000, Zagreb, Croatia
| | - Zlatko Liber
- Centre of Excellence for Biodiversity and Molecular Plant Breeding, Svetošimunska Cesta 25, 10000, Zagreb, Croatia
- Division of Botany, Department of Biology, Faculty of Science, University of Zagreb, Marulićev Trg 9A, 10000, Zagreb, Croatia
| | - Ivan Radosavljević
- Centre of Excellence for Biodiversity and Molecular Plant Breeding, Svetošimunska Cesta 25, 10000, Zagreb, Croatia
- Division of Botany, Department of Biology, Faculty of Science, University of Zagreb, Marulićev Trg 9A, 10000, Zagreb, Croatia
| | - Regine Classen-Bockhoff
- Institute of Organismic and Molecular Evolution, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
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Brzosko E, Bajguz A, Burzyńska J, Chmur M. In Which Way Do the Flower Properties of the Specialist Orchid Goodyera repens Meet the Requirements of Its Generalist Pollinators? Int J Mol Sci 2023; 24:ijms24108602. [PMID: 37239948 DOI: 10.3390/ijms24108602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/08/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
This article is the next part of a series of studies documenting the influence of flower traits on the reproductive success (RS) of orchids. Knowledge of factors influencing RS helps to understand the mechanisms and processes crucial for shaping plant-pollinator interactions. The aim of the present study was to determine the role of flower structure and nectar composition in shaping the RS of the specialist orchid Goodyea repens, which is pollinated by generalist bumblebees. We found a high level of pollinaria removal (PR) and female reproductive success (fruiting, FRS) as well as a high level of variation between populations, although in certain populations pollination efficiency was low. Floral display traits, mainly inflorescence length, influenced FRS in certain populations. Among the flower traits, only the height of flowers was correlated with FRS in one population, suggesting that the flower structure of this orchid is well adapted to pollination by bumblebees. The nectar of G. repens is diluted and dominated by hexoses. Sugars were less important in shaping RS than amino acids. At the species level, twenty proteogenic and six non-proteogenic AAs were noted, along with their differentiated amounts and participation in particular populations. We found that distinct AAs or their groups mainly shaped PR, especially when correlations were considered at the species level. Our results suggest that both the individual nectar components and the ratios between them have an impact on G. repens RS. Because different nectar components influence the RS parameters in different ways (i.e., negatively or positively), we suggest that different Bombus species play the role of main pollinators in distinct populations.
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Affiliation(s)
- Emilia Brzosko
- Department of Biology and Plant Ecology, Faculty of Biology, University of Bialystok, Ciolkowskiego 1J, 15-245 Bialystok, Poland
| | - Andrzej Bajguz
- Department of Biology and Plant Ecology, Faculty of Biology, University of Bialystok, Ciolkowskiego 1J, 15-245 Bialystok, Poland
| | - Justyna Burzyńska
- Department of Biology and Plant Ecology, Faculty of Biology, University of Bialystok, Ciolkowskiego 1J, 15-245 Bialystok, Poland
| | - Magdalena Chmur
- Department of Biology and Plant Ecology, Faculty of Biology, University of Bialystok, Ciolkowskiego 1J, 15-245 Bialystok, Poland
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Lanzino M, Palermo AM, Pellegrino G. The effect of inflorescence display size and flower position on pollination success in two deceptive and one rewarding orchid. PLANT BIOLOGY (STUTTGART, GERMANY) 2023; 25:396-402. [PMID: 36719068 DOI: 10.1111/plb.13505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 01/17/2023] [Indexed: 06/18/2023]
Abstract
Inflorescence display size and flower position on the inflorescence play important roles in plant reproduction, in the formation of fruits and are primarily linked to pollinator behaviour. We used three orchids to determine how visitation rates and choice of pollinator depend on number and position of the flowers along the inflorescence. We measured reproductive success in (1) natural conditions, (2) hand-pollination experiments and (3) an experimental design, by modifying composition of inflorescences in populations of two deceptive orchids, Orchis anthropophora and O. italica, and one rewarding orchid, Anacamptis coriophora subsp. fragrans. There were no differences in natural fruit production in relation to flower position on the inflorescence (i.e. upper versus lower part), suggesting no preference of pollinators for different parts of the inflorescence. Hand-pollination experiments highlighted low pollen limitation in A. coriophora subsp. fragrans but high limitation in O. italica and O. anthropophora. Reproductive success of deceptive orchids in experimental plots decreased significantly when flowers on the upper half of the inflorescence were removed leading to reduced floral display, while reproductive success of the nectariferous species did not differ significantly. Our data highlight that in the examined orchids there is no clear relationship between fruit formation and flower position along inflorescences. Thus we can affirm that, for orchids, the entire inflorescence plays a dominant role in insect attraction but the part of the flower spike does not influence the choice of the insect. This implies that all flowers have the same possibility of receiving visits from pollinators, and therefore each flower has the same opportunity to set fruit.
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Affiliation(s)
- M Lanzino
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Cosenza, Italy
| | - A M Palermo
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Cosenza, Italy
| | - G Pellegrino
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Cosenza, Italy
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Brzosko E, Bajguz A, Burzyńska J, Chmur M. Does Reproductive Success in Natural and Anthropogenic Populations of Generalist Epipactis helleborine Depend on Flower Morphology and Nectar Composition? Int J Mol Sci 2023; 24:4276. [PMID: 36901705 PMCID: PMC10001846 DOI: 10.3390/ijms24054276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/17/2023] [Accepted: 02/18/2023] [Indexed: 02/24/2023] Open
Abstract
The purpose of our study was to determine the role of flower structure and nectar composition in shaping the reproductive success (RS) of the generalist orchid Epipactis helleborine in natural and anthropogenic populations. We supposed that the distinct character of two groups of habitats creates different conditions for plant-pollinator relationships, thus influencing reproductive success in E. helleborine populations. Both pollinaria removal (PR) and fruiting (FRS) were differentiated between the populations. On average, FRS was almost two times higher in the anthropogenic than in the natural populations. The difference between the two population groups in PR was smaller but still statistically significant. RS parameters were correlated with some floral display and flower traits. Floral display influenced RS only in three anthropogenic populations. Flower traits had a weak influence on RS (10 of the 192 cases analyzed). The more important trait in shaping RS was nectar chemistry. The nectar of E. helleborine is relatively diluted with a lower sugar concentration in the anthropogenic than in the natural populations. In the natural populations, domination of sucrose over hexoses was found, while in the anthropogenic populations, hexoses were more abundant and the participation of sugars was balanced. In some populations, sugars influenced RS. In E. helleborine nectar, 20 proteogenic and 7 non-proteogenic amino acids (AAs) were found with a clear domination of glutamic acid. We noted relationships between some AAs and RS, but distinct AAs shaped RS in different populations, and their impact was independent of their participation. Our results indicate that the flower structure and nectar composition of E. helleborine reflect its generalistic character and meet the requirements of a wide range of pollinators. Simultaneously, the differentiation of flower traits suggests a variation in pollinator assemblages in particular populations. Knowledge about the factors influencing RS in distinct habitats helps to understand the evolutionary potential of species and to understand mechanisms and processes crucial for shaping interactions between plants and pollinators.
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Affiliation(s)
- Emilia Brzosko
- Department of Biology and Plant Ecology, Faculty of Biology, University of Bialystok, Ciolkowskiego 1J, 15-245 Bialystok, Poland
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Koski MH. Pollinators exert selection on floral traits in a pollen-limited, narrowly endemic spring ephemeral. AMERICAN JOURNAL OF BOTANY 2023; 110:e16101. [PMID: 36371765 PMCID: PMC10108127 DOI: 10.1002/ajb2.16101] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
PREMISE Floral traits are frequently under pollinator-mediated selection, especially in taxa subject to strong pollen-limitation, such as those reliant on pollinators. However, antagonists can be agents of selection on floral traits as well. The causes of selection acting on spring ephemerals are understudied though these species can experience particularly strong pollen-limitation. I examined pollinator- and antagonist-mediated selection in a narrowly endemic spring ephemeral, Trillium discolor. METHODS I measured pollen limitation in T. discolor across two years and evaluated its breeding system. I compared selection on floral traits (display height, petal size, petal color, flowering time) between open-pollinated, and pollen-supplemented plants to measure the strength and mode of pollinator-mediated selection. I assessed whether natural levels of antagonism impacted selection on floral traits. RESULTS Trillium discolor was self-incompatible and experienced pollen limitation in both years of the study. Pollinators exerted negative disruptive selection on display height and petals size. In one year, pollinator-mediated selection favored lighter petals but in the second year pollinators favored darker petals. Antagonist damage did not alter selection on floral traits. CONCLUSIONS Results demonstrate that pollinators mediate the strength and mode of selection on floral traits in T. discolor. Interannual variation in the strength, mode, and direction of pollinator-mediated selection on floral traits could be important for maintaining of floral diversity in this system. Observed levels of antagonism were weak agents of selection on floral traits.
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Affiliation(s)
- Matthew H. Koski
- Department of Biological SciencesClemson UniversityClemsonSouth Carolina29634USA
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Chen M, Zhao XY, Yue P, Guo XX, Qiao JJ, Li XY. Effect of grazing disturbance on floral display, pollen limitation and plant pollination efficiency in the desert steppe. BMC PLANT BIOLOGY 2022; 22:514. [PMID: 36329386 PMCID: PMC9635133 DOI: 10.1186/s12870-022-03899-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 10/21/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Grazing disturbance usually affects floral display and pollination efficiency in the desert steppe, which may cause pollen limitation in insect-pollinated plants. Effective pollination is essential for the reproductive success of insect-pollinated plants and insufficient pollen transfer may result in pollen limitation. Caragana microphylla Lam is an arid region shrub with ecological importance. Few studies have been conducted on how grazing disturbance influences pollen limitation and pollination efficiency of C. microphylla. Here, we quantify the effect of different grazing intensities on floral display, pollinator visitation frequency and seed production in the Urat desert steppe. RESULTS In C. microphylla, supplemental hand pollination increased the seed set, and pollen limitation was the predominant limiting factor. As the heavy grazing significantly reduced the seed set in plants that underwent open-pollination, but there was no significant difference in the seed set between plants in the control plots and plants in the moderate grazing plots. Furthermore, there was a higher pollinator visitation frequency in plants in the control plots than in plants in the heavy grazing plots. CONCLUSIONS We found that pollinator visitation frequency was significantly associated with the number of open flowers. Our findings also demonstrated that seed production is associated with pollinator visitation frequency, as indicated by increased seed production in flowers with higher pollinator visitation frequency. Therefore, this study provides insight into the effect of different grazing intensities on floral display that are important for influencing pollinator visitation frequency and pollination efficiency in desert steppes.
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Affiliation(s)
- Min Chen
- Northwest Institute of Eco-Environment and Resources, CAS, Lanzhou, 730000, China.
- Urat Desert-Grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China.
- Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions, Lanzhou, 730000, Gansu Province, China.
| | - Xue-Yong Zhao
- Northwest Institute of Eco-Environment and Resources, CAS, Lanzhou, 730000, China
- Urat Desert-Grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
- Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Ping Yue
- Northwest Institute of Eco-Environment and Resources, CAS, Lanzhou, 730000, China
- Urat Desert-Grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
- Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions, Lanzhou, 730000, Gansu Province, China
| | - Xin-Xin Guo
- Northwest Institute of Eco-Environment and Resources, CAS, Lanzhou, 730000, China
- Urat Desert-Grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Jing-Juan Qiao
- Northwest Institute of Eco-Environment and Resources, CAS, Lanzhou, 730000, China
- Urat Desert-Grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Xiang-Yun Li
- Northwest Institute of Eco-Environment and Resources, CAS, Lanzhou, 730000, China
- Urat Desert-Grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
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Artuso S, Gamisch A, Staedler YM, Schönenberger J, Comes HP. Evidence for an evo-devo-derived hypothesis on three-dimensional flower shape modularity in a tropical orchid clade. Evolution 2022; 76:2587-2604. [PMID: 36128635 PMCID: PMC9828045 DOI: 10.1111/evo.14621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 08/21/2022] [Accepted: 08/26/2022] [Indexed: 01/22/2023]
Abstract
Covarying suites of phenotypic traits, or modules, are increasingly recognized to promote morphological evolution. However, information on how modularity influences flower diversity is rare and lacking for Orchidaceae. Here, we combine high-resolution X-ray computed tomography scanning with three-dimensional geometric morphometrics and phylogenetic comparative methods to test various hypotheses about three-dimensional patterns of flower evolutionary modularity in Malagasy Bulbophyllum orchids and examine rates and modes of module evolution. Based on the four evolutionary modules identified (i.e., sepals, lateral petals, labellum + column-foot, and column-part), our data support the hypothesis that both genetic-developmental and functional adaptive factors shaped evolutionary flower trait covariation in these tropical orchids. In line with "evo-devo" studies, we also find that the labellum evolved independently from the rest of the petal whorl. Finally, we show that modules evolved with different rates, and either in a neutral fashion (only column-part) or under selective constraints, as likely imposed by pollinators. Overall, this study supports current views that modular units can enhance the range and rate of morphological evolution.
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Affiliation(s)
- Silvia Artuso
- Department of Environment and BiodiversityUniversity of SalzburgSalzburg5020Austria
| | - Alexander Gamisch
- Department of Environment and BiodiversityUniversity of SalzburgSalzburg5020Austria
| | - Yannick M. Staedler
- Department of Botany and Biodiversity ResearchUniversity of ViennaVienna1030Austria
| | - Jürg Schönenberger
- Department of Botany and Biodiversity ResearchUniversity of ViennaVienna1030Austria
| | - Hans Peter Comes
- Department of Environment and BiodiversityUniversity of SalzburgSalzburg5020Austria
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Predicting the potential distribution of Dactylorhiza hatagirea (D. Don) Soo-an important medicinal orchid in the West Himalaya, under multiple climate change scenarios. PLoS One 2022; 17:e0269673. [PMID: 35714160 PMCID: PMC9205508 DOI: 10.1371/journal.pone.0269673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 05/25/2022] [Indexed: 12/03/2022] Open
Abstract
Climate variability coupled with anthropogenic pressures is the most critical driver in the Himalayan region for forest ecosystem vulnerability. Dactylorhiza hatagirea (D.Don) Soo is an important yet highly threatened medicinal orchid from the Himalayan region. Poor regenerative power and growing demand have resulted in the steep decline of its natural habitats populations. The present study aims to identify the habitat suitability of D. hatagirea in the Western Himalaya using the maximum entropy model (MaxEnt). The community climate system model (CCSM ver. 4) based on representative concentration pathways (RCPs) was used to determine suitable future areas. Sixteen least correlated (< 0.8) bioclimatic, topographical and geomorphic variables were used to construct the species climatic niche. The dominant contributing variables were elevation (34.85%) followed by precipitation of the coldest quarter (23.04%), soil type (8.77%), land use land cover (8.26%), mean annual temperature (5.51%), and temperature seasonality (5.11%). Compared to the present distribution, habitat suitability under future projection, i.e., RCP 4.5 and RCP 8.5 (2050 and 2070), was found to shift to higher elevation towards the northwest direction, while lower altitudes will invariably be less suitable. Further, as compared to the current distribution, the climatic niche space of the species is expected to expand in between11.41–22.13% in the near future. High habitats suitability areas are mainly concentrated in the forest range like Dharchula and Munsyari range, Pindar valley, Kedarnath Wildlife Sanctuary, West of Nanda Devi Biosphere Reserve, and Uttarkashi forest division. The present study delineated the fundamental niche baseline map of D. hatagirea in the Western Himalayas and highlighted regions/areas where conservation and management strategies should be intensified in the next 50 years. In addition, as the species is commercially exploited illegally, the information gathered is essential for conservationists and planners who protect the species at the regional levels.
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Huang X, Chen M, Wang L, Yang M, Yang N, Li Z, Duan Y. Phenotypic Selection in Halenia elliptica D. Don (Gentianaceae), an Alpine Biennial with Mixed Mating System. PLANTS (BASEL, SWITZERLAND) 2022; 11:1488. [PMID: 35684261 PMCID: PMC9183009 DOI: 10.3390/plants11111488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/30/2022] [Accepted: 05/30/2022] [Indexed: 11/16/2022]
Abstract
The transition from outcrossing to selfing is a common evolutionary trend in flowering plants, and floral traits change significantly with the evolution of selfing. Whether or not plant traits are subjected to selection remains an open question in species with mixed mating systems. We examined phenotypic selection in two populations of Halenia elliptica with different selfing rates. We found that the pollen-ovule ratio, seed size, plant height, spur length, and pollinator visitation rate in the population with the higher selfing rate were lower than those in the population with the lower selfing rate. Selfing provides reproductive assurance for populations when pollinator service is low, and the floral traits that are associated with selfing syndrome are evident in populations with a higher selfing rate but are subjected to weak selection in each of the two populations with different selfing rates. Directional selection for an early flowering time indicated that late blooming flowers could experience a risk of seed development in alpine environments, and for large plants, selection indicated that seed production could be limited by the available resources. The floral traits that are associated with pollinator attraction and specialization could be subjected to weak selection at the plant level as selfing evolves, and the selective pressures that are independent of pollinators might not change significantly; highlighting the selective biotic and abiotic pressures that shape the morphological traits of plant species and their independence from the mating system.
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Affiliation(s)
- Xiaojuan Huang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi’an 710069, China;
- The Germplasm Bank of Wild Species, Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; (M.C.); (L.W.); (N.Y.)
| | - Minyu Chen
- The Germplasm Bank of Wild Species, Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; (M.C.); (L.W.); (N.Y.)
| | - Linlin Wang
- The Germplasm Bank of Wild Species, Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; (M.C.); (L.W.); (N.Y.)
| | - Mingliu Yang
- School of Ecology and Environmental Science, Yunnan University, Kunming 650091, China;
| | - Nacai Yang
- The Germplasm Bank of Wild Species, Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; (M.C.); (L.W.); (N.Y.)
| | - Zhonghu Li
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi’an 710069, China;
| | - Yuanwen Duan
- The Germplasm Bank of Wild Species, Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; (M.C.); (L.W.); (N.Y.)
- Yunnan Lijiang Forest Ecosystem National Observation and Research Station, Kunming Institute of Botany, Chinese Academy of Sciences, Lijiang 674100, China
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13
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Cabon V, Kracht A, Seitz B, Kowarik I, von der Lippe M, Buchholz S. Urbanisation modulates the attractiveness of plant communities to pollinators by filtering for floral traits. OIKOS 2022. [DOI: 10.1111/oik.09071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Valentin Cabon
- Technische Univ. Berlin, Dept of Ecology Berlin Germany
- Univ. de Rennes 1, CNRS‐ECOBIO (Ecosystèmes, Biodiversité, Évolution) UMR 6553 Rennes France
| | - Alice Kracht
- Technische Univ. Berlin, Dept of Ecology Berlin Germany
| | - Birgit Seitz
- Technische Univ. Berlin, Dept of Ecology Berlin Germany
- Berlin‐Brandenburg Inst. of Advanced Biodiversity Research (BBIB) Berlin Germany
| | - Ingo Kowarik
- Technische Univ. Berlin, Dept of Ecology Berlin Germany
- Berlin‐Brandenburg Inst. of Advanced Biodiversity Research (BBIB) Berlin Germany
| | - Moritz von der Lippe
- Technische Univ. Berlin, Dept of Ecology Berlin Germany
- Berlin‐Brandenburg Inst. of Advanced Biodiversity Research (BBIB) Berlin Germany
| | - Sascha Buchholz
- Berlin‐Brandenburg Inst. of Advanced Biodiversity Research (BBIB) Berlin Germany
- Inst. of Landscape Ecology, Univ. of Münster Münster Germany
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14
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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] [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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15
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Knauer AC, Kokko H, Schiestl FP. Pollinator behaviour and resource limitation maintain honest floral signalling. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Anina C. Knauer
- Department of Systematic and Evolutionary Botany University of Zurich Zürich Switzerland
| | - Hanna Kokko
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zürich Switzerland
| | - Florian P. Schiestl
- Department of Systematic and Evolutionary Botany University of Zurich Zürich Switzerland
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16
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Lu NN, Ma Y, Hou M, Zhao ZG. The function of floral traits and phenotypic selection in Aconitum gymnandrum (Ranunculaceae). PLANT BIOLOGY (STUTTGART, GERMANY) 2021; 23:931-938. [PMID: 34396652 DOI: 10.1111/plb.13305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 06/07/2021] [Indexed: 06/13/2023]
Abstract
Floral evolution in angiosperms is thought to be driven by pollinator-mediated selection. Understanding flower integration and adaptation requires resolving the additive and nonadditive contributions of floral pollinator attraction and pollination efficiency traits to fitness components. In this study, a flower manipulation experiment with a factorial design was used to study the adaptive significance of galea height (a putative attraction trait) and entrance width (a putative efficiency trait) in Aconitum gymnandrum Maxim. flowers. Simultaneously, phenotypic selection analysis was conducted to examine selection by pollinators on galea height, entrance width, nectar production and plant height. Increased galea height increased the pollinator visitation rate, which confirmed its attractiveness function. Increasing floral entrance width by spreading the lower sepals increased the seed number per fruit without affecting pollinator visitation. This suggests a pollination efficiency role for the entrance width. The phenotypic selection analysis, however, did not provide evidence of pollinator-mediated selection for either of these traist, but it did for plant height. According to the manipulation treatment and correlational selection results, the combined variation in galea height and entrance width of A. gymnandrum flowers did not have nonadditive effects on female reproductive success. This study demonstrated the adaptive value of A. gymnandrum flowers through manipulation of an attractiveness trait and an efficiency trait. However, neither trait was associated with pollinator-mediated selection. A combination of manipulating traits and determining current phenotypic selection could help to elucidate the mechanism of selection on floral traits involved in different functions and flower integration.
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Affiliation(s)
- N-N Lu
- School of Life Science, North-West Normal University, Lanzhou, China
| | - Y Ma
- State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - M Hou
- State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Z-G Zhao
- State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, China
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17
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Chen M, Zhao XY, Zuo XA, Wang SK, Qu H, Ping Y, Ma XJ, Liu LX. Comparative effects of pollen limitation, floral traits and pollinators on reproductive success of Hedysarum scoparium Fisch. et Mey. in different habitats. BMC PLANT BIOLOGY 2021; 21:426. [PMID: 34537013 PMCID: PMC8449482 DOI: 10.1186/s12870-021-03211-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 07/10/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Reproduction in most flowering plants may be limited because of the decreased visitation or activity of pollinators in fragmented habitats. Hedysarum scoparium Fisch. et Mey. is an arid region shrub with ecological importance. We explored the pollen limitation and seed set of Hedysarum scoparium in fragmented and restored environments, and examined whether pollen limitation is a significant limiting factor for seed set. We also compared floral traits and pollinator visitation between both habitats, and we determined the difference of floral traits and pollinators influenced reproductive success in Hedysarum scoparium. RESULTS Our results indicated that supplementation with pollen significantly increased seed set per flower, which is pollen-limited in this species. Furthermore, there was greater seed set of the hand cross-pollination group in the restored habitat compared to the fragmented environment. More visits by Apis mellifera were recorded in the restored habitats, which may explain the difference in seed production between the fragmented and restored habitats. CONCLUSIONS In this study, a positive association between pollinator visitation frequency and open flower number was observed. The findings of this study are important for experimentally quantifying the effects of floral traits and pollinators on plant reproductive success in different habitats.
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Affiliation(s)
- Min Chen
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
- Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China.
- Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China.
| | - Xue-Yong Zhao
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Xiao-An Zuo
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
- Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions, Gansu Province, Lanzhou, 730000, China
| | - Shao-Kun Wang
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Hao Qu
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Yue Ping
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Xu-Jun Ma
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Liang-Xu Liu
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
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18
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Waterton J, Cleland EE. Vertebrate herbivory weakens directional selection for earlier emergence in competition. Evol Lett 2021; 5:265-276. [PMID: 34136274 PMCID: PMC8190447 DOI: 10.1002/evl3.222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 01/08/2021] [Accepted: 02/04/2021] [Indexed: 11/10/2022] Open
Abstract
The timing of seedling emergence is strongly linked with fitness because it determines the biotic and abiotic environment experienced by plants in this vulnerable life stage. Experiments and observations consistently find that earlier-emerging plants have a competitive advantage over those emerging later. However, substantial genetic and phenotypic variation in emergence timing is harbored within and among plant populations, making it important to characterize the selective agents-including biotic interactions-that contribute to this variation. In seasonal herbaceous communities, we hypothesized that consumption of early-emerging individuals by vertebrates could weaken the strength of directional selection for earlier emergence in competitive environments. To investigate this, we carried out phenotypic selection analyses on emergence timing in two California grass species, the native Stipa pulchra and non-native Bromus diandrus, growing in intraspecific competitive neighborhoods with and without vertebrate herbivore exclusion. Vertebrate herbivores consistently weakened directional selection for earlier emergence. Our results demonstrate that vertebrate herbivores play an underappreciated selective role on phenology in plant populations, with implications for contemporary evolution, such as the potential of species to adapt to global environmental changes.
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Affiliation(s)
- Joseph Waterton
- Department of Ecology, Behavior, and Evolution Section University of California San Diego La Jolla California 92093.,Current Address: Department of Biology Indiana University Bloomington Indiana 47405
| | - Elsa E Cleland
- Department of Ecology, Behavior, and Evolution Section University of California San Diego La Jolla California 92093
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19
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Chen XH, Tan SL, Liang YL, Huang L, Xiao HW, Luo HL, Xiong DJ, Yang BY, Ren ZX. The pollination of Habenaria rhodocheila (Orchidaceae) in South China: When butterflies take sides. Ecol Evol 2021; 11:2849-2861. [PMID: 33767841 PMCID: PMC7981216 DOI: 10.1002/ece3.7242] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/06/2021] [Accepted: 01/13/2021] [Indexed: 11/10/2022] Open
Abstract
Habenaria is one of the largest terrestrial genera in the family Orchidaceae. Most field studies on Habenaria species with greenish-white and nocturnal scented flowers are pollinated by nocturnal hawkmoths and settling moths. However, H. rhodocheila presents reddish flowers lacking a detectable scent and fails to fit the moth pollination syndrome. We investigated the pollinators, breeding system, and functional traits of H. rhodocheila in South China and found that two diurnal swallowtail butterflies Papilio helenus and Papilio nephelus (Papilionidae) were the effective pollinators. When butterflies foraged for nectar in the spur, the pollinia became attached between the palpi. A triangular projected median rostellar lobe was found at the entrance (sinus) of the spur of H. rhodocheila. This lobe divided the spur opening into two entrances forcing butterflies to enter their proboscides through the left or right side. When the projection of median rostellar lobe was removed, the site of pollinium attachment changed to the eyes of the butterflies, leading to a higher rate of pollinium removal but lower rate of pollinium deposition. Our quartz glass cylinder choice experiment suggested that visual rather than olfactory cues provided the major stimuli for butterflies to locate these flowers. Hand pollination experiments suggested this species was self-compatible but pollinator-dependent. However, the proportion of seeds with large embryos produced in self-pollinated fruits was significantly lower than in cross-pollinated fruits, indicating a significant inbreeding depression. Unlike many other orchid species, fruit set was higher than rates of pollinium removal, indicating a high level of pollination efficiency in a species with friable pollinia. Shifts from moth to butterfly pollination in the genus Habenaria parallel other orchid lineages providing insights into the potential for pollinator-mediated floral trait selection.
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Affiliation(s)
- Xing-Hui Chen
- Jiangxi Key Laboratory of Plant Resources School of Life Sciences Nanchang University Nanchang China
| | - Shao-Lin Tan
- Jiangxi Key Laboratory of Plant Resources School of Life Sciences Nanchang University Nanchang China
| | - Yue-Long Liang
- Jiulianshan National Natural Reserve Administration Bureau Ganzhou China
| | - Lang Huang
- Jiangxi Key Laboratory of Plant Resources School of Life Sciences Nanchang University Nanchang China
| | - Han-Wen Xiao
- Jiangxi Key Laboratory of Plant Resources School of Life Sciences Nanchang University Nanchang China
| | - Huo-Lin Luo
- Jiangxi Key Laboratory of Plant Resources School of Life Sciences Nanchang University Nanchang China
| | - Dong-Jin Xiong
- Jiangxi Key Laboratory of Plant Resources School of Life Sciences Nanchang University Nanchang China
| | - Bo-Yun Yang
- Jiangxi Key Laboratory of Plant Resources School of Life Sciences Nanchang University Nanchang China
| | - Zong-Xin Ren
- 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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20
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Zu P, Schiestl FP, Gervasi D, Li X, Runcie D, Guillaume F. Floral signals evolve in a predictable way under artificial and pollinator selection in Brassica rapa. BMC Evol Biol 2020; 20:127. [PMID: 32972368 PMCID: PMC7517814 DOI: 10.1186/s12862-020-01692-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 09/16/2020] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Angiosperms employ an astonishing variety of visual and olfactory floral signals that are generally thought to evolve under natural selection. Those morphological and chemical traits can form highly correlated sets of traits. It is not always clear which of these are used by pollinators as primary targets of selection and which would be indirectly selected by being linked to those primary targets. Quantitative genetics tools for predicting multiple traits response to selection have been developed since long and have advanced our understanding of evolution of genetically correlated traits in various biological systems. We use these tools to predict the evolutionary trajectories of floral traits and understand the selection pressures acting on them. RESULTS We used data from an artificial selection and a pollinator (bumblebee, hoverfly) evolution experiment with fast cycling Brassica rapa plants to predict evolutionary changes of 12 floral volatiles and 4 morphological floral traits in response to selection. Using the observed selection gradients and the genetic variance-covariance matrix (G-matrix) of the traits, we showed that the observed responses of most floral traits including volatiles were predicted in the right direction in both artificial- and bumblebee-selection experiment. Genetic covariance had a mix of constraining and facilitating effects on evolutionary responses. We further revealed that G-matrices also evolved in the selection processes. CONCLUSIONS Overall, our integrative study shows that floral signals, especially volatiles, evolve under selection in a mostly predictable way, at least during short term evolution. Evolutionary constraints stemming from genetic covariance affected traits evolutionary trajectories and thus it is important to include genetic covariance for predicting the evolutionary changes of a comprehensive suite of traits. Other processes such as resource limitation and selfing also need to be considered for a better understanding of floral trait evolution.
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Affiliation(s)
- Pengjuan Zu
- Department of Systematic and Evolutionary Botany, University of Zürich, Zollikerstrasse 107, CH-8008, Zürich, Switzerland
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Florian P Schiestl
- Department of Systematic and Evolutionary Botany, University of Zürich, Zollikerstrasse 107, CH-8008, Zürich, Switzerland
| | - Daniel Gervasi
- Department of Systematic and Evolutionary Botany, University of Zürich, Zollikerstrasse 107, CH-8008, Zürich, Switzerland
| | - Xin Li
- Department of Plant Sciences, University of California Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Daniel Runcie
- Department of Plant Sciences, University of California Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Frédéric Guillaume
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland.
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21
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Baguette M, Bertrand JAM, Stevens VM, Schatz B. Why are there so many bee-orchid species? Adaptive radiation by intra-specific competition for mnesic pollinators. Biol Rev Camb Philos Soc 2020; 95:1630-1663. [PMID: 32954662 DOI: 10.1111/brv.12633] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 06/09/2020] [Accepted: 06/15/2020] [Indexed: 01/08/2023]
Abstract
Adaptive radiations occur mostly in response to environmental variation through the evolution of key innovations that allow emerging species to occupy new ecological niches. Such biological innovations may play a major role in niche divergence when emerging species are engaged in reciprocal ecological interactions. To demonstrate coevolution is a difficult task; only a few studies have confirmed coevolution as driver of speciation and diversification. Herein we review current knowledge about bee orchid (Ophrys spp.) reproductive biology. We propose that the adaptive radiation of the Mediterranean orchid genus Ophrys, comprising several hundred species, is due to coevolutionary dynamics between these plants and their pollinators. We suggest that pollination by sexual swindling used by Ophrys orchids is the main driver of this coevolution. Flowers of each Ophrys species mimic a sexually receptive female of one particular insect species, mainly bees. Male bees are first attracted by pseudo-pheromones emitted by Ophrys flowers that are similar to the sexual pheromones of their females. Males then are lured by the flower shape, colour and hairiness, and attempt to copulate with the flower, which glues pollen onto their bodies. Pollen is later transferred to the stigma of another flower of the same Ophrys species during similar copulation attempts. In contrast to rewarding pollination strategies, Ophrys pollinators appear to be parasitized. Here we propose that this apparent parasitism is in fact a coevolutionary relationship between Ophrys and their pollinators. For plants, pollination by sexual swindling could ensure pollination efficiency and specificity, and gene flow among populations. For pollinators, pollination by sexual swindling could allow habitat matching and inbreeding avoidance. Pollinators might use the pseudo-pheromones emitted by Ophrys to locate suitable habitats from a distance within complex landscapes. In small populations, male pollinators would disperse once they have memorized the local diversity of sexual pseudo-pheromone bouquets or if all Ophrys flowers are fertilized and thus repel pollinators via production of repulsive pheromones that mimic those produced by fertilized female bees. We propose the following evolutionary scenario: Ophrys radiation is driven by strong intra-specific competition among Ophrys individuals for the attraction of species-specific pollinators, which is a consequence of the high cognitive abilities of pollinators. Male bees record the pheromone signatures of kin or of previously courted partners to avoid further copulation attempts, thereby inducing strong selection on Ophrys for variation in odour bouquets emitted by individual flowers. The resulting odour bouquets could by chance correspond to pseudo-pheromones of the females of another bee species, and thus attract a new pollinator. If such pollinator shifts occur simultaneously in several indivuals, pollen exchanges might occur and initiate speciation. To reinforce the attraction of the new pollinator and secure prezygotic isolation, the following step is directional selection on flower phenotypes (shape, colour and hairiness) towards a better match with the body of the pollinator's female. Pollinator shift and the resulting prezygotic isolation is adaptive for new Ophrys species because they may benefit from competitor-free space for limited pollinators. We end our review by proritizing several critical research avenues.
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Affiliation(s)
- Michel Baguette
- Institut Systématique, Evolution, Biodiversité (ISYEB), UMR 7205 Museum National d'Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, F-75005, Paris, France.,Centre National de la Recherche Scientifique and Université Paul Sabatier Toulouse III, SETE Station d'Ecologie Théorique et Expérimentale, UMR 5321, F-09200, Moulis, France
| | - Joris A M Bertrand
- LGDP (Laboratoire Génome et Développement des Plantes) UMR5096, Université de Perpignan Via Domitia -CNRS, F-66860, Perpignan, France
| | - Virginie M Stevens
- Centre National de la Recherche Scientifique and Université Paul Sabatier Toulouse III, SETE Station d'Ecologie Théorique et Expérimentale, UMR 5321, F-09200, Moulis, France
| | - Bertrand Schatz
- CEFE (Centre d'Ecologie Fonctionnelle et Evolutive) UMR 5175, CNRS - Université de Montpellier - Université Paul Valéry - EPHE, 1919 Route de Mende, 34293, Montpellier, France
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22
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Sutherland BL, Miranda-Katz T, Galloway LF. Strength in numbers? Cytotype frequency mediates effect of reproductive barriers in mixed-ploidy arrays. Evolution 2020; 74:2281-2292. [PMID: 32776511 DOI: 10.1111/evo.14077] [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: 09/05/2019] [Revised: 05/14/2020] [Accepted: 05/18/2020] [Indexed: 01/14/2023]
Abstract
When differentiated lineages come into contact, their fates depend on demographic and reproductive factors. These factors have been well-studied in taxa of the same ploidy, but less is known about sympatric lineages that differ in ploidy, particularly with respect to demographic factors. We assessed prezygotic, postzygotic, and total reproductive isolation in naturally pollinated arrays of diploid-tetraploid and tetraploid-hexaploid population mixes of Campanula rotundifolia by measuring pollinator transitions, seed yield, germination rate, and proportion of hybrid offspring. Four frequencies of each cytotype were tested, and pollinators consistently overvisited rare cytotypes. Seed yield and F1 hybrid production were greater in 4X-6X arrays than 2X-4X arrays, whereas germination rates were similar, creating two distinct patterns of reproductive isolation. In 2X-4X arrays, postzygotic isolation was near complete (3% hybrid offspring), and prezygotic isolation associated with pollinator preference is expected to facilitate the persistence of minority cytotypes. However, in 4X-6X arrays where postzygotic isolation permitted hybrid formation (44% hybrids), pollinator behavior drove patterns of reproductive isolation, with rare cytotypes being more isolated and greater gene flow expected from rare into common cytotypes. In polyploid complexes, both the specific cytotypes in contact and local cytotype frequency, likely reflecting spatial demography, will influence likelihood of gene exchange.
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Affiliation(s)
- Brittany L Sutherland
- Mountain Lake Biological Station and Department of Biology, University of Virginia, Charlottesville, Virginia, 22904
| | - Tomas Miranda-Katz
- Mountain Lake Biological Station and Department of Biology, University of Virginia, Charlottesville, Virginia, 22904
| | - Laura F Galloway
- Mountain Lake Biological Station and Department of Biology, University of Virginia, Charlottesville, Virginia, 22904
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Joffard N, Le Roncé I, Langlois A, Renoult J, Buatois B, Dormont L, Schatz B. Floral trait differentiation in Anacamptis coriophora: Phenotypic selection on scents, but not on colour. J Evol Biol 2020; 33:1028-1038. [PMID: 32500947 DOI: 10.1111/jeb.13657] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 05/14/2020] [Accepted: 05/23/2020] [Indexed: 01/26/2023]
Abstract
Current divergent selection may promote floral trait differentiation among conspecific populations in flowering plants. However, whether this applies to complex traits such as colour or scents has been little studied, even though these traits often vary within species. In this study, we compared floral colour and odour as well as selective pressures imposed upon these traits among seven populations belonging to three subspecies of the widespread, generalist orchid Anacamptis coriophora. Colour was characterized using calibrated photographs, and scents were sampled using dynamic headspace extraction and analysed using gas chromatography-mass spectrometry. We then quantified phenotypic selection exerted on these traits by regressing fruit set values on floral trait values. We showed that the three studied subspecies were characterized by different floral colour and odour, with one of the two predominant floral volatiles emitted by each subspecies being taxon-specific. Plant size was positively correlated with fruit set in most populations, whereas we found no apparent link between floral colour and female reproductive success. We detected positive selection on several taxon-specific compounds in A. coriophora subsp. fragrans, whereas no selection was found on floral volatiles of A. coriophora subsp. coriophora and A. coriophora subsp. martrinii. This study is one of the first to document variation in phenotypic selection exerted on floral scents among conspecific populations. Our results suggest that selection could contribute to ongoing chemical divergence among A. coriophora subspecies.
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Affiliation(s)
- Nina Joffard
- Centre d'Ecologie Fonctionnelle et Evolutive, EPHE-PSL, CNRS, Univ. Montpellier, Univ. Paul Valéry Montpellier 3, IRD, Montpellier, France
- Evolutionsbiologiskt Centrum (EBC), Uppsala, Sweden
| | - Iris Le Roncé
- Centre d'Ecologie Fonctionnelle et Evolutive, EPHE-PSL, CNRS, Univ. Montpellier, Univ. Paul Valéry Montpellier 3, IRD, Montpellier, France
- Département de biologie, École Normale Supérieure de Lyon, Lyon, France
| | - Alban Langlois
- Centre d'Ecologie Fonctionnelle et Evolutive, EPHE-PSL, CNRS, Univ. Montpellier, Univ. Paul Valéry Montpellier 3, IRD, Montpellier, France
- Université Toulouse III Paul Sabatier, Toulouse, France
| | - Julien Renoult
- Centre d'Ecologie Fonctionnelle et Evolutive, EPHE-PSL, CNRS, Univ. Montpellier, Univ. Paul Valéry Montpellier 3, IRD, Montpellier, France
| | - Bruno Buatois
- Centre d'Ecologie Fonctionnelle et Evolutive, EPHE-PSL, CNRS, Univ. Montpellier, Univ. Paul Valéry Montpellier 3, IRD, Montpellier, France
| | - Laurent Dormont
- Centre d'Ecologie Fonctionnelle et Evolutive, EPHE-PSL, CNRS, Univ. Montpellier, Univ. Paul Valéry Montpellier 3, IRD, Montpellier, France
| | - Bertrand Schatz
- Centre d'Ecologie Fonctionnelle et Evolutive, EPHE-PSL, CNRS, Univ. Montpellier, Univ. Paul Valéry Montpellier 3, IRD, Montpellier, France
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Chen M, Zuo XA, Zhao XY. Comparative Floral Characters, Pollinator Limitation, and Pollination Success in Different Habitats of Caragana microphylla Lam. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Chapurlat E, Le Roncé I, Ågren J, Sletvold N. Divergent selection on flowering phenology but not on floral morphology between two closely related orchids. Ecol Evol 2020; 10:5737-5747. [PMID: 32607187 PMCID: PMC7319237 DOI: 10.1002/ece3.6312] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/09/2020] [Accepted: 03/30/2020] [Indexed: 11/08/2022] Open
Abstract
Closely related species often differ in traits that influence reproductive success, suggesting that divergent selection on such traits contribute to the maintenance of species boundaries. Gymnadenia conopsea ss. and Gymnadenia densiflora are two closely related, perennial orchid species that differ in (a) floral traits important for pollination, including flowering phenology, floral display, and spur length, and (b) dominant pollinators. If plant-pollinator interactions contribute to the maintenance of trait differences between these two taxa, we expect current divergent selection on flowering phenology and floral morphology between the two species. We quantified phenotypic selection via female fitness in one year on flowering start, three floral display traits (plant height, number of flowers, and corolla size) and spur length, in six populations of G. conopsea s.s. and in four populations of G. densiflora. There was indication of divergent selection on flowering start in the expected direction, with selection for earlier flowering in two populations of the early-flowering G. conopsea s.s. and for later flowering in one population of the late-flowering G. densiflora. No divergent selection on floral morphology was detected, and there was no significant stabilizing selection on any trait in the two species. The results suggest ongoing adaptive differentiation of flowering phenology, strengthening this premating reproductive barrier between the two species. Synthesis: This study is among the first to test whether divergent selection on floral traits contribute to the maintenance of species differences between closely related plants. Phenological isolation confers a substantial potential for reproductive isolation, and divergent selection on flowering time can thus greatly influence reproductive isolation and adaptive differentiation.
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Affiliation(s)
- Elodie Chapurlat
- Plant Ecology and EvolutionDepartment of Ecology and GeneticsEvolutionary Biology CentreUppsala UniversityUppsalaSweden
| | - Iris Le Roncé
- Plant Ecology and EvolutionDepartment of Ecology and GeneticsEvolutionary Biology CentreUppsala UniversityUppsalaSweden
- Master BioSciencesÉcole Normale Supérieure de LyonUniversité Claude Bernard Lyon 1Université de LyonLyonFrance
| | - Jon Ågren
- Plant Ecology and EvolutionDepartment of Ecology and GeneticsEvolutionary Biology CentreUppsala UniversityUppsalaSweden
| | - Nina Sletvold
- Plant Ecology and EvolutionDepartment of Ecology and GeneticsEvolutionary Biology CentreUppsala UniversityUppsalaSweden
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Tye M, Dahlgren JP, Sletvold N. Pollen limitation in a single year is not compensated by future reproduction. Oecologia 2020; 192:989-997. [PMID: 32078036 PMCID: PMC7165156 DOI: 10.1007/s00442-020-04623-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 02/08/2020] [Indexed: 11/30/2022]
Abstract
Seed production is critical to the persistence of most flowering plant populations, but may be strongly pollen limited. To what extent long-lived plants can compensate pollen limitation by increasing future reproduction is poorly understood. We tested for compensation in two Dactylorhiza species that differ in reproductive investment by experimentally reducing and increasing pollination in two independent annual cohorts and monitoring demographic responses in the subsequent 2 years for the 2014 cohort and in 1 year for the 2015 cohort. Demographic rates in the second year were significantly affected by pollination treatment in both species, but specific responses differed both between species and years. There was no effect of pollination treatment on demographic responses in the third year. In sum, effects were too weak to make up for the lost reproduction; total fruit production across all 3 years was by far highest in the increased pollination treatment in both species. These results show that long-lived plants do not necessarily compensate for pollen limitation by increasing future reproduction. It further suggests that even periodic declines in pollination rates may have severe demographic consequences, particularly in populations where germination is not density dependent. This has implications for predicting plant population viability in response to changes in pollination intensity.
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Affiliation(s)
- Matthew Tye
- Department of Ecology and Genetics, Uppsala University, SE-752 36, Uppsala, Sweden
| | - Johan P Dahlgren
- Department of Biology and The SDU Interdisciplinary Centre on Population Dynamics, University of Southern Denmark, 5230, Odense, Denmark
| | - Nina Sletvold
- Department of Ecology and Genetics, Uppsala University, SE-752 36, Uppsala, Sweden.
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Roberts WR, Roalson EH. Co-expression clustering across flower development identifies modules for diverse floral forms in Achimenes (Gesneriaceae). PeerJ 2020; 8:e8778. [PMID: 32201652 PMCID: PMC7071821 DOI: 10.7717/peerj.8778] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 02/21/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Genetic pathways involved with flower color and shape are thought to play an important role in the development of flowers associated with different pollination syndromes, such as those associated with bee, butterfly, or hummingbird pollination. Because pollination syndromes are complex traits that are orchestrated by multiple genes and pathways, the gene regulatory networks have not been explored. Gene co-expression networks provide a systems level approach to identify important contributors to floral diversification. METHODS RNA-sequencing was used to assay gene expression across two stages of flower development (an early bud and an intermediate stage) in 10 species of Achimenes (Gesneriaceae). Two stage-specific co-expression networks were created from 9,503 orthologs and analyzed to identify module hubs and the network periphery. Module association with bee, butterfly, and hummingbird pollination syndromes was tested using phylogenetic mixed models. The relationship between network connectivity and evolutionary rates (d N/d S) was tested using linear models. RESULTS Networks contained 65 and 62 modules that were largely preserved between developmental stages and contained few stage-specific modules. Over a third of the modules in both networks were associated with flower color, shape, and pollination syndrome. Within these modules, several hub nodes were identified that related to the production of anthocyanin and carotenoid pigments and the development of flower shape. Evolutionary rates were decreased in highly connected genes and elevated in peripheral genes. DISCUSSION This study aids in the understanding of the genetic architecture and network properties underlying the development of floral form and provides valuable candidate modules and genes for future studies.
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Affiliation(s)
- Wade R. Roberts
- School of Biological Sciences, Washington State University, Pullman, WA, USA
- Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | - Eric H. Roalson
- School of Biological Sciences, Washington State University, Pullman, WA, USA
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Zhou ZL, Duan YW, Luo Y, Yang YP, Zhang ZQ. Cell number explains the intraspecific spur-length variation in an Aquilegia species. PLANT DIVERSITY 2019; 41:307-314. [PMID: 31934675 PMCID: PMC6951270 DOI: 10.1016/j.pld.2019.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 06/06/2019] [Accepted: 06/10/2019] [Indexed: 06/10/2023]
Abstract
Variations of nectar spur length allow pollinators to utilize resources in novel ways, leading to the different selective pressures on spurs and allowing taxa to diversify. However, the mechanisms underlying spur length variation remain unclear. Interspecific comparisons of spur length suggest that both cell division and anisotropic expansion could explain the changes of spur length, and that hormone-related genes contribute to the process of spur formation. In contrast, little is known about intraspecific spur length variation. In Aquilegia rockii, spur length varies strikingly, ranging from 1 mm to 18 mm. To examine the potential mechanisms underlying spur length variation in A. rockii, we observed cell morphology and analyzed RNA-seq of short- and long-spurred flowers. Scanning electron microscopy revealed that at two positions on spurs there were no differences in either cell density or cell anisotropy between short- and long-spurred flowers, suggesting that in A. rockii changes in cell number may explain variations in spur length. In addition, we screened transcriptomes of short- and long-spurred flowers for differentially expressed genes; this screen identified several genes linked to cell division (e.g., F-box, CDKB2-2, and LST8), a finding which is consistent with our analysis of the cellular morphology of spurs. However, we did not find any highly expressed genes involved in the hormone pathway in long-spurred flowers. In contrast to previous hypotheses that anisotropic cell expansion leads to interspecific spur variation in Aquilegia, our results suggest that cell number changes and related genes are mainly responsible for spur length variations of A. rockii. Furthermore, the underlying mechanisms of similar floral traits in morphology may be quite different, enriching our understanding of the mechanisms of flower diversity in angiosperms.
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Affiliation(s)
- Zhi-Li Zhou
- Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuan-Wen Duan
- Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Yan Luo
- Gardening and Horticulture Department, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303, China
| | - Yong-Ping Yang
- Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Zhi-Qiang Zhang
- Laboratory of Ecology and Evolutionary Biology, Yunnan University, Kunming, 650091, China
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Impact of floral characters, pollen limitation, and pollinator visitation on pollination success in different populations of Caragana korshinskii Kom. Sci Rep 2019; 9:9741. [PMID: 31278340 PMCID: PMC6611805 DOI: 10.1038/s41598-019-46271-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 06/26/2019] [Indexed: 11/22/2022] Open
Abstract
Caragana korshinskii Kom. has a significant function in desert-grassland revegetation in arid regions. Plant reproduction in arid regions can be restricted due to inadequate pollen receipt and reduced pollen transfer. An assessment of pollination success as a result of pollen limitation and pollinator visitation in various C. korshinskii populations is presently lacking. We thus tested three different treatments (pollen addition, control, and procedural control) to elucidate how pollen limitation affects seed numbers per flower in C. korshinskii. We also determined the effect of pollinator visit frequency on seeds per flower. Our results demonstrated that there was a higher proportion of open flowers and mature fruits in the managed population than in the natural population. Pollen addition significantly increased seed number per flower, and pollen limitation was determined to be a significant limiting factor in seed production. Furthermore, Apis mellifera was determined to be the principal pollinator, and pollinator visitation frequency was significantly correlated with open flower number. Our findings also demonstrated that pollinator visitation rate and seed production were positively correlated. Management and pollinator visitation could affect seed production, which may explain the higher seeds per flower in the managed population compared with the natural population.
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Chen M, Zuo XA. Effect of Pollen Limitation and Pollinator Visitation on Pollination Success of Haloxylon ammodendron (C. A. Mey.) Bunge in Fragmented Habitats. FRONTIERS IN PLANT SCIENCE 2019; 10:327. [PMID: 30984212 PMCID: PMC6448003 DOI: 10.3389/fpls.2019.00327] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 02/28/2019] [Indexed: 06/09/2023]
Abstract
Haloxylon ammodendron (C. A. Mey.) Bunge is an ecologically important species in arid regions. Pollen limitation may decrease plant reproduction due to low levels of pollen transfer and inadequate pollen receipt. In arid regions, pollen limitations of many plant species may be influenced by habitat fragmentation. However, whether pollen limitation and pollinator visitation affect the pollination success of H. ammodendron (Amaranthaceae) in fragmented habitats still needs further study. In this study, we calculated the pollen limitation in natural and fragmented habitats to estimate the effect of habitat fragmentation on pollen limitation. In different habitats, we investigated the relationship between the number of open flowers and pollinator visiting frequency. In addition, we examined how habitat fragmentation affects pollination success through the influence of pollinator visitation rate on seed set. Our results indicated that pollen limitation was the important limiting factor for seed set in fragmented and natural habitats. The results showed higher pollinator visitation rates resulted in a higher percentage of seeds in both habitats. In H. ammodendron, Apis mellifera was found to be the dominant pollinator. These results may support the assertion that plants evolve traits to attract pollinators and pollinators increase their visiting frequency to better exploit the floral resources. We also determined that outcrossing was dominant in the breeding system and that wind pollination played an important role in pollination success. This study aims to contribute to a better understanding of how environmental heterogeneity affects pollen limitation, pollinator visitation, and pollination success in arid regions.
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Trunschke J, Sletvold N, Ågren J. The independent and combined effects of floral traits distinguishing two pollination ecotypes of a moth-pollinated orchid. Ecol Evol 2019; 9:1191-1201. [PMID: 30805152 PMCID: PMC6374684 DOI: 10.1002/ece3.4808] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 10/22/2018] [Accepted: 11/01/2018] [Indexed: 11/26/2022] Open
Abstract
Identifying traits and agents of selection involved in local adaptation is important for understanding population divergence. In southern Sweden, the moth-pollinated orchid Platanthera bifolia occurs as a woodland and a grassland ecotype that differ in dominating pollinators. The woodland ecotype is taller (expected to influence pollinator attraction) and produces flowers with longer spurs (expected to influence efficiency of pollen transfer) compared to the grassland ecotype. We examined whether plant height and spur length affect pollination and reproductive success in a woodland population, and whether effects are non-additive, as expected for traits influencing two multiplicative components of pollen transfer. We reduced plant height and spur length to match trait values observed in the grassland ecotype and determined the effects on pollen removal, pollen receipt, and fruit production. In addition, to examine the effects of naturally occurring variation, we quantified pollinator-mediated selection through pollen removal and seed production in the same population. Reductions of plant height and spur length decreased pollen removal, number of flowers receiving pollen, mean pollen receipt per pollinated flower, and fruit production per plant, but no significant interaction effect was detected. The selection analysis demonstrated pollinator-mediated selection for taller plants via female fitness. However, there was no current selection mediated by pollinators on spur length, and pollen removal was not related to plant height or spur length. The results show that, although both traits are important for pollination success and female fitness in the woodland habitat, only plant height was sufficiently variable in the study population for current pollinator-mediated selection to be detected. More generally, the results illustrate how a combination of experimental approaches can be used to identify both traits and agents of selection.
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Affiliation(s)
- Judith Trunschke
- Plant Ecology and Evolution, Department of Ecology and Genetics, Evolutionary Biology CentreUppsala UniversityUppsalaSweden
| | - Nina Sletvold
- Plant Ecology and Evolution, Department of Ecology and Genetics, Evolutionary Biology CentreUppsala UniversityUppsalaSweden
| | - Jon Ågren
- Plant Ecology and Evolution, Department of Ecology and Genetics, Evolutionary Biology CentreUppsala UniversityUppsalaSweden
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de Jager ML, Peakall R. Experimental examination of pollinator-mediated selection in a sexually deceptive orchid. ANNALS OF BOTANY 2019; 123:347-354. [PMID: 29878057 PMCID: PMC6344214 DOI: 10.1093/aob/mcy083] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 04/30/2018] [Indexed: 05/11/2023]
Abstract
BACKGROUND AND AIMS Selection exerted by pollinators on flowers is predicted to occur along two distinct axes. While pollinator attraction to flowers is governed by pollinator preferences, pollen transfer efficiency is mediated by the mechanical fit of pollinators to flower morphology. Although pollinator attraction in sexually deceptive orchids is typically underpinned by floral odour, morphological traits are expected to play a vital role in mechanical fit during floral contact with pollinators. METHODS Here we utilize a comprehensive and novel procedure to test for pollinator-mediated selection through mechanical fit with the flower labellum in the orchid Chiloglottis trapeziformis. This approach combines detailed pollinator observations related to plant reproductive fitness with complementary experimental manipulation and phenotypic selection analysis. KEY RESULTS Experiments with virgin flowers revealed that pollen removal occurs only during vigorous pseudocopulation. This behaviour involves male wasps that grasp the insectiform callus structure on the labellum while probing the labellum tip in a forward orientation. Both orientation and duration of pseudocopulation were significant predictors of pollen removal, confirming a direct relationship between pollinator behaviour and plant fitness. Controlled floral manipulation that either shortened or elongated the distance between the callus and the labellum tip detected no change in pollinator attraction. The duration of pseudocopulation, however, was significantly reduced on flowers with shortened or elongated callus-tip distances, consistent with stabilizing selection. Phenotypic selection analysis confirmed this prediction in natural populations by uncovering evidence for stabilizing selection on the distance between the callus and the labellum tip. CONCLUSIONS Our experimental manipulations and selection analysis in natural populations thus demonstrate stabilizing selection on the distance from the callus to the labellum tip, and illustrate the utility of employing multiple approaches to confirm selection exerted by pollinators on floral form.
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Affiliation(s)
- Marinus L de Jager
- Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa
- For correspondence. E-mail
| | - Rod Peakall
- Ecology and Evolution, Research School of Biology, The Australian National University, Acton, ACT, Australia
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Texier N, Deblauwe V, Stévart T, Sonké B, Simo-Droissart M, Azandi L, Bose R, Djuikouo MN, Kamdem G, Kamdem N, Mayogo S, Zemagho L, Droissart V. Spatio-temporal patterns of orchids flowering in Cameroonian rainforests. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2018; 62:1931-1944. [PMID: 30215186 DOI: 10.1007/s00484-018-1594-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 07/23/2018] [Accepted: 07/24/2018] [Indexed: 06/08/2023]
Abstract
We characterized the flowering patterns of 45 epiphytic orchid species occurring in Cameroonian rainforests to explore the environmental and evolutionary forces driving their phenology. We used a dataset of 3470 flowering events recorded over a period of 11 years in the Yaoundé living collection (82% of the flowering events) and from in situ observations (18% of the flowering events) to (i) describe flowering frequency and timing and synchronization among taxa; (ii) test flowering patterns for phylogenetic relatedness at the generic level; and (iii) investigate the spatial patterns of phenology. An annual flowering pattern prevailed among the species selected for this study. The species-rich African genera Angraecum and Polystachya are characterized by subannual and annual frequency patterns, respectively. However, in terms of flowering time, no phylogenetic signal was detected for the four most diverse genera (Ancistrorhynchus, Angraecum, Bulbophyllum, and Polystachya). Results suggest also an important role of photoperiod and precipitation as climatic triggers of flowering patterns. Moreover, 16% of the taxa cultivated ex situ, mostly Polystachya, showed significant differences in flowering time between individuals originating from distinct climatic regions, pointing toward the existence of phenological ecotypes. Phenological plasticity, suggested by the lack of synchronized flowering in spatially disjunct populations of Polystachya, could explain the widespread radiation of this genus throughout tropical Africa. Our study highlights the need to take the spatial pattern of flowering time into account when interpreting phylogeographic patterns in central African rainforests.
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Affiliation(s)
- N Texier
- Faculty of Sciences, Evolutionary Biology and Ecology, Université Libre de Bruxelles, CP160/12, 50 Av. F. Roosevelt, 1050, Brussels, Belgium.
- Herbarium et Bibliothèque de Botanique africaine, Université Libre de Bruxelles, CP 265, Boulevard du Triomphe, B-1050, Brussels, Belgium.
- Plant Systematics and Ecology Laboratory, Higher Teachers' Training College, University of Yaoundé I, Yaoundé, Cameroon.
- Africa & Madagascar Department, Missouri Botanical Garden, P.O. Box 299, St. Louis, MO, 63166-0299, USA.
| | - V Deblauwe
- Herbarium et Bibliothèque de Botanique africaine, Université Libre de Bruxelles, CP 265, Boulevard du Triomphe, B-1050, Brussels, Belgium
- Center for Tropical Research, Institute of the Environment and Sustainability, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- International Institute of Tropical Agriculture, Yaoundé, Cameroon
| | - T Stévart
- Herbarium et Bibliothèque de Botanique africaine, Université Libre de Bruxelles, CP 265, Boulevard du Triomphe, B-1050, Brussels, Belgium
- Africa & Madagascar Department, Missouri Botanical Garden, P.O. Box 299, St. Louis, MO, 63166-0299, USA
- Agentschap Plantentuin Meise, Domein van Bouchout, Nieuwelaan 38, BE-1860, Meise, Belgium
| | - B Sonké
- Herbarium et Bibliothèque de Botanique africaine, Université Libre de Bruxelles, CP 265, Boulevard du Triomphe, B-1050, Brussels, Belgium
- Plant Systematics and Ecology Laboratory, Higher Teachers' Training College, University of Yaoundé I, Yaoundé, Cameroon
- Africa & Madagascar Department, Missouri Botanical Garden, P.O. Box 299, St. Louis, MO, 63166-0299, USA
| | - M Simo-Droissart
- Plant Systematics and Ecology Laboratory, Higher Teachers' Training College, University of Yaoundé I, Yaoundé, Cameroon
| | - L Azandi
- Plant Systematics and Ecology Laboratory, Higher Teachers' Training College, University of Yaoundé I, Yaoundé, Cameroon
| | - R Bose
- AMAP, IRD, CIRAD, CNRS, INRA, Univ Montpellier, Montpellier, France
| | - M-N Djuikouo
- Department of Botany and Plant Physiology, University of Buea, Buea, Cameroon
| | - G Kamdem
- Plant Systematics and Ecology Laboratory, Higher Teachers' Training College, University of Yaoundé I, Yaoundé, Cameroon
| | - N Kamdem
- Plant Systematics and Ecology Laboratory, Higher Teachers' Training College, University of Yaoundé I, Yaoundé, Cameroon
| | - S Mayogo
- Plant Systematics and Ecology Laboratory, Higher Teachers' Training College, University of Yaoundé I, Yaoundé, Cameroon
| | - L Zemagho
- Plant Systematics and Ecology Laboratory, Higher Teachers' Training College, University of Yaoundé I, Yaoundé, Cameroon
| | - V Droissart
- Herbarium et Bibliothèque de Botanique africaine, Université Libre de Bruxelles, CP 265, Boulevard du Triomphe, B-1050, Brussels, Belgium
- Plant Systematics and Ecology Laboratory, Higher Teachers' Training College, University of Yaoundé I, Yaoundé, Cameroon
- Africa & Madagascar Department, Missouri Botanical Garden, P.O. Box 299, St. Louis, MO, 63166-0299, USA
- AMAP, IRD, CIRAD, CNRS, INRA, Univ Montpellier, Montpellier, France
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Klecka J, Hadrava J, Koloušková P. Vertical stratification of plant-pollinator interactions in a temperate grassland. PeerJ 2018; 6:e4998. [PMID: 29942686 PMCID: PMC6016531 DOI: 10.7717/peerj.4998] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 05/28/2018] [Indexed: 12/02/2022] Open
Abstract
Visitation of plants by different pollinators depends on individual plant traits, spatial context, and other factors. A neglected aspect of small-scale variation of plant–pollinator interactions is the role of vertical position of flowers. We conducted a series of experiments to study vertical stratification of plant–pollinator interactions in a dry grassland. We observed flower visitors on cut inflorescences of Centaurea scabiosa and Inula salicina placed at different heights above ground in two types of surrounding vegetation: short and tall. Even at such a small-scale, we detected significant shift in total visitation rate of inflorescences in response to their vertical position. In short vegetation, inflorescences close to the ground were visited more frequently, while in tall vegetation, inflorescences placed higher received more visits. Moreover, we found major differences in the composition of the pollinator community on flowers at different heights. In a second experiment, we measured flower visitation rate in inflorescences of Salvia verticillata of variable height. Total flower visitation rate increased markedly with inflorescence height in this case. Data on seed set of individual plants provide evidence for a corresponding positive pollinator-mediated selection on increased inflorescence height. Overall, our results demonstrate strong vertical stratification of plant–pollinator interactions at the scale of mere decimetres. This may have important ecological as well as evolutionary implications.
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Affiliation(s)
- Jan Klecka
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, České Budějovice, Czech Republic
| | - Jiří Hadrava
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, České Budějovice, Czech Republic.,Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Pavla Koloušková
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, České Budějovice, Czech Republic
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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] [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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Lebel M, Obolski U, Hadany L, Sapir Y. Pollinator-mediated selection on floral size and tube color in Linum pubescens: Can differential behavior and preference in different times of the day maintain dimorphism? Ecol Evol 2018; 8:1096-1106. [PMID: 29375782 PMCID: PMC5773291 DOI: 10.1002/ece3.3683] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 10/01/2017] [Accepted: 11/08/2017] [Indexed: 12/16/2022] Open
Abstract
Diversity of flower traits is often proposed as the outcome of selection exerted by pollinators. Positive directional pollinator-mediated selection on floral size has been widely shown to reduce phenotypic variance. However, the underlying mechanism of maintaining within-population floral color polymorphism is poorly understood. Divergent selection, mediated by different pollinators or by both mutualists and antagonists, may create and maintain such polymorphism, but it has rarely been shown to result from differential behavior of one pollinator. We tested whether different behaviors of the same pollinators in morning and evening are associated with dimorphic floral trait in Linum pubescens, a Mediterranean annual plant that exhibits variable within-population frequencies of dark- and light-colored flower tubes. Usia bicolor bee-flies, the major pollinators of L. pubescens, are mostly feeding in the flower in the morning, while in the evening they are mostly visiting the flowers for mating. In 2 years of studying L. pubescens in a single large population in the Carmel, Israel, we found in one year that dark-centered flowers received significantly higher fraction of visits in the morning. Fitness was positively affected by number of visits, but no fitness differences were found between tube-color morphs, suggesting that both morphs have similar pollination success. Using mediation analysis, we found that flower size was under positive directional pollinator-mediated selection in both years, but pollinator behavior did not explain entirely this selection, which was possibly mediated also by other agents, such as florivores or a-biotic stresses. While most pollinator-mediated selection studies show that flower size signals food reward, in L. pubescens, it may also signal for mating place, which may drive positive selection. While flower size found to be under pollinator-mediated selection in L. pubescens, differential behavior of the pollinators in morning and evening did not seem to explain flower color polymorphism.
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Affiliation(s)
- Merav Lebel
- The Botanical GardenTel Aviv UniversityTel AvivIsrael
- School of Plant Sciences and Food SecurityTel Aviv UniversityTel AvivIsrael
- Present address:
Science DivisionNature‐Parks AuthorityJerusalemIsrael
| | - Uri Obolski
- The Botanical GardenTel Aviv UniversityTel AvivIsrael
- Present address:
Department of ZoologyUniversity of OxfordOxfordUK
| | - Lilach Hadany
- The Botanical GardenTel Aviv UniversityTel AvivIsrael
| | - Yuval Sapir
- The Botanical GardenTel Aviv UniversityTel AvivIsrael
- School of Plant Sciences and Food SecurityTel Aviv UniversityTel AvivIsrael
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Friberg M, Waters MT, Thompson JN. Nutrient availability affects floral scent much less than other floral and vegetative traits in Lithophragma bolanderi. ANNALS OF BOTANY 2017; 120:471-478. [PMID: 28655187 PMCID: PMC5591434 DOI: 10.1093/aob/mcx069] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 01/09/2017] [Indexed: 05/29/2023]
Abstract
Background and Aims Many plant-pollinator interactions are mediated by floral scents that can vary among species, among populations within species and even among individuals within populations. This variation could be innate and unaffected by the environment, but, because many floral volatiles have amino-acid precursors, scent variation also could be affected by differences in nutrient availability among environments. In plants that have coevolved with specific pollinators, natural selection is likely to favour low phenotypic plasticity in floral scent even under different conditions of nutrient availability if particular scents or scent combinations are important for attracting local pollinators. Methods Clonal pairs of multiple seed-families of two Lithophragma bolanderi (Saxifragaceae) populations were subjected to a high and a low nutrient treatment. These plants are pollinated primarily by host-specific Greya moths. It was evaluated how nutrient treatment affected variation in floral scent relative to other vegetative and reproductive traits. Key Results Floral scent strength (the per-flower emission rate) and composition were unaffected by nutrient treatment, but low-nutrient plants produced fewer and lighter leaves, fewer scapes and fewer flowers than high-nutrient plants. The results held in both populations, which differed greatly in the number and composition of floral scents produced. Conclusions The results reveal a strong genetic component both to scent composition and emission level, and partly contrasts with the only previous study that has assessed the susceptibility of floral volatile signals to variation in the abundance of nutrients. These results, and the tight coevolutionary relationship between Lithophragma plants and their specialized Greya moth pollinators, indicate that reproductive traits important to coevolving interactions, such as the floral scent of L. bolanderi, may be locally specialized and more canalized than other traits important for plant fitness.
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Affiliation(s)
- Magne Friberg
- Uppsala University, Department of Plant Ecology and Evolution, Evolutionary Biology Centre, EBC, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
| | - Mia T Waters
- University of California, Santa Cruz, Department of Ecology and Evolutionary Biology, Santa Cruz, CA, USA
| | - John N Thompson
- University of California, Santa Cruz, Department of Ecology and Evolutionary Biology, Santa Cruz, CA, USA
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Scopece G, Juillet N, Lexer C, Cozzolino S. Fluctuating selection across years and phenotypic variation in food-deceptive orchids. PeerJ 2017; 5:e3704. [PMID: 28852594 PMCID: PMC5572944 DOI: 10.7717/peerj.3704] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 07/27/2017] [Indexed: 11/20/2022] Open
Abstract
Nectarless flowers that deceive pollinators offer an opportunity to study asymmetric plant-insect interactions. Orchids are a widely used model for studying these interactions because they encompass several thousand species adopting deceptive pollination systems. High levels of intra-specific phenotypic variation have been reported in deceptive orchids, suggesting a reduced consistency of pollinator-mediated selection on their floral traits. Nevertheless, several studies report on widespread directional selection mediated by pollinators even in these deceptive orchids. In this study we test the hypothesis that the observed selection can fluctuate across years in strength and direction thus likely contributing to the phenotypic variability of this orchid group. We performed a three-year study estimating selection differentials and selection gradients for nine phenotypic traits involved in insect attraction in two Mediterranean orchid species, namely Orchis mascula and O. pauciflora, both relying on a well-described food-deceptive pollination strategy. We found weak directional selection and marginally significant selection gradients in the two investigated species with significant intra-specific differences in selection differentials across years. Our data do not link this variation with a specific environmental cause, but our results suggest that pollinator-mediated selection in food-deceptive orchids can change in strength and in direction over time. In perennial plants, such as orchids, different selection differentials in the same populations in different flowering seasons can contribute to the maintenance of phenotypic variation often reported in deceptive orchids.
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Affiliation(s)
- Giovanni Scopece
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Nicolas Juillet
- UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical, Université de la Réunion, Pôle de Protection des Plantes, Saint Pierre, La Réunion, France
| | - Christian Lexer
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
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Wu Y, Li QJ. Phenotypic selection on flowering phenology and pollination efficiency traits between Primula populations with different pollinator assemblages. Ecol Evol 2017; 7:7599-7608. [PMID: 29043017 PMCID: PMC5632619 DOI: 10.1002/ece3.3258] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 06/13/2017] [Accepted: 06/28/2017] [Indexed: 12/12/2022] Open
Abstract
Floral traits have largely been attributed to phenotypic selection in plant–pollinator interactions. However, the strength of this link has rarely been ascertained with real pollinators. We conducted pollinator observations and estimated selection through female fitness on flowering phenology and floral traits between two Primula secundiflora populations. We quantified pollinator‐mediated selection by subtracting estimates of selection gradients of plants receiving supplemental hand pollination from those of plants receiving open pollination. There was net directional selection for an earlier flowering start date at populations where the dominant pollinators were syrphid flies, and flowering phenology was also subjected to stabilized quadratic selection. However, a later flowering start date was significantly selected at populations where the dominant pollinators were legitimate (normal pollination through the corolla tube entrance) and illegitimate bumblebees (abnormal pollination through nectar robbing hole which located at the corolla tube), and flowering phenology was subjected to disruptive quadratic selection. Wider corolla tube entrance diameter was selected at both populations. Furthermore, the strength of net directional selection on flowering start date and corolla tube entrance diameter was stronger at the population where the dominant pollinators were syrphid flies. Pollinator‐mediated selection explained most of the between‐population variations in the net directional selection on flowering phenology and corolla tube entrance diameter. Our results suggested the important influence of pollinator‐mediated selection on floral evolution. Variations in pollinator assemblages not only resulted in variation in the direction of selection but also the strength of selection on floral traits.
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Affiliation(s)
- Yun Wu
- Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Menglun, Mengla County China.,University of Chinese Academy of Sciences Beijing China
| | - Qing-Jun Li
- Laboratory of Ecology and Evolutionary Biology State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University Kunming China
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40
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Pellegrino G, Bellusci F, Palermo AM. Functional differentiation in pollination processes among floral traits in Serapias species (Orchidaceae). Ecol Evol 2017; 7:7171-7177. [PMID: 28944008 PMCID: PMC5606857 DOI: 10.1002/ece3.3264] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/21/2017] [Accepted: 06/25/2017] [Indexed: 11/08/2022] Open
Abstract
Floral displays, influencing attractiveness to insects, increase the number of pollinator visits and the efficiency of each visit in terms of pollen exchange and thus affect the plant reproductive success. Here, we conducted an in situ manipulation experiment to investigate whether the floral modifications affect reproductive success in natural orchid populations of Serapias lingua and Serapias vomeracea. We estimated male and female reproductive success of three treatment groups, disassembly of floral tube, cutting of lip, and painting of the callus surface, in terms of pollinaria removed/deposited and fruit production. Results revealed that phenotypic modification had opposite effects on reproductive success of two examine species. Indeed, reproductive success was significantly increased by the detached of the petals and sepals, and decreased, due to callus painting and lip removal, in S. lingua. On the contrary, unmanipulated plants of S. vomeracea showed significantly higher value of pollinaria removed and deposited and fruit set than manipulated ones. The differences between S. lingua and S. vomeracea agree to the different pollination strategy of examined species. S. vomeracea shows shelter imitation strategy, and thus, the disassembly of tunnel-like corolla does not allow the insects to use the flower as a refuge, while S. lingua is a sexually deceptive orchid and therefore the opening of the flower made more visible callus (visible at a greater distance) increasing the pollinators attraction. This study provides evidence that pollinators were largely sensitive to the experimental modification of the flower phenotype, which is consistent with the presence of significant selection on individual floral characters. Our experimental investigations of the effects of variation in display on pollinator visitation provide insights into the evolution of floral morphology in orchid with shelter imitation strategy.
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Affiliation(s)
- Giuseppe Pellegrino
- Department of Biology, Ecology and Earth Sciences University of Calabria Rende CS Italy
| | - Francesca Bellusci
- Department of Biology, Ecology and Earth Sciences University of Calabria Rende CS Italy
| | - Anna Maria Palermo
- Department of Biology, Ecology and Earth Sciences University of Calabria Rende CS Italy
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Zhang G, Meng L, Wu Z, Zhang Z, Yin L, Yang Y, Duan Y. Natural selection on floral traits of Caltha scaposa (Ranunculaceae), an alpine perennial with generalized pollination system from Northwest Yunnan. PLANT DIVERSITY 2017; 39:202-207. [PMID: 30159512 PMCID: PMC6112295 DOI: 10.1016/j.pld.2017.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 03/16/2017] [Indexed: 05/23/2023]
Abstract
Floral traits, including those invisible to humans but visible to pollinators, that increase pollination efficiency may be selected by pollinators in plant species with pollen limitation of seed production, but the importance of pollinators as selective agents on different floral traits needs to be further quantified experimentally. In the present study, we examined selective strength on flower diameter, flower height, UV bulls-eye size, sepal size and UV proportion via female fitness in Caltha scaposa, based on open-pollinated and hand-pollinated flowers, through which pollinator-mediated selection was calculated for each of floral traits. Our results suggest that seed production of C. scaposa is pollen limited in natural conditions. There was directional selection (Δβpollinator = -0.12) for larger flowers in open-pollinated flowers, while no significant selection was found in flower height, UV bulls-eye size, sepal size or UV proportion. Statistically significant selection was found in UV bulls-eye size, sepal size and UV proportion in hand-pollinated flowers, but interactions with pollinators contributed only to flower diameter. We conclude that in C. scaposa, floral traits that are subjected to selection might be driven by multiple selective agents, and suggest the importance of investigating floral traits that are invisible to human but visible to pollinators in measuring pollinator-mediated selection via male fitness.
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Affiliation(s)
- Guopeng Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, PR China
- School of Life Sciences, Yunnan Normal University, Kunming 650092, PR China
| | - Lihua Meng
- School of Life Sciences, Yunnan Normal University, Kunming 650092, PR China
| | - Zhikun Wu
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, PR China
| | - Zhiqiang Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, PR China
| | - Lingjuan Yin
- National Technical Secondary School of Lijiang, Lijiang 674119, PR China
| | - Yongping Yang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, PR China
| | - Yuanwen Duan
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, PR China
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Balao F, Trucchi E, Wolfe TM, Hao B, Lorenzo MT, Baar J, Sedman L, Kosiol C, Amman F, Chase MW, Hedrén M, Paun O. Adaptive sequence evolution is driven by biotic stress in a pair of orchid species (Dactylorhiza) with distinct ecological optima. Mol Ecol 2017; 26:3649-3662. [PMID: 28370647 PMCID: PMC5518283 DOI: 10.1111/mec.14123] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 02/24/2017] [Accepted: 03/15/2017] [Indexed: 12/23/2022]
Abstract
The orchid family is the largest in the angiosperms, but little is known about the molecular basis of the significant variation they exhibit. We investigate here the transcriptomic divergence between two European terrestrial orchids, Dactylorhiza incarnata and Dactylorhiza fuchsii, and integrate these results in the context of their distinct ecologies that we also document. Clear signals of lineage-specific adaptive evolution of protein-coding sequences are identified, notably targeting elements of biotic defence, including both physical and chemical adaptations in the context of divergent pools of pathogens and herbivores. In turn, a substantial regulatory divergence between the two species appears linked to adaptation/acclimation to abiotic conditions. Several of the pathways affected by differential expression are also targeted by deviating post-transcriptional regulation via sRNAs. Finally, D. incarnata appears to suffer from insufficient sRNA control over the activity of RNA-dependent DNA polymerase, resulting in increased activity of class I transposable elements and, over time, in larger genome size than that of D. fuchsii. The extensive molecular divergence between the two species suggests significant genomic and transcriptomic shock in their hybrids and offers insights into the difficulty of coexistence at the homoploid level. Altogether, biological response to selection, accumulated during the history of these orchids, appears governed by their microenvironmental context, in which biotic and abiotic pressures act synergistically to shape transcriptome structure, expression and regulation.
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Affiliation(s)
- Francisco Balao
- Department of Botany and Biodiversity ResearchUniversity of ViennaViennaAustria
- Departamento de Biología Vegetal y EcologíaUniversity of SevilleSevillaSpain
| | - Emiliano Trucchi
- Department of Botany and Biodiversity ResearchUniversity of ViennaViennaAustria
- Department of Life Sciences and BiotechnologiesUniversity of FerraraFerraraItaly
| | - Thomas M. Wolfe
- Department of Botany and Biodiversity ResearchUniversity of ViennaViennaAustria
- Vienna Graduate School of Population GeneticsViennaAustria
| | - Bao‐Hai Hao
- Department of Botany and Biodiversity ResearchUniversity of ViennaViennaAustria
| | - Maria Teresa Lorenzo
- Department of Botany and Biodiversity ResearchUniversity of ViennaViennaAustria
- Departamento de Biología Vegetal y EcologíaUniversity of SevilleSevillaSpain
| | - Juliane Baar
- Department of Botany and Biodiversity ResearchUniversity of ViennaViennaAustria
| | - Laura Sedman
- Gregor Mendel Institute for Plant Molecular BiologyViennaAustria
| | - Carolin Kosiol
- Institut für PopulationsgenetikVetmeduni ViennaViennaAustria
- Centre of Biological DiversitySchool of BiologyUniversity of St AndrewsSt AndrewsUK
| | - Fabian Amman
- Department of Chromosome BiologyUniversity of ViennaViennaAustria
| | - Mark W. Chase
- Royal Botanic Gardens KewRichmondUK
- School of Plant BiologyUniversity of Western AustraliaCrawley, PerthWAAustralia
| | | | - Ovidiu Paun
- Department of Botany and Biodiversity ResearchUniversity of ViennaViennaAustria
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Emel SL, Franks SJ, Spigler RB. Phenotypic selection varies with pollination intensity across populations of Sabatia angularis. THE NEW PHYTOLOGIST 2017; 215:813-824. [PMID: 28542815 DOI: 10.1111/nph.14608] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 04/05/2017] [Indexed: 06/07/2023]
Abstract
Pollinators are considered primary selective agents acting on plant traits, and thus variation in the strength of the plant-pollinator interaction might drive variation in the opportunity for selection and selection intensity across plant populations. Here, we examine whether these critical evolutionary parameters covary with pollination intensity across wild populations of the biennial Sabatia angularis. We quantified pollination intensity in each of nine S. angularis populations as mean stigmatic pollen load per population. For female fitness and three components, fruit number, fruit set (proportion of flowers setting fruit) and number of seeds per fruit, we evaluated whether the opportunity for selection varied with pollination intensity. We used phenotypic selection analyses to test for interactions between pollination intensity and selection gradients for five floral traits, including flowering phenology. The opportunity for selection via fruit set and seeds per fruit declined significantly with increasing pollen receipt, as expected. We demonstrated significant directional selection on multiple traits across populations. We also found that selection intensity for all traits depended on pollination intensity. Consistent with general theory about the relationship between biotic interaction strength and the intensity of selection, our study suggests that variation in pollination intensity drives variation in selection across S. angularis populations.
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Affiliation(s)
- Sarah L Emel
- Department of Biology, Temple University, BioLife Building, 1900 N. 12th St, Philadelphia, PA, 19122, USA
| | - Steven J Franks
- Department of Biological Sciences, Fordham University, Larkin Hall, 441 E. Fordham Road, Bronx, NY, 20458, USA
| | - Rachel B Spigler
- Department of Biology, Temple University, BioLife Building, 1900 N. 12th St, Philadelphia, PA, 19122, USA
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44
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Jiang XF, Li QJ. Self- and intra-morph incompatibility and selection analysis of an inconspicuous distylous herb growing on the Tibetan plateau ( Primula tibetica). Ecol Evol 2017; 7:5746-5753. [PMID: 28811881 PMCID: PMC5552904 DOI: 10.1002/ece3.3151] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Revised: 05/11/2017] [Accepted: 05/17/2017] [Indexed: 11/09/2022] Open
Abstract
There is discussion over whether pollen limitation exerts selection on floral traits to increase floral display or selects for traits that promote autonomous self‐fertilization. Some studies have indicated that pollen limitation does not mediate selection on traits associated with either pollinator attraction or self‐fertilization. Primula tibetica is an inconspicuous cross‐fertilized plant that may suffer from pollen limitation. We conducted a selection analysis on P. tibetica to investigate whether pollen limitation results in selection for an increased floral display in case the evolution of autonomous self‐fertilization has been difficult for this plant. The self‐ and intra‐morph incompatibility features, the capacity for autonomous self‐fertilization, and the magnitude of pollen limitation were examined through hand‐pollination experiments. In 2016, we applied selection analysis on the flowering time, corolla width, stalk height, flower tube length, and flower number in P. tibetica by tagging 76 open‐pollinated plants and 37 hand‐pollinated plants in the field. Our results demonstrated that P. tibetica was strictly self‐ and intra‐morph incompatible. Moreover, the study population underwent severe pollen limitation during the 2016 flowering season. The selection gradients were found to be significantly positive for flowering time, flower number, and corolla width, and marginally significant for the stalk height. Pollinator‐mediated selection was found to be significant on the flower number and corolla width, and marginally significant on stalk height. Our results indicate that the increased floral display may be a vital strategy for small distylous species that have faced difficulty in evolving autonomous self‐fertilization.
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Affiliation(s)
- Xian-Feng Jiang
- Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Mengla China.,University of Chinese Academy of Sciences Beijing China
| | - Qing-Jun Li
- Laboratory of Ecology and Evolutionary Biology State Key Laboratory in Conservation and Utilization of Bioresources in Yunnan Yunnan University Kunming Yunnan China
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45
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Thomsen CJM, Sargent RD. Evidence that a herbivore tolerance response affects selection on floral traits and inflorescence architecture in purple loosestrife (Lythrum salicaria). ANNALS OF BOTANY 2017; 119:1295-1303. [PMID: 28369263 PMCID: PMC5604591 DOI: 10.1093/aob/mcx026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 02/22/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND AND AIMS The study of the evolution of floral traits has generally focused on pollination as the primary driver of selection. However, herbivores can also impose selection on floral traits through a variety of mechanisms, including florivory and parasitism. Less well understood is whether floral and inflorescence architecture traits that influence a plant's tolerance to herbivory, such as compensatory regrowth, alter pollinator-mediated selection. METHODS Because herbivore damage to Lythrum salicaria meristems typically leads to an increase in the number of inflorescences and the size of the floral display, an experiment was conducted to test whether simulated herbivory (i.e. clipping the developing meristem) could alter the magnitude or direction of pollinator-mediated selection on a suite of floral and inflorescence architecture traits. Using a pollen supplementation protocol, pollen limitation was compared in the presence and absence of meristem damage in order to quantify any interaction between pollinator and herbivore-mediated selection on floral traits. KEY RESULTS Surprisingly, in spite of an obvious impact on floral display and architecture, with clipped plants producing more inflorescences and more flowers, there was no difference in pollen limitation between clipped and unclipped plants. Correspondingly, there was no evidence that imposing herbivore damage altered pollinator-mediated selection in this system. Rather, the herbivory treatment alone was found to alter direct selection on floral display, with clipped plants experiencing greater selection for earlier flowering and weaker selection for number of inflorescences when compared with unclipped plants. CONCLUSIONS These findings imply that herbivory on its own can drive selection on plant floral traits and inflorescence architecture in this species, even more so than pollinators. Specifically, herbivory can impose selection on floral traits if such traits influence a plant's tolerance to herbivory, such as through the timing of flowering and/or the compensatory regrowth response.
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Affiliation(s)
- Christina J. M. Thomsen
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada
| | - Risa D. Sargent
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada
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Zu P, Schiestl FP. The effects of becoming taller: direct and pleiotropic effects of artificial selection on plant height in Brassica rapa. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 89:1009-1019. [PMID: 27889935 DOI: 10.1111/tpj.13440] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 10/07/2016] [Accepted: 11/18/2016] [Indexed: 06/06/2023]
Abstract
Plant height is an important trait for plant reproductive success. Plant height is often under pollinator-mediated selection, and has been shown to be correlated with various other traits. However, few studies have examined the evolutionary trajectory of plant height under selection and the pleiotropic effects of plant height evolution. We conducted a bi-directional artificial selection experiment on plant height with fast cycling Brassica rapa plants to estimate its heritability and genetic correlations, and to reveal evolutionary responses to artificial selection on height and various correlated traits. With the divergent lines obtained through artificial selection, we subsequently conducted pollinator-choice assays and investigated resource limitation of fruit production. We found that plant height variation is strongly genetically controlled (with a realized heritability of 41-59%). Thus, plant height can evolve rapidly under phenotypic selection. In addition, we found remarkable pleiotropic effects in phenology, morphology, floral scent, color, nectar and leaf glucosinolates. Most traits were increased in tall-line plants, but flower size, UV reflection and glucosinolates were decreased, indicating potential trade-offs. Pollinators preferred plants of the tall selection lines over the short selection lines in both greenhouse experiments with bumblebees and field experiment with natural pollinators. We did not detect any differences in resource limitation between plants of the different selection lines. Overall, our study predicts that increased height should evolve under positive pollinator-mediated directional selection with potential trade-offs in floral signals and herbivore defense.
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Affiliation(s)
- Pengjuan Zu
- Department of Systematic and Evolutionary Botany, University of Zürich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland
| | - Florian P Schiestl
- Department of Systematic and Evolutionary Botany, University of Zürich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland
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La Rosa RJ, Conner JK. Floral function: effects of traits on pollinators, male and female pollination success, and female fitness across three species of milkweeds (Asclepias). AMERICAN JOURNAL OF BOTANY 2017; 104:150-160. [PMID: 28104591 DOI: 10.3732/ajb.1600328] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 12/19/2016] [Indexed: 06/06/2023]
Abstract
PREMISE OF THE STUDY Central questions in plant reproductive ecology are whether the functions of floral traits in hermaphrodites create conflict between sexes that could slow evolution, and whether individual floral traits function in pollinator attraction, efficiency, or both. We studied how floral traits affect pollinator visitation and efficiency, and how they affect male and female function and female fitness within and across three Asclepias species that differ in floral morphology. METHODS Using separate multiple regressions, we regressed pollen removal, deposition, and fruit number onto six floral traits. We also used path analyses integrating these variables with pollinator visitation data for two of the species to further explore floral function and its effects on fruit production. KEY RESULTS Most traits affected male pollination success only, and these effects often differed between species. The exception was increased slit length, which increased pollinia insertion in two of the species. There were no interspecific differences in the effects of the traits on female pollination success. All traits except horn reach affected pollination efficiency in at least one species, and horn reach and two hood dimensions were the only traits to affect pollinator attraction, but in just one species. CONCLUSIONS Traits tended to function in only one sex, and more traits affected function through pollinator efficiency than through attraction. There was no significant link between female pollination success and female fitness in any of the three species; this pattern is consistent with fruit production not being limited by pollen deposition.
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Affiliation(s)
- Raffica J La Rosa
- W. K. Kellogg Biological Station, Department of Plant Biology, and Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, 3700 E. Gull Lake Dr., Hickory Corners, Michigan 49060
| | - Jeffrey K Conner
- W. K. Kellogg Biological Station, Department of Plant Biology, and Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, 3700 E. Gull Lake Dr., Hickory Corners, Michigan 49060
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Affiliation(s)
- Nina Sletvold
- Plant Ecology and Evolution Department of Ecology and Genetics Evolutionary Biology Centre Uppsala University Norbyvägen 18 D SE‐752 36 Uppsala Sweden
| | - Matthew Tye
- Plant Ecology and Evolution Department of Ecology and Genetics Evolutionary Biology Centre Uppsala University Norbyvägen 18 D SE‐752 36 Uppsala Sweden
| | - Jon Ågren
- Plant Ecology and Evolution Department of Ecology and Genetics Evolutionary Biology Centre Uppsala University Norbyvägen 18 D SE‐752 36 Uppsala Sweden
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Paudel BR, Shrestha M, Burd M, Adhikari S, Sun YS, Li QJ. Coevolutionary elaboration of pollination-related traits in an alpine ginger (Roscoea purpurea) and a tabanid fly in the Nepalese Himalayas. THE NEW PHYTOLOGIST 2016; 211:1402-11. [PMID: 27112321 DOI: 10.1111/nph.13974] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 03/17/2016] [Indexed: 05/27/2023]
Abstract
Geographical variation in the interacting traits of plant-pollinator mutualism can lead to local adaptive differentiation. We tested Darwin's hypothesis of reciprocal selection as a key driving force for the evolution of floral traits of an alpine ginger (Roscoea purpurea) and proboscis length of a tabanid fly (Philoliche longirostris). We documented the pattern of trait variation in R. purpurea and P. longirostris across five populations. At each site, we quantified pollinator-mediated selection on floral display area, inflorescence height and corolla length of R. purpurea by comparing selection gradients for flowers exposed to natural pollination and to supplemental hand pollination. Reciprocal selection between plant and fly was examined at two sites via the relationship between proboscis length and nectar consumption (fly benefit) and corolla length and pollen deposition (plant benefit). Local corolla tube length was correlated with local fly proboscis length among the five sites. We found strong linear selection imposed by pollinators on corolla tube length at all sites, but there was no consistent relationship of fitness to inflorescence height or floral display area. Selection between corolla length and proboscis length was reciprocal at the two experimental sites examined. The geographical pattern of trait variation and the evidence of selection is consistent with a mosaic of local, species-specific reciprocal selection acting as the major driving force for the evolution of corolla length of R. purpurea and proboscis length of P. longirostris.
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Affiliation(s)
- Babu Ram Paudel
- Plant Evolutionary Ecology Research Group, Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun Town, Mengla County, Yunnan, 666303, China
- University of Chinese Academy of Sciences, Beijing, 100039, China
- Tribhuvan University, Department of Botany, Prithvi Narayan Campus, Pokhara, Nepal
| | - Mani Shrestha
- School of Media and Communication, RMIT University, Melbourne, Victoria, 3001, Australia
- Faculty of Information Technology, Monash University, Melbourne, Victoria, 3800, Australia
| | - Martin Burd
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia
| | - Subodh Adhikari
- Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, 59715, USA
| | - Yong-Shuai Sun
- Plant Evolutionary Ecology Research Group, Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun Town, Mengla County, Yunnan, 666303, China
| | - Qing-Jun Li
- Laboratory of Ecology and Evolutionary Biology, State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, Yunnan, 650091, China
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Nunes CEP, Peñaflor MFGV, Bento JMS, Salvador MJ, Sazima M. The dilemma of being a fragrant flower: the major floral volatile attracts pollinators and florivores in the euglossine-pollinated orchid Dichaea pendula. Oecologia 2016; 182:933-946. [PMID: 27538674 DOI: 10.1007/s00442-016-3703-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 08/09/2016] [Indexed: 01/01/2023]
Abstract
Volatile organic compounds (VOCs) mediate both mutualistic and antagonistic plant-animal interactions; thus, the attraction of mutualists and antagonists by floral VOCs constitutes an important trade-off in the evolutionary ecology of angiosperms. Here, we evaluate the role of VOCs in mediating communication between the plant and its mutualist and antagonist floral visitors. To assess the evolutionary consequences of VOC-mediated signalling to distinct floral visitors, we studied the reproductive ecology of Dichaea pendula, assessing the effects of florivores on fruit set, the pollination efficiency of pollinators and florivores, the floral scent composition and the attractiveness of the major VOC to pollinators and florivores. The orchid depends entirely on orchid-bees for sexual reproduction, and the major florivores, the weevils, feed on corollas causing self-pollination, triggering abortion of 26.4 % of the flowers. Floral scent was composed of approximately 99 % 2-methoxy-4-vinylphenol, an unusual floral VOC attractive to pollinators and florivores. The low fruit set from natural pollination (5.6 %) compared to hand cross-pollination (45.5 %) and low level of pollinator visitation [0.02 visits (flower hour)-1] represent the limitations to pollination. Our research found that 2-methoxy-4-vinylphenol mediates both mutualistic and antagonistic interactions, which could result in contrary evolutionary pressures on novo-emission. The scarcity of pollinators, not florivory, was the major constraint to fruit set. Our results suggest that, rather than anti-florivory adaptations, adaptations to enhance pollinator attraction and cross-pollination might be the primary drivers of the evolution of VOC emission in euglossine-pollinated flowers.
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Affiliation(s)
- Carlos E P Nunes
- Graduate Program in Plant Biology, University of Campinas, Rua Monteiro Lobato 255, Cidade Universitária "Zeferino Vaz", Campinas, 13083-970, Brazil.
| | - Maria Fernanda G V Peñaflor
- Department of Entomology and Acarology, University of São Paulo, Escola Superior de Agricultura "Luiz de Queiroz" (ESALQ), Piracicaba, Brazil
| | - José Maurício S Bento
- Department of Entomology and Acarology, University of São Paulo, Escola Superior de Agricultura "Luiz de Queiroz" (ESALQ), Piracicaba, Brazil
| | - Marcos José Salvador
- Department of Plant Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Marlies Sazima
- Department of Plant Biology, Institute of Biology, University of Campinas, Campinas, Brazil
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