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Núñez-Hidalgo S, Cascante-Marín A. Selfing in epiphytic bromeliads compensates for the limited pollination services provided by nectarivorous bats in a neotropical montane forest. AoB Plants 2024; 16:plae011. [PMID: 38497049 PMCID: PMC10944016 DOI: 10.1093/aobpla/plae011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 02/23/2024] [Indexed: 03/19/2024]
Abstract
Abstract. Plants with specialized pollination systems frequently exhibit adaptations for self-pollination, and this contradictory situation has been explained in terms of the reproductive assurance function of selfing. In the neotropics, several plant lineages rely on specialized vertebrate pollinators for sexual reproduction, including the highly diverse Bromeliaceae family, which also displays a propensity for selfing. Thus far, the scarce evidence on the role of selfing in bromeliads and in other neotropical plant groups is inconclusive. To provide insights into the evolution and persistence of self-fertilization in the breeding systems of Bromeliaceae, we studied four sympatric epiphytic species from the genus Werauhia (Tillandsioideae) in Costa Rica. We documented their floral biology, pollination ecology and breeding systems. We estimated the contribution of selfing by comparing the reproductive success between emasculated flowers requiring pollinator visits and un-manipulated flowers capable of selfing and exposed to open pollination across two flowering seasons. The studied species displayed specialized pollination by nectar-feeding bats as well as a high selfing ability (auto-fertility index values > 0.53), which was attained by a delayed selfing mechanism. Fruit set from natural cross-pollination was low (<26% in both years) and suggested limited pollinator visitation. In line with this, we found a very low bat visitation to flowers using video-camera recording, from 0 to 0.24 visits per plant per night. On the contrary, the contribution of selfing was comparatively significant since 54-80% of the fruit set from un-manipulated flowers can be attributed to autonomous self-pollination. We concluded that inadequate cross-pollination services diminished the reproductive success of the studied Werauhia, which was compensated for by a delayed selfing mechanism. The low negative effects of inbreeding on seed set and germination likely reinforce the persistence of selfing in this bromeliad group. These results suggest that selfing in bat-pollinated bromeliads may have evolved as a response to pollinator limitation.
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Affiliation(s)
- Stephanie Núñez-Hidalgo
- Sistema de Estudios de Posgrado, Universidad de Costa Rica, San Pedro de Montes de Oca, 11501-2060 San José, Costa Rica
| | - Alfredo Cascante-Marín
- Escuela de Biología y Centro de Investigación en Biodiversidad y Ecología Terrestre (CIBET), Universidad de Costa Rica, San Pedro de Montes de Oca, 11501-2060 San José, Costa Rica
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Spigler RB, Maguiña R. Changes in female function and autonomous selfing across floral lifespan interact to drive variation in the cost of selfing. Am J Bot 2022; 109:616-627. [PMID: 35075632 PMCID: PMC9315013 DOI: 10.1002/ajb2.1816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 12/29/2021] [Accepted: 12/30/2021] [Indexed: 06/14/2023]
Abstract
PREMISE Morphological and developmental changes as flowers age can impact patterns of mating. At the same time, direct or indirect costs of floral longevity can alter their fitness outcomes. This influence has been less appreciated, particularly with respect to the timing of selfing. We investigated changes in stigma events, autonomous selfing, outcross seed set capacity, and autofertility-a measure representing the potential for reproductive assurance-across floral lifespan in the mixed-mating biennial Sabatia angularis. METHODS We examined stigma morphology and receptivity, autonomous self-pollen deposition, and seed number and size under autonomous self-pollination and hand outcross-pollination for flowers of different ages, from 1 d of female phase until 14 d. We compared autonomous seed production to maximal outcross seed production at each flower age to calculate an index of autofertility. RESULTS The stigmatic lobes begin to untwist 1 d post anthesis. They progressively open, sextend, coil, and increase in receptivity, peaking or saturating at 8-11 d, depending on the measure. Autonomous seed production can occur early, but on average remains low until 6 d, when it doubles. In contrast, outcross seed number and size start out high, then decline precipitously. Consequently, autofertility increases steeply across floral lifespan. CONCLUSIONS Changes in stigma morphology and receptivity, timing of autonomous self-pollen deposition, and floral senescence can interact to influence the relative benefit of autonomous selfing across floral lifespan. Our work highlights the interplay between evolution of floral longevity and the mating system, with implications for the maintenance of mixed mating in S. angularis.
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Affiliation(s)
- Rachel B. Spigler
- Department of BiologyTemple University1900 N 12th St.PhiladelphiaPA19122USA
| | - Rossana Maguiña
- Department of BiologyTemple University1900 N 12th St.PhiladelphiaPA19122USA
- Present address:
Rossana Maguiña, Ecology and Evolutionary Biology DepartmentUniversity of California Santa Cruz130 McAllister WaySanta CruzCA95060USA
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Laina D, Gfrerer E, Scheurecker V, Fuchs R, Schleifer M, Zittra C, Wagner R, Gibernau M, Comes HP, Hörger AC, Dötterl S. Local Insect Availability Partly Explains Geographical Differences in Floral Visitor Assemblages of Arum maculatum L. (Araceae). Front Plant Sci 2022; 13:838391. [PMID: 35350299 PMCID: PMC8957888 DOI: 10.3389/fpls.2022.838391] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
Geographical variation in abundance and composition of pollinator assemblages may result in variable selection pressures among plant populations and drive plant diversification. However, there is limited knowledge on whether differences in local visitor and pollinator assemblages are the result of site-specific strategies of plants to interact with their pollinators and/or merely reflect the pollinator availability at a given locality. To address this question, we compared locally available insect communities obtained by light-trapping with assemblages of floral visitors in populations of Arum maculatum (Araceae) from north vs. south of the Alps. We further investigated whether and how the abundance of different visitors affects plants' female reproductive success and examined the pollen loads of abundant visitors. Local insect availability explained inter-regional differences in total visitor abundance, but only partly the composition of visitor assemblages. Northern populations predominantly attracted females of Psychoda phalaenoides (Psychodidae, Diptera), reflecting the high availability of this moth fly in this region. More generalized visitor assemblages, including other psychodid and non-psychodid groups, were observed in the south, where the availability of P. phalaenoides/Psychodidae was limited. Fruit set was higher in the north than in the south but correlated positively in both regions with the abundance of total visitors and psychodids; in the north, however, this relationship disappeared when visitor abundances were too high. High pollen loads were recorded on both psychodids and other Diptera. We demonstrate for the first time that the quantitative assessment of floral visitor assemblages in relation to locally available insect communities is helpful to understand patterns of geographical variation in plant-pollinator interactions. This combined approach revealed that geographical differences in floral visitors of A. maculatum are only partly shaped by the local insect availability. Potential other factors that may contribute to the geographical pattern of visitor assemblages include the region-specific attractiveness of this plant species to flower visitors and the population-specific behavior of pollinators.
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Affiliation(s)
- Danae Laina
- Department of Environment and Biodiversity, Paris Lodron University of Salzburg, Salzburg, Austria
| | - Eva Gfrerer
- Department of Environment and Biodiversity, Paris Lodron University of Salzburg, Salzburg, Austria
| | - Valerie Scheurecker
- Department of Environment and Biodiversity, Paris Lodron University of Salzburg, Salzburg, Austria
| | - Roman Fuchs
- Department of Environment and Biodiversity, Paris Lodron University of Salzburg, Salzburg, Austria
| | - Marielle Schleifer
- Department of Environment and Biodiversity, Paris Lodron University of Salzburg, Salzburg, Austria
| | - Carina Zittra
- Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria
| | - Rüdiger Wagner
- Department of Limnology, University of Kassel, Kassel, Germany
| | - Marc Gibernau
- Laboratory of Sciences for the Environment, CNRS – University of Corsica, Ajaccio, France
| | - Hans Peter Comes
- Department of Environment and Biodiversity, Paris Lodron University of Salzburg, Salzburg, Austria
| | - Anja C. Hörger
- Department of Environment and Biodiversity, Paris Lodron University of Salzburg, Salzburg, Austria
| | - Stefan Dötterl
- Department of Environment and Biodiversity, Paris Lodron University of Salzburg, Salzburg, Austria
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Zhang W, Hu YF, He X, Zhou W, Shao JW. Evolution of Autonomous Selfing in Marginal Habitats: Spatiotemporal Variation in the Floral Traits of the Distylous Primula wannanensis. Front Plant Sci 2021; 12:781281. [PMID: 34975966 PMCID: PMC8716950 DOI: 10.3389/fpls.2021.781281] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 11/09/2021] [Indexed: 06/08/2023]
Abstract
Outcrossing plant species are more likely to exhibit autonomous selfing in marginal habitats to ensure reproduction under conditions of limited pollinator and/or mate availability. Distyly is a classical paradigm that promotes outcrossing; however, little is known about the variation in floral traits associated with distylous syndrome in marginal populations. In this study, we compared the variation in floral traits including stigma and anther height, corolla tube length, herkogamy, and corolla diameter between the central and peripheral populations of the distylous Primula wannanensis, and assessed the variation of floral traits at early and late florescence stages for each population. To evaluate the potential consequences of the variation in floral traits on the mating system, we investigated seed set in each population under both open-pollinated and pollinator-excluded conditions. The flower size of both short- and long-styled morphs was significantly reduced in late-opening flowers compared with early opening flowers in both central and peripheral populations. Sex-organ reciprocity was perfect in early opening flowers; however, it was largely weakened in the late-opening flowers of peripheral populations compared with central populations. Of these flowers, disproportionate change in stigma height (elongated in S-morph and shortened in L-morph) was the main cause of reduced herkogamy, and seed set was fairly high under pollinator-excluded condition. Our results provide empirical support for the hypothesis on the evolution of delayed autonomous selfing in marginal populations of distylous species. Unsatisfactory pollinator service is likely to have promoted reproductive assurance of distylous plants with largely reduced herkogamy mimicking "homostyles."
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Affiliation(s)
- Wei Zhang
- College of Life Sciences, Anhui Normal University, Wuhu, China
- Provincial Key Laboratory of Conservation and Utilization of Biological Resources, Wuhu, China
| | - Ying Feng Hu
- College of Life Sciences, Anhui Normal University, Wuhu, China
| | - Xiao He
- College of Life Sciences, Anhui Normal University, Wuhu, China
| | - Wei Zhou
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- Lijiang Forest Biodiversity National Observation and Research Station, Kunming Institute of Botany, Chinese Academy of Sciences, Lijiang, China
| | - Jian Wen Shao
- College of Life Sciences, Anhui Normal University, Wuhu, China
- Provincial Key Laboratory of Conservation and Utilization of Biological Resources, Wuhu, China
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5
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Buide ML, Del Valle JC, Prado-Comesaña A, Narbona E. The effects of pollination, herbivory and autonomous selfing on the maintenance of flower colour variation in Silenelittorea. Plant Biol (Stuttg) 2021; 23:275-284. [PMID: 33179369 DOI: 10.1111/plb.13209] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 10/30/2020] [Indexed: 05/23/2023]
Abstract
Intraspecific flower colour variation has been generally proposed to evolve as a result of selection driven by biotic or abiotic agents. In a polymorphic population of Silene littorea with pink- and white-flowered plants, we studied pollinators, analysed flower colour perception and tested for differences in pollinator visitation. We also experimentally analysed pollinator limitation in fruit and seed set, and the degree of autonomous selfing. The incidence of florivory and leaf herbivory was compared over 3-4 years. Silene littorea is mainly pollinated by bees and butterflies. Pollinators preferred pink flowers, which did not show pollinator limitation. On the contrary, white flowers showed pollinator limitation in fruit set. White-flowered plants had less floral display and higher levels of florivory than pink plants. Flower colour morphs of S. littorea can reproduce in the absence of pollinators by autonomous selfing, setting 20% and 12% of fruit and seeds in the pink morph and 27% and 20% in the white morph, respectively. Fruit set of white flowers produced by autonomous selfing did not differ from open-pollinated flowers. In conclusion, S. littorea is pollinated by insects of different orders that more frequently visit pink flowers, which is reflected in pollinator limitation of fruit set in white flowers. Moreover, this species has a mixed mating system in which both colour morphs can reproduce in the absence of pollinators by autonomous selfing, although white flowers mainly produce fruits by autogamy. We suggest that reproductive assurance by autonomous selfing helps to maintain flower colour polymorphism in this population.
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Affiliation(s)
- M L Buide
- Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Seville, Spain
| | - J C Del Valle
- Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Seville, Spain
| | - A Prado-Comesaña
- Department of Analytical and Food Chemistry, University of Vigo, Vigo, Spain
| | - E Narbona
- Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Seville, Spain
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Fan YL, Barrett SCH, Yang JQ, Zhao JL, Xia YM, Li QJ. Water mediates fertilization in a terrestrial flowering plant. New Phytol 2019; 224:1133-1141. [PMID: 31032938 DOI: 10.1111/nph.15873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 04/17/2019] [Indexed: 06/09/2023]
Abstract
Water-mediated fertilization is ubiquitous in early land plants. This ancestral mode of fertilization has, however, generally been considered to have been lost during the evolutionary history of terrestrial flowering plants. We investigated reproductive mechanisms in the subtropical ginger Cautleya gracilis (Zingiberaceae), which has two pollen conditions - granular and filiform masses - depending on external conditions. We tested whether rain transformed granular pollen into filiform masses and whether this then promoted pollen-tube growth and fertilization of ovules. Using experimental manipulations in the field we investigated the contribution of water-mediated fertilization to seed production. Rain caused granular pollen to form filiform masses of germinating pollen tubes, which transported sperm to ovules, resulting in fertilization and seed set. Flowers exposed to rain produced significantly more seeds than those protected from the rain, which retained granular pollen. Insect pollination made only a limited contribution to seed set because rainy conditions limited pollinator service. Our results reveal a previously undescribed fertilization mechanism in flowering plants involving water-mediated fertilization stimulated by rain. Water-mediated fertilization is likely to be adaptive in the subtropical monsoon environments in which C. gracilis occurs by ensuring reproductive assurance when persistent rain prevents insect-mediated pollination.
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Affiliation(s)
- Yong-Li Fan
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Mengla, 666303, China
- Kunming Survey & Design Institute of State Forestry and Grassland Administration, Kunming, Yunnan, 650216, China
| | - Spencer C H Barrett
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| | - Ji-Qin Yang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
| | - Jian-Li Zhao
- Yunnan Key Laboratory of Plant Reproductive Adaption and Evolutionary Ecology, Yunnan University, Kunming, Yunnan, 650091, China
- Laboratory of Ecology and Evolutionary Biology, State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, Yunnan, 650216, China
| | - Yong-Mei Xia
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
| | - Qing-Jun Li
- Yunnan Key Laboratory of Plant Reproductive Adaption and Evolutionary Ecology, Yunnan University, Kunming, Yunnan, 650091, China
- Laboratory of Ecology and Evolutionary Biology, State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, Yunnan, 650216, China
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Devaux C, Porcher E, Lande R. Mating systems and avoidance of inbreeding depression as evolutionary drivers of pollen limitation in animal-pollinated self-compatible plants. Ann Bot 2019; 123:327-336. [PMID: 30351386 PMCID: PMC6344218 DOI: 10.1093/aob/mcy181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 10/15/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND AND AIMS Most theory addressing the evolution of pollen limitation in flowering plants focuses on stochasticity in the relative abundance of plant and pollinator populations affecting trade-offs in resource allocation to ovule production or pollinator attraction vs. seed maturation. Mating system evolution is an underappreciated but potentially widespread additional mechanism for the evolutionary emergence of pollen limitation in animal-pollinated self-compatible plants. METHODS We model individual plant flowering phenologies influencing both pollinator attraction and geitonogamous self-fertilization caused by pollinator movements among flowers within plants, incorporating demographic but not environmental stochasticity. Plant phenology and the resulting pollen limitation are analysed at evolutionarily stable equilibria (ESS). Pollen limitation is measured by two quantities: the proportion of unpollinated flowers and the reduction in maternal fitness caused by inbreeding depression in selfed seeds. KEY RESULTS When pollinators visit multiple flowers per plant, pollen limitation is never minimized at an ESS and results from the evolution of flowering phenologies balancing the amount and genetic composition (outbred vs. inbred) of pollen receipt. CONCLUSIONS Results are consistent with previous theory demonstrating that pollen limitation can be an evolved property, not just a constraint; they complement existing models by showing that plant avoidance of inbreeding depression constitutes a genetic mechanism contributing to evolution of pollen limitation, in addition to ecological mechanisms previously studied.
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Affiliation(s)
- Céline Devaux
- Institut des Sciences de l’Evolution de Montpellier, UMR, Montpellier, France
| | - Emmanuelle Porcher
- Centre d’Ecologie et des Sciences de la Conservation, UMR, Muséum national d’Histoire naturelle, Centre National de la Recherche Scientifique, Sorbonne Université, Paris, France
| | - Russell Lande
- Center for Biodiversity Dynamics, Norwegian University of Science and Technology, Trondheim, Norway
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8
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Delmas CEL, Fort TLC, Escaravage N, Pornon A. Pollen transfer in fragmented plant populations: insight from the pollen loads of pollinators and stigmas in a mass-flowering species. Ecol Evol 2016; 6:5663-73. [PMID: 27547345 PMCID: PMC4983582 DOI: 10.1002/ece3.2280] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 06/06/2016] [Accepted: 06/07/2016] [Indexed: 11/07/2022] Open
Abstract
Pollinator and/or mate scarcity affects pollen transfer, with important ecological and evolutionary consequences for plant reproduction. However, the way in which the pollen loads transported by pollinators and deposited on stigmas are affected by pollination context has been little studied. We investigated the impacts of plant mate and visiting insect availabilities on pollen transport and receipt in a mass-flowering and facultative autogamous shrub (Rhododendron ferrugineum). First, we recorded insect visits to R. ferrugineum in plant patches of diverse densities and sizes. Second, we analyzed the pollen loads transported by R. ferrugineum pollinators and deposited on stigmas of emasculated and intact flowers, in the same patches. Overall, pollinators (bumblebees) transported much larger pollen loads than the ones found on stigmas, and the pollen deposited on stigmas included a high proportion of conspecific pollen. However, comparing pollen loads of emasculated and intact flowers indicated that pollinators contributed only half the conspecific pollen present on the stigma. At low plant density, we found the highest visitation rate and the lowest proportion of conspecific pollen transported and deposited by pollinators. By contrast, at higher plant density and lower visitation rate, pollinators deposited larger proportion of conspecific pollen, although still far from sufficient to ensure that all the ovules were fertilized. Finally, self-pollen completely buffered the detrimental effects on pollination of patch fragmentation and pollinator failure. Our results indicate that pollen loads from pollinators and emasculated flowers should be quantified for an accurate understanding of the relative impacts of pollinator and mate limitation on pollen transfer in facultative autogamous species.
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Affiliation(s)
- Chloé E L Delmas
- UMR SAVE INRA, BSA, Univ. Bordeaux 33882 Villenave d'Ornon France
| | - Thomas L C Fort
- Lab Evolution & Diversité Biologique EDB Université Toulouse III Paul Sabatier F-31062 Toulouse France; CNRS EDB UMR 5174F-31062 Toulouse France
| | - Nathalie Escaravage
- Lab Evolution & Diversité Biologique EDB Université Toulouse III Paul Sabatier F-31062 Toulouse France; CNRS EDB UMR 5174F-31062 Toulouse France
| | - André Pornon
- Lab Evolution & Diversité Biologique EDB Université Toulouse III Paul Sabatier F-31062 Toulouse France; CNRS EDB UMR 5174F-31062 Toulouse France
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9
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Kormann U, Scherber C, Tscharntke T, Klein N, Larbig M, Valente JJ, Hadley AS, Betts MG. Corridors restore animal-mediated pollination in fragmented tropical forest landscapes. Proc Biol Sci 2016; 283:20152347. [PMID: 26817765 PMCID: PMC4795022 DOI: 10.1098/rspb.2015.2347] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 01/04/2016] [Indexed: 11/12/2022] Open
Abstract
Tropical biodiversity and associated ecosystem functions have become heavily eroded through habitat loss. Animal-mediated pollination is required in more than 94% of higher tropical plant species and 75% of the world's leading food crops, but it remains unclear if corridors avert deforestation-driven pollination breakdown in fragmented tropical landscapes. Here, we used manipulative resource experiments and field observations to show that corridors functionally connect neotropical forest fragments for forest-associated hummingbirds and increase pollen transfer. Further, corridors boosted forest-associated pollinator availability in fragments by 14.3 times compared with unconnected equivalents, increasing overall pollination success. Plants in patches without corridors showed pollination rates equal to bagged control flowers, indicating pollination failure in isolated fragments. This indicates, for the first time, that corridors benefit tropical forest ecosystems beyond boosting local species richness, by functionally connecting mutualistic network partners. We conclude that small-scale adjustments to landscape configuration safeguard native pollinators and associated pollination services in tropical forest landscapes.
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Affiliation(s)
- Urs Kormann
- Agroecology, Georg-August University Göttingen, Göttingen, Germany Forest Biodiversity Research Network, Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA
| | - Christoph Scherber
- Agroecology, Georg-August University Göttingen, Göttingen, Germany Institute of Landscape Ecology, University of Münster, Münster, Germany
| | - Teja Tscharntke
- Agroecology, Georg-August University Göttingen, Göttingen, Germany
| | - Nadja Klein
- Chair of Statistics, Georg-August University Göttingen, Göttingen, Germany
| | - Manuel Larbig
- Agroecology, Georg-August University Göttingen, Göttingen, Germany
| | - Jonathon J Valente
- Forest Biodiversity Research Network, Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA
| | - Adam S Hadley
- Forest Biodiversity Research Network, Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA
| | - Matthew G Betts
- Forest Biodiversity Research Network, Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA
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Pannell JR, Auld JR, Brandvain Y, Burd M, Busch JW, Cheptou PO, Conner JK, Goldberg EE, Grant AG, Grossenbacher DL, Hovick SM, Igic B, Kalisz S, Petanidou T, Randle AM, de Casas RR, Pauw A, Vamosi JC, Winn AA. The scope of Baker's law. New Phytol 2015; 208:656-67. [PMID: 26192018 DOI: 10.1111/nph.13539] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 05/27/2015] [Indexed: 05/13/2023]
Abstract
Baker's law refers to the tendency for species that establish on islands by long-distance dispersal to show an increased capacity for self-fertilization because of the advantage of self-compatibility when colonizing new habitat. Despite its intuitive appeal and broad empirical support, it has received substantial criticism over the years since it was proclaimed in the 1950s, not least because it seemed to be contradicted by the high frequency of dioecy on islands. Recent theoretical work has again questioned the generality and scope of Baker's law. Here, we attempt to discern where the idea is useful to apply and where it is not. We conclude that several of the perceived problems with Baker's law fall away when a narrower perspective is adopted on how it should be circumscribed. We emphasize that Baker's law should be read in terms of an enrichment of a capacity for uniparental reproduction in colonizing situations, rather than of high selfing rates. We suggest that Baker's law might be tested in four different contexts, which set the breadth of its scope: the colonization of oceanic islands, metapopulation dynamics with recurrent colonization, range expansions with recurrent colonization, and colonization through species invasions.
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Affiliation(s)
- John R Pannell
- Department of Ecology and Evolution, University of Lausanne, 1015, Lausanne, Switzerland
| | - Josh R Auld
- Department of Biology, West Chester University, West Chester, PA, 19383, USA
| | - Yaniv Brandvain
- Department of Plant Biology, University of Minnesota, St Paul, MN, 55108, USA
| | - Martin Burd
- School of Biological Sciences, Monash University, Melbourne, VIC, 3800, Australia
| | - Jeremiah W Busch
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Pierre-Olivier Cheptou
- CEFE UMR 5175, CNRS, Universite de Montpellier, Université Paul-Valery Montpellier, EPHE, CEFE 34293, Montpellier Cedex 05, France
| | - Jeffrey K Conner
- Kellogg Biological Station and Department of Plant Biology, Michigan State University, Hickory Corners, MI, 49060, USA
| | - Emma E Goldberg
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St Paul, MN, 55108, USA
| | | | | | - Stephen M Hovick
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH, 43210, USA
| | - Boris Igic
- Department of Biological Sciences, University of Illinois at Chicago, 840 W Taylor St, M/C 067, Chicago, IL, 60607, USA
| | - Susan Kalisz
- Department of Biology, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Theodora Petanidou
- Laboratory of Biogeography and Ecology, Department of Geography, University of the Aegean, 81100 Mytilene, Lesvos, Greece
| | - April M Randle
- Department of Environmental Science, University of San Francisco, San Francisco, CA, 94117-1049, USA
| | - Rafael Rubio de Casas
- CEFE UMR 5175, CNRS, Universite de Montpellier, Université Paul-Valery Montpellier, EPHE, CEFE 34293, Montpellier Cedex 05, France
- Departmento Ecología, Facultad de Ciencias, Universidad de Granada, UGR, 18071, Granada, Spain
- Estación Experimental de Zonas Áridas, EEZA-CSIC, Carretera de Sacramento s/n, La Cañada de San Urbano, EEZA 04120, Almeria, Spain
| | - Anton Pauw
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, 7602, South Africa
| | - Jana C Vamosi
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, T2N1N4, Canada
| | - Alice A Winn
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
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Ai H, Zhou W, Xu K, Wang H, Li D. The reproductive strategy of a pollinator-limited Himalayan plant, Incarvillea mairei (Bignoniaceae). BMC Plant Biol 2013; 13:195. [PMID: 24289097 PMCID: PMC4219382 DOI: 10.1186/1471-2229-13-195] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 11/26/2013] [Indexed: 05/25/2023]
Abstract
BACKGROUND Plants may adapt to alpine habitats by specialization in the reproductive strategy and functional aspects of their flowers and pollination systems. Alpine habitats reduce the opportunities for cross-pollination in a relatively high proportion of alpine plant species, and self-pollination may be favored in these adverse conditions. Here, we investigated the mating system and pollination of Incarvillea mairei, a perennial Himalayan herb typically found at altitudes between 3000 and 4500 m. RESULTS Analyses of floral morphology, observation of plant-pollinator interactions, and hand pollination experiments were conducted in three natural populations. Outcrossing rates and effective numbers of pollen donors were assessed in 45 open-pollinated families by using progeny analysis based on seven microsatellite markers. Incarvillea mairei displayed a set of apparently specialized floral traits, the stigma is sensitive to touch and close immediately and its reopening allows a second opportunity for the receipt of pollen. The species is fully self-compatible but employs a predominantly outcrossing mating system according to parentage analysis (tm > 0.9). Fruit set was low (26.3%), whereas seed set was high (67.2%), indicating that this species suffers pollinator limitation. Its main effective pollinator was Halictus sp., and visitation frequency was low. CONCLUSIONS Floral features such as having a sensitive stigma and anther-prongs, in conjunction with pollinator behavior, function together contributing to a set of unique reproductive adaptations that enhance outcrossing success. The increased floral longevity and high pollination efficiency operated as compensatory mechanisms to counteract low pollinator visitation frequency.
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Affiliation(s)
- Honglian Ai
- Key Laboratory for Plant Biodiversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Wei Zhou
- Key Laboratory for Plant Biodiversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Kun Xu
- Lijiang Alpine Botanic Garden, Kunming Institute of Botany, Chinese Academy of Sciences, Lijiang, China
| | - Hong Wang
- Key Laboratory for Plant Biodiversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Dezhu Li
- Key Laboratory for Plant Biodiversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
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12
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Xiong YZ, Fang Q, Huang SQ. Pollinator scarcity drives the shift to delayed selfing in Himalayan mayapple Podophyllum hexandrum (Berberidaceae). AoB Plants 2013; 5:plt037. [PMCID: PMC4455658 DOI: 10.1093/aobpla/plt037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 08/06/2013] [Indexed: 05/30/2023]
Abstract
American mayapple and Himalayan mayapple are a pair of sister species with disjunct distribution between eastern Asia and eastern North America, which the former was considered to be self-incompatible but the later to be self-compatible. We are interested in the diversification of breeding systems in the two species, particularly a usual mode of self pollination in Himalayan mayapple (Podophyllum hexandrum) which is achieved by movement of the pistil as a previous study suggested. By contrast, our observations and flower manipulations show that delayed selfing was facilitated by petals closing and stamens moving simultaneously to contact the stigma, and bees were effective pollinators although they were few. Recent molecular phylogenetics have indicated that American mayapple (mainly self-incompatible, SI) and Himalayan mayapple, which was considered to be self-compatible (SC), are sister species with disjunct distribution between eastern Asia and eastern North America. We test a hypothesis that the persistence of this early spring flowering herb in the Himalayan region is attributable to the transition from SI to SC, the capacity for selfing in an unpredictable pollination environment. Pollinator observations were conducted in an alpine meadow with hundreds of Himalayan mayapple (Podophyllum hexandrum Royle) individuals over 2 years. To examine autogamy, seed set under different pollination treatments was compared. To clarify whether automatic self-pollination is achieved by movement of the pistil as a previous study suggested, we measured incline angles of the pistil and observed flower movement during anthesis using video. Floral visitors to the nectarless flowers were very rare, but solitary bees and honeybees could be potential pollinators. Seed set of bagged flowers was not significantly different from that of open-pollinated, self- or cross-pollinated flowers. However, removal of petals or stamens lowered seed yield. The angles of inclination of pistils did not change during the process of pollination. Automatic self-pollination was facilitated by petals closing and stamens moving simultaneously to contact the stigma. Stigmatic pollen load increased little during the day time, in contrast to a sharp increase when the flowers closed during the night-time. These observations indicated that Himalayan mayapple was SC and delayed self-pollination was facilitated by the movement of petals rather than the pistil. Compared with SI American mayapple, no obvious inbreeding depression in SC Himalayan mayapple may contribute its existence in the uplifting zone. A scarcity of pollinators may have driven the shift to delayed selfing in P. hexandrum.
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Affiliation(s)
- Ying-Ze Xiong
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Qiang Fang
- College of Agriculture, Henan University of Science and Technology, Luoyang, Henan 471003, China
| | - Shuang-Quan Huang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
- College of Life Sciences, Central China Normal University, Wuhan 430079, China
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Young AG, Broadhurst LM, Thrall PH. Non-additive effects of pollen limitation and self-incompatibility reduce plant reproductive success and population viability. Ann Bot 2012; 109:643-53. [PMID: 22184620 PMCID: PMC3278296 DOI: 10.1093/aob/mcr290] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
BACKGROUND AND AIMS Mating system is a primary determinant of the ecological and evolutionary dynamics of wild plant populations. Pollen limitation and loss of self-incompatibility genotypes can both act independently to reduce seed set and these effects are commonly observed in fragmented landscapes. This study used a simulation modelling approach to assess the interacting effects of these two processes on plant reproductive performance and population viability for a range of pollination likelihood, self-incompatibility systems and S-allele richness conditions. METHODS A spatially explicit, individual-based, genetic and demographic simulation model parameterized to represent a generic self-incompatible, short-lived perennial herb was used to conduct simulation experiments in which pollination probability, self-incompatibility type (gametophytic and sporophytic) and S-allele richness were systematically varied in combination to assess their independent and interacting effects on the demographic response variables of mate availability, seed set, population size and population persistence. KEY RESULTS Joint effects of reduced pollination probability and low S-allele richness were greater than independent effects for all demographic response variables except population persistence under high pollinator service (>50 %). At intermediate values of 15-25 % pollination probability, non-linear interactions with S-allele richness generated significant reductions in population performance beyond those expected by the simple additive effect of each independently. This was due to the impacts of reduced effective population size on the ability of populations to retain S alleles and maintain mate availability. Across a limited set of pollination and S-allele conditions (P = 0·15 and S = 20) populations with gametophytic SI showed reduced S-allele erosion relative to those with sporophytic SI, but this had limited effects on individual fecundity and translated into only modest increases in population persistence. CONCLUSIONS Interactions between pollen limitation and loss of S alleles have the potential to significantly reduce the viability of populations of a few hundred plants. Population decline may occur more rapidly than expected when pollination probabilities drop below 25 % and S alleles are fewer than 20 due to non-additive interactions. These are likely to be common conditions experienced by plants in small populations in fragmented landscapes and are also those under which differences in response between gameptophytic and sporophtyic systems are observed.
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14
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Sun HQ, Huang BQ, Yu XH, Kou Y, An DJ, Luo YB, Ge S. Reproductive isolation and pollination success of rewarding Galearis diantha and non-rewarding Ponerorchis chusua (Orchidaceae). Ann Bot 2011; 107:39-47. [PMID: 20961923 PMCID: PMC3002470 DOI: 10.1093/aob/mcq210] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2010] [Revised: 07/02/2010] [Accepted: 09/24/2010] [Indexed: 05/30/2023]
Abstract
BACKGROUND AND AIMS Increasing evidence challenges the conventional perception that orchids are the most distinct example of floral diversification due to floral or prezygotic isolation. Regarding the relationship between co-flowering plants, rewarding and non-rewarding orchids in particular, few studies have investigated whether non-rewarding plants affect the pollination success of rewarding plants. Here, floral isolation and mutual effects between the rewarding orchid Galearis diantha and the non-rewarding orchid Ponerorchis chusua were investigated. METHODS Flowering phenological traits were monitored by noting the opening and wilting dates of the chosen individual plants. The pollinator pool and pollinator behaviour were assessed from field observations. Key morphological traits of the flowers and pollinators were measured directly in the field. Pollinator limitation and interspecific compatibility were evaluated by hand-pollination experiments. Fruit set was surveyed in monospecific and heterospecific plots. KEY RESULTS The species had overlapping peak flowering periods. Pollinators of both species displayed a certain degree of constancy in visiting each species, but they also visited other flowers before landing on the focal orchids. A substantial difference in spur size between the species resulted in the deposition of pollen on different regions of the body of the shared pollinator. Hand-pollination experiments revealed that fruit set was strongly pollinator-limited in both species. No significant difference in fruit set was found between monospecific plots and heterospecific plots. CONCLUSIONS A combination of mechanical isolation and incomplete ethological isolation eliminates the possibility of pollen transfer between the species. These results do not support either the facilitation or competition hypothesis regarding the effect of nearby rewarding flowers on non-rewarding plants. The absence of a significant effect of non-rewarding P. chusua on rewarding G. diantha can be ascribed to low levels of overlap between the pollinator pools of two species.
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Affiliation(s)
- Hai-Qin Sun
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
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Holmes GD, James EA, Hoffmann AA. Limitations to reproductive output and genetic rescue in populations of the rare shrub Grevillea repens (Proteaceae). Ann Bot 2008; 102:1031-41. [PMID: 18922849 PMCID: PMC2712411 DOI: 10.1093/aob/mcn195] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
BACKGROUND AND AIMS When conserving rare plant species, managers are often faced with small and/or isolated populations displaying low levels of sexual reproduction and genetic variation. One option for reinvigorating these populations is the introduction of genetic material from other sites, but in some cases fitness may be reduced as a result of outbreeding depression. Here the pollination biology of the rare shrub Grevillea repens is studied across its natural range and reproductive responses following cross-pollination among populations are examined to determine factors that may be limiting sexual reproduction and the potential for genetic rescue. METHODS Pollen manipulation treatments (self-, autogamous self-, cross- and open pollination) were applied to flowers to examine the breeding system and fruit and seed production in five populations of G. repens. Pollen production, presentation and viability were investigated and interpopulation crosses of increasing genetic distance performed among the populations. KEY RESULTS The study species is self-incompatible and displayed very low natural seed set over two seasons, due partly to low pollen viability in one of the populations. Within-population crossing increased fruit and seed production at some sites, indicating pollinator limitation. Interpopulation crosses further increased reproductive output in one population, suggesting mate limitation, and for this site there was a positive relationship between genetic distance among populations and the size of genetic rescue benefits. However, in other populations there was a decrease in fruit and seed set with increasing genetic distance. CONCLUSIONS The results highlight that management strategies involving interpopulation crosses can improve reproductive output in small, isolated populations of rare plants, but guidelines need to be developed on a population by population basis.
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Affiliation(s)
- G D Holmes
- Centre for Environmental Stress and Adaptation Research (CESAR), Department of Genetics, Bio21 Institute, University of Melbourne, 30 Flemington Rd, Parkville, VIC 3010, Australia.
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