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Ostevik KL, Alabady M, Zhang M, Rausher MD. Whole-genome sequence and annotation of Penstemon davidsonii. G3 (BETHESDA, MD.) 2024; 14:jkad296. [PMID: 38155402 PMCID: PMC10917496 DOI: 10.1093/g3journal/jkad296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 11/30/2023] [Accepted: 12/01/2023] [Indexed: 12/30/2023]
Abstract
Penstemon is the most speciose flowering plant genus endemic to North America. Penstemon species' diverse morphology and adaptation to various environments have made them a valuable model system for studying evolution. Here, we report the first full reference genome assembly and annotation for Penstemon davidsonii. Using PacBio long-read sequencing and Hi-C scaffolding technology, we constructed a de novo reference genome of 437,568,744 bases, with a contig N50 of 40 Mb and L50 of 5. The annotation includes 18,199 gene models, and both the genome and transcriptome assembly contain over 95% complete eudicot BUSCOs. This genome assembly will serve as a valuable reference for studying the evolutionary history and genetic diversity of the Penstemon genus.
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Affiliation(s)
- Kate L Ostevik
- Department of Evolution, Ecology, and Organismal Biology, University of California Riverside, Riverside, CA 92521, USA
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Magdy Alabady
- Department of Plant Biology, University of Georgia, Athens, GA 30602, USA
| | - Mengrui Zhang
- Department of Statistics, University of Georgia, Athens, GA 30602, USA
| | - Mark D Rausher
- Department of Biology, Duke University, Durham, NC 27708, USA
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2
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Stone BW, Wessinger CA. Ecological Diversification in an Adaptive Radiation of Plants: The Role of De Novo Mutation and Introgression. Mol Biol Evol 2024; 41:msae007. [PMID: 38232726 PMCID: PMC10826641 DOI: 10.1093/molbev/msae007] [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: 11/01/2023] [Revised: 01/01/2024] [Accepted: 01/10/2024] [Indexed: 01/19/2024] Open
Abstract
Adaptive radiations are characterized by rapid ecological diversification and speciation events, leading to fuzzy species boundaries between ecologically differentiated species. Adaptive radiations are therefore key systems for understanding how species are formed and maintained, including the role of de novo mutations versus preexisting variation in ecological adaptation and the genome-wide consequences of hybridization events. For example, adaptive introgression, where beneficial alleles are transferred between lineages through hybridization, may fuel diversification in adaptive radiations and facilitate adaptation to new environments. In this study, we employed whole-genome resequencing data to investigate the evolutionary origin of hummingbird-pollinated flowers and to characterize genome-wide patterns of phylogenetic discordance and introgression in Penstemon subgenus Dasanthera, a small and diverse adaptive radiation of plants. We found that magenta hummingbird-adapted flowers have apparently evolved twice from ancestral blue-violet bee-pollinated flowers within this radiation. These shifts in flower color are accompanied by a variety of inactivating mutations to a key anthocyanin pathway enzyme, suggesting that independent de novo loss-of-function mutations underlie the parallel evolution of this trait. Although patterns of introgression and phylogenetic discordance were heterogenous across the genome, a strong effect of gene density suggests that, in general, natural selection opposes introgression and maintains genetic differentiation in gene-rich genomic regions. Our results highlight the importance of both de novo mutation and introgression as sources of evolutionary change and indicate a role for de novo mutation in driving parallel evolution in adaptive radiations.
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Affiliation(s)
- Benjamin W Stone
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208-3401, USA
| | - Carolyn A Wessinger
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208-3401, USA
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3
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Stone BW, Wessinger CA. Ecological diversification in an adaptive radiation of plants: the role of de novo mutation and introgression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.01.565185. [PMID: 37961506 PMCID: PMC10635055 DOI: 10.1101/2023.11.01.565185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Adaptive radiations are characterized by rapid ecological diversification and speciation events, leading to fuzzy species boundaries between ecologically differentiated species. Adaptive radiations are therefore key systems for understanding how species are formed and maintained, including the role of de novo mutations vs. pre-existing variation in ecological adaptation and the genome-wide consequences of hybridization events. For example, adaptive introgression, where beneficial alleles are transferred between lineages through hybridization, may fuel diversification in adaptive radiations and facilitate adaptation to new environments. In this study, we employed whole-genome resequencing data to investigate the evolutionary origin of hummingbird-pollinated flowers and to characterize genome-wide patterns of phylogenetic discordance and introgression in Penstemon subgenus Dasanthera, a small and diverse adaptive radiation of plants. We found that magenta hummingbird-adapted flowers have apparently evolved twice from ancestral blue-violet bee-pollinated flowers within this radiation. These shifts in flower color are accompanied by a variety of inactivating mutations to a key anthocyanin pathway enzyme, suggesting that independent de novo loss-of-function mutations underlie parallel evolution of this trait. Although patterns of introgression and phylogenetic discordance were heterogenous across the genome, a strong effect of gene density suggests that, in general, natural selection opposes introgression and maintains genetic differentiation in gene-rich genomic regions. Our results highlight the importance of both de novo mutation and introgression as sources of evolutionary change and indicate a role for de novo mutation in driving parallel evolution in adaptive radiations.
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Affiliation(s)
- Benjamin W. Stone
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208-3401, USA
| | - Carolyn A. Wessinger
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208-3401, USA
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4
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Stevens JTE, Wheeler LC, Williams NH, Norton AM, Wessinger CA. Predictive Links between Petal Color and Pigment Quantities in Natural Penstemon Hybrids. Integr Comp Biol 2023; 63:1340-1351. [PMID: 37327076 DOI: 10.1093/icb/icad073] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 06/05/2023] [Accepted: 06/13/2023] [Indexed: 06/18/2023] Open
Abstract
Flowers have evolved remarkable diversity in petal color, in large part due to pollinator-mediated selection. This diversity arises from specialized metabolic pathways that generate conspicuous pigments. Despite the clear link between flower color and floral pigment production, quantitative models inferring predictive relationships between pigmentation and reflectance spectra have not been reported. In this study, we analyze a dataset consisting of hundreds of natural Penstemon hybrids that exhibit variation in flower color, including blue, purple, pink, and red. For each individual hybrid, we measured anthocyanin pigment content and petal spectral reflectance. We found that floral pigment quantities are correlated with hue, chroma, and brightness as calculated from petal spectral reflectance data: hue is related to the relative amounts of delphinidin vs. pelargonidin pigmentation, whereas brightness and chroma are correlated with the total anthocyanin pigmentation. We used a partial least squares regression approach to identify predictive relationships between pigment production and petal reflectance. We find that pigment quantity data provide robust predictions of petal reflectance, confirming a pervasive assumption that differences in pigmentation should predictably influence flower color. Moreover, we find that reflectance data enables accurate inferences of pigment quantities, where the full reflectance spectra provide much more accurate inference of pigment quantities than spectral attributes (brightness, chroma, and hue). Our predictive framework provides readily interpretable model coefficients relating spectral attributes of petal reflectance to underlying pigment quantities. These relationships represent key links between genetic changes affecting anthocyanin production and the ecological functions of petal coloration.
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Affiliation(s)
- Joshua T E Stevens
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Lucas C Wheeler
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Noah H Williams
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Alice M Norton
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Carolyn A Wessinger
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
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5
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Larson AJS, Cartwright MM, Jones WD, Luce K, Chen MY, Petersen K, Nelson SV, Michaelis DJ, Madsen MD. Slow Release of GA 3 Hormone from Polymer Coating Overcomes Seed Dormancy and Improves Germination. PLANTS (BASEL, SWITZERLAND) 2023; 12:4139. [PMID: 38140466 PMCID: PMC10748187 DOI: 10.3390/plants12244139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 12/24/2023]
Abstract
Seed dormancy often hinders direct seeding efforts that are attempting to restore degraded landscapes. Gibberellic acid (GA3) can be applied to physiologically dormant seeds to induce germination, but this hormone is rarely effective, as it can degrade or be leached from the seed. We tested different polymer matrixes (polylactic acid, polyvinylpyrrolidone, and ethylcellulose) to apply and slowly release GA3 to the seed. These polymers were tested as seed coatings in either a powder, liquid, or a combination of powder and liquid forms. We found that a liquid ethylcellulose/GA3 coating generally outperformed the other polymers and applications methods using our test species Penstemon palmeri. With this top-performing treatment, seed germination was 3.0- and 3.9-fold higher at 15 °C and 25 °C, respectively. We also evaluated the liquid ethylcellulose/GA3 coating on P. comharrenus, P. strictus, P. pachyphyllus, and P. eatonii. Again, the coating had a strong treatment response, with the degree of difference related to the relative level of dormancy of the species. Growth studies were also performed in pots to ensure that the side effects of GA3 overdosing were not present. Here, we found minimal differences in root length, shoot length, or biomass between plants grown from untreated and GA3-coated seeds.
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Affiliation(s)
- Alexandra J. S. Larson
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602, USA; (A.J.S.L.); (W.D.J.); (K.L.); (M.-Y.C.); (S.V.N.)
| | - Maureen M. Cartwright
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602, USA; (A.J.S.L.); (W.D.J.); (K.L.); (M.-Y.C.); (S.V.N.)
| | - Whitney D. Jones
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602, USA; (A.J.S.L.); (W.D.J.); (K.L.); (M.-Y.C.); (S.V.N.)
| | - Katrina Luce
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602, USA; (A.J.S.L.); (W.D.J.); (K.L.); (M.-Y.C.); (S.V.N.)
| | - Mei-Yu Chen
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602, USA; (A.J.S.L.); (W.D.J.); (K.L.); (M.-Y.C.); (S.V.N.)
| | - Kate Petersen
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA; (K.P.); (D.J.M.)
| | - Shannon V. Nelson
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602, USA; (A.J.S.L.); (W.D.J.); (K.L.); (M.-Y.C.); (S.V.N.)
| | - David J. Michaelis
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA; (K.P.); (D.J.M.)
| | - Matthew D. Madsen
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602, USA; (A.J.S.L.); (W.D.J.); (K.L.); (M.-Y.C.); (S.V.N.)
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Mochizuki K, Okamoto T, Chen KH, Wang CN, Evans M, Kramer AT, Kawakita A. Adaptation to pollination by fungus gnats underlies the evolution of pollination syndrome in the genus Euonymus. ANNALS OF BOTANY 2023; 132:319-333. [PMID: 37610846 PMCID: PMC10583214 DOI: 10.1093/aob/mcad081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 07/04/2023] [Indexed: 08/25/2023]
Abstract
BACKGROUND AND AIMS Dipteran insects are known pollinators of many angiosperms, but knowledge on how flies affect floral evolution is relatively scarce. Some plants pollinated by fungus gnats share a unique set of floral characters (dark red display, flat shape and short stamens), which differs from any known pollination syndromes. We tested whether this set of floral characters is a pollination syndrome associated with pollination by fungus gnats, using the genus Euonymus as a model. METHODS The pollinator and floral colour, morphology and scent profile were investigated for ten Euonymus species and Tripterygium regelii as an outgroup. The flower colour was evaluated using bee and fly colour vision models. The evolutionary association between fungus gnat pollination and each plant character was tested using a phylogenetically independent contrast. The ancestral state reconstruction was performed on flower colour, which is associated with fungus gnat pollination, to infer the evolution of pollination in the genus Euonymus. KEY RESULTS The red-flowered Euonymus species were pollinated predominantly by fungus gnats, whereas the white-flowered species were pollinated by bees, beetles and brachyceran flies. The colour vision analysis suggested that red and white flowers are perceived as different colours by both bees and flies. The floral scents of the fungus gnat-pollinated species were characterized by acetoin, which made up >90 % of the total scent in three species. Phylogenetically independent contrast showed that the evolution of fungus gnat pollination is associated with acquisition of red flowers, short stamens and acetoin emission. CONCLUSIONS Our results suggest that the observed combination of floral characters is a pollination syndrome associated with the parallel evolution of pollination by fungus gnats. Although the role of the red floral display and acetoin in pollinator attraction remains to be elucidated, our finding underscores the importance of fungus gnats as potential contributors to floral diversification.
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Affiliation(s)
- Ko Mochizuki
- Botanical Gardens, Graduate School of Science, The University of Tokyo, 3-7-1 Hakusan, Bunkyo-ku, Tokyo, Japan
| | - Tomoko Okamoto
- Faculty of Applied Biological Sciences, Gifu University, Yanagido 1-1, Gifu, Japan
| | - Kai-Hsiu Chen
- Department of Ecology and Evolution, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Chun-Neng Wang
- Department of Life Science, Institute of Ecology and Evolutionary Biology, National Taiwan University, Taipei 10617, Taiwan
| | - Matthew Evans
- Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL 60022, USA
| | - Andrea T Kramer
- Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL 60022, USA
| | - Atsushi Kawakita
- Botanical Gardens, Graduate School of Science, The University of Tokyo, 3-7-1 Hakusan, Bunkyo-ku, Tokyo, Japan
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7
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Kiel CA, Manzitto-Tripp E, Fisher AE, Porter JM, McDade LA. Remarkable variation in androecial morphology is closely associated with corolla traits in Western Hemisphere Justiciinae (Acanthaceae: Justicieae). ANNALS OF BOTANY 2023; 132:43-60. [PMID: 37279362 PMCID: PMC10550274 DOI: 10.1093/aob/mcad068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 05/30/2023] [Indexed: 06/08/2023]
Abstract
BACKGROUND AND AIMS Few studies of angiosperms have focused on androecial evolution in conjunction with evolutionary shifts in corolla morphology and pollinator relationships. The Western Hemisphere clade of Justiciinae (Acanthaceae) presents the rare opportunity to examine remarkable diversity in staminal morphology. We took a phylogenetically informed approach to examine staminal diversity in this hypervariable group and asked whether differences in anther thecae separation is associated with phylogenetically informed patterns of variation in corolla morphology. We further discuss evidence for associations between anther diversity and pollinators in this lineage. METHODS For the Dianthera/Sarotheca/Plagiacanthus (DSP) clade of Western Hemisphere Justiciinae, we characterized floral diversity based on a series of corolla measurements and using a model-based clustering approach. We then tested for correlations between anther thecae separation and corolla traits, and for shifts in trait evolution, including evidence for convergence. KEY RESULTS There is evolutionary vagility in corolla and anther traits across the DSP clade with little signal of phylogenetic constraint. Floral morphology clusters into four distinct groups that are, in turn, strongly associated with anther thecae separation, a novel result in Acanthaceae and, to our knowledge, across flowering plants. These cluster groups are marked by floral traits that strongly point to associations with pollinating animals. Specifically, species that are known or likely to be hummingbird pollinated have stamens with parallel thecae, whereas those that are likely bee or fly pollinated have stamens with offset, divergent thecae. CONCLUSIONS Our results suggest that anther thecae separation is likely under selection in concert with other corolla characters. Significant morphological shifts detected by our analyses corresponded to putative shifts from insect to hummingbird pollination. Results from this study support the hypothesis that floral structures function in an integrated manner and are likely subject to selection as a suite. Further, these changes can be hypothesized to represent adaptive evolution.
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Affiliation(s)
- Carrie A Kiel
- California Botanic Garden, 1500 North College Avenue, Claremont, CA 91711, USA
| | - Erin Manzitto-Tripp
- University of Colorado, Museum of Natural History and Department of Ecology and Evolutionary Biology, Boulder, CO 80309, USA
| | - Amanda E Fisher
- California State University, Long Beach, 1250 Bellflower Boulevard, Long Beach, CA 90807, USA
| | - J Mark Porter
- California Botanic Garden, 1500 North College Avenue, Claremont, CA 91711, USA
| | - Lucinda A McDade
- California Botanic Garden, 1500 North College Avenue, Claremont, CA 91711, USA
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8
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Kriebel R, Rose JP, Bastide P, Jolles D, Reginato M, Sytsma KJ. The evolution of Ericaceae flowers and their pollination syndromes at a global scale. AMERICAN JOURNAL OF BOTANY 2023; 110:e16220. [PMID: 37551426 DOI: 10.1002/ajb2.16220] [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: 10/31/2022] [Revised: 07/10/2023] [Accepted: 07/12/2023] [Indexed: 08/09/2023]
Abstract
PREMISE Floral evolution in large clades is difficult to study not only because of the number of species involved, but also because they often are geographically widespread and include a diversity of outcrossing pollination systems. The cosmopolitan blueberry family (Ericaceae) is one such example, most notably pollinated by bees and multiple clades of nectarivorous birds. METHODS We combined data on floral traits, pollination ecology, and geography with a comprehensive phylogeny to examine the structuring of floral diversity across pollination systems and continents. We focused on ornithophilous systems to test the hypothesis that some Old World Ericaceae were pollinated by now-extinct hummingbirds. RESULTS Despite some support for floral differentiation at a continental scale, we found a large amount of variability within and among landmasses, due to both phylogenetic conservatism and parallel evolution. We found support for floral differentiation in anther and corolla traits across pollination systems, including among different ornithophilous systems. Corolla traits show inconclusive evidence that some Old World Ericaceae were pollinated by hummingbirds, while anther traits show stronger evidence. Some major shifts in floral traits are associated with changes in pollination system, but shifts within bee systems are likely also important. CONCLUSIONS Studying the floral evolution of large, morphologically diverse, and widespread clades is feasible. We demonstrate that continent-specific radiations have led to widespread parallel evolution of floral morphology. We show that traits outside of the perianth may hold important clues to the ecological history of lineages.
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Affiliation(s)
- Ricardo Kriebel
- Department of Botany, California Academy of Sciences, San Francisco, California, 94118, USA
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
| | - Jeffrey P Rose
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
| | - Paul Bastide
- IMAG, Université de Montpellier, CNRS, Montpellier, France
| | - Diana Jolles
- Department of Biological Sciences, Plymouth State University, 17 High Street, Plymouth, New Hampshire, 03264-1594, USA
| | - Marcelo Reginato
- Departamento de Botânica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Kenneth J Sytsma
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
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9
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Wessinger CA, Katzer AM, Hime PM, Rausher MD, Kelly JK, Hileman LC. A few essential genetic loci distinguish Penstemon species with flowers adapted to pollination by bees or hummingbirds. PLoS Biol 2023; 21:e3002294. [PMID: 37769035 PMCID: PMC10538765 DOI: 10.1371/journal.pbio.3002294] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 08/11/2023] [Indexed: 09/30/2023] Open
Abstract
In the formation of species, adaptation by natural selection generates distinct combinations of traits that function well together. The maintenance of adaptive trait combinations in the face of gene flow depends on the strength and nature of selection acting on the underlying genetic loci. Floral pollination syndromes exemplify the evolution of trait combinations adaptive for particular pollinators. The North American wildflower genus Penstemon displays remarkable floral syndrome convergence, with at least 20 separate lineages that have evolved from ancestral bee pollination syndrome (wide blue-purple flowers that present a landing platform for bees and small amounts of nectar) to hummingbird pollination syndrome (bright red narrowly tubular flowers offering copious nectar). Related taxa that differ in floral syndrome offer an attractive opportunity to examine the genomic basis of complex trait divergence. In this study, we characterized genomic divergence among 229 individuals from a Penstemon species complex that includes both bee and hummingbird floral syndromes. Field plants are easily classified into species based on phenotypic differences and hybrids displaying intermediate floral syndromes are rare. Despite unambiguous phenotypic differences, genome-wide differentiation between species is minimal. Hummingbird-adapted populations are more genetically similar to nearby bee-adapted populations than to geographically distant hummingbird-adapted populations, in terms of genome-wide dXY. However, a small number of genetic loci are strongly differentiated between species. These approximately 20 "species-diagnostic loci," which appear to have nearly fixed differences between pollination syndromes, are sprinkled throughout the genome in high recombination regions. Several map closely to previously established floral trait quantitative trait loci (QTLs). The striking difference between the diagnostic loci and the genome as whole suggests strong selection to maintain distinct combinations of traits, but with sufficient gene flow to homogenize the genomic background. A surprisingly small number of alleles confer phenotypic differences that form the basis of species identity in this species complex.
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Affiliation(s)
- Carolyn A. Wessinger
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, United States of America
| | - Amanda M. Katzer
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, United States of America
| | - Paul M. Hime
- Biodiversity Institute and Natural History Museum, University of Kansas, Lawrence, Kansas, United States of America
| | - Mark D. Rausher
- Department of Biology, Duke University, Durham, North Carolina, United States of America
| | - John K. Kelly
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, United States of America
| | - Lena C. Hileman
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, United States of America
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10
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Floral scent divergence across an elevational hybrid zone with varying pollinators. Oecologia 2023; 201:45-57. [PMID: 36374316 DOI: 10.1007/s00442-022-05289-3] [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: 02/16/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022]
Abstract
Divergence in floral traits attractive to different pollinators can promote reproductive isolation in related species. When isolation is incomplete, hybridization may occur, which offers the opportunity to explore mechanisms underlying reproductive isolation. Recent work suggests that divergence in floral scent may frequently contribute to reproductive barriers, although such divergence has seldom been examined in species with generalized pollination. Here, we used two closely related Penstemon species, P. newberryi and P. davidsonii, and their natural hybrids from an elevational gradient with pollinator communities that are predicted to vary in their reliance on floral scent (i.e., primarily hummingbirds at low elevation vs. bees at high elevation). The species vary in a suite of floral traits, but scent is uncharacterized. To address whether scent varies along elevation and potentially contributes to reproductive isolation, we genetically characterized individuals collected at field and identified whether they were parental species or hybrids. We then characterized scent amount and composition. Although the parental species had similar total emissions, some scent characteristics (i.e., scent composition, aromatic emission) diverged between them and may contribute to their isolation. However, the species emitted similar compound sets which could explain hybridization in the contact area. Hybrids were similar to the parents for most scent traits, suggesting that their floral scent would not provide a strong barrier to backcrossing. Our study suggests floral scent may be a trait contributing to species boundaries even in plants with generalized pollination, and reinforces the idea that evolutionary pollinator transitions may involve changes in multiple floral traits.
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11
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Burkle LA, Zabinski CA. Mycorrhizae influence plant vegetative and floral traits and intraspecific trait variation. AMERICAN JOURNAL OF BOTANY 2023; 110:e16099. [PMID: 36371729 DOI: 10.1002/ajb2.16099] [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: 03/01/2022] [Revised: 10/19/2022] [Accepted: 10/20/2022] [Indexed: 06/16/2023]
Abstract
PREMISE Arbuscular mycorrhizal fungi (AMF) can strongly influence host plant vegetative growth, but less is known about AMF effects on other plant traits, the relative impacts of AMF on vegetative growth versus floral traits, or AMF-induced intraspecific variation in traits. METHODS In an experimental greenhouse study, we inoculated seven species of wildflowers with six species of AMF in a factorial design. We assessed how the AMF-forb combinations influenced plant survival, vegetative biomass, and floral traits and whether AMF effects on floral traits were similar in magnitude and direction to effects on vegetative biomass. For one forb species, we investigated intraspecific plant trait variation within and across AMF treatments. RESULTS AMF species varied from negative to positive in their effects on host plants. AMF often had inconsistent effects on vegetative biomass versus floral traits, and therefore, quantifying one or the other may provide a misleading representation of potential AMF effects. AMF treatments generated key variation in plant traits, especially floral traits, with potential consequences for plant-pollinator interactions. Given increased intraspecific trait variation in Linum lewisii plants across AMF species compared to uninoculated individuals or single AMF treatments, local AMF diversity and their host plant associations may scale up to influence community-wide patterns of trait variation and species interactions. CONCLUSIONS These results have implications for predicting how aboveground communities are affected by belowground communities. Including AMF effects on not just host plant biomass but also functional traits and trait variation will deepen our understanding of community structure and function, including pollination.
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Affiliation(s)
- Laura A Burkle
- Department of Ecology, Montana State University, Bozeman, MT, 59717, USA
| | - Catherine A Zabinski
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, 59717, USA
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12
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Kay KM, Grossenbacher DL. Evolutionary convergence on hummingbird pollination in Neotropical Costus provides insight into the causes of pollinator shifts. THE NEW PHYTOLOGIST 2022; 236:1572-1583. [PMID: 36068995 PMCID: PMC9826479 DOI: 10.1111/nph.18464] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 08/10/2022] [Indexed: 06/15/2023]
Abstract
The evolution of hummingbird pollination is common across angiosperms throughout the Americas, presenting an opportunity to examine convergence in both traits and environments to better understand how complex phenotypes arise. Here we examine independent shifts from bee to hummingbird pollination in the Neotropical spiral gingers (Costus) and address common explanations for the prevalence of transitions from bee to hummingbird pollination. We use floral traits of species with observed pollinators to predict pollinators of unobserved species and reconstruct ancestral pollination states on a well-resolved phylogeny. We examine whether independent transitions evolve towards the same phenotypic optimum and whether shifts to hummingbird pollination correlate with elevation or climate. Traits predicting hummingbird pollination include small flower size, brightly colored floral bracts and the absence of nectar guides. We find many shifts to hummingbird pollination and no reversals, a single shared phenotypic optimum across hummingbird flowers, and no association between pollination and elevation or climate. Evolutionary shifts to hummingbird pollination in Costus are highly convergent and directional, involve a surprising set of traits when compared with other plants with analogous transitions and refute the generality of several common explanations for the prevalence of transitions from bee to hummingbird pollination.
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Affiliation(s)
- Kathleen M. Kay
- Department of Ecology and Evolutionary BiologyUniversity of California, Santa CruzSanta CruzCA95060USA
| | - Dena L. Grossenbacher
- Department of BiologyCalifornia Polytechnic State UniversitySan Luis ObispoCA93401USA
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13
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Pauw A. Pollination syndrome accurately predicts pollination by tangle-veined flies (Nemestrinidae: Prosoeca s.s.) across multiple plant families. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:1010-1021. [PMID: 35975653 PMCID: PMC9804979 DOI: 10.1111/plb.13461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 08/15/2022] [Indexed: 06/15/2023]
Abstract
The idea that a syndrome of floral traits predicts pollination by a particular functional group of pollinators remains simultaneously controversial and widely used because it allows plants to be rapidly assigned to pollinators. To test the idea requires demonstrating that there is an association between floral traits and pollinator type. I conducted such a test in the Cape Floristic Region of South Africa, by studying the pollination of eight plant species from six families that flower in spring and have scentless, actinomorphic, upwards-facing flowers, with orbicular petals all held in the same plane. The petals are brilliant-white with red-purple nectar guides. The tubes are short and hold small volumes of concentrated nectar, except in the rewardless Disa fasciata (Orchidaceae). Pollinators were photographed and captured, pollen loads were analysed and pollination networks were constructed. Consistent with the pollination syndrome hypothesis, the species with the defined syndrome shared a small group of pollinators. The most frequent pollinators belonged to a clade of four tangle-veined fly species with relatively short proboscises (Nemestrinidae: Prosoeca s.s.), while functionally similar Bombyliidae and Tabanidae played minor roles. Among the four Prosoeca species, only Prosoeca westermanni has been described, a result that highlights our ignorance about pollinators. The demonstration of an association between the syndrome of traits and pollination by this group of flies explains the repeated evolution of the syndrome across multiple plant families, and allows prediction of pollinators in additional species. More generally, the result validates the idea that the traits of organisms determine their ecology.
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Affiliation(s)
- A. Pauw
- Department of Botany and ZoologyStellenbosch UniversityMatielandSouth Africa
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14
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Silva DM, Luna ALL, Souza CS, Nunes YRF, Fonseca RS, Azevedo IFPD. Sexual and reproductive systems of woody species in
vereda
are distributed according to the life form and habitat occurrence. AUSTRAL ECOL 2022. [DOI: 10.1111/aec.13235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Danila Moreira Silva
- Programa de Pós‐Graduação em Botânica Aplicada Universidade Estadual de Montes Claros Avenida Dr. Ruy Braga, S/N – Bairro Vila Mauricéia Montes Claros 39401‐089 Brazil
| | - Andressa Laís Lacerda Luna
- Programa de Pós‐Graduação em Botânica Aplicada Universidade Estadual de Montes Claros Avenida Dr. Ruy Braga, S/N – Bairro Vila Mauricéia Montes Claros 39401‐089 Brazil
| | - Camila Silveira Souza
- Programa de Pós‐Graduação em Botânica Aplicada Universidade Estadual de Montes Claros Avenida Dr. Ruy Braga, S/N – Bairro Vila Mauricéia Montes Claros 39401‐089 Brazil
- Laboratório de Ecologia Vegetal, Departamento de Biologia Geral Universidade Estadual de Montes Claros Montes Claros Brazil
| | - Yule Roberta Ferreira Nunes
- Programa de Pós‐Graduação em Botânica Aplicada Universidade Estadual de Montes Claros Avenida Dr. Ruy Braga, S/N – Bairro Vila Mauricéia Montes Claros 39401‐089 Brazil
- Laboratório de Ecologia Vegetal, Departamento de Biologia Geral Universidade Estadual de Montes Claros Montes Claros Brazil
| | - Rúbia Santos Fonseca
- Instituto de Ciências Agrárias Universidade Federal de Minas Gerais, Bairro Universitário Montes Claros Brazil
| | - Islaine Franciely Pinheiro de Azevedo
- Programa de Pós‐Graduação em Botânica Aplicada Universidade Estadual de Montes Claros Avenida Dr. Ruy Braga, S/N – Bairro Vila Mauricéia Montes Claros 39401‐089 Brazil
- Laboratório de Ecologia Vegetal, Departamento de Biologia Geral Universidade Estadual de Montes Claros Montes Claros Brazil
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15
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Berardi AE, Betancourt Morejón AC, Hopkins R. Convergence without divergence in North American red-flowering Silene. FRONTIERS IN PLANT SCIENCE 2022; 13:945806. [PMID: 36147235 PMCID: PMC9485837 DOI: 10.3389/fpls.2022.945806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 07/06/2022] [Indexed: 06/16/2023]
Abstract
Combinations of correlated floral traits have arisen repeatedly across angiosperms through convergent evolution in response to pollinator selection to optimize reproduction. While some plant groups exhibit very distinct combinations of traits adapted to specific pollinators (so-called pollination syndromes), others do not. Determining how floral traits diverge across clades and whether floral traits show predictable correlations in diverse groups of flowering plants is key to determining the extent to which pollinator-mediated selection drives diversification. The North American Silene section Physolychnis is an ideal group to investigate patterns of floral evolution because it is characterized by the evolution of novel red floral color, extensive floral morphological variation, polyploidy, and exposure to a novel group of pollinators (hummingbirds). We test for correlated patterns of trait evolution that would be consistent with convergent responses to selection in the key floral traits of color and morphology. We also consider both the role of phylogenic distance and geographic overlap in explaining patterns of floral trait variation. Inconsistent with phenotypically divergent pollination syndromes, we find very little clustering of North American Silene into distinct floral morphospace. We also find little evidence that phylogenetic history or geographic overlap explains patterns of floral diversity in this group. White- and pink-flowering species show extensive phenotypic diversity but are entirely overlapping in morphological variation. However, red-flowering species have much less phenotypic disparity and cluster tightly in floral morphospace. We find that red-flowering species have evolved floral traits that align with a traditional hummingbird syndrome, but that these trait values overlap with several white and pink species as well. Our findings support the hypothesis that convergent evolution does not always proceed through comparative phenotypic divergence, but possibly through sorting of standing ancestral variation.
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Affiliation(s)
- Andrea E. Berardi
- Harvard University Herbaria, Cambridge, MA, United States
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, United States
- The Arnold Arboretum, Boston, MA, United States
| | - Ana C. Betancourt Morejón
- Department of Biology, University of Puerto Rico - Rio Piedras Campus, San Juan, Puerto Rico
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, United States
| | - Robin Hopkins
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, United States
- The Arnold Arboretum, Boston, MA, United States
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16
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Hamilton AM, Wessinger CA. Adaptation to lower latitudes and lower elevations precedes the evolution of hummingbird pollination in western North American Penstemon. AMERICAN JOURNAL OF BOTANY 2022; 109:1047-1055. [PMID: 35471733 DOI: 10.1002/ajb2.1857] [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: 01/01/2022] [Revised: 04/12/2022] [Accepted: 04/12/2022] [Indexed: 06/14/2023]
Abstract
PREMISE A switch in pollinator can occur when a plant lineage enters a new habitat where the ancestral pollinator is less common, and a novel pollinator is more common. Because pollinator communities vary according to environmental tolerances and availability of resources, there may be consistent associations between pollination mode and specific regions and habitats. Such associations can be studied in lineages that have experienced multiple pollinator transitions, representing evolutionary replicates. METHODS Our study focused on a large clade of Penstemon wildflower species in western North America, which has repeatedly evolved hummingbird-adapted flowers from ancestral bee-adapted flowers. For each species, we estimated geographic ranges from occurrence data and inferred environmental niches from climate, topographical, and soil data. Using a phylogenetic comparative approach, we investigated whether hummingbird-adapted species occupy distinct geographic regions or habitats relative to bee-adapted species. RESULTS Hummingbird-adapted species occur at lower latitudes and lower elevations than bee-adapted species, resulting in a difference in their environmental niche. Bee-adapted species sister to hummingbird-adapted species are also found in relatively low elevations and latitudes, similar to their hummingbird-adapted sister species, suggesting ecogeographic shifts precede pollinator divergence. Sister species pairs-regardless of whether they differ in pollinator-show relatively little geographic range overlap. CONCLUSIONS Adaptation to a novel pollinator may often occur in geographic and ecological isolation from ancestral populations. The ability of a given lineage to adapt to novel pollinators may critically depend on its ability to colonize regions and habitats associated with novel pollinator communities.
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Affiliation(s)
- Ashley M Hamilton
- Department of Biological Sciences, University of South Carolina, 715 Sumter St, Columbia, SC 29208, USA
| | - Carolyn A Wessinger
- Department of Biological Sciences, University of South Carolina, 715 Sumter St, Columbia, SC 29208, USA
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17
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Venjakob C, Ruedenauer FA, Klein AM, Leonhardt SD. Variation in nectar quality across 34 grassland plant species. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:134-144. [PMID: 34618397 DOI: 10.1111/plb.13343] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 09/01/2021] [Indexed: 06/13/2023]
Abstract
Floral nectar is considered the most important floral reward for attracting pollinators. It contains large amounts of carbohydrates besides variable concentrations of amino acids and thus represents an important food source for many pollinators. Its nutrient content and composition can, however, strongly vary within and between plant species. The factors driving this variation in nectar quality are still largely unclear. We investigated factors underlying interspecific variation in macronutrient composition of floral nectar in 34 different grassland plant species. Specifically, we tested for correlations between the phylogenetic relatedness and morphology of plants and the carbohydrate (C) and total amino acid (AA) composition and C:AA ratios of nectar. We found that compositions of carbohydrates and (essential) amino acids as well as C:AA ratios in nectar varied significantly within and between plant species. They showed no clear phylogenetic signal. Moreover, variation in carbohydrate composition was related to family-specific structural characteristics and combinations of morphological traits. Plants with nectar-exposing flowers, bowl- or parabolic-shaped flowers, as often found in the Apiaceae and Asteraceae, had nectar with higher proportions of hexoses, indicating a selective pressure to decelerate evaporation by increasing nectar osmolality. Our study suggests that variation in nectar nutrient composition is, among others, affected by family-specific combinations of morphological traits. However, even within species, variation in nectar quality is high. As nectar quality can strongly affect visitation patterns of pollinators and thus pollination success, this intra- and interspecific variation requires more studies to fully elucidate the underlying causes and the consequences for pollinator behaviour.
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Affiliation(s)
- C Venjakob
- Institute of Ecology, Ecosystem Functions, Leuphana University of Lüneburg, Lüneburg, Germany
- Agroecology, DNPW, University of Göttingen, Göttingen, Germany
| | - F A Ruedenauer
- Plant-Insect Interactions, TUM School of Life Science Systems, Technical University of Munich, Freising, Germany
| | - A-M Klein
- Faculty of Environment and Natural Resources, Nature Conservation and Landscape Ecology, University of Freiburg, Freiburg, Germany
| | - S D Leonhardt
- Plant-Insect Interactions, TUM School of Life Science Systems, Technical University of Munich, Freising, Germany
- Department of Animal Ecology and Tropical Biology, University of Würzburg, Würzburg, Germany
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18
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Santos‐Gómez SM, Figueroa‐Castro DM, Castañeda‐Posadas C. Are floral traits good predictors of effective pollinators? A test of pollination syndromes. Ecol Res 2021. [DOI: 10.1111/1440-1703.12285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Samantha Maite Santos‐Gómez
- Facultad de Ciencias Biológicas Benemérita Universidad Autónoma de Puebla Puebla Mexico
- Maestría en Ciencias Biológicas, Facultad de Ciencias Biológicas Benemérita Universidad Autónoma de Puebla Puebla Mexico
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19
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Abdallah M, Hervías-Parejo S, Traveset A. Low Pollinator Sharing Between Coexisting Native and Non-native Plant Pairs: The Effect of Corolla Length and Flower Abundance. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.709876] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Understanding the mechanisms by which non-native plants can attract pollinators in their new geographical zones is important because such species infiltrate native communities and can disrupt native ecological interactions. Despite the large number of studies assessing how invasive plants impact plant–pollinator interactions, the specific comparison of pollination interactions between native and non-native plant pairs has received much less attention. Here we focused on four coexisting co-flowering pairs of common native and non-native species, both with abundant flowers but different floral traits, and asked: (1) to what extent native and non-native plants share pollinator species, and whether the non-native plants attract a different set of pollinators, (2) whether the most shared pollinators are the most frequent floral visitors and the most generalized in their interactions, and (3) how much of the variation in the diversity and frequency of pollinator species between native and non-native plant species can be explained by floral trait dissimilarity and flower abundance. Direct pollinator observations revealed that the plant pairs shared a low fraction (0–33%) of insect species, i.e., non-native plants tended to acquire a different set of pollinators than their native counterparts. The most shared pollinators in each plant pair were the most common but not the most generalized species, and non-native species attracted both generalized and specialized pollinators. Corolla length at opening and flower abundance showed to be important in determining the differences in flower visitation rate between natives and non-natives. Our findings support the general pattern that non-native species have no barriers at the pollination stage to integrate into native communities and that they may attract a different assemblage of pollinators relative to those that visit native plants with which they coexist.
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20
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Chmel K, Ewome FL, Gómez GU, Klomberg Y, Mertens JEJ, Tropek R, Janeček Š. Bird pollination syndrome is the plant's adaptation to ornithophily, but nectarivorous birds are not so selective. OIKOS 2021. [DOI: 10.1111/oik.08052] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Kryštof Chmel
- Dept. of Ecology, Faculty of Science, Charles Univ. Viničná Prague Czechia
- Inst. of Entomology, Biology Centre, Czech Academy of Sciences Branišovská České Budějovice Czechia
| | | | | | - Yannick Klomberg
- Dept. of Ecology, Faculty of Science, Charles Univ. Viničná Prague Czechia
- Naturalis Biodiversity Center Darwinweg Leiden the Netherlands
| | - Jan E. J. Mertens
- Dept. of Ecology, Faculty of Science, Charles Univ. Viničná Prague Czechia
| | - Robert Tropek
- Dept. of Ecology, Faculty of Science, Charles Univ. Viničná Prague Czechia
- Inst. of Entomology, Biology Centre, Czech Academy of Sciences Branišovská České Budějovice Czechia
| | - Štěpán Janeček
- Dept. of Ecology, Faculty of Science, Charles Univ. Viničná Prague Czechia
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21
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Roguz K, Hill L, Koethe S, Lunau K, Roguz A, Zych M. Visibility and attractiveness of Fritillaria (Liliaceae) flowers to potential pollinators. Sci Rep 2021; 11:11006. [PMID: 34040041 PMCID: PMC8155214 DOI: 10.1038/s41598-021-90140-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 05/05/2021] [Indexed: 02/04/2023] Open
Abstract
Visual floral characters play an important role in shaping plant-pollinator interactions. The genus Fritillaria L. (Liliaceae), comprising approximately 140 species, is described as displaying a remarkable variety of flower colours and sizes. Despite this variation in visual floral traits of fritillaries, little is known about the potential role of these features in shaping plant-pollinator interactions. Here, we seek to clarify the role of visual attraction in species offering a robust food reward for pollinators early in the spring, which is the case for Fritillaria. We also searched for potential tendencies in the evolution of floral traits crucial for plant-pollinator communication. The generality of species with green and purple flowers may indicate an influence of environmental factors other than pollinators. The flowers of the studied species seem to be visible but not very visually attractive to potential pollinators. The food rewards are hidden within the nodding perianth, and both traits are conserved among fritillaries. Additionally, visual floral traits are not good predictors of nectar properties. When in the flowers, pollinators are navigated by nectar guides in the form of contrasting nectary area colouration. Flower colour does not serve as a phenotypic filter against illegitimate pollinators-red and orange bird-pollinated fritillaries are visible to bees.
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Affiliation(s)
- Katarzyna Roguz
- Botanic Garden, Faculty of Biology, University of Warsaw, Warsaw, Poland.
| | | | - Sebastian Koethe
- Institute of Sensory Ecology, Faculty of Biology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Klaus Lunau
- Institute of Sensory Ecology, Faculty of Biology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Agata Roguz
- National Information Processing Institute, Al. Niepodległości 188 B, 00-608, Warszawa, Poland
| | - Marcin Zych
- Botanic Garden, Faculty of Biology, University of Warsaw, Warsaw, Poland
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22
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Unraveling the ecological and evolutionary impacts of a plant invader on the pollination of a native plant. Biol Invasions 2021. [DOI: 10.1007/s10530-021-02457-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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23
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Rose JP, Sytsma KJ. Complex interactions underlie the correlated evolution of floral traits and their association with pollinators in a clade with diverse pollination systems. Evolution 2021; 75:1431-1449. [PMID: 33818785 DOI: 10.1111/evo.14220] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 02/15/2021] [Accepted: 03/14/2021] [Indexed: 11/28/2022]
Abstract
Natural selection by pollinators is an important factor in the morphological diversity and adaptive radiation of flowering plants. Selection by similar pollinators in unrelated plants leads to convergence in floral morphology, or "floral syndromes." Previous investigations into floral syndromes have mostly studied relatively small and/or simple systems, emphasizing vertebrate pollination. Despite the importance of multiple floral traits in plant-pollinator interactions, these studies have examined few quantitative traits, so their co-variation and phenotypic integration have been underexplored. To gain better insights into pollinator-trait dynamics, we investigate the model system of the phlox family (Polemoniaceae), a clade of ∼400 species pollinated by a diversity of vectors. Using a comprehensive phylogeny and large dataset of traits and observations of pollinators, we reconstruct ancestral pollination system, accounting for the temporal history of pollinators. We conduct phylogenetically controlled analyses of trait co-variation and association with pollinators, integrating many analyses over phylogenetic uncertainty. Pollinator shifts are more heterogeneous than previously hypothesized. The evolution of floral traits is partially constrained by phylogenetic history and trait co-variation, but traits are convergent and differences are associated with different pollinators. Trait shifts are usually gradual, rather than rapid, suggesting complex genetic and ecological interactions of flowers at macroevolutionary scales.
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Affiliation(s)
- Jeffrey P Rose
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, 53706.,Current Address: Department of Biology, University of Nebraska at Kearney, Kearney, Nebraska, 68849
| | - Kenneth J Sytsma
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, 53706
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24
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Roguz K, Hill L, Roguz A, Zych M. Evolution of Bird and Insect Flower Traits in Fritillaria L. (Liliaceae). FRONTIERS IN PLANT SCIENCE 2021; 12:656783. [PMID: 33868353 PMCID: PMC8044542 DOI: 10.3389/fpls.2021.656783] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/03/2021] [Indexed: 05/27/2023]
Abstract
Pollinators are often perceived as a primary selective agent influencing flower traits such as colour, size, and nectar properties. The genus Fritillaria L. (Liliaceae), comprising approximately 150 species, is described as generally insect pollinated. However, there are at least three exceptions: two hummingbird-pollinated North American species and one passerine-pollinated Asian species. Despite this variation in pollination, little is known about flower traits that may accompany this shift in fritillaries. In this study, we aimed to assess the attractiveness of the floral traits for (new) pollinators and track the evolution of flowers traits in the context of a shift in the principal pollinator. Therefore, we studied 14 flower traits related to the pollination in 60 Fritillaria species and traced the evolutionary trajectory of these traits. We used a phylogenetic tree of the genus, based on five DNA markers (matK, rpl16, and rbcL, 18S, and ITS) to reconstruct the ancestral state of studied flower traits. The results show that in bird-pollinated species several new traits evolved. For example, flower colouration, nectar sugar, and amino acid concentration and composition fulfil the criteria of ornithophilous flowers, although flower traits do not exclude insect pollinators in bird-pollinated fritillaries. Interestingly, we recorded potential reversals from bird to insect pollination. Our analysis, showing a broad study of flower traits among closely related species in the context of pollinator shift, serves as a starting point for future work exploring the genetic and physiological mechanisms controlling flower traits in the genus Fritillaria.
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Affiliation(s)
- Katarzyna Roguz
- Botanic Garden, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | | | | | - Marcin Zych
- Botanic Garden, Faculty of Biology, University of Warsaw, Warsaw, Poland
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25
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Wessinger CA. From pollen dispersal to plant diversification: genetic consequences of pollination mode. THE NEW PHYTOLOGIST 2021; 229:3125-3132. [PMID: 33159813 DOI: 10.1111/nph.17073] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 11/02/2020] [Indexed: 06/11/2023]
Abstract
Pollinators influence patterns of plant speciation, and one intuitive hypothesis is that pollinators affect rates of plant diversification through their effects on pollen dispersal. By specifying mating events and pollen flow across the landscape, distinct types of pollinators may cause different opportunities for allopatric speciation. This pollen dispersal-dependent speciation hypothesis predicts that pollination mode has effects on the spatial context of mating events that scale up to impact population structure and rates of species formation. Here I consider recent comparative studies, including genetic analyses of plant mating events, population structure and comparative phylogenetic analyses, to examine evidence for this model. These studies suggest that highly mobile pollinators conduct greater gene flow within and among populations, compared to less mobile pollinators. These differences influence patterns of population structure across the landscape. However, the effects of pollination mode on speciation rates is less predictable. In some contexts, the predicted effects of pollen dispersal are outweighed by other factors that govern speciation rates. A multiscale approach to examine effects of pollination mode on plant mating system, population structure and rates of diversification is key to determining the role of pollen dispersal on plant speciation for model clades.
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Affiliation(s)
- Carolyn A Wessinger
- Department of Biological Sciences, University of South Carolina, Columbia, SC, 27708, USA
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26
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van der Niet T. Paucity of natural history data impedes phylogenetic analyses of pollinator-driven evolution. THE NEW PHYTOLOGIST 2021; 229:1201-1205. [PMID: 32786085 DOI: 10.1111/nph.16813] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 07/03/2020] [Indexed: 06/11/2023]
Affiliation(s)
- Timotheüs van der Niet
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, P. Bag X01, Pietermaritzburg, South Africa
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27
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Johnson SD, Kiepiel I, Robertson AW. Functional consequences of flower curvature, orientation and perch position for nectar feeding by sunbirds. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa154] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Mutualisms between nectarivorous birds and the plants they pollinate are functionally diverse. Nectarivorous birds which hover while feeding (the majority of hummingbirds) tend to have straight bills, while those that perch while feeding (some hummingbirds and almost all passerine nectarivores) tend to have decurved bills. Sunbirds typically use their curved bills to feed in an arc from a perching position and we thus predicted that they would prefer, and feed most efficiently on, flowers that are curved towards a perching position. To test this, we examined the responses of sunbirds to model flowers differing in curvature (straight or curved), orientation (facing upwards or downwards), and availability of a top perch (present or absent). Birds did not show preferences among model flower types in terms of number of landings to feed or number of probes. In general they preferred to use perches above model flowers, particularly those that curved upwards, but they tended to perch below model flowers that curve downwards and in such cases also took the least time to insert their bills. These results are consistent with the idea that perching birds with curved beaks will feed most efficiently from flowers that are curved towards the perching position. We discuss the implications of these results for the evolution of floral architecture, including provision of perches.
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Affiliation(s)
- Steven D Johnson
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, South Africa
| | - Ian Kiepiel
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, South Africa
| | - Alastair W Robertson
- Wildlife & Ecology, School of Agriculture & Environment, Massey University, Palmerston North, New Zealand
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Dellinger AS. Pollination syndromes in the 21 st century: where do we stand and where may we go? THE NEW PHYTOLOGIST 2020; 228:1193-1213. [PMID: 33460152 DOI: 10.1111/nph.16793] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 05/31/2020] [Indexed: 06/12/2023]
Abstract
Pollination syndromes, recurring suites of floral traits appearing in connection with specific functional pollinator groups, have served for decades to organise floral diversity under a functional-ecological perspective. Some potential caveats, such as over-simplification of complex plant-animal interactions or lack of empirical observations, have been identified and discussed in recent years. Which of these caveats do indeed cause problems, which have been solved and where do future possibilities lie? I address these questions in a review of the pollination-syndrome literature of 2010 to 2019. I show that the majority of studies was based on detailed empirical pollinator observations and could reliably predict pollinators based on a few floral traits such as colour, shape or reward. Some traits (i.e. colour) were less reliable in predicting pollinators than others (i.e. reward, corolla width), however. I stress that future studies should consider floral traits beyond those traditionally recorded to expand our understanding of mechanisms of floral evolution. I discuss statistical methods suitable for objectively analysing the interplay of system-specific evolutionary constraints, pollinator-mediated selection and adaptive trade-offs at microecological and macroecological scales. I exemplify my arguments on an empirical dataset of floral traits of a neotropical plant radiation in the family Melastomataceae.
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Farré-Armengol G, Fernández-Martínez M, Filella I, Junker RR, Peñuelas J. Deciphering the Biotic and Climatic Factors That Influence Floral Scents: A Systematic Review of Floral Volatile Emissions. FRONTIERS IN PLANT SCIENCE 2020; 11:1154. [PMID: 32849712 PMCID: PMC7412988 DOI: 10.3389/fpls.2020.01154] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 07/15/2020] [Indexed: 06/02/2023]
Abstract
Currently, a global analysis of the information available on the relative composition of the floral scents of a very diverse variety of plant species is missing. Such analysis may reveal general patterns on the distribution and dominance of the volatile compounds that form these mixtures, and may also allow measuring the effects of factors such as the phylogeny, pollination vectors, and climatic conditions on the floral scents of the species. To fill this gap, we compiled published data on the relative compositions and emission rates of volatile organic compounds (VOCs) in the floral scents of 305 plant species from 66 families. We also gathered information on the groups of pollinators that visited the flowers and the climatic conditions in the areas of distribution of these species. This information allowed us to characterize the occurrence and relative abundances of individual volatiles in floral scents and the effects of biotic and climatic factors on floral scent. The monoterpenes trans-β-ocimene and linalool and the benzenoid benzaldehyde were the most abundant floral VOCs, in both ubiquity and predominance in the floral blends. Floral VOC richness and relative composition were moderately preserved traits across the phylogeny. The reliance on different pollinator groups and the climate also had important effects on floral VOC richness, composition, and emission rates of the species. Our results support the hypothesis that key compounds or compounds originating from specific biosynthetic pathways mediate the attraction of the main pollinators. Our results also indicate a prevalence of monoterpenes in the floral blends of plants that grow in drier conditions, which could link with the fact that monoterpene emissions protect plants against oxidative stresses throughout drought periods and their emissions are enhanced under moderate drought stress. Sesquiterpenes, in turn, were positively correlated with mean annual temperature, supporting that sesquiterpene emissions are dominated mainly by ambient temperature. This study is the first to quantitatively summarise data on floral-scent emissions and provides new insights into the biotic and climatic factors that influence floral scents.
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Affiliation(s)
- Gerard Farré-Armengol
- Department of Biosciences, University of Salzburg, Salzburg, Austria
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Barcelona, Spain
- CREAF, Barcelona, Spain
| | | | - Iolanda Filella
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Barcelona, Spain
- CREAF, Barcelona, Spain
| | - Robert R. Junker
- Department of Biosciences, University of Salzburg, Salzburg, Austria
- Evolutionary Ecology of Plants, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Josep Peñuelas
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Barcelona, Spain
- CREAF, Barcelona, Spain
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Pollinator divergence and pollination isolation between hybrids with different floral color and morphology in two sympatric Penstemon species. Sci Rep 2020; 10:8126. [PMID: 32415216 PMCID: PMC7229217 DOI: 10.1038/s41598-020-64964-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 04/27/2020] [Indexed: 11/08/2022] Open
Abstract
Differential visitation of pollinators due to divergent floral traits can lead to reproductive isolation via assortative pollen flow, which may ultimately be a driving force in plant speciation, particularly in areas of overlap. We evaluate the effects of pollinator behavioral responses to variation of intraspecific floral color and nectar rewards, on reproductive isolation between two hybrid flower color morphs (fuchsia and blue) and their parental species Penstemon roseus and P. gentianoides with a mixed-pollination system. We show that pollinators (bumblebees and hummingbirds) exhibit different behavioral responses to fuchsia and blue morphs, which could result from differential attraction or deterrence. In addition to differences in color (spectral reflectance), we found that plants with fuchsia flowers produced more and larger flowers, produced more nectar and were more visited by pollinators than those with blue flowers. These differences influenced the foraging behavior and effectiveness as pollinators of both bumblebees and hummingbirds, which contributed to reproductive isolation between the two hybrid flower color morphs and parental species. This study demonstrates how differentiation of pollination traits promotes the formation of hybrid zones leading to pollinator shifts and reproductive isolation. While phenotypic traits of fuchsia and red flowers might encourage more efficient hummingbird pollination in a mixed-pollination system, the costs of bumblebee pollination on plant reproduction could be the drivers for the repeated shifts from bumblebee- to hummingbird-mediated pollination.
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Wessinger CA, Rausher MD, Hileman LC. Adaptation to hummingbird pollination is associated with reduced diversification in Penstemon. Evol Lett 2019; 3:521-533. [PMID: 31636944 PMCID: PMC6791294 DOI: 10.1002/evl3.130] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 06/12/2019] [Accepted: 07/12/2019] [Indexed: 12/24/2022] Open
Abstract
A striking characteristic of the Western North American flora is the repeated evolution of hummingbird pollination from insect-pollinated ancestors. This pattern has received extensive attention as an opportunity to study repeated trait evolution as well as potential constraints on evolutionary reversibility, with little attention focused on the impact of these transitions on species diversification rates. Yet traits conferring adaptation to divergent pollinators potentially impact speciation and extinction rates, because pollinators facilitate plant reproduction and specify mating patterns between flowering plants. Here, we examine macroevolutionary processes affecting floral pollination syndrome diversity in the largest North American genus of flowering plants, Penstemon. Within Penstemon, transitions from ancestral bee-adapted flowers to hummingbird-adapted flowers have frequently occurred, although hummingbird-adapted species are rare overall within the genus. We inferred macroevolutionary transition and state-dependent diversification rates and found that transitions from ancestral bee-adapted flowers to hummingbird-adapted flowers are associated with reduced net diversification rate, a finding based on an estimated 17 origins of hummingbird pollination in our sample. Although this finding is congruent with hypotheses that hummingbird adaptation in North American Flora is associated with reduced species diversification rates, it contrasts with studies of neotropical plant families where hummingbird pollination has been associated with increased species diversification. We further used the estimated macroevolutionary rates to predict the expected pattern of floral diversity within Penstemon over time, assuming stable diversification and transition rates. Under these assumptions, we find that hummingbird-adapted species are expected to remain rare due to their reduced diversification rates. In fact, current floral diversity in the sampled Penstemon lineage, where less than one-fifth of species are hummingbird adapted, is consistent with predicted levels of diversity under stable macroevolutionary rates.
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Affiliation(s)
- Carolyn A Wessinger
- Department of Ecology and Evolutionary Biology University of Kansas Lawrence Kansas 66045
| | - Mark D Rausher
- Department of Biology Duke University Durham North Carolina 27708
| | - Lena C Hileman
- Department of Ecology and Evolutionary Biology University of Kansas Lawrence Kansas 66045
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Katzer AM, Wessinger CA, Hileman LC. Nectary size is a pollination syndrome trait in Penstemon. THE NEW PHYTOLOGIST 2019; 223:377-384. [PMID: 30834532 PMCID: PMC6593460 DOI: 10.1111/nph.15769] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 02/24/2019] [Indexed: 05/22/2023]
Abstract
Evolution of complex phenotypes depends on the adaptive importance of individual traits, and the developmental changes required to modify traits. Floral syndromes are complex adaptations to pollinators that include color, nectar, and shape variation. Hummingbird-adapted flowers have evolved a remarkable number of times from bee-adapted ancestors in Penstemon, and previous work demonstrates that color over shape better distinguishes bee from hummingbird syndromes. Here, we examined the relative importance of nectar volume and nectary development in defining Penstemon pollination syndromes. We tested the evolutionary association of nectar volume and nectary area with pollination syndrome across 19 Penstemon species. In selected species, we assessed cellular-level processes shaping nectary size. Within a segregating population from an intersyndrome cross, we assessed trait correlations between nectar volume, nectary area, and the size of stamens on which nectaries develop. Nectar volume and nectary area displayed an evolutionary association with pollination syndrome. These traits were correlated within a genetic cross, suggesting a mechanistic link. Nectary area evolution involves parallel processes of cell expansion and proliferation. Our results demonstrate that changes to nectary patterning are an important contributor to pollination syndrome diversity and provide further evidence that repeated origins of hummingbird adaptation involve parallel developmental processes in Penstemon.
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Affiliation(s)
- Amanda M. Katzer
- Department of Ecology and Evolutionary BiologyUniversity of Kansas1200 Sunnyside AvenueLawrenceKS66045USA
| | - Carolyn A. Wessinger
- Department of Ecology and Evolutionary BiologyUniversity of Kansas1200 Sunnyside AvenueLawrenceKS66045USA
| | - Lena C. Hileman
- Department of Ecology and Evolutionary BiologyUniversity of Kansas1200 Sunnyside AvenueLawrenceKS66045USA
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Rodríguez-Flores CI, Ornelas JF, Wethington S, Arizmendi MDC. Are hummingbirds generalists or specialists? Using network analysis to explore the mechanisms influencing their interaction with nectar resources. PLoS One 2019; 14:e0211855. [PMID: 30811515 PMCID: PMC6392410 DOI: 10.1371/journal.pone.0211855] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 01/23/2019] [Indexed: 11/30/2022] Open
Abstract
Mutualistic interactions are powerful drivers of biodiversity on Earth that can be represented as complex interaction networks that vary in connection pattern and intensity. One of the most fascinating mutualisms is the interaction between hummingbirds and the plants they visit. We conducted an exhaustive search for articles, theses, reports, and personal communications with researchers (unpublished data) documenting hummingbird visits to flowers of nectar-rewarding plants. Based on information gathered from 4532 interactions between 292 hummingbird species and 1287 plant species, we built an interaction network between nine hummingbird clades and 100 plant families used by hummingbirds as nectar resources at a continental scale. We explored the network architecture, including phylogenetic, morphological, biogeographical, and distributional information. As expected, the network between hummingbirds and their nectar plants was heterogeneous and nested, but not modular. When we incorporated ecological and historical information in the network nodes, we found a generalization gradient in hummingbird morphology and interaction patterns. The hummingbird clades that most recently diversified in North America acted as generalist nodes and visited flowers with ornithophilous, intermediate and non-ornithophilous morphologies, connecting a high diversity of plant families. This pattern was favored by intermediate morphologies (bill, wing, and body size) and by the low niche conservatism in these clades compared to the oldest clades that diversified in South America. Our work is the first effort exploring the hummingbird-plant mutualistic network at a continental scale using hummingbird clades and plant families as nodes, offering an alternative approach to exploring the ecological and evolutionary factors that explain plant-animal interactions at a large scale.
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Affiliation(s)
- Claudia I. Rodríguez-Flores
- Ecology Laboratory (Laboratorio de Ecología), Biotechnology and Prototype Unit (Unidad de Biotecnología y Prototipos [UBIPRO]), Iztacala Faculty of Higher Studies (Facultad de Estudios Superiores Iztacala), National Autonomous University of Mexico (Universidad Nacional Autónoma de México), Los Reyes Iztacala, Tlalnepantla de Baz, Estado de México, México
- Biological Sciences Postgraduate Program (Posgrado en Ciencias Biológicas), National Autonomous University of Mexico (Universidad Nacional Autónoma de México), Posgraduate Unit (Unidad de Posgrados), Ciudad de México, México
| | - Juan Francisco Ornelas
- Department of Evolutionary Biology (Departamento de Biología Evolutiva), Institute of Ecology (Instituto de Ecología, A.C.), Xalapa, Veracruz, Mexico
| | - Susan Wethington
- The Hummingbird Monitoring Network, Patagonia, Arizona, United States of America
| | - María del Coro Arizmendi
- Ecology Laboratory (Laboratorio de Ecología), Biotechnology and Prototype Unit (Unidad de Biotecnología y Prototipos [UBIPRO]), Iztacala Faculty of Higher Studies (Facultad de Estudios Superiores Iztacala), National Autonomous University of Mexico (Universidad Nacional Autónoma de México), Los Reyes Iztacala, Tlalnepantla de Baz, Estado de México, México
- Biological Sciences Postgraduate Program (Posgrado en Ciencias Biológicas), National Autonomous University of Mexico (Universidad Nacional Autónoma de México), Posgraduate Unit (Unidad de Posgrados), Ciudad de México, México
- * E-mail:
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“Pro-bird” floral traits discourage bumblebee visits to Penstemon gentianoides (Plantaginaceae), a mixed-pollinated herb. Naturwissenschaften 2018; 106:1. [DOI: 10.1007/s00114-018-1595-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 11/06/2018] [Accepted: 11/13/2018] [Indexed: 10/27/2022]
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Ng J, Smith SD. Why are red flowers so rare? Testing the macroevolutionary causes of tippiness. J Evol Biol 2018; 31:1863-1875. [PMID: 30256485 DOI: 10.1111/jeb.13381] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 09/19/2018] [Accepted: 09/21/2018] [Indexed: 01/05/2023]
Abstract
Traits that have arisen multiple times yet still remain rare present a curious paradox. A number of these rare traits show a distinct tippy pattern, where they appear widely dispersed across a phylogeny, are associated with short branches and differ between recently diverged sister species. This phylogenetic pattern has classically been attributed to the trait being an evolutionary dead end, where the trait arises due to some short-term evolutionary advantage, but it ultimately leads species to extinction. While the higher extinction rate associated with a dead end trait could produce such a tippy pattern, a similar pattern could appear if lineages with the trait speciated slower than other lineages, or if the trait was lost more often that it was gained. In this study, we quantify the degree of tippiness of red flowers in the tomato family, Solanaceae, and investigate the macroevolutionary processes that could explain the sparse phylogenetic distribution of this trait. Using a suite of metrics, we confirm that red-flowered lineages are significantly overdispersed across the tree and form smaller clades than expected under a null model. Next, we fit 22 alternative models using HiSSE (Hidden State Speciation and Extinction), which accommodates asymmetries in speciation, extinction and transition rates that depend on observed and unobserved (hidden) character states. Results of the model fitting indicated significant variation in diversification rates across the family, which is best explained by the inclusion of hidden states. Our best fitting model differs between the maximum clade credibility tree and when incorporating phylogenetic uncertainty, suggesting that the extreme tippiness and rarity of red Solanaceae flowers makes it difficult to distinguish among different underlying processes. However, both of the best models strongly support a bias towards the loss of red flowers. The best fitting HiSSE model when incorporating phylogenetic uncertainty lends some support to the hypothesis that lineages with red flowers exhibit reduced diversification rates due to elevated extinction rates. Future studies employing simulations or targeting population-level processes may allow us to determine whether red flowers in Solanaceae or other angiosperms clades are rare and tippy due to a combination of processes, or asymmetrical transitions alone.
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Affiliation(s)
- Julienne Ng
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Stacey D Smith
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
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Smith SD, Kriebel R. Convergent evolution of floral shape tied to pollinator shifts in Iochrominae (Solanaceae)*. Evolution 2018; 72:688-697. [DOI: 10.1111/evo.13416] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 12/01/2017] [Accepted: 12/08/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Stacey D. Smith
- Department of Ecology and Evolutionary Biology University of Colorado Boulder Colorado 80305
| | - Ricardo Kriebel
- Department of Botany University of Wisconsin – Madison Madison Wisconsin 53706
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Salas-Arcos L, Lara C, Ornelas JF. Reproductive biology and nectar secretion dynamics of Penstemon gentianoides (Plantaginaceae): a perennial herb with a mixed pollination system? PeerJ 2017; 5:e3636. [PMID: 28828248 PMCID: PMC5554440 DOI: 10.7717/peerj.3636] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 07/12/2017] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND In many plant species, pollination syndromes predict the most effective pollinator. However, other floral visitors may also offer effective pollination services and promote mixed pollination systems. Several species of the species-rich Penstemon (Plantaginaceae) exhibit a suite of floral traits that suggest adaptation for pollination by both hymenopterans and hummingbirds. Transitions from the ancestral hymenopteran pollination syndrome to more derived hummingbird pollination syndrome may be promoted if the quantity or quality of visits by hummingbirds is increased and if the ancestral pollinator group performs less efficiently. The quantification of such shifts in pollination systems in the group is still limited. We aimed to investigate floral traits linked to this pollination syndrome in Penstemon gentianoides with flowers visited by bumblebees and hummingbirds. METHODS We investigated the floral biology, pollinator assemblages, breeding system and nectar production patterns of P. gentianoides inhabiting a temperate montane forest in central Mexico. Pollination experiments were also conducted to assess the pollinator effectiveness of bumblebees and hummingbirds. RESULTS P. gentianoides flowers are protandrous, with 8-d male phase (staminate) flowers, followed by the ∼1-7 d female phase (pistillate phase). Flowers display traits associated with hymenopteran pollination, including purple flowers abruptly ampliate-ventricose to a broad throat with anthers and stigmas included, and long lifespans. However, the nectar available in the morning hours was abundant and dilute, traits linked to flowers with a hummingbird pollination syndrome. Two hummingbird species made most of the visits to flowers, Selasphorus platycercus (30.3% of all visits), followed by Archilochus colubris (11.3%). Bumblebees (Bombus ephippiatus, B. huntii and B. weisi) accounted for 51.8% of all recorded visits, but their foraging activity was restricted to the warmer hours. Hummingbirds made more foraging bouts and visited more flowers than hymenopteran species. Flowers experimentally pollinated by B. ephippiatus produced significantly more fruits than those pollinated by S. platycercus. However, there was no statistical difference in the number of seeds produced per fruit when a bumblebee or a hummingbird was the pollinator. CONCLUSIONS We have shown that bumblebees and hummingbirds visit and pollinate P. gentianoides flowers. Despite floral traits resembling the hymenoptera pollination syndrome, flowers of P. gentianoides offer characteristic nectar rewards to flowers with a hummingbird pollination syndrome. Although pollination efficiency is higher among flowers visited by hymenoptera, the noteworthy percentage of fruit production and number of seeds per fruit derived from hummingbird pollination highlights the importance of hummingbirds as a functional group of pollinators that might have potential evolutionary consequences to the plants.
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Affiliation(s)
- Lucía Salas-Arcos
- Doctorado en Ciencias Biológicas, Universidad Autónoma de Tlaxcala, Tlaxala, Mexico
| | - Carlos Lara
- Centro de Investigaciones en Ciencias Biológicas, Universidad Autónoma de Tlaxcala, Tlaxcala, Mexico
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Guzmán B, Gómez JM, Vargas P. Is floral morphology a good predictor of floral visitors to Antirrhineae (snapdragons and relatives)? PLANT BIOLOGY (STUTTGART, GERMANY) 2017; 19:515-524. [PMID: 28316136 DOI: 10.1111/plb.12567] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 03/13/2017] [Indexed: 06/06/2023]
Abstract
The association between plants and flower visitors has been historically proposed as a main factor driving the evolutionary change of both flower and pollinator phenotypes. The considerable diversity in floral morphology within the tribe Antirrhineae has been traditionally related to pollinator types. We used empirical data on the flower visitors from 59 Antirrhineae taxa from the literature and our own field surveys, which provide an opportunity to test whether flower phenotypes are reliable predictors of visitors and pollinator niches. The degree of adjustment between eight key floral traits and actual visitors was explored by testing the predictive value of inferred pollinator syndromes (i.e. suites of floral traits that characterise groups of plant species related to pollination). Actual visitors and inferred pollinator niches (categorisation of visitors' association using a modularity algorithm) were also explored using Linear Discriminant Analysis (LDA). The bee pollinator niche is correctly classified for flowers with dull corolla colour, without nectar guides, as the most important predictor. Both predictive value and statistical classification prove useful in classifying Antirrhineae taxa and the bee pollinator niche, mostly as a consequence of the high proportion of genera and taxa with occluded corollas primarily visited by bees. Our predictive approach rendered a high Positive Predictive Value (PPV) of floral traits in the diagnosis of visitors/pollinator niches. In particular, a high PPV was found for bees as both visitors and forming pollinator niches. In addition, LDA showed that four pollinator niches are well defined based on floral traits. The large number of species visited by bees irrespective of pollinator syndromes leads us to hypothesise their generalist pollinator role, despite the phenotypically specialised flowers of Antirrhineae.
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Affiliation(s)
- B Guzmán
- Dpto. de Biodiversidad y Conservación, Real Jardín Botánico, CSIC, Madrid, Spain
| | - J M Gómez
- Dpto. de Ecología Funcional y Evolutiva, Estación Experimental de Zonas Áridas, CSIC, Almería, Spain
- Dpto. de Ecología, Universidad de Granada, Granada, Spain
| | - P Vargas
- Dpto. de Biodiversidad y Conservación, Real Jardín Botánico, CSIC, Madrid, Spain
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Katsuhara KR, Kitamura S, Ushimaru A. Functional significance of petals as landing sites in fungus‐gnat pollinated flowers of
Mitella pauciflora
(Saxifragaceae). Funct Ecol 2017. [DOI: 10.1111/1365-2435.12842] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Koki R. Katsuhara
- Graduate School of Human Development and Environment Kobe University 3‐11, Tsurukabuto Kobe657‐8501 Japan
| | - Shumpei Kitamura
- Department of Environmental Science Faculty of Bioresources and Environmental Sciences Ishikawa Prefectural University 1‐308, Suematsu Nonoichi Ishikawa921‐8836 Japan
| | - Atushi Ushimaru
- Graduate School of Human Development and Environment Kobe University 3‐11, Tsurukabuto Kobe657‐8501 Japan
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Armbruster WS. The specialization continuum in pollination systems: diversity of concepts and implications for ecology, evolution and conservation. Funct Ecol 2016. [DOI: 10.1111/1365-2435.12783] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- William Scott Armbruster
- School of Biological Sciences University of Portsmouth PortsmouthPO1 2DY UK
- Institute of Arctic Biology University of Alaska Fairbanks Fairbanks AK99775‐7000 USA
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Wessinger CA, Freeman CC, Mort ME, Rausher MD, Hileman LC. Multiplexed shotgun genotyping resolves species relationships within the North American genus Penstemon. AMERICAN JOURNAL OF BOTANY 2016; 103:912-22. [PMID: 27208359 PMCID: PMC10874106 DOI: 10.3732/ajb.1500519] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 03/16/2016] [Indexed: 06/05/2023]
Abstract
PREMISE OF THE STUDY Evolutionary radiations provide opportunities to examine large-scale patterns in diversification and character evolution, yet are often recalcitrant to phylogenetic resolution due to rapid speciation events. The plant genus Penstemon has been difficult to resolve using Sanger sequence-based markers, leading to the hypothesis that it represents a recent North American radiation. The current study demonstrates the utility of multiplexed shotgun genotyping (MSG), a style of restriction site-associated DNA sequencing (RADseq), to infer phylogenetic relationships within a subset of species in this genus and provide insight into evolutionary patterns. METHODS We sampled genomic DNA, primarily from herbarium material, and subjected it to MSG library preparation and Illumina sequencing. The resultant sequencing reads were clustered into homologous loci, aligned, and concatenated into data matrices that differed according to clustering similarity and amount of missing data. We performed phylogenetic analyses on these matrices using maximum likelihood (RAxML) and a species tree approach (SVDquartets). KEY RESULTS MSG data provide a highly resolved estimate of species relationships within Penstemon. While most species relationships were highly supported, the position of certain taxa remains ambiguous, suggesting that increased taxonomic sampling or additional methodologies may be required. The data confirm that evolutionary shifts from hymenopteran- to hummingbird-adapted flowers have occurred independently many times. CONCLUSIONS This study demonstrates that phylogenomic approaches yielding thousands of variable sites can greatly improve species-level resolution of recent and rapid radiations. Similar to other studies, we found that less conservative similarity and missing data thresholds resulted in more highly supported topologies.
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Affiliation(s)
- Carolyn A Wessinger
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas 66045 USA
| | - Craig C Freeman
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas 66045 USA R.L. McGregor Herbarium and Kansas Biological Survey, University of Kansas, Lawrence, Kansas 66047 USA
| | - Mark E Mort
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas 66045 USA
| | - Mark D Rausher
- Department of Biology, Duke University, Box 90338 Durham, North Carolina 27708 USA
| | - Lena C Hileman
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas 66045 USA
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Strelin MM, Benitez-Vieyra S, Ackermann M, Cocucci AA. Flower reshaping in the transition to hummingbird pollination in Loasaceae subfam. Loasoideae despite absence of corolla tubes or spurs. Evol Ecol 2016. [DOI: 10.1007/s10682-016-9826-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Gorostiague P, Ortega-Baes P. How specialised is bird pollination in the Cactaceae? PLANT BIOLOGY (STUTTGART, GERMANY) 2016; 18:63-72. [PMID: 25545418 DOI: 10.1111/plb.12297] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 12/12/2014] [Indexed: 06/04/2023]
Abstract
Many cactus species produce 'bird' flowers; however, the reproductive biology of the majority of these species has not been studied. Here, we report on a study of the pollination of two species from the Cleistocactus genus, cited as an ornithophilous genus, in the context of the different ways in which they are specialised to bird pollination. In addition, we re-evaluate the level of specialisation of previous studies of cacti with bird pollination and evaluate how common phenotypic specialisation to birds is in this family. Both Cleistocactus species exhibited ornithophilous floral traits. Cleistocactus baumannii was pollinated by hummingbirds, whereas Cleistocactus smaragdiflorus was pollinated by hummingbirds and bees. Pollination by birds has been recorded in 27 cactus species, many of which exhibit ornithophilous traits; however, they show generalised pollination systems with bees, bats or moths in addition to birds being their floral visitors. Of all cactus species, 27% have reddish flowers. This trait is associated with diurnal anthesis and a tubular shape. Phenotypic specialisation to bird pollination is recognised in many cactus species; however, it is not predictive of functional and ecological specialisation in this family.
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Affiliation(s)
- P Gorostiague
- Laboratorio de Investigaciones Botánicas (LABIBO), Facultad de Ciencias Naturales, Universidad Nacional de Salta-CONICET, Salta, Argentina
| | - P Ortega-Baes
- Laboratorio de Investigaciones Botánicas (LABIBO), Facultad de Ciencias Naturales, Universidad Nacional de Salta-CONICET, Salta, Argentina
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Buide ML, del Valle JC, Pissatto M, Narbona E. Night life on the beach: selfing to avoid pollinator competition between two sympatric Silene species. ANNALS OF BOTANY 2015; 116:201-11. [PMID: 26070638 PMCID: PMC4512190 DOI: 10.1093/aob/mcv078] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 04/24/2015] [Indexed: 05/10/2023]
Abstract
BACKGROUND AND AIMS Evolution of autonomous selfing may be advantageous because it allows for reproductive assurance. In co-flowering plants competing for pollinators, the least common and/or attractive could suffer pollen limitations. Silene niceensis and S. ramosissima are taxonomically related species sharing the same habitat, although S. ramosissima is less abundant and has a more restricted distribution. They also have the same a priori nocturnal pollinator syndrome, and show an overlapping flowering phenology. The aim of this study was to investigate whether a selfing strategy in S. ramosissima allows it to avoid pollinator competition and/or interspecific pollen transfer with S. niceensis, which would thus enable both species to reach high levels of fruit and seed set. METHODS The breeding system, petal colour, flower life span and degree of overlap between male and female phases, floral visitor abundance and visitation rates were analysed in two sympatric populations of S. niceensis and S. ramosissima in southern Spain. KEY RESULTS Autonomous selfing in S. ramosissima produced very high fruit and seed set, which was also similar to open-pollinated plants. Silene niceensis showed minimum levels of autonomous selfing, and pollen/ovule ratios were within the range expected for the breeding system. In contrast to S. niceensis, flower life span was much shorter in S. ramosissima, and male and female organs completely overlapped in space and time. Upper surface petals of both species showed differing brightness, chroma and hue. Flowers of S. niceensis were actively visited by moths, hawkmoths and syrphids, whereas those of S. ramosissima were almost never visited. CONCLUSIONS The findings show that different breeding strategies exist between the sympatric co-flowering S. niceensis and S. ramosissima, the former specializing in crepuscular-nocturnal pollination and the latter mainly based on autonomous selfing. These two strategies allow both species to share the restricted dune habitat in which they exist, with a high female reproductive success due to the absence of pollinator competition and/or interspecific pollen flow.
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Affiliation(s)
- M Luisa Buide
- Área de Botánica, Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Carretera de de Utrera, km 1, 41013, Sevilla, Spain
| | - José Carlos del Valle
- Área de Botánica, Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Carretera de de Utrera, km 1, 41013, Sevilla, Spain
| | - Mônica Pissatto
- Área de Botánica, Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Carretera de de Utrera, km 1, 41013, Sevilla, Spain
| | - Eduardo Narbona
- Área de Botánica, Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Carretera de de Utrera, km 1, 41013, Sevilla, Spain
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Bee- to bird-pollination shifts in Penstemon: effects of floral-lip removal and corolla constriction on the preferences of free-foraging bumble bees. Evol Ecol 2015. [DOI: 10.1007/s10682-014-9716-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Nectar robbery by a hermit hummingbird: association to floral phenotype and its influence on flowers and network structure. Oecologia 2015; 178:783-93. [DOI: 10.1007/s00442-015-3275-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 02/16/2015] [Indexed: 10/23/2022]
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Wessinger CA, Hileman LC, Rausher MD. Identification of major quantitative trait loci underlying floral pollination syndrome divergence in Penstemon. Philos Trans R Soc Lond B Biol Sci 2015; 369:rstb.2013.0349. [PMID: 24958923 DOI: 10.1098/rstb.2013.0349] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Distinct floral pollination syndromes have emerged multiple times during the diversification of flowering plants. For example, in western North America, a hummingbird pollination syndrome has evolved more than 100 times, generally from within insect-pollinated lineages. The hummingbird syndrome is characterized by a suite of floral traits that attracts and facilitates pollen movement by hummingbirds, while at the same time discourages bee visitation. These floral traits generally include large nectar volume, red flower colour, elongated and narrow corolla tubes and reproductive organs that are exerted from the corolla. A handful of studies have examined the genetic architecture of hummingbird pollination syndrome evolution. These studies find that mutations of relatively large effect often explain increased nectar volume and transition to red flower colour. In addition, they suggest that adaptive suites of floral traits may often exhibit a high degree of genetic linkage, which could facilitate their fixation during pollination syndrome evolution. Here, we explore these emerging generalities by investigating the genetic basis of floral pollination syndrome divergence between two related Penstemon species with different pollination syndromes--bee-pollinated P. neomexicanus and closely related hummingbird-pollinated P. barbatus. In an F2 mapping population derived from a cross between these two species, we characterized the effect size of genetic loci underlying floral trait divergence associated with the transition to bird pollination, as well as correlation structure of floral trait variation. We find the effect sizes of quantitative trait loci for adaptive floral traits are in line with patterns observed in previous studies, and find strong evidence that suites of floral traits are genetically linked. This linkage may be due to genetic proximity or pleiotropic effects of single causative loci. Interestingly, our data suggest that the evolution of floral traits critical for hummingbird pollination was not constrained by negative pleiotropy at loci that show co-localization for multiple traits.
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Affiliation(s)
- Carolyn A Wessinger
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA
| | - Lena C Hileman
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA
| | - Mark D Rausher
- Department of Biology, Duke University, Durham, NC 27708, USA
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Gómez JM, Perfectti F, Abdelaziz M, Lorite J, Muñoz-Pajares AJ, Valverde J. Evolution of pollination niches in a generalist plant clade. THE NEW PHYTOLOGIST 2015; 205:440-53. [PMID: 25252267 DOI: 10.1111/nph.13016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 07/29/2014] [Indexed: 05/27/2023]
Abstract
It is widely assumed that floral diversification occurs by adaptive shifts between pollination niches. In contrast to specialized flowers, identifying pollination niches of generalist flowers is a challenge. Consequently, how generalist pollination niches evolve is largely unknown. We apply tools from network theory and comparative methods to investigate the evolution of pollination niches among generalist species belonging to the genus Erysimum. These species have similar flowers. We found that the studied species may be grouped in several multidimensional niches separated not by a shift of pollinators, but instead by quantitative variation in the relative abundance of pollinator functional groups. These pollination niches did not vary in generalization degree; we did not find any evolutionary trend toward specialization within the studied clade. Furthermore, the evolution of pollination niche fitted to a Brownian motion model without phylogenetic signal, and was characterized by frequent events of niche convergences and divergences. We presume that the evolution of Erysimum pollination niches has occurred mostly by recurrent shifts between slightly different generalized pollinator assemblages varying spatially as a mosaic and without any change in specialization degree. Most changes in pollination niches do not prompt floral divergence, a reason why adaptation to pollinators is uncommon in generalist plants.
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Affiliation(s)
- José María Gómez
- Dpto de Ecología Funcional y Evolutiva, Estación Experimental de Zonas Aridas (EEZA-CSIC), E-04120, Almería, Spain; Dpto de Ecología, Universidad de Granada, E-18071, Granada, Spain
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Lavi R, Sapir Y. Are pollinators the agents of selection for the extreme large size and dark color in Oncocyclus irises? THE NEW PHYTOLOGIST 2015; 205:369-377. [PMID: 25157604 DOI: 10.1111/nph.12982] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 07/08/2014] [Indexed: 06/03/2023]
Abstract
Pollinator-mediated selection is a major evolutionary driver of floral traits; yet, such selection has rarely been tested for floral extreme traits. The Oncocyclus irises have exceptionally large, dark-colored flowers, associated with night-sheltering pollination and heat reward by the dark flowers. We quantified phenotypic selection on stem length, floral size and color in two species of iris (Iris atropurpurea and I. haynei), using an experimental approach. We estimated selection gradients for both flowers open to natural pollination and for flowers receiving supplementary hand pollination, assuming that open-pollinated flowers are affected by all factors that could influence fitness, whereas supplementary pollination removes the possible influence of pollinators. We found evidence for pollinator-mediated selection to increase floral size and stem length in I. atropurpurea, but floral color in this species was not under pollinator-mediated selection. In I. haynei, no pollinator-mediated selection on any of the traits was detected. We conclude that the extreme floral size of I. atropurpurea has probably evolved as a result of pollinator behavior. Lack of such evidence for I. haynei and for the dark floral color in both species suggests that other non-pollinator agents are selecting for these prominent traits, or that phenotypic color variation in these irises is neutral.
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Affiliation(s)
- Renana Lavi
- Department of Molecular Biology and Ecology of Plants, The Botanical Garden, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
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Chartier M, Jabbour F, Gerber S, Mitteroecker P, Sauquet H, von Balthazar M, Staedler Y, Crane PR, Schönenberger J. The floral morphospace--a modern comparative approach to study angiosperm evolution. THE NEW PHYTOLOGIST 2014; 204:841-53. [PMID: 25539005 PMCID: PMC5526441 DOI: 10.1111/nph.12969] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Morphospaces are mathematical representations used for studying the evolution of morphological diversity and for the evaluation of evolved shapes among theoretically possible ones. Although widely used in zoology, they--with few exceptions--have been disregarded in plant science and in particular in the study of broad-scale patterns of floral structure and evolution. Here we provide basic information on the morphospace approach; we review earlier morphospace applications in plant science; and as a practical example, we construct and analyze a floral morphospace. Morphospaces are usually visualized with the help of ordination methods such as principal component analysis (PCA) or nonmetric multidimensional scaling (NMDS). The results of these analyses are then coupled with disparity indices that describe the spread of taxa in the space. We discuss these methods and apply modern statistical tools to the first and only angiosperm-wide floral morphospace published by Stebbins in 1951. Despite the incompleteness of Stebbins’ original dataset, our analyses highlight major, angiosperm-wide trends in the diversity of flower morphology and thereby demonstrate the power of this previously neglected approach in plant science.
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Affiliation(s)
- Marion Chartier
- Department of Botany and Biodiversity Research, University of
Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Florian Jabbour
- Institute of Systematics, Evolution and Biodiversity, National
Museum of Natural History, 57 rue Cuvier – CP 39, 75231 Paris Cedex 05,
France
| | - Sylvain Gerber
- Department of Earth Sciences, University of Cambridge, Downing
Street, Cambridge, CB2 3EQ, UK
| | - Philipp Mitteroecker
- Department of Theoretical Biology, Vienna University, Althanstrasse
14, 1090 Vienna, Austria
| | - Hervé Sauquet
- Laboratoire Écologie, Systématique, Évolution,
Université Paris-Sud, CNRS UMR 8079, 91405 Orsay, France
| | - Maria von Balthazar
- Department of Botany and Biodiversity Research, University of
Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Yannick Staedler
- Department of Botany and Biodiversity Research, University of
Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Peter R. Crane
- Yale School of Forestry and Environmental Studies, 195 Prospect
Street, New Haven, CT 06511, USA
| | - Jürg Schönenberger
- Department of Botany and Biodiversity Research, University of
Vienna, Rennweg 14, 1030 Vienna, Austria
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