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Toll K. An evolutionary framework for understanding habitat partitioning in plants. AMERICAN JOURNAL OF BOTANY 2023; 110:e16119. [PMID: 36585942 PMCID: PMC10107657 DOI: 10.1002/ajb2.16119] [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: 08/27/2022] [Revised: 11/29/2022] [Accepted: 12/01/2022] [Indexed: 06/17/2023]
Abstract
Many plant species with overlapping geographic ranges segregate at smaller spatial scales. This spatial segregation-zonation when it follows an abiotic gradient and habitat partitioning when it does not-has been experimentally investigated for over a century often using distantly related taxa, such as different genera of algae or barnacles. In those foundational studies, trade-offs between stress tolerance and competitive ability were found to be the major driving factors of habitat partitioning for both animals and plants. Yet, the evolutionary relationships among segregating species are usually not taken into account. Since close relatives are hypothesized to compete more intensely and are more likely to interact during mating compared to distant relatives, the mechanisms underlying habitat partitioning may differ depending on the relatedness of the species in question. Here, I propose an integration of ecological and evolutionary factors contributing to habitat partitioning in plants, specifically how the relative contributions of factors predictably change with relatedness of taxa. Interspecific reproductive interactions in particular are understudied, yet important drivers of habitat partitioning. In spatially segregated species, interspecific mating can reduce the fitness of rare immigrants, preventing their establishment and maintaining patterns of spatial segregation. In this synthesis, I review the literature on mechanisms of habitat partitioning in plants within an evolutionary framework, identifying knowledge gaps and detailing future directions for this rapidly growing field of study.
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Affiliation(s)
- Katherine Toll
- Department of Plant BiologyMichigan State UniversityEast LansingMI48824USA
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2
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Joffard N, Olofsson C, Friberg M, Sletvold N. Extensive pollinator sharing does not promote character displacement in two orchid congeners. Evolution 2022; 76:749-764. [PMID: 35188979 DOI: 10.1111/evo.14446] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 01/07/2022] [Accepted: 01/18/2022] [Indexed: 01/22/2023]
Abstract
Pollinator sharing between close relatives can be costly and can promote pollination niche partitioning and floral divergence. This should be reflected by a higher species divergence in sympatry than in allopatry. We tested this hypothesis in two orchid congeners with overlapping distributions and flowering times. We characterized floral traits and pollination niches and quantified pollen limitation in 15 pure and mixed populations, and we measured phenotypic selection on floral traits and performed controlled crosses in one mixed site. Most floral traits differed between species, yet pollinator sharing was extensive. Only the timing of scent emission diverged more in mixed sites than in pure sites, and this was not mirrored by the timing of pollinator visitation. We did not detect divergent selection on floral traits. Seed production was pollen limited in most populations but not more severely in mixed sites than in pure sites. Interspecific crosses produced the same or a higher proportion of viable seeds than intraspecific crosses. The two orchid species attract the same pollinator species despite showing divergent floral traits. However, this does not promote character displacement, implying a low cost of pollinator sharing. Our results highlight the importance of characterizing both traits and ecological niches in character displacement studies.
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Affiliation(s)
- Nina Joffard
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, Uppsala, 752 36, Sweden.,University of Lille, UMR 8198 - Evo-Eco-Paleo, Villeneuve d'Ascq, F-59655, France
| | - Caroliné Olofsson
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, Uppsala, 752 36, Sweden
| | - Magne Friberg
- Department of Biology, Lund University, Lund, SE-223 62, Sweden
| | - Nina Sletvold
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, Uppsala, 752 36, Sweden
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3
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Cna'ani A, Dener E, Ben-Zeev E, Günther J, Köllner TG, Tzin V, Seifan M. Phylogeny and abiotic conditions shape the diel floral emission patterns of desert Brassicaceae species. PLANT, CELL & ENVIRONMENT 2021; 44:2656-2671. [PMID: 33715174 DOI: 10.1111/pce.14045] [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: 12/10/2020] [Revised: 03/04/2021] [Accepted: 03/08/2021] [Indexed: 06/12/2023]
Abstract
A key facet of floral scent is diel fluctuations in emission, often studied in the context of plant-pollinator interactions, while contributions of environment and phylogeny remain overlooked. Here, we ask if these factors are involved in shaping temporal variations in scent emission. To that end, we coupled light/dark floral emission measurements of 17 desert Brassicaceae species with environmental and phylogenetic data to explore the individual/combined impacts of these predictors on diel emission patterns. We further investigated these patterns by conducting high-resolution emission measurements in a subset of genetically distant species with contrasting temporal dynamics. While diel shifts in magnitude and richness of emission were strongly affected by genetic relatedness, they also reflect the environmental conditions under which the species grow. Specifically, light/dark emission ratios were negatively affected by an increase in winter temperatures, known to impact both plant physiology and insect locomotion, and sandy soil fractions, previously shown to exert stress that tempers with diel metabolic rhythms. Additionally, the biosynthetic origins of the compounds were associated with their corresponding production patterns, possibly to maximize emission efficacy. Using a multidisciplinary chemical/ecological approach, we uncover and differentiate the main factors shaping floral scent diel fluctuations, highlighting their consequences under changing global climate.
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Affiliation(s)
- Alon Cna'ani
- Jacob Blaustein Center for Scientific Cooperation, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer campus, Midreshet Ban-Gurion, Israel
| | - Efrat Dener
- The Albert Katz International School for Desert Studies, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer campus, Midreshet Ban-Gurion, Israel
| | - Efrat Ben-Zeev
- Nancy and Stephen Grand Israel National Center for Personalized Medicine, The Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Jan Günther
- Department of Natural Product Biosynthesis, Max Planck Institute for Chemical Ecology, Jena, Germany
- Section of Plant Biochemistry, Department of Plant and Environmental Science, University of Copenhagen, Copenhagen, Denmark
| | - Tobias G Köllner
- Department of Natural Product Biosynthesis, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Vered Tzin
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer campus, Midreshet Ban-Gurion, Israel
| | - Merav Seifan
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer campus, Midreshet Ban-Gurion, Israel
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4
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Christie K, Doan JP, Mcbride WC, Strauss SY. Asymmetrical reproductive barriers in sympatric jewelflowers: are floral isolation, genetic incompatibilities and floral trait displacement connected? Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Floral visitors influence reproductive interactions among sympatric plant species, either by facilitating assortative mating and contributing to reproductive isolation, or by promoting heterospecific pollen transfer, potentially leading to reproductive interference or hybridization. We assessed preference and constancy of floral visitors on two co-occurring jewelflowers [Streptanthus breweri and Streptanthus hesperidis (Brassicaceae)] using field arrays, and quantified two floral rewards potentially important to foraging choice – pollen production and nectar sugar concentration – in a greenhouse common garden. Floral visitors made an abundance of conspecific transitions between S. breweri individuals, which thus experienced minimal opportunities for heterospecific pollen transfer from S. hesperidis. In contrast, behavioural isolation for S. hesperidis was essentially absent due to pollinator inconstancy. This pattern emerged across multiple biotic environments and was unrelated to local density dependence. S. breweri populations that were sympatric with S. hesperidis had higher nectar sugar concentrations than their sympatric congeners, as well as allopatric conspecifics. Previous work shows that S. breweri suffers a greater cost to hybridization than S. hesperidis, and here we find that it also shows asymmetrical floral isolation and floral trait displacement in sympatry. These findings suggest that trait divergence may reduce negative reproductive interactions between sympatric but genetically incompatible relatives.
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Affiliation(s)
- Kyle Christie
- Department of Evolution and Ecology, University of California Davis, One Shields Avenue, Davis, CA, USA
- Center for Population Biology, University of California Davis, One Shields Avenue, Davis, CA, USA
| | - Jonathan P Doan
- Department of Evolution and Ecology, University of California Davis, One Shields Avenue, Davis, CA, USA
| | - Wendy C Mcbride
- Deaver Herbarium, Northern Arizona University, Flagstaff, AZ, USA
| | - Sharon Y Strauss
- Department of Evolution and Ecology, University of California Davis, One Shields Avenue, Davis, CA, USA
- Center for Population Biology, University of California Davis, One Shields Avenue, Davis, CA, USA
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5
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Tripp EA, Dexter KG, Stone HB. Reproductive character displacement and potential underlying drivers in a species-rich and florally diverse lineage of tropical angiosperms ( Ruellia; Acanthaceae). Ecol Evol 2021; 11:4719-4730. [PMID: 33976842 PMCID: PMC8093712 DOI: 10.1002/ece3.7371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 12/05/2020] [Accepted: 12/10/2020] [Indexed: 11/08/2022] Open
Abstract
Reproductive character displacement is a pattern whereby sympatric lineages diverge more in reproductive character morphology than allopatric lineages. This pattern has been observed in many plant species, but comparably few have sought to disentangle underlying mechanisms. Here, in a diverse lineage of Neotropical plants (Ruellia; Acanthaceae), we present evidence of reproductive character displacement in a macroevolutionary framework (i.e., among species) and document mechanistic underpinnings. In a series of interspecific hand pollinations in a controlled glasshouse environment, we found that crosses between species that differed more in overall flower size, particularly in style length, were significantly less likely to produce viable seeds. Further, species pairs that failed to set seed were more likely to have sympatric distributions in nature. Competition for pollinators and reinforcement to avoid costly interspecific mating could both result in these patterns and are not mutually exclusive processes. Our results add to growing evidence that reproductive character displacement contributes to exceptional floral diversity of angiosperms.
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Affiliation(s)
- Erin A. Tripp
- Department of Ecology and Evolutionary BiologyUniversity of ColoradoBoulderCOUSA
- Museum of Natural HistoryUniversity of ColoradoBoulderCOUSA
| | - Kyle G. Dexter
- School of GeoSciencesUniversity of EdinburghEdinburghUK
- Royal Botanic Garden EdinburghEdinburghUK
| | - Heather B. Stone
- Department of Ecology and Evolutionary BiologyUniversity of ColoradoBoulderCOUSA
- Museum of Natural HistoryUniversity of ColoradoBoulderCOUSA
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6
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Orsucci M, Sicard A. Flower evolution in the presence of heterospecific gene flow and its contribution to lineage divergence. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:971-989. [PMID: 33537708 DOI: 10.1093/jxb/eraa549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 11/16/2020] [Indexed: 06/12/2023]
Abstract
The success of species depends on their ability to exploit ecological resources in order to optimize their reproduction. However, species are not usually found within single-species ecosystems but in complex communities. Because of their genetic relatedness, closely related lineages tend to cluster within the same ecosystem, rely on the same resources, and be phenotypically similar. In sympatry, they will therefore compete for the same resources and, in the case of flowering plants, exchange their genes through heterospecific pollen transfer. These interactions, nevertheless, pose significant challenges to species co-existence because they can lead to resource limitation and reproductive interference. In such cases, divergent selective pressures on floral traits will favour genotypes that isolate or desynchronize the reproduction of sympatric lineages. The resulting displacement of reproductive characters will, in turn, lead to pre-mating isolation and promote intraspecific divergence, thus initiating or reinforcing the speciation process. In this review, we discuss the current theoretical and empirical knowledge on the influence of heterospecific pollen transfer on flower evolution, highlighting its potential to uncover the ecological and genomic constraints shaping the speciation process.
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Affiliation(s)
- Marion Orsucci
- Department of Plant Biology, Swedish University of Agricultural, Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Adrien Sicard
- Department of Plant Biology, Swedish University of Agricultural, Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
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Koski MH, Berardi AE, Galloway LF. Pollen colour morphs take different paths to fitness. J Evol Biol 2020; 33:388-400. [PMID: 32012387 DOI: 10.1111/jeb.13599] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 12/04/2019] [Accepted: 01/24/2020] [Indexed: 01/23/2023]
Abstract
Colour phenotypes are often involved in communication and are thus under selection by species interactions. However, selection may also act on colour through correlated traits or alternative functions of biochemical pigments. Such forms of selection are instrumental in maintaining petal colour diversity in plants. Pollen colour also varies markedly, but the maintenance of this variation is little understood. In Campanula americana, pollen ranges from white to dark purple, with darker morphs garnering more pollinator visits and exhibiting elevated pollen performance under heat stress. Here, we generate an F2 population segregating for pollen colour and measure correlations with floral traits, pollen attributes and plant-level traits related to fitness. We determine the pigment biochemistry of colour variants and evaluate maternal and paternal fitness of light and dark morphs by crossing within and between morphs. Pollen colour was largely uncorrelated with floral traits (petal colour, size, nectar traits) suggesting it can evolve independently. Darker pollen grains were larger and had higher anthocyanin content (cyanidin and peonidin) which may explain why they outperform light pollen under heat stress. Overall, pollen-related fitness metrics were greater for dark pollen, and dark pollen sires generated seeds with higher germination potential. Conversely, light pollen plants produce 61% more flowers than dark, and 18% more seeds per fruit, suggesting a seed production advantage. Results indicate that light and dark morphs may achieve fitness through different means-dark morphs appear to have a pollen advantage whereas light morphs have an ovule advantage-helping to explain the maintenance of pollen colour variation.
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Affiliation(s)
- Matthew H Koski
- Department of Biological Sciences, Clemson University, Clemson, SC, USA.,Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Andrea E Berardi
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Laura F Galloway
- Department of Biology, University of Virginia, Charlottesville, VA, USA
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8
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Eisen KE, Geber MA. Ecological sorting and character displacement contribute to the structure of communities of Clarkia species. J Evol Biol 2018; 31:1440-1458. [PMID: 30099807 DOI: 10.1111/jeb.13365] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 07/10/2018] [Accepted: 08/06/2018] [Indexed: 01/27/2023]
Abstract
Despite long-standing interest in the evolutionary ecology of plants that share pollinators, few studies have explored how these interactions may affect communities during both community assembly (ecological sorting) and through ongoing, in situ evolution (character displacement), and how the effects of these interactions may change with community context. To determine if communities display patterns consistent with ecological sorting, we assessed the frequency of co-occurrence of four species of Clarkia in the southern Sierra foothills (Kern County, CA, USA). To investigate potential character displacement, we measured pollination-related traits on plants grown in a greenhouse common garden from seed collected in communities with one, two or four Clarkia species. Among the four species of Clarkia in this region, the two species that are often found in multi-species communities also co-occur with one another more frequently than expected under a null model. This pattern is consistent with ecological sorting, although further investigation is needed to determine the role of pollinators in shaping community assembly. Patterns of trait variation in a common garden suggest that these two species have diverged in floral traits and converged in flowering time where they co-occur, which is consistent with character displacement. Trait variation across community types also suggests that the process and outcome of character displacement may vary with community context. Because community context appears to affect both the direction and magnitude of character displacement, change in more species-rich communities may not be predictable from patterns of change in simpler communities.
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Affiliation(s)
- Katherine E Eisen
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
| | - Monica A Geber
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
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9
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Bergamo PJ, Telles FJ, Arnold SEJ, de Brito VLG. Flower colour within communities shifts from overdispersed to clustered along an alpine altitudinal gradient. Oecologia 2018; 188:223-235. [DOI: 10.1007/s00442-018-4204-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 06/06/2018] [Indexed: 12/14/2022]
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10
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Weber MG, Cacho NI, Phan MJQ, Disbrow C, Ramírez SR, Strauss SY. The evolution of floral signals in relation to range overlap in a clade of California Jewelflowers (Streptanthus s.l.). Evolution 2018; 72:798-807. [PMID: 29464694 DOI: 10.1111/evo.13456] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 02/05/2018] [Accepted: 02/06/2018] [Indexed: 01/18/2023]
Abstract
Because of their function as reproductive signals in plants, floral traits experience distinct selective pressures related to their role in speciation, reinforcement, and prolonged coexistence with close relatives. However, few studies have investigated whether population-level processes translate into detectable signatures at the macroevolutionary scale. Here, we ask whether patterns of floral trait evolution and range overlap across a clade of California Jewelflowers reflect processes hypothesized to shape floral signal differentiation at the population level. We found a pattern of divergence in floral scent composition across the clade such that close relatives had highly disparate floral scents given their age. Accounting for range overlap with close relatives explained additional variation in floral scent over time, with sympatric species pairs having diverged more than allopatric species pairs given their age. However, three other floral traits (flower size, scent complexity and flower color) did not fit these patterns, failing to deviate from a null Brownian motion model of evolution. Together, our results suggest that selection for divergence among close relatives in the composition of floral scents may play a key, sustained role in mediating speciation and coexistence dynamics across this group, and that signatures of these dynamics may persist at the macroevolutionary scale.
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Affiliation(s)
- Marjorie G Weber
- Center for Population Biology, University of California, Davis, California 95616.,Current Address: Department of Plant Biology and Ecology, Evolutionary Biology and Behavior Program, Michigan State University, East Lansing, Michigan 48823
| | - N Ivalú Cacho
- Instituto de Biología, Universidad Nacional Autónoma de México, CDMX 04510, México.,Department of Evolution and Ecology, University of California, Davis, California 95616
| | - Martin J Q Phan
- Department of Evolution and Ecology, University of California, Davis, California 95616
| | - Caprice Disbrow
- Department of Evolution and Ecology, University of California, Davis, California 95616
| | - Santiago R Ramírez
- Center for Population Biology, University of California, Davis, California 95616.,Department of Evolution and Ecology, University of California, Davis, California 95616
| | - Sharon Y Strauss
- Center for Population Biology, University of California, Davis, California 95616.,Department of Evolution and Ecology, University of California, Davis, California 95616
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11
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Eisen KE. Digest: Trait variation in Mimulus
provides new evidence for the joint action of ecological sorting and character displacement*. Evolution 2017; 71:1425-1427. [DOI: 10.1111/evo.13233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 03/15/2017] [Indexed: 11/29/2022]
Affiliation(s)
- Katherine E. Eisen
- Department of Ecology and Evolutionary Biology; Cornell University; New York 14850
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