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McCarren S, Midgley JJ, Coetzee A, Johnson SD. Pollen transfer efficiency in Erica depends on type of pollinator. PHYTOKEYS 2024; 244:237-248. [PMID: 39086738 PMCID: PMC11289515 DOI: 10.3897/phytokeys.244.107288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 04/15/2024] [Indexed: 08/02/2024]
Abstract
Pollen transfer efficiency (PTE; the proportion of pollen removed from flowers that reaches conspecific stigmas) is expected to vary with the type of pollinator and flower morphology, and to influence male siring success. Many species in the genus Erica are pollinated by bees (which consume pollen and should thus lower PTE) but during its radiation in the Cape, several independent shifts to both sunbird and long-proboscid fly (LP fly) pollinators, which do not consume pollen have taken place. Improvements in PTE could be one of the factors driving these pollinator shifts. PTE data for 15 Erica species (five for each of the three pollinator types) were collected and compared in relation to type of pollinator and anther exsertion. LP fly- and bird-pollinated species had higher PTE in comparison with bee-pollinated species. Species with inserted anthers had higher PTE than those with exserted anthers. This suggests that sunbirds and LP flies are more efficient pollinators than bees. Additionally, the study suggests that insertion of anthers within the corolla tube can reduce pollen losses.
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Affiliation(s)
- Sam McCarren
- Department of Biological Sciences, University of Cape Town, 7701 Cape Town, South AfricaUniversity of Cape TownCape TownSouth Africa
| | - Jeremy J. Midgley
- Department of Biological Sciences, University of Cape Town, 7701 Cape Town, South AfricaUniversity of Cape TownCape TownSouth Africa
| | - Anina Coetzee
- Department of Conservation Management, Nelson Mandela University, 6530 George, South AfricaNelson Mandela UniversityGeorgeSouth Africa
| | - Steven D. Johnson
- Centre for Functional Biodiversity School of Life Sciences, University of Kwazulu-Natal, 3209 Pietermaritzburg, South AfricaUniversity of Kwazulu-NatalPietermaritzburgSouth Africa
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2
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Luo Y, Xie J, Zhu L, Dai C. Successive stamen movement in Saxifraga candelabrum is responsive to weather and pollinator visits. MOVEMENT ECOLOGY 2024; 12:43. [PMID: 38851751 PMCID: PMC11162003 DOI: 10.1186/s40462-024-00483-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 05/31/2024] [Indexed: 06/10/2024]
Abstract
BACKGROUND Successive stamen movement is a complex plant behavior involving successive uplift of stamens and pollen release, which plays a role in reducing sexual interference, increasing pollen deposition and promoting pollen export. Although reported from several taxa, studies on whether the movement can be influenced by abiotic and biotic factors are scarce. METHODS In this study, we here for the first time described a pattern of successive stamen movement in Saxifraga candelabrum (Saxifragaceae). We then compared the rates of stamen movement in S. candelabrum under different weather and varying pollinator visits. Pollen packaging and presentation schedule of S. candelabrum were also investigated. RESULTS The results showed that the number of stamens bent per day in sunny days was significantly higher than overcast and rain. Flowers that receive more pollinator visits (control treatment) had significantly higher number of stamen movement than those that received fewer (removal treatment) and none (bagging treatment). Throughout the staminate phase of a flower, there was a progressive increase in both pollen quantity of individual stamens and pollen presentation during each day. CONCLUSION Our research demonstrates that successive stamen movement in S. candelabrum was accelerated by favorable weather and increased pollinator visits, which may promote pollen export. Moreover, incremental pollen packaging is likely an adaptation to seasonal regularity in variations of sex ratio resulting from protandry.
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Affiliation(s)
- Yumei Luo
- School of Resources and Environmental Science, Hubei University, Wuhan, 430062, China
- Hubei Key Laboratory of Regional Development and Environmental Response, Hubei University, Wuhan, 430062, China
| | - Jiming Xie
- School of Resources and Environmental Science, Hubei University, Wuhan, 430062, China
- Xiangshan School Affiliated to Huaibei Normal University, Huaibei, 235099, China
| | - Lin Zhu
- School of Resources and Environmental Science, Hubei University, Wuhan, 430062, China
- Hubei Key Laboratory of Regional Development and Environmental Response, Hubei University, Wuhan, 430062, China
| | - Can Dai
- School of Resources and Environmental Science, Hubei University, Wuhan, 430062, China.
- Hubei Key Laboratory of Regional Development and Environmental Response, Hubei University, Wuhan, 430062, China.
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3
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Vieira ALC, Pataca LC, Oliveira R, Schlindwein C. Fields of flowers with few strikes: how oligolectic bees manage their foraging behavior on Calibrachoa elegans (Solanaceae). THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2024; 111:26. [PMID: 38647655 DOI: 10.1007/s00114-024-01912-w] [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: 03/13/2024] [Revised: 04/10/2024] [Accepted: 04/11/2024] [Indexed: 04/25/2024]
Abstract
In specialized plant-pollinator associations, partners may exhibit adaptive traits, which favor the maintenance of the interaction. The association between Calibrachoa elegans (Solanaceae) and its oligolectic bee pollinator, Hexantheda missionica (Colletidae), is mutualistic and forms a narrowly specialized pollination system. Flowers of C. elegans are pollinated exclusively by this bee species, and the bees restrict their pollen resources to this plant species. The pollen presentation schedules of C. elegans were evaluated at the population level to test the hypothesis that H. missionica females adjust their foraging behavior to the resource offering regime of C. elegans plants. For this, the number of new flowers and anthers opened per hour (as a proxy for pollen offering) was determined, and pollen advertisement was correlated with the frequency of flower visits during the day. Preferences of female bees for flowers of different stages were also investigated, and their efficiency as pollinators was evaluated. Pollen offering by C. elegans was found to be partitioned throughout the day through scattered flower openings. Females of H. missionica indeed adjusted their foraging activity to the most profitable periods of pollen availability. The females preferred new, pollen-rich flowers over old ones and gathered pollen and nectar selectively according to flower age. Such behaviors must optimize female bee foraging efficiency on flowers. Female bees set 93% of fruit after a single visit. These findings guarantee their importance as pollinators and the persistence of the specialized plant-pollinator association.
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Affiliation(s)
- Ana Luísa Cordeiro Vieira
- Programa de Pós-Graduação em Biologia Vegetal-Departamento de Botânica, Grupo Plebeia-Ecologia de Abelhas e da Polinização, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Letícia Cândida Pataca
- Programa de Pós-Graduação em Biologia Vegetal-Departamento de Botânica, Grupo Plebeia-Ecologia de Abelhas e da Polinização, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Reisla Oliveira
- Departamento de Genética, Ecologia e Evolução, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Clemens Schlindwein
- Departamento de Botânica, Grupo Plebeia-Ecologia de Abelhas e da Polinização, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
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4
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Vallejo-Marin M, Russell AL. Harvesting pollen with vibrations: towards an integrative understanding of the proximate and ultimate reasons for buzz pollination. ANNALS OF BOTANY 2024; 133:379-398. [PMID: 38071461 PMCID: PMC11006549 DOI: 10.1093/aob/mcad189] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 12/08/2023] [Indexed: 04/12/2024]
Abstract
Buzz pollination, a type of interaction in which bees use vibrations to extract pollen from certain kinds of flowers, captures a close relationship between thousands of bee and plant species. In the last 120 years, studies of buzz pollination have contributed to our understanding of the natural history of buzz pollination, and basic properties of the vibrations produced by bees and applied to flowers in model systems. Yet, much remains to be done to establish its adaptive significance and the ecological and evolutionary dynamics of buzz pollination across diverse plant and bee systems. Here, we review for bees and plants the proximate (mechanism and ontogeny) and ultimate (adaptive significance and evolution) explanations for buzz pollination, focusing especially on integrating across these levels to synthesize and identify prominent gaps in our knowledge. Throughout, we highlight new technical and modelling approaches and the importance of considering morphology, biomechanics and behaviour in shaping our understanding of the adaptive significance of buzz pollination. We end by discussing the ecological context of buzz pollination and how a multilevel perspective can contribute to explain the proximate and evolutionary reasons for this ancient bee-plant interaction.
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Affiliation(s)
- Mario Vallejo-Marin
- Department of Ecology and Genetics, Uppsala University, Uppsala, 752 36, Sweden
| | - Avery L Russell
- Department of Biology, Missouri State University, Springfield, MO, 65897, USA
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5
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Johnson SD, Harder LD. The economy of pollen dispersal in flowering plants. Proc Biol Sci 2023; 290:20231148. [PMID: 37788703 PMCID: PMC10547555 DOI: 10.1098/rspb.2023.1148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 09/06/2023] [Indexed: 10/05/2023] Open
Abstract
Mating success of flowering plants depends strongly on the efficiencies of pollen removal from flowers and its subsequent dispersal to conspecific stigmas. We characterized the economy of pollen dispersal in flowering plants by analysing pollen fates and their correlates for 228 species. The mean percentage of pollen removed from flowers (removal efficiency) varied almost twofold according to the type of pollen-dispersal unit, from less than 45% for orchids and milkweeds with solid pollinia, to greater than 80% for species with granular monads or sectile (segmented) pollinia. The mean percentage of removed pollen reaching stigmas (pollen transfer efficiency, PTE) varied from 2.4% for species with separate monads to 27.0% for orchids with solid pollinia. These values tended to be higher in plants with single pollinator species and in those with non-grooming pollinators. Nectar production increased removal efficiency, but did not influence PTE. Among types of pollen-dispersal units, the net percentage of produced pollen that was dispersed to stigmas varied negatively with removal efficiency and positively with PTE, indicating the relative importance of the latter for overall pollen economy. These findings confirm the key importance of floral traits, particularly pollen packaging, for pollen dispersal outcomes and highlight the under-appreciated pollination efficiency of non-grooming pollinators.
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Affiliation(s)
- Steven D. Johnson
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa
| | - Lawrence D. Harder
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4
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6
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Li DF, Chen YD, Liu Z, Liang AT, Tang J, Yan XC. Staminal hairs increase pollinator attraction and pollination accuracy in Tradescantia fluminensis (Commelinaceae). AOB PLANTS 2023; 15:plad067. [PMID: 37899981 PMCID: PMC10601385 DOI: 10.1093/aobpla/plad067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 09/29/2023] [Indexed: 10/31/2023]
Abstract
Staminal hairs are the particular appendages of stamens, which may affect pollinator foraging behaviour and pollen transfer. However, experimental evidence of the functions of staminal hairs in pollination remains scarce. Here, we conducted staminal hair manipulation experiments in Tradescantia fluminensis (Commelinaceae) to investigate their effects on visitation and pollen transfer by bees. Our observations revealed that both visitation rates and visit duration of honeybees (Apis cerana) to control flowers were significantly higher than that of hairless flowers. Moreover, removing the staminal hairs significantly decreased pollen deposition by honeybees (A. cerana), but did not affect pollen removal. The staminal hair was similar in length to the stamen and the pistil of T. fluminensis. The staminal hairs provide more footholds for honeybees, and they lay prone on the staminal hairs to collect pollen, which increased the accuracy of pollination through the consistent pollen placement and pick-up on the ventral surface of honeybees. These results showed that the staminal hairs in T. fluminensis may represent an adaptation to attract pollinators and enhance pollination accuracy.
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Affiliation(s)
- Deng-Fei Li
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637002, China
| | - Yi-Dan Chen
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637002, China
| | - Zhen Liu
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637002, China
| | - Ai-Ting Liang
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637002, China
| | - Ju Tang
- College of Life Sciences, Anhui Normal University, Wuhu 241000, Anhui, China
| | - Xian-Chun Yan
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637002, China
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Nepal S, Trunschke J, Ren ZX, Burgess KS, Wang H. Community-wide patterns in pollen and ovule production, their ratio (P/O), and other floral traits along an elevation gradient in southwestern China. BMC PLANT BIOLOGY 2023; 23:425. [PMID: 37710175 PMCID: PMC10500814 DOI: 10.1186/s12870-023-04433-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 08/31/2023] [Indexed: 09/16/2023]
Abstract
BACKGROUND As the male and female gametophytes of flowering plants, pollen and ovules largely determine the upper and lower boundaries of plant reproductive success. It is commonly predicted that pollen and ovule number per flower should increase, and pollen-ovule ratio (P/O) per flower should decrease with increasing elevation in response to a more stochastic pollination environment. Here, we aimed to determine the response of pollen number, ovule number, and P/O to other floral traits and elevation gradients for 84 insect-pollinated herbaceous flowering plant species in five sub-alpine and alpine communities (2709 to 3896 m a.s.l.) on Yulong Snow Mountain, southwestern China. RESULTS Six floral traits, including P/O, floral display area, flower number, tube depth, flower shape, and pollen presentation, were highly correlated with pollen and ovule number per flower. With increasing elevation, pollen number and P/O per flower increased marginally and significantly, respectively; ovule number per individual, flower number per individual, stigma stamen separation, and inflorescence height decreased significantly. However, ovule number per flower and other floral traits (i.e., floral display area, tube depth, stigma height, stamen height, and pollen and P/O per individual) did not change with elevation. We detected significant phylogenetic signals for pollen number, ovule number, and P/O, suggesting that these traits may be highly conserved and with limited response to changing environmental conditions. CONCLUSIONS Results revealed patterns of plant reproductive character evolution along elevation gradients and the potential factors governing their spatial variation in high-elevation environments. Plant species at high elevations are more likely adapted to cross-pollination, indicated by increased P/O per flower at high elevations on Yulong Mountain. Combined effects of phylogenetic history and plant-pollinator interactions should determine plant trait evolution.
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Affiliation(s)
- Shristhi Nepal
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Judith Trunschke
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- Nature Conservation and Landscape Ecology, Faculty of Environment and Natural Resources, University of Freiburg, Freiburg, Germany
| | - Zong-Xin Ren
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Kevin S Burgess
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.
- Department of Biology, College of Letters and Sciences, Columbus State University, University System of Georgia, Columbus, GA, 31907-5645, USA.
| | - Hong Wang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.
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8
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Štenc J, Janošík L, Matoušková E, Hadrava J, Mikát M, Janovský Z. Pollinator visitation closely tracks diurnal patterns in pollen release. AMERICAN JOURNAL OF BOTANY 2023:e16179. [PMID: 37200483 DOI: 10.1002/ajb2.16179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 05/20/2023]
Abstract
PREMISE Animal-pollinated plants face a high risk of pollen loss during its transfer. To limit the negative effect of pollen losses by pollen consumption and heterospecific transfer, plant species may adjust and stratify their pollen availability during the day (i.e., "schedule" their pollen presentation) and attract pollinators in specific time frames. METHODS We investigated diurnal patterns of pollen availability and pollinator visitation in three coflowering plant species: Succisa pratensis with open flowers and accessible pollen, pollinated mainly by pollen-feeding hoverflies; Centaurea jacea with open flowers and less accessible pollen, pollinated mainly by pollen-collecting bees; and Trifolium hybridum with closed flowers and pollen accessible only after the active opening of the flower, pollinated exclusively by bees. RESULTS The three plant species differed in the peak pollen availability, tracked by the visitation activity of their pollinators. Succisa pratensis released all pollen in the morning, while pollinator activity was still low and peaked with a slight delay. In contrast, C. jacea and T. hybridum had distinct pollen presentation schedules, peaking in the early afternoon. The pollinator visitation to both of these species closely matched their pollen availability. CONCLUSIONS Stratifying pollen availability to pollinators during the day may be one of several mechanisms that allow coflowering plants to share their pollinators and decrease the probability of heterospecific pollen transfer.
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Affiliation(s)
- Jakub Štenc
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 41, Prague, Czech Republic
| | - Lukáš Janošík
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 41, Prague, Czech Republic
| | - Eva Matoušková
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, CZ-128 41, Prague, Czech Republic
| | - Jiří Hadrava
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, CZ-128 41, Prague, Czech Republic
| | - Michael Mikát
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, CZ-128 41, Prague, Czech Republic
- Department of Biology, Faculty of Science, York University, 4700 Keele Street, 203D, M3J 1P3, Toronto, Canada
- Department of General Zoology, Faculty of Natural Sciences 1-Biosciences, Martin Luther University, Hoher Weg 8, 06100 Halle (Saale), Germany
| | - Zdeněk Janovský
- Svatý Jan t. Krsovice 1, 285 04 Uhlířské Janovice, Czech Republic
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9
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Heiling JM, Irwin RE, Morris WF. Conflicting constraints on male mating success shape reward size in pollen-rewarding plants. AMERICAN JOURNAL OF BOTANY 2023:e16158. [PMID: 37040609 DOI: 10.1002/ajb2.16158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/08/2023] [Accepted: 01/09/2023] [Indexed: 06/19/2023]
Abstract
PREMISE Pollen-rewarding plants face two conflicting constraints: They must prevent consumptive emasculation while remaining attractive to pollen-collecting visitors. Small pollen packages (the quantity of pollen available in a single visit) may discourage visitors from grooming (reducing consumptive loss) but may also decrease a plant's attractiveness to pollen-collecting visitors. What package size best balances these two constraints? METHODS We modeled the joint effects of pollinators' grooming behaviors and package size preferences on the optimal package size (i.e., the size that maximizes pollen donation). We then used this model to examine Darwin's conjecture that selection should favor increased pollen production in pollen-rewarding plants. RESULTS When package size preferences are weak, minimizing package size reduces grooming losses and should be favored (as in previous theoretical studies). Stronger preferences select for larger packages despite the associated increase to grooming loss because loss associated with nonremoval of smaller packages is even greater. Total pollen donation increases with production (as Darwin suggested). However, if floral visitation declines or packages size preference increases with overall pollen availability, the fraction of pollen donated may decline as per-plant pollen production increases. Hence, increasing production may result in diminishing returns. CONCLUSIONS Pollen-rewarding plants can balance conflicting constraints on pollen donation by producing intermediate-sized pollen packages. Strictly pollen-rewarding plants may have responded to past selection to produce more pollen in total, but diminishing returns may limit the strength of that selection.
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Affiliation(s)
- Jacob M Heiling
- Department of Applied Ecology, North Carolina State University, Raleigh, NC, USA
- Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, SC, USA
| | - Rebecca E Irwin
- Department of Applied Ecology, North Carolina State University, Raleigh, NC, USA
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10
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Hold tight or loosen up? Functional consequences of a shift in anther architecture depend substantially on bee body size. Oecologia 2022; 200:119-131. [DOI: 10.1007/s00442-022-05246-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 08/13/2022] [Indexed: 10/15/2022]
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11
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Chen S, Wang Y, Li Y, Zhang X, Wu J. Effects of honeybee ( Apis cerana) visiting behaviour on toxic plant ( Tripterygium hypoglaucum) reproduction. AOB PLANTS 2022; 14:plac002. [PMID: 35531307 PMCID: PMC9071085 DOI: 10.1093/aobpla/plac002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 04/12/2022] [Indexed: 06/14/2023]
Abstract
Honeybees play a significant role in the plant-pollinator interactions of many flowering plants. The ecological and evolutionary consequences of plant-pollinator interactions vary by geographic region, and the effects of honeybees on the reproduction of toxic plants have not been well studied. We measured the florescence of toxic plants, the flower-visiting behaviour of honeybees and the effects of pollination on the fertility, weight and moisture content of seeds. The effects of climatic factors on the number of flowers, and the spatial and temporal variation in pollinator visits were evaluated, and the effects of pollinator visits on seed quality were evaluated. Flower visitors were diverse, climatic factors had a great impact on spatio-temporal flowering variation and the number of bee visits was strongly correlated with the spatio-temporal variation in the number of flowers. Honeybees strongly increase the fullness and weight of seeds. Our study demonstrated a good ecological fit between the spatio-temporal variation in the flowering of toxic plants and the general validity of honeybee pollination syndrome in the south of Hengduan Mountains in East Asia. A linear relationship between honeybee visitation and plant reproduction can benefit the stabilization of plant reproduction.
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Affiliation(s)
- Shunan Chen
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences; Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture and Rural Affairs; Key Laboratory of Bee Products for Quality and Safety Control, Ministry of Agriculture and Rural Affairs; Bee Product Quality Supervision and Testing Center, Ministry of Agriculture and Rural Affairs; Beijing 100093, People’s Republic of China
| | - Yunfei Wang
- Committee of Communist Youth League, Yunnan Agricultural University, Kunming 650201, People’s Republic of China
| | - Yi Li
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100093, People’s Republic of China
| | - Xuewen Zhang
- Yunnan Academy of Agricultural Sciences, Kunming 661101, People’s Republic of China
| | - Jie Wu
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences; Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture and Rural Affairs; Key Laboratory of Bee Products for Quality and Safety Control, Ministry of Agriculture and Rural Affairs; Bee Product Quality Supervision and Testing Center, Ministry of Agriculture and Rural Affairs; Beijing 100093, People’s Republic of China
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12
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Jankauski M, Ferguson R, Russell A, Buchmann S. Structural dynamics of real and modelled Solanum stamens: implications for pollen ejection by buzzing bees. J R Soc Interface 2022; 19:20220040. [PMID: 35259960 PMCID: PMC8905162 DOI: 10.1098/rsif.2022.0040] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
An estimated 10% of flowering plant species conceal their pollen within tube-like anthers that dehisce through small apical pores (poricidal anthers). Bees extract pollen from poricidal anthers through a complex motor routine called floral buzzing, whereby the bee applies vibratory forces to the flower stamen by rapidly contracting its flight muscles. The resulting deformation depends on the stamen's natural frequencies and vibration mode shapes, yet for most poricidal species, these properties have not been sufficiently characterized. We performed experimental modal analysis on Solanum elaeagnifolium stamens to quantify their natural frequencies and vibration modes. Based on morphometric and dynamic measurements, we developed a finite-element model of the stamen to identify how variable material properties, geometry and bee weight could affect its dynamics. In general, stamen natural frequencies fell outside the reported floral buzzing range, and variations in stamen geometry and material properties were unlikely to bring natural frequencies within this range. However, inclusion of bee mass reduced natural frequencies to within the floral buzzing frequency range and gave rise to an axial-bending vibration mode. We hypothesize that floral buzzing bees exploit the large vibration amplification factor of this mode to increase anther deformation, which may facilitate pollen ejection.
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Affiliation(s)
- Mark Jankauski
- Department of Mechanical and Industrial Engineering, Montana State University, Bozeman, MT, USA
| | - Riggs Ferguson
- Department of Mechanical and Industrial Engineering, Montana State University, Bozeman, MT, USA
| | - Avery Russell
- Department of Biology, Missouri State University, Springfield, MO, USA
| | - Stephen Buchmann
- Department of Ecology and Evolutionary Biology,, University of Arizona, Tucson, AZ, USA.,Department of Entomology, University of Arizona, Tucson, AZ, USA
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13
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Xu K, Servedio MR. The evolution of flower longevity in unpredictable pollination environments. J Evol Biol 2021; 34:1781-1792. [PMID: 34536252 DOI: 10.1111/jeb.13936] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 08/31/2021] [Accepted: 09/13/2021] [Indexed: 11/29/2022]
Abstract
Pollination requires a flower to remain open for long enough to allow for the arrival of pollinators. However, maintaining flowers costs energy and resources. Therefore, flower longevity, the length of time a flower remains viable, is critical for the outcome of plant reproduction. Although previous studies showed that the evolution of flower longevity depends on the rates of pollen deposition and removal, whether plants should increase or decrease flower life span when the pollination environment is unpredictable has not been explored. Moreover, the common hypothesis that an unpredictable pollination environment should select for increased flower longevity may be too simplistic since there is no distinction drawn between the effects of spatial and temporal variation. Adopting evolutionary game theory, we investigate the evolution of flower longevity under three types of variation: spatial heterogeneity, daily fluctuations within a flowering season and yearly fluctuations between flowering seasons. We find that spatial heterogeneity often selects for a shorter flower lifespan, while temporal fluctuations of fitness accrual rates at both daily and yearly time scales tends to favour greater longevity, although daily and yearly fluctuations have somewhat different effects. However, the presence of correlation between female and male fitness accrual rates seems to have no effect on flower longevity. Our work suggests that explicit measurements of spatial and temporal variation in both female and male functions may provide a better understanding of the evolution of flower longevity and reproduction.
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Affiliation(s)
- Kuangyi Xu
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Maria R Servedio
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, USA
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Xu K. The coevolution of flower longevity and self-fertilization in hermaphroditic plants. Evolution 2021; 75:2114-2123. [PMID: 34192348 DOI: 10.1111/evo.14303] [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: 12/09/2020] [Revised: 05/06/2021] [Accepted: 05/25/2021] [Indexed: 11/26/2022]
Abstract
Self-fertilization, prevalent in plants, is typically divided into three modes - prior, competing, and delayed selfing - based on the timing in which it occurs. Flower longevity affects both the opportunity for pollination and the resources allocated for fertility, and thus may influence the selection on different modes of self-fertilization. Additionally, selfing causes fertilization to depend less on pollinators, which may also influence the evolution of flower longevity. Using game-theoretical models, I investigate how inbreeding depression and the pollination environment influences the coevolution of the three modes of self-fertilization with flower longevity. Invasion of prior selfing allows the subsequent evolution of shorter flower longevity, and thus is favored over competing selfing. Prior selfing can also invade even under high inbreeding depression when the pollen deposition rate is low, but is inhibited by a higher level of delayed selfing. In general, the evolution of selfing decreases flower longevity, and reveals asymmetric effects of pollen deposition and removal on flower longevity. This study suggests considering realization of selfing and outcrossing as concrete processes by incorporating flower reproductive strategies (e.g., flower longevity) and pollination ecology (e.g., accrual rate) may offer better understanding of the evolution of mating systems and flower reproductive traits.
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Affiliation(s)
- Kuangyi Xu
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, USA
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15
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Dellinger AS, Pérez-Barrales R, Michelangeli FA, Penneys DS, Fernández-Fernández DM, Schönenberger J. Low bee visitation rates explain pollinator shifts to vertebrates in tropical mountains. THE NEW PHYTOLOGIST 2021; 231:864-877. [PMID: 33864287 DOI: 10.1111/nph.17390] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 03/26/2021] [Indexed: 06/12/2023]
Abstract
Evolutionary shifts from bee to vertebrate pollination are common in tropical mountains. Reduction in bee pollination efficiency under adverse montane weather conditions was proposed to drive these shifts. Although pollinator shifts are central to the evolution and diversification of angiosperms, we lack experimental evidence of the ecological processes underlying such shifts. Here, we combine phylogenetic and distributional data for 138 species of the Neotropical plant tribe Merianieae (Melastomataceae) with pollinator observations of 11 and field pollination experiments of six species to test whether the mountain environment may indeed drive such shifts. We demonstrate that shifts from bee to vertebrate pollination coincided with occurrence at high elevations. We show that vertebrates were highly efficient pollinators even under the harsh environmental conditions of tropical mountains, whereas bee pollination efficiency was lowered significantly through reductions in flower visitation rates. Furthermore, we show that pollinator shifts in Merianieae coincided with the final phases of the Andean uplift and were contingent on adaptive floral trait changes to alternative rewards and mechanisms facilitating pollen dispersal. Our results provide evidence that abiotic environmental conditions (i.e. mountain climate) may indeed reduce the efficiency of a plant clade's ancestral pollinator group and correlate with shifts to more efficient new pollinators.
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Affiliation(s)
- Agnes S Dellinger
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, Vienna, 1030, Austria
| | - Rocio Pérez-Barrales
- School of Biological Sciences, University of Portsmouth, King Henry 1st Street, Portsmouth, PO1 2DY, UK
| | - Fabián A Michelangeli
- Institute of Systematic Botany, The New York Botanical Garden, 2900 Southern Blvd, Bronx, NY, 10458-5125, USA
| | - Darin S Penneys
- Biology & Marine Biology, University of North Carolina Wilmington, 601 South College Road, Wilmington, NC, 28403-5915, USA
| | | | - Jürg Schönenberger
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, Vienna, 1030, Austria
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16
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Kemp JE, Vallejo-Marín M. Pollen dispensing schedules in buzz-pollinated plants: experimental comparison of species with contrasting floral morphologies. AMERICAN JOURNAL OF BOTANY 2021; 108:993-1005. [PMID: 34196392 DOI: 10.1002/ajb2.1680] [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: 08/06/2020] [Accepted: 01/12/2021] [Indexed: 06/13/2023]
Abstract
PREMISE Plants can mitigate the fitness costs associated with pollen consumption by floral visitors by optimizing pollen release rates. In buzz-pollinated plants, bees apply vibrations to remove pollen from anthers with small pores. These poricidal anthers potentially function as mechanism staggering pollen release, but this has rarely been tested across plant species differing in anther morphology. METHODS In Solanum Section Androceras, three pairs of buzz-pollinated species have undergone independent evolutionary shifts between large- and small-flowers, which are accompanied by replicate changes in anther morphology. We used these shifts in anther morphology to characterize the association between anther morphology and pollen dispensing schedules. We applied simulated bee-like vibrations to anthers to elicit pollen release, and compared pollen dispensing schedules across anther morphologies. We also investigated how vibration velocity affects pollen release. RESULTS Replicate transitions in Solanum anther morphology are associated with consistent changes in pollen dispensing schedules. We found that small-flowered taxa release their pollen at higher rates than their large-flowered counterparts. Higher vibration velocities resulted in quicker pollen dispensing and more total pollen released. Finally, both the pollen dispensing rate and the amount of pollen released in the first vibration were negatively related to anther wall area, but we did not observe any association between pore size and pollen dispensing. CONCLUSIONS Our results provide the first empirical demonstration that the pollen dispensing properties of poricidal anthers depend on both floral characteristics and bee vibration properties. Morphological modification of anthers could thus provide a mechanism to exploit different pollination environments.
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Affiliation(s)
- Jurene E Kemp
- Department of Biological and Environmental Sciences, University of Stirling, Stirling, Scotland, United Kingdom, FK9 4LA
| | - Mario Vallejo-Marín
- Department of Biological and Environmental Sciences, University of Stirling, Stirling, Scotland, United Kingdom, FK9 4LA
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17
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Dellinger AS, Artuso S, Fernández-Fernández DM, Schönenberger J. Stamen dimorphism in bird-pollinated flowers: Investigating alternative hypotheses on the evolution of heteranthery. Evolution 2021; 75:2589-2599. [PMID: 33963764 DOI: 10.1111/evo.14260] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 04/19/2021] [Accepted: 04/27/2021] [Indexed: 01/09/2023]
Abstract
Heteranthery, the presence of distinct stamen types within a flower, is commonly explained as functional adaptation to alleviate the "pollen dilemma," defined as the dual and conflicting function of pollen as pollinator food resource and male reproductive agent. A single primary hypothesis, "division of labor," has been central in studies on heteranthery. This hypothesis postulates that one stamen type functions in rewarding pollen-collecting pollinators and the other in reproduction, thereby minimizing pollen loss. Only recently, alternative functions (i.e., staggered pollen release), were proposed, but comparative and experimental investigations are lagging behind. Here, we used 63 species of the tribe Merianieae (Melastomataceae) to demonstrate that, against theory, heteranthery occurs in flowers offering rewards other than pollen, such as staminal food bodies or nectar. Although shifts in reward type released species from the "pollen dilemma," heteranthery has evolved repeatedly de novo in food-body-rewarding, passerine-pollinated flowers. We used field investigations to show that foraging passerines discriminated between stamen types and removed large stamens more quickly than small stamens. Passerines removed small stamens on separate visits towards the end of flower anthesis. We propose that the staggered increase in nutritive content of small stamens functions to increase chances for outcross-pollen transfer.
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Affiliation(s)
| | - Silvia Artuso
- Department of Biosciences, University of Salzburg, Salzburg, Austria
| | | | - Jürg Schönenberger
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
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18
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Optimal pollen stickiness to pollinators for maximizing paternal fitness: Increased number of recipient flowers or increased pollen deposition on recipient flowers? J Theor Biol 2021; 524:110731. [PMID: 33915145 DOI: 10.1016/j.jtbi.2021.110731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 03/31/2021] [Accepted: 04/16/2021] [Indexed: 11/22/2022]
Abstract
A plant can sire more seeds by increasing the number of pollen recipient flowers or the amount of pollen deposited on recipient flowers. We theoretically analyzed how pollen stickiness contributes to paternal fitness through changing the pattern of pollen dispersal including both the number of recipient flowers and overall pollen deposition (the overall amount of pollen deposited on recipient flowers) in animal-pollinated plants. We developed a numerical model in which pollen stickiness to pollinators increases with production of expensive materials on pollen surfaces, and a high level of stickiness diminishes the proportions of pollen lost from a pollinator body during a flight and pollen deposited on a stigma during a visit. We found that the number of recipient flowers monotonically increased with increasing pollen stickiness allocation while overall pollen deposition was maximized at a certain amount of stickiness allocation. We demonstrated that evolutionarily stable pollen stickiness attained many recipient flowers at the expense of overall pollen deposition in most cases while it merely favored maximization of overall pollen deposition in all other cases. Sticky pollen evolved if pollinators were highly likely to drop pollen during flights and did not diffuse well. In this situation, the evolutionarily stable pattern of pollen dispersal was acquisition of many pollen recipient flowers rather than maximization of overall pollen deposition. Sticky pollen also evolved if additional sticking elements were moderately effective in increasing the force of adhesion to pollinators. Pollen stickiness has a significant effect on the pattern of pollen dispersal via the extent of pollen carryover, and our results suggest that plants maximize paternal fitness by giving pollen the optimal stickiness, which varies with pollinating partners.
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19
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Shortlidge EE, Carey SB, Payton AC, McDaniel SF, Rosenstiel TN, Eppley SM. Microarthropod contributions to fitness variation in the common moss Ceratodon purpureus. Proc Biol Sci 2021; 288:20210119. [PMID: 33784868 PMCID: PMC8059975 DOI: 10.1098/rspb.2021.0119] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The evolution of sustained plant–animal interactions depends critically upon genetic variation in the fitness benefits from the interaction. Genetic analyses of such interactions are limited to a few model systems, in part because genetic variation may be absent or the interacting species may be experimentally intractable. Here, we examine the role of sperm-dispersing microarthropods in shaping reproduction and genetic variation in mosses. We established experimental mesocosms with known moss genotypes and inferred the parents of progeny from mesocosms with and without microarthropods, using a pooled sequencing approach. Moss reproductive rates increased fivefold in the presence of microarthropods, relative to control mesocosms. Furthermore, the presence of microarthropods increased the total number of reproducing moss genotypes, and changed the rank-order of fitness of male and female moss genotypes. Interestingly, the genotypes that reproduced most frequently did not produce sporophytes with the most spores, highlighting the challenge of defining fitness in mosses. These results demonstrate that microarthropods provide a fitness benefit for mosses, and highlight the potential for biotic dispersal agents to alter fitness among moss genotypes.
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Affiliation(s)
- Erin E Shortlidge
- Department of Biology, Portland State University, PO Box 751, Portland, OR 97202-0751, USA
| | - Sarah B Carey
- Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611-8525, USA
| | - Adam C Payton
- Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611-8525, USA
| | - Stuart F McDaniel
- Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611-8525, USA
| | - Todd N Rosenstiel
- Department of Biology, Portland State University, PO Box 751, Portland, OR 97202-0751, USA
| | - Sarah M Eppley
- Department of Biology, Portland State University, PO Box 751, Portland, OR 97202-0751, USA
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20
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Telles FJ, Klunk CL, Maia FRD, de Brito VLG, Varassin IG. Towards a new understanding of the division of labour in heterantherous flowers: the case of Pterolepis glomerata (Melastomataceae). Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa107] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Abstract
Pollen-flowers with heteromorphic stamens have been shown to promote an intrafloral division of labour as a solution to fitness costs arising from pollen consumption by bees, known as the pollen dilemma. Usually, the division is based on morphological differences in anther and pollen traits that correlate with stamen function: pollinating anthers are larger and contain more and higher-quality pollen grains than feeding anthers. Here, we present a new strategy based on a high investment in reward production and thus attraction, in the heterantherous Pterolepis glomerata, to overcome short flower longevity and maintain reproductive success. In P. glomerata small feeding anthers not only produced more pollen grains and more grains with cytoplasmic content, but also released more pollen than pollinating anthers after a single visit. This pattern was consistent until the end of floral anthesis, showing the existence of pollen-dosing mechanisms. Bees equally visited flowers with yellow feeding anthers and pollinating anthers with yellow connective appendages, indicating a visual similarity, as predicted by bee vision modelling. Our results demonstrate that the division of labour might have different outcomes. Instead of the classical expectation of more investment in reproductive pollen in pollinating stamens, P. glomerata invested more in attraction and reward in feeding stamens.
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Affiliation(s)
- Francismeire Jane Telles
- Programa de Pós-Graduação em Ecologia e Conservação de Recursos Naturais, Universidade Federal de Uberlândia, Campus Umuarama, Sala, Uberlândia, MG, Brazil
- Programa de Pós-Graduação em Ecologia e Conservação, Centro Politécnico, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
| | - Cristian Luan Klunk
- Programa de Pós-Graduação em Ecologia e Conservação, Centro Politécnico, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
| | - Fabiano Rodrigo da Maia
- Programa de Pós-Graduação em Botânica, Centro Politécnico, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
| | | | - Isabela Galarda Varassin
- Departamento de Botânica, Centro Politécnico, Universidade Federal do Paraná, Curitiba, PR, Brazil
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21
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Siriani-Oliveira S, Cerceau I, Schlindwein C. Specialised protagonists in a plant-pollinator interaction: the pollination of Blumenbachia insignis (Loasaceae). PLANT BIOLOGY (STUTTGART, GERMANY) 2020; 22:167-176. [PMID: 31710763 DOI: 10.1111/plb.13072] [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: 08/06/2019] [Accepted: 10/27/2019] [Indexed: 06/10/2023]
Abstract
Analyses of resource presentation, floral morphology and pollinator behaviour are essential for understanding specialised plant-pollinator systems. We investigated whether foraging by individual bee pollinators fits the floral morphology and functioning of Blumenbachia insignis, whose flowers are characterised by a nectar scale-staminode complex and pollen release by thigmonastic stamen movements. We described pollen and nectar presentation, analysed the breeding system and the foraging strategy of bee pollinators. We determined the nectar production pattern and documented variations in the longevity of floral phases and stigmatic pollen loads of pollinator-visited and unvisited flowers. Bicolletes indigoticus (Colletidae) was the sole pollinator with females revisiting flowers in staminate and pistillate phases at short intervals, guaranteeing cross-pollen flow. Nectar stored in the nectar scale-staminode complex had a high sugar concentration and was produced continuously in minute amounts (~0.09 μl·h-1 ). Pushing the scales outward, bees took up nectar, triggering stamen movements and accelerating pollen presentation. Experimental simulation of this nectar uptake increased the number of moved stamens per hour by a factor of four. Flowers visited by pollinators received six-fold more pollen on the stigma than unvisited flowers, had shortened staminate and pistillate phases and increased fruit and seed set. Flower handling and foraging by Bicolletes indigoticus were consonant with the complex flower morphology and functioning of Blumenbachia insignis. Continuous nectar production in minute quantities but at high sugar concentration influences the pollen foraging of the bees. Partitioning of resources lead to absolute flower fidelity and stereotyped foraging behaviour by the sole effective oligolectic bee pollinator.
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Affiliation(s)
- S Siriani-Oliveira
- Programa de Pós-Graduação em Biologia Vegetal, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - I Cerceau
- Programa de Pós-Graduação em Biologia Vegetal, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - C Schlindwein
- Departamento de Botânica, Plebeia - Ecologia de Abelhas e da Polinização, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
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22
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Zhang H, Zhou Z, An J. Pollen Release Dynamics and Daily Patterns of Pollen-Collecting Activity of Honeybee Apis mellifera and Bumblebee Bombus lantschouensis in Solar Greenhouse. INSECTS 2019; 10:insects10070216. [PMID: 31336589 PMCID: PMC6681390 DOI: 10.3390/insects10070216] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/13/2019] [Accepted: 07/17/2019] [Indexed: 11/16/2022]
Abstract
Pollen is important not only for pollination and fertilization of plants, but also for colony development of bee pollinators. Anther dehiscence determines the available pollen that can be collected by foragers. In China, honeybees and bumblebees are widely used as pollinators in solar greenhouse agriculture. To better understand the effect of solar greenhouse microclimates on pollen release and pollen-foraging behaviour, we observed the anther dehiscence dynamics and daily pollen-collecting activity of Apis mellifera and Bombus lantschouensis during peach anthesis in a solar greenhouse in Beijing. Microclimate factors had a significant effect on anther dehiscence and bee foraging behaviour. The proportion of dehisced anthers increased with increasing temperature and decreasing relative humidity and peaked from 11:00 h to 14:00 h, coinciding with the peak pollen-collecting activity of bees. On sunny days, most pollen grains were collected by the two pollinators within two hours after anther dehiscence, at which time the viability of pollen had not yet significantly decreased. Our study helps us to better understand the relationship between food resources and pollinator foraging behaviour and to make better use of bees for pollination in Chinese solar greenhouses.
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Affiliation(s)
- Hong Zhang
- Key Laboratory for Insect-Pollinator Biology of the Ministry of Agriculture and Rural Affairs, Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Zhiyong Zhou
- Key Laboratory for Insect-Pollinator Biology of the Ministry of Agriculture and Rural Affairs, Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093, China
| | - Jiandong An
- Key Laboratory for Insect-Pollinator Biology of the Ministry of Agriculture and Rural Affairs, Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093, China.
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23
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Francis JS, Acevedo CR, Muth F, Leonard AS. Nectar quality changes the ecological costs of chemically defended pollen. Curr Biol 2019; 29:R679-R680. [DOI: 10.1016/j.cub.2019.05.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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24
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Yang S, Chu G, Shi X, Wang S. Elaborated pollen packaging and dispensing mechanism induced by petal architecture from a Papaveraceae species. PeerJ 2019; 7:e7066. [PMID: 31218126 PMCID: PMC6568250 DOI: 10.7717/peerj.7066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 04/30/2019] [Indexed: 11/20/2022] Open
Abstract
Secondary pollen presentation (SPP) is a reproductive strategy that enhances the efficiency of pollen transfer, which has been explored for more than 200 years, resulting in 10 identified types of SPP. The ephemeral plant Hypecoum erectum L. (Papaveraceae) has an elaborate petal structure. The middle lobe is a key functional organ in SPP. To explore the importance of the middle lobe structure, we measured the flowering process, the curling movement and growth of the middle lobe, pollination characteristics, pollination efficiency, and the mating system in H. erectum in the field. The yellow middle lobe structure had an important role in attracting pollinators. The middle lobes on the inner petals function as a redundant cucullate structure and wrapped about 84% of the total pollen grains as soon as the anthers dehisced. These then grew upward and gradually presented pollen to pollinators via the roll out of the middle lobes. One bee species, Colletes vestitus from Colletidae, was the only effective pollinator of H. erectum. The SPP mechanism increased the efficiency of pollen transfer by C. vestitus. The middle lobes, which wrapped pollen and grew upward, contacted the stigma and provided an advantage for self-pollination and outcrossing by growing upward higher than the corolla. Hypecoum erectum L. has a mixed mating system with selfing and outcrossing. Thus, the SPP mechanism plays a key role during the pollination process and is necessary for improving pollination efficiency and promoting reproductive success.
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Affiliation(s)
- Shanlin Yang
- College of Agriculture, Shihezi University, Shihezi, China
| | - Guangming Chu
- College of Agriculture, Shihezi University, Shihezi, China
| | - Xiang Shi
- College of Agriculture, Shihezi University, Shihezi, China
| | - Shaoming Wang
- College of Life Sciences, Shihezi University, Shihezi, China
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25
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Mittelbach M, Kolbaia S, Weigend M, Henning T. Flowers anticipate revisits of pollinators by learning from previously experienced visitation intervals. PLANT SIGNALING & BEHAVIOR 2019; 14:1595320. [PMID: 30912478 PMCID: PMC6546139 DOI: 10.1080/15592324.2019.1595320] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/05/2019] [Accepted: 03/07/2019] [Indexed: 05/30/2023]
Abstract
Plants - and their pollinating counterparts - display complex and sophisticated mechanisms to achieve successful pollination. It probably was only a matter of time for proof of plant intelligence in the context of floral ecology to surface, i.e. the memorization of previous events and a corresponding adjustment of flower behavior. In a recent study we presented a large experimental dataset on the evolution of stamen movement patterns observed in Loasaceae and the apparent role of plant behavior in the diversification of this plant group. The findings at species level suggest that individual plants may be able to adjust the timing of their pollen presentation to the actual pollination scenario they experience. Here we provide first evidence for a pre-emptive stamen presentation in Nasa poissoniana (Loasaceae), based on previously experienced pollinator visitation intervals. Using the unique ability of fast and precise stamen movements in response to a previous stimulus of the nectar scales, the plants should be able to reduce pollen loss and increase outbreeding success via optimizing the timing of male function. We discuss this behavior and its implications in the light of the recent literature and propose questions for future investigations.
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Affiliation(s)
- Moritz Mittelbach
- Ökologie der Pflanzen, Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, Berlin 14195, Germany
| | - Sandro Kolbaia
- Nees Institut für Biodiversität der Pflanzen, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 170, Bonn 53115, Germany
| | - Maximilian Weigend
- Nees Institut für Biodiversität der Pflanzen, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 170, Bonn 53115, Germany
| | - Tilo Henning
- Botanic Garden and Botanical Museum, Freie Universität Berlin, Königin-Luise-Str. 6-8, Berlin 14195, Germany
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26
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D'Antraccoli M, Roma-Marzio F, Benelli G, Canale A, Peruzzi L. Dynamics of secondary pollen presentation in Campanula medium (Campanulaceae). JOURNAL OF PLANT RESEARCH 2019; 132:251-261. [PMID: 30758751 DOI: 10.1007/s10265-019-01090-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 01/14/2019] [Indexed: 06/09/2023]
Abstract
After several decades of research, dynamics and patterns of mating system in floral evolution remain incompletely understood, especially with regards to strategies that combine both outcrossing and selfing, as frequently recorded in the genus Campanula. Data about temporal and spatial dynamics of secondary pollen presentation are still scarce in literature: we investigated them using Campanula medium (Campanulaceae) as case study. Experimental pollinations were conducted under natural conditions, to characterise the breeding system of this species. Effects on stigma opening and stigma receptivity of stylar pollen presence were investigated in manipulated flowers. The temporal dynamics and fitness of male and female functional phases were estimated. Flower visitors and their interactions with sexual parts of the flower were also annotated. C. medium is xenogamous and self-incompatible, with a clear temporal separation between sexual functional phases. Floral lifespan is shortened by experimental outcrossing. Removal of pollen from the style shortened the time span of male function. Pollen viability was highest at the beginning of the anthesis, decreasing during the flowering period, whereas stigmatic receptivity shows an opposite trend. We found a severe pollen limitation in the studied population. Bees were the most frequent floral visitors. In some of these insects we observed stereotyped interactions with the reproductive structures of the flower, in particular with the pollen, exposed along the upper and median portion of the style. Sexual phases in C. medium are inversely correlated and finely spatially and temporally coordinated, since stigma maturation is scalar along its length and depends on pollen presence on the style. Overall, our findings push forward the knowledge on reproductive strategies in Campanula.
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Affiliation(s)
- Marco D'Antraccoli
- Department of Biology, Unit of Botany, University of Pisa, Via Derna 1, 56126, Pisa, Italy.
| | - Francesco Roma-Marzio
- Department of Biology, Unit of Botany, University of Pisa, Via Derna 1, 56126, Pisa, Italy
| | - Giovanni Benelli
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy
| | - Angelo Canale
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy
| | - Lorenzo Peruzzi
- Department of Biology, Unit of Botany, University of Pisa, Via Derna 1, 56126, Pisa, Italy
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27
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Arroyo-Correa B, Beattie C, Vallejo-Marín M. Bee and floral traits affect the characteristics of the vibrations experienced by flowers during buzz pollination. ACTA ACUST UNITED AC 2019; 222:jeb.198176. [PMID: 30760551 DOI: 10.1242/jeb.198176] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 01/17/2019] [Indexed: 01/09/2023]
Abstract
During buzz pollination, bees use their indirect flight muscles to produce vibrations that are transmitted to the flowers and result in pollen release. Although buzz pollination has been known for >100 years, we are still in the early stages of understanding how bee and floral characteristics affect the production and transmission of floral vibrations. Here, we analysed floral vibrations produced by four closely related bumblebee taxa (Bombus spp.) on two buzz-pollinated plants species (Solanum spp.). We measured floral vibrations transmitted to the flower to establish the extent to which the mechanical properties of floral vibrations depend on bee and plant characteristics. By comparing four bee taxa visiting the same plant species, we found that peak acceleration, root mean-squared acceleration (RMS) and frequency vary between bee taxa, but that neither bee size (intertegular distance) nor flower biomass (dry mass) affects peak acceleration, RMS or frequency. A comparison of floral vibrations of two bee taxa visiting flowers of two plant species showed that, while bee species affects peak acceleration, RMS and frequency, plant species only affects acceleration (peak acceleration and RMS), not frequency. When accounting for differences in the transmission of vibrations across the two types of flower, using a species-specific 'coupling factor', we found that RMS acceleration and peak displacement do not differ between plant species. This suggests that bees produce the same initial acceleration in different plants but that transmission of these vibrations through the flower is affected by floral characteristics.
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Affiliation(s)
- Blanca Arroyo-Correa
- Biological and Environmental Sciences, School of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK.,Integrative Ecology Group, Estación Biológica de Doñana (EBD-CSIC), 21760 Sevilla, Spain
| | - Ceit Beattie
- Biological and Environmental Sciences, School of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK
| | - Mario Vallejo-Marín
- Biological and Environmental Sciences, School of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK
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Minnaar C, Anderson B, de Jager ML, Karron JD. Plant-pollinator interactions along the pathway to paternity. ANNALS OF BOTANY 2019; 123:225-245. [PMID: 30535041 PMCID: PMC6344347 DOI: 10.1093/aob/mcy167] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 11/23/2018] [Indexed: 05/09/2023]
Abstract
Background The male fitness pathway, from pollen production to ovule fertilization, is thought to strongly influence reproductive trait evolution in animal-pollinated plants. This pathway is characterized by multiple avenues of pollen loss which may lead to reductions in male fitness. However, empirical data on the mechanistic processes leading to pollen loss during transport are limited, and we therefore lack a comprehensive understanding of how male fitness is influenced by each step in the pollination process. Scope This review assesses the history of studying male function in plants and identifies critical gaps in our understanding of the ecology and evolution of pollen transport. We explore male reproductive function along the steps of the pathway to paternity and discuss evolutionary options to overcome barriers to siring success. In particular, we present a newly emerging idea that bodies of pollinators function as a dynamic arena facilitating intense male-male competition, where pollen of rival males is constantly covered or displaced by competitors. This perspective extends the pollen-competitive arena beyond the confines of the stigma and style, and highlights the opportunity for important new breakthroughs in the study of male reproductive strategies and floral evolution.
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Affiliation(s)
- Corneile Minnaar
- Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa
| | - Bruce Anderson
- Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa
| | - Marinus L de Jager
- Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa
| | - Jeffrey D Karron
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
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Song YP, Huang ZH, Huang SQ. Pollen aggregation by viscin threads in Rhododendron varies with pollinator. THE NEW PHYTOLOGIST 2019; 221:1150-1159. [PMID: 30121952 DOI: 10.1111/nph.15391] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Accepted: 07/13/2018] [Indexed: 06/08/2023]
Abstract
Pollen grains can be dispersed singly or variously aggregated in groups. Whether the evolution of pollen aggregation is driven by the pollinator remains unexplored. We hypothesize that an extensive pollen aggregation is favored under a scarcity of pollinators. Variation in pollen aggregation by viscin threads in 13 Rhododendron species was measured as it is related to pollen removal in a visit. Visitation rates of functional pollinator groups that vary in their grooming behavior were investigated in each species. Pollen deposited on stigmas in the field was also sampled. Seven Rhododendron species were infrequently pollinated by low-intensity grooming animals, including birds, butterflies and moths. The other six species were more frequently pollinated by bees with a high intensity of pollen grooming. Bird- and Lepidoptera-pollinated species produced longer pollen-connecting threads that connected more pollen grains. Phylogenetically independent contrast analysis of the 13 species showed that pollinator visitation frequency was negatively related to amounts of pollen removal per visit but not to stigmatic pollen loads. The finding of interspecific patterns in pollen removal related to pollinator visitation frequency suggests pollinator-mediated selection on pollen packaging strategies, supporting the hypothesis of floral evolution via pollen export.
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Affiliation(s)
- Yun-Peng Song
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Zhi-Huan Huang
- Guangxi Institute of Botany, Guangxi Zhuang Autonomous Region and Chinese Academy of Sciences, Guilin, 541006, China
| | - Shuang-Quan Huang
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
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Henning T, Mittelbach M, Ismail SA, Acuña-Castillo RH, Weigend M. A case of behavioural diversification in male floral function - the evolution of thigmonastic pollen presentation. Sci Rep 2018; 8:14018. [PMID: 30232353 PMCID: PMC6145904 DOI: 10.1038/s41598-018-32384-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 09/05/2018] [Indexed: 11/09/2022] Open
Abstract
Obvious movements of plant organs have fascinated scientists for a long time. They have been studied extensively, but few behavioural studies to date have dealt with them, and hardly anything is known about their evolution. Here, we present a large experimental dataset on the stamen movement patterns found in the Loasaceae subfam. Loasoideae (Cornales). An evolutionary transition from autonomous-only to a combination of autonomous and thigmonastic stamen movement with increased complexity was experimentally demonstrated. We compare the stamen movement patterns with extensive pollinator observations and discuss it in the context of male mating behavior. Thigmonastic pollen presentation via stamen movements appears to be a crucial component of floral adaptation to pollinator behaviour, evolving in concert with complex adjustments of flower signal, reward and morphology. We hypothesize that rapid adjustments of pollen presentation timing may play a significant role in the diversification of this plant group, representing a striking example for the evolutionary significance of plant behaviour.
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Affiliation(s)
- Tilo Henning
- Botanic Garden and Botanical Museum Berlin-Dahlem, Freie Universität Berlin, Königin-Luise-Str. 6-8, 14195, Berlin, Germany.
| | - Moritz Mittelbach
- Institute of Biologie, Freie Universität Berlin, Altensteinstr. 6, 14195, Berlin, Germany
| | - Sascha A Ismail
- School of Biological Sciences, University of Aberdeen, 23 St. Machar Drive, Aberdeen, AB24 3UU, Scotland
| | - Rafael H Acuña-Castillo
- Nees Institut für Biodiversität der Pflanzen, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 170, 53115, Bonn, Germany.,Universidad de Costa Rica, Escuela de Biología, Apdo, Postal: 11501-2060, San Pedro de Montes de Oca, Costa Rica
| | - Maximilian Weigend
- Nees Institut für Biodiversität der Pflanzen, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 170, 53115, Bonn, Germany
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31
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Siriani-Oliveira S, Oliveira R, Schlindwein C. Pollination of Blumenbachia amana (Loasaceae): flower morphology and partitioned pollen presentation guarantee a private reward to a specialist pollinator. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly061] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Samuel Siriani-Oliveira
- Programa de Pós-Graduação em Biologia Vegetal, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Reisla Oliveira
- Departamento de Biologia Geral, Universidade Federal de Minas Gerais, Av. Antônio Carlos, Pampulha, Belo Horizonte, MG, Brazil
| | - Clemens Schlindwein
- Instituto de Ciências Biológicas, Departamento de Botânica, Universidade Federal de Minas Gerais, Av. Antônio Carlos, Pampulha, Belo Horizonte, Minas Gerais, Brazil
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Correlation between the timing of autonomous selfing and floral traits: a comparative study from three selfing Gentianopsis species (Gentianaceae). Sci Rep 2018; 8:3634. [PMID: 29483537 PMCID: PMC5827715 DOI: 10.1038/s41598-018-21930-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 02/13/2018] [Indexed: 11/11/2022] Open
Abstract
About 20% of angiosperms employ self-fertilization as their main mating strategy. In this study, we aimed to examine how the selfing timing correlated with floral traits in three Gentianopsis species in which autonomous selfing is achieved through filament elongation. Although the three Gentianopsis species exhibit no significant variation in their capacity for autonomous selfing, flowers of G. grandis last longer, are larger and have a higher corolla biomass, P/O ratios and male biomass allocation than those of G. paludosa, and especially those of G. contorta. Autonomous selfing occurs in the early floral life of G. paludosa and G. contorta and in the later floral life of G. grandis. Seed production mainly results from autonomous selfing in G. paludosa and G. contorta; however, G. grandis could be more described as having a mixed mating system. We suggest that autonomous selfing in later floral life increases the chance of cross-pollination prior to this, while autonomous selfing in early floral life offers a selective advantage to plants by reducing the resource investment in traits that may increase pollinator attraction and visitation.
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Barrett SC, Harder LD. The Ecology of Mating and Its Evolutionary Consequences in Seed Plants. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2017. [DOI: 10.1146/annurev-ecolsys-110316-023021] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Spencer C.H. Barrett
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S 3B2, Canada
| | - Lawrence D. Harder
- Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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34
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The Floral Biology, Breeding System and Pollination Efficiency of Schima superba Gardn. et Champ. (Theaceae). FORESTS 2017. [DOI: 10.3390/f8100404] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Córdova-Acosta E, Zavala-Hurtado JA, Golubov J, Casas A. Reproductive biology of Ferocactus recurvus (Mill.) Borg subsp. recurvus (Cactaceae) in the Tehuacán-Cuicatlán Valley, Mexico. PLANT BIOLOGY (STUTTGART, GERMANY) 2017; 19:798-805. [PMID: 28561940 DOI: 10.1111/plb.12585] [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: 04/16/2015] [Accepted: 05/26/2017] [Indexed: 06/07/2023]
Abstract
Mexico has one of the highest diversities of barrel cacti species worldwide; however, all are threatened and require conservation policies. Information on their reproductive biology is crucial, but few studies are available. Ferocactus recurvus subsp. recurvus is a barrel cactus endemic to the Tehuacán-Cuicatlán Valley. Our research aimed to characterise its floral and pollination biology. We hypothesised bee pollination, as suggested by its floral morphology and behaviour, and self-incompatibility, like most barrel cacti studied. Three study sites were selected in the semiarid Zapotitlán Valley, Mexico. We examined 190 flowers from 180 plants to determine: morphometry and behaviour of flowers, flower visitors and probable pollinators, and breeding system. Flowers showed diurnal anthesis, lasting 2-5 days, the stigma being receptive on day 2 or 3 after the start of anthesis. Flowers produced scarce/no nectar and main visitors were bees (Apidae), followed by flies (Muscidae), ants (Formicidae), thrips (Thripidae) and hummingbirds (Throchilidae); however, only native bees and occasionally wasps contacted the stigma and anthers. Pollination experiments revealed that this species is self-incompatible and xenogamous. In natural conditions, fruit set was 60% and cross-pollination fruit set was 100%. Percentage seed germination resulting from cross-pollination was higher than in the control treatment. Our results provide ecological information for conservation programmes to ensure a high probability of breeding and seed production in natural populations of F. recurvus.
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Affiliation(s)
- E Córdova-Acosta
- Universidad Autónoma Metropolitana-Iztapalapa, México, México
- Departamento de Biología, Universidad Autónoma Metropolitana-Iztapalapa, México, México
| | - J A Zavala-Hurtado
- Departamento de Biología, Universidad Autónoma Metropolitana-Iztapalapa, México, México
| | - J Golubov
- Departamento El Hombre y su Ambiente, Universidad Autónoma Metropolitana-Xochimilco, Col. Villa Quietud, México, México
| | - A Casas
- Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, Morelia, Michoacán, México
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Xiao CL, Deng H, Xiang GJ, Luguba KE, Guo YH, Yang CF. Sequential stamen maturation and movement in a protandrous herb: mechanisms increasing pollination efficiency and reducing sexual interference. AOB PLANTS 2017; 9:plx019. [PMID: 28698790 PMCID: PMC5499893 DOI: 10.1093/aobpla/plx019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 05/21/2017] [Accepted: 05/24/2017] [Indexed: 06/02/2023]
Abstract
Successive stamen movement directly controls pollen presentation schedules through sequential stamen maturation and changes the extent of herkogamy by altering the positions of sexual organs. However, the implications of such movements in terms of pollination are not well understood. Pollen presentation theory predicts that staggered pollen presentation should be favoured when plants are subject to diminishing returns on pollen transfer. Herkogamy on the other hand, has been interpreted as an adaptive trait that reduces sexual interference in hermaphrodite flowers. In this study, we conducted floral manipulations to determine the function of successive stamen movement in pollen transfer. By artificially manipulating the flowers to present two anthers simultaneously in the floral centre, we attempted to investigate whether changes in the anther presentation strategy affect pollen removal, deposition and the efficiency of pollinators. Compared with the natural treatment, the pollen transfer efficiency of halictid bees decreased significantly when the flowers were manipulated to present two anthers simultaneously. Although the presentation of two anthers simultaneously led to a similar pollen removal rate, there was a significant reduction in pollen deposition on neighbouring stigmas. To evaluate the effect of movement herkogamy on pollen export and deposition and seed set, the flowers were manipulated with or without the movement of stamen bending out from the floral centre. Pollen export decreased significantly when the central anther was moved away from the pistil, and pollen deposition and seed set declined significantly when the five spent anthers were retained on the pistil. Our study provides good support for the pollen presentation theory and provides direct experimental evidence that successive stamen movement could increase pollen transfer efficiency by sequential stamen maturation. Moreover, movement herkogamy promotes pollen export, deposition and seed set, and could therefore be regarded as an effective mechanism to reduce interference between male and female functions.
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Affiliation(s)
- Chang-Long Xiao
- College of Life Sciences, Wuhan University, 430072 Wuhan, China
| | - Hui Deng
- College of Life Sciences, Wuhan University, 430072 Wuhan, China
| | - Gan-Ju Xiang
- College of Life Sciences, Wuhan University, 430072 Wuhan, China
| | - Kadiori Edwin Luguba
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, 430074 Wuhan, China
| | - You-Hao Guo
- College of Life Sciences, Wuhan University, 430072 Wuhan, China
| | - Chun-Feng Yang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, 430074 Wuhan, China
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Francis JS, Muth F, Papaj DR, Leonard AS. Nutritional complexity and the structure of bee foraging bouts. Behav Ecol 2016. [DOI: 10.1093/beheco/arv229] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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38
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Fan YL, Kress WJ, Li QJ. A New Secondary Pollen Presentation Mechanism from a Wild Ginger (Zingiber densissimum) and Its Functional Roles in Pollination Process. PLoS One 2015; 10:e0143812. [PMID: 26637125 PMCID: PMC4670160 DOI: 10.1371/journal.pone.0143812] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 11/10/2015] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND AND AIMS Secondary pollen presentation (SPP), a floral mechanism of reproductive adaptation, has been described for more than 200 years, with nine types SPP recorded. However, few studies have been done experimentally to link the floral mechanism of SPP to its functional roles in pollination process. This study aims to describe a new SPP mechanism from a wild ginger (Zingiber densissimum, Zingiberaceae) and explore how the pollen arrangement of SPP affects pollen removal during the interaction with different pollinators. METHODOLOGY/PRINCIPAL FINDINGS Field observations and experiments revealed that flowers lasted for less than one day. The breeding system was partially self-incompatible. Two bee species, Macropis hedini (which carried pollen dorsally) and Amegilla zonata (which carried pollen ventrally) were the primary pollinators. About a third of pollen grains were relocated from the anther to the labellum staminode of flowers through the adherence of aggregated pollen chains, while other grains were presented on the anther. In a single visit, each bee species removed pollen grains from both the labellum staminode and the anther. Macropis hedini was more effective than Amegilla zonata. CONCLUSIONS/SIGNIFICANCE Our study describes a new SPP mechanism in angiosperms. The new SPP mode enables pollen grains presented on the anther and the labellum staminode simultaneously via the adherence of aggregated pollen chains, thus promoting pollen to be taken away by different pollinators. This SPP mechanism plays a key role during pollen removal and may have evolved under the pressure to improve male fitness.
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Affiliation(s)
- Yong-Li Fan
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, The Chinese Academy of Sciences, Menglun Town, Mengla County, Yunnan, China
- University of Chinese Academy of Sciences, Beijing, China
- China Forest Exploration and Design Institute of Kunming, Kunming, China
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, DC, United States of America
| | - W. John Kress
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, DC, United States of America
| | - Qing-Jun Li
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, The Chinese Academy of Sciences, Menglun Town, Mengla County, Yunnan, China
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Niu Y, Zhang ZQ, Liu CQ, Li ZM, Sun H. A sexually dimorphic corolla appendage affects pollen removal and floral longevity in gynodioecious Cyananthus delavayi (Campanulaceae). PLoS One 2015; 10:e0117149. [PMID: 25603479 PMCID: PMC4300179 DOI: 10.1371/journal.pone.0117149] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 12/18/2014] [Indexed: 11/19/2022] Open
Abstract
The floral traits of bisexual flowers may evolve in response to selection on both male and female functions, but the relative importance of selection associated with each of these two aspects is poorly resolved. Sexually dimorphic traits in plants with unisexual flowers may reflect gender-specific selection, providing opportunities for gaining an increased understanding of the evolution of specific floral traits. We examined sexually dimorphic patterns of floral traits in perfect and female flowers of the gynodioecious species Cyananthus delavayi. A special corolla appendage, the throat hair, was investigated experimentally to examine its influences on male and female function. We found that perfect flowers have larger corollas and much longer throat hairs than female flowers, while female ones have much exerted stigmas. The presence of throat hairs prolonged the duration of pollen presentation by restricting the amount of pollen removed by pollen-collecting bees during each visit. Floral longevity was negatively related to the rate of pollen removal. When pollen removal rate was limited in perfect flowers, the duration of the female phases diminished with the increased male phase duration. There was a weak negative correlation between throat hair length and seed number per fruit in female flowers, but this correlation was not significant in perfect flowers. These results suggest that throat hairs may enhance male function in terms of prolonged pollen presentation. However, throat hairs have no obvious effect on female function in terms of seed number per fruit. The marked sexual dimorphism of this corolla appendage in C. delavayi is likely to have evolved and been maintained by gender-specific selection.
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Affiliation(s)
- Yang Niu
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Zhi-Qiang Zhang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Chang-Qiu Liu
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Zhi-Min Li
- School of Life Sciences, Yunnan Normal University, Kunming, Yunnan, China
| | - Hang Sun
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
- * E-mail:
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Dötterl S, Glück U, Jürgens A, Woodring J, Aas G. Floral reward, advertisement and attractiveness to honey bees in dioecious Salix caprea. PLoS One 2014; 9:e93421. [PMID: 24676333 PMCID: PMC3968154 DOI: 10.1371/journal.pone.0093421] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Accepted: 03/06/2014] [Indexed: 11/21/2022] Open
Abstract
In dioecious, zoophilous plants potential pollinators have to be attracted to both sexes and switch between individuals of both sexes for pollination to occur. It often has been suggested that males and females require different numbers of visits for maximum reproductive success because male fertility is more likely limited by access to mates, whereas female fertility is rather limited by resource availability. According to sexual selection theory, males therefore should invest more in pollinator attraction (advertisement, reward) than females. However, our knowledge on the sex specific investment in floral rewards and advertisement, and its effects on pollinator behaviour is limited. Here, we use an approach that includes chemical, spectrophotometric, and behavioural studies i) to elucidate differences in floral nectar reward and advertisement (visual, olfactory cues) in dioecious sallow, Salix caprea, ii) to determine the relative importance of visual and olfactory floral cues in attracting honey bee pollinators, and iii) to test for differential attractiveness of female and male inflorescence cues to honey bees. Nectar amount and sugar concentration are comparable, but sugar composition varies between the sexes. Olfactory sallow cues are more attractive to honey bees than visual cues; however, a combination of both cues elicits the strongest behavioural responses in bees. Male flowers are due to the yellow pollen more colourful and emit a higher amount of scent than females. Honey bees prefer the visual but not the olfactory display of males over those of females. In all, the data of our multifaceted study are consistent with the sexual selection theory and provide novel insights on how the model organism honey bee uses visual and olfactory floral cues for locating host plants.
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Affiliation(s)
- Stefan Dötterl
- Department of Plant Systematics, University of Bayreuth, Bayreuth, Germany
- * E-mail:
| | - Ulrike Glück
- Ecological-Botanical Garden, University of Bayreuth, Bayreuth, Germany
| | - Andreas Jürgens
- School of Biological and Conservation Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Joseph Woodring
- Department of Animal Ecology, University of Bayreuth, Bayreuth, Germany
| | - Gregor Aas
- Ecological-Botanical Garden, University of Bayreuth, Bayreuth, Germany
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Is there 'anther-anther interference' within a flower? Evidences from one-by-one stamen movement in an insect-pollinated plant. PLoS One 2014; 9:e86581. [PMID: 24475150 PMCID: PMC3903572 DOI: 10.1371/journal.pone.0086581] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 12/16/2013] [Indexed: 11/29/2022] Open
Abstract
The selective pressure imposed by maximizing male fitness (pollen dispersal) in shaping floral structures is increasingly recognized and emphasized in current plant sciences. To maximize male fitness, many flowers bear a group of stamens with temporally separated anther dehiscence that prolongs presentation of pollen grains. Such an advantage, however, may come with a cost resulting from interference of pollen removal by the dehisced anthers. This interference between dehisced and dehiscing anthers has received little attention and few experimental tests to date. Here, using one-by-one stamen movement in the generalist-pollinated Parnassia palustris, we test this hypothesis by manipulation experiments in two years. Under natural conditions, the five fertile stamens in P. palustris flowers elongate their filaments individually, and anthers dehisce successively one-by-one. More importantly, the anther-dehisced stamen bends out of the floral center by filament deflexion before the next stamen's anther dehiscence. Experimental manipulations show that flowers with dehisced anther remaining at the floral center experience shorter (1/3–1/2 less) visit durations by pollen-collecting insects (mainly hoverflies and wasps) because these ‘hungry’ insects are discouraged by the scant and non-fresh pollen in the dehisced anther. Furthermore, the dehisced anther blocks the dehiscing anther's access to floral visitors, resulting in a nearly one third decrease in their contact frequency. As a result, pollen removal of the dehiscing anther decreases dramatically. These results provide the first direct experimental evidence that anther-anther interference is possible in a flower, and that the selection to reduce such interferences can be a strong force in floral evolution. We also propose that some other floral traits, usually interpreted as pollen dispensing mechanisms, may function, at least partially, as mechanisms to promote pollen dispersal by reducing interferences between dehisced and dehiscing anthers.
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Li XX, Wang H, Gituru RW, Guo YH, Yang CF. Pollen packaging and dispensing: adaption of patterns of anther dehiscence and flowering traits to pollination in three Epimedium species. PLANT BIOLOGY (STUTTGART, GERMANY) 2014; 16:227-233. [PMID: 23614841 DOI: 10.1111/plb.12040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 03/20/2013] [Indexed: 06/02/2023]
Abstract
Pollen presentation theory (PPT) predicts that plant species typically pollinated by frequent and wasteful pollinators ought to be much more parsimonious and only gradually release pollen compared to plant species pollinated by infrequent pollinators that are efficient at delivering the pollen they remove. To test PPT, we compare the pollen presentation schedules and pollination systems in three related Epimedium species, having different pollinators. Results showed that differences in anther dehiscence and flowering traits resulted in different pollen packaging schedules. For E. sutchuenense and E. franchetii, a special 'roll-up' movement of the anther wall during anther dehiscence increased pollen removal compared to the dehiscence pattern in E. mikinorii, which lacked the 'roll-up' movement. Investigations revealed that honeybees had a higher pollen removal rate and lower stigmatic pollen load compared to bumblebees. In accordance with PPT, E. sutchuenense presents pollen sequentially and slowly for the frequent and wasteful honeybees. In comparison to E. sutchuenense, E. franchetii had a faster presentation rate and was adapted to the efficient and infrequent bumblebees. However, E. mikinorii was pollinated by both bumblebees and honeybees at high frequency and had the fastest pollen presentation. This pattern could reduce pollen wastage by honeybees and might be an adaptation to its short flower longevity (less than 1 day), to increase the chances of pollen deposition on stigmas. The study indicates that pollen presentation schedules can be a consequence of interactions among anther dehiscence, flowering traits and pollination environments for a given species.
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Affiliation(s)
- X-X Li
- College of Life Sciences, Wuhan University, Wuhan, China
| | - H Wang
- College of Life Sciences, Wuhan University, Wuhan, China
| | - R W Gituru
- Sino-African Biodiversity Resource Conservation centre, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - Y-H Guo
- College of Life Sciences, Wuhan University, Wuhan, China
| | - C-F Yang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, The Chinese Academy of Sciences, Wuhan, China
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Armbruster WS, Corbet SA, Vey AJM, Liu SJ, Huang SQ. In the right place at the right time: Parnassia resolves the herkogamy dilemma by accurate repositioning of stamens and stigmas. ANNALS OF BOTANY 2014; 113:97-103. [PMID: 24265349 PMCID: PMC3864732 DOI: 10.1093/aob/mct261] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
BACKGROUND AND AIMS Spatial (herkogamy) and temporal (dichogamy) separation of pollen presentation and stigma receptivity have been interpreted as reducing interference between male and female functions in hermaphroditic flowers. However, spatial separation leads to a potential conflict: reduced pollination accuracy, where pollen may be placed in a location on the pollinator different from the point of stigma contact. METHODS To understand better how herkogamous flowers resolve this conflict, a study was made of a subalpine herb, Parnassia epunctulata, the nectariferous flowers of which exhibit sequential anther dehiscence (staggered pollen presentation) and stamen movements; usually one newly dehisced anther is positioned each day over the central gynoecium, while the older stamens bend away from the central position. KEY RESULTS The open flowers were visited by a variety of pollinators, most of which were flies. Seed set was pollinator-dependent (bagged flowers set almost no seeds) and pollen-limited (manual pollination increased seed set over open pollination). Analyses of adaptive accuracy showed that coordinated stamen movements and style elongation (movement herkogamy) dramatically increased pollination accuracy. Specifically, dehiscing anthers and receptive stigmas were positioned accurately in the vertical and horizontal planes in relation to the opposite sexual structure and pollinator position. By contrast, the spatial correspondence between anthers and stigma was dramatically lower before the anthers dehisced and after stamens bent outwards, as well as before and after the period of stigmatic receptivity. CONCLUSIONS It is shown for the first time that a combination of movement herkogamy and dichogamy can maintain high pollination accuracy in flowers with generalized pollination. Staggered pollen and stigma presentation with spatial correspondence can both reduce sexual interference and improve pollination accuracy.
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Affiliation(s)
- W. Scott Armbruster
- School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, UK
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775-7000, USA
- Department of Biology, NTNU, N-7491 Trondheim, Norway
| | - Sarah A. Corbet
- 1 St Loy Cottages, St Buryan, Penzance, Cornwall TR19 6DH, UK
| | - Aidan J. M. Vey
- School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, UK
| | - Shu-Juan Liu
- College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Shuang-Quan Huang
- College of Life Sciences, Central China Normal University, Wuhan 430079, China
- For correspondence. E-mail
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Harder LD, Prusinkiewicz P. The interplay between inflorescence development and function as the crucible of architectural diversity. ANNALS OF BOTANY 2013; 112:1477-93. [PMID: 23243190 PMCID: PMC3828939 DOI: 10.1093/aob/mcs252] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
BACKGROUND Most angiosperms present flowers in inflorescences, which play roles in reproduction, primarily related to pollination, beyond those served by individual flowers alone. An inflorescence's overall reproductive contribution depends primarily on the three-dimensional arrangement of the floral canopy and its dynamics during its flowering period. These features depend in turn on characteristics of the underlying branching structure (scaffold) that supports and supplies water and nutrients to the floral canopy. This scaffold is produced by developmental algorithms that are genetically specified and hormonally mediated. Thus, the extensive inflorescence diversity evident among angiosperms evolves through changes in the developmental programmes that specify scaffold characteristics, which in turn modify canopy features that promote reproductive performance in a particular pollination and mating environment. Nevertheless, developmental and ecological aspects of inflorescences have typically been studied independently, limiting comprehensive understanding of the relations between inflorescence form, reproductive function, and evolution. SCOPE This review fosters an integrated perspective on inflorescences by summarizing aspects of their development and pollination function that enable and guide inflorescence evolution and diversification. CONCLUSIONS The architecture of flowering inflorescences comprises three related components: topology (branching patterns, flower number), geometry (phyllotaxis, internode and pedicel lengths, three-dimensional flower arrangement) and phenology (flower opening rate and longevity, dichogamy). Genetic and developmental evidence reveals that these components are largely subject to quantitative control. Consequently, inflorescence evolution proceeds along a multidimensional continuum. Nevertheless, some combinations of topology, geometry and phenology are represented more commonly than others, because they serve reproductive function particularly effectively. For wind-pollinated species, these combinations often represent compromise solutions to the conflicting physical influences on pollen removal, transport and deposition. For animal-pollinated species, dominant selective influences include the conflicting benefits of large displays for attracting pollinators and of small displays for limiting among-flower self-pollination. The variety of architectural components that comprise inflorescences enable diverse resolutions of these conflicts.
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Affiliation(s)
- Lawrence D. Harder
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4
- For correspondence. Email
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Poor correlation between the removal or deposition of pollen grains and frequency of pollinator contact with sex organs. Naturwissenschaften 2013; 100:871-6. [PMID: 23928839 DOI: 10.1007/s00114-013-1087-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 07/25/2013] [Accepted: 07/26/2013] [Indexed: 10/26/2022]
Abstract
Pollinators deposit pollen grains on stigmas and remove pollen grains from anthers. The mechanics of these transfers can now be quantified with the use of high-speed video. We videoed hawkmoths, carpenter bees, and swallowtail butterflies pollinating Clerodendrum trichotomum. The number of grains deposited on stigmas did not vary significantly with the number of times pollinators contacted stigmas. In contrast, pollen removal from the anthers increased significantly with the number of contacts to anthers. Pollen removal varied among the three types of pollinators. Also, the three types carried pollen on different parts of their bodies. In hawkmoths and carpenter bees, a large number of contacted body part with anthers differed significantly from the body part that attached a large number of pollen grains. Our results indicate that a large number of contacts by pollinators does not increase either the male or female reproductive success of plants compared to a small number of contacts during a visit.
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48
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Pannell JR, Labouche AM. The incidence and selection of multiple mating in plants. Philos Trans R Soc Lond B Biol Sci 2013; 368:20120051. [PMID: 23339242 DOI: 10.1098/rstb.2012.0051] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mating with more than one pollen donor, or polyandry, is common in land plants. In flowering plants, polyandry occurs when the pollen from different potential sires is distributed among the fruits of a single individual, or when pollen from more than one donor is deposited on the same stigma. Because polyandry typically leads to multiple paternity among or within fruits, it can be indirectly inferred on the basis of paternity analysis using molecular markers. A review of the literature indicates that polyandry is probably ubiquitous in plants except those that habitually self-fertilize, or that disperse their pollen in pollen packages, such as polyads or pollinia. Multiple mating may increase plants' female component by alleviating pollen limitation or by promoting competition among pollen grains from different potential sires. Accordingly, a number of traits have evolved that should promote polyandry at the flower level from the female's point of view, e.g. the prolongation of stigma receptivity or increases in stigma size. However, many floral traits, such as attractiveness, the physical manipulation of pollinators and pollen-dispensing mechanisms that lead to polyandrous pollination, have probably evolved in response to selection to promote male siring success in general, so that polyandry might often best be seen as a by-product of selection to enhance outcross siring success. In this sense, polyandry in plants is similar to geitonogamy (selfing caused by pollen transfer among flowers of the same plant), because both polyandry and geitonogamy probably result from selection to promote outcross siring success, although geitonogamy is almost always deleterious while polyandry in plants will seldom be so.
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Affiliation(s)
- John R Pannell
- Department of Ecology and Evolution, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland.
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Ren MX, Tang JY. Up and down: stamen movements in Ruta graveolens (Rutaceae) enhance both outcrossing and delayed selfing. ANNALS OF BOTANY 2012; 110:1017-25. [PMID: 22875813 PMCID: PMC3448434 DOI: 10.1093/aob/mcs181] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 06/29/2012] [Indexed: 05/24/2023]
Abstract
BACKGROUND AND AIMS Stamen movements directly determine pollen fates and mating patterns by altering positions of female and male organs. However, the implications of such movements in terms of pollination are not well understood. Recently, complex patterns of stamen movements have been identified in Loasaceae, Parnassiaceae, Rutaceae and Tropaeolaceae. In this study the stamen movements in Ruta graveolens (Rutaceae) and their impact on pollination are determined. METHODS Pollination effects of stamen movements were studied in Ruta graveolens, in which one-by-one uplifting and falling back is followed by simultaneous movement of all stamens in some flowers. Using 30 flowers, one stamen was manipulated either to be immobilized or to be allowed to move freely towards the centre of the flower but be prevented from falling back. Pollen loads on stigmas and ovule fertilization in flowers with or without simultaneous stamen movement were determined. RESULTS Pollen removal decreased dramatically (P < 0·001) when the stamen was stopped from uplifting because its anther was seldom contacted by pollinators. When a stamen stayed at the flower's centre, pollen removal of the next freely moved anther decreased significantly (P < 0·005) because of fewer touches by pollinators and quick leaving of pollinators that were discouraged by the empty anther. Simultaneous stamen movement occurred only in flowers with low pollen load on the stigma and the remaining pollen in anthers dropped onto stigma surfaces after stamens moved to the flower's centre. CONCLUSIONS In R. graveolens pollen removal is promoted through one-by-one movement of the stamen, which presents pollen in doses to pollinators by successive uplifting of the stamen and avoids interference of two consecutively dehisced anthers by falling back of the former stamen before the next one moves into the flower's centre. Simultaneous stamen movement at the end of anthesis probably reflects an adaptation for late-acting self-pollination.
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Affiliation(s)
- Ming-Xun Ren
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China.
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Till-Bottraud I, Gouyon PH, Ressayre A, Godelle B. Gametophytic vs. sporophytic control of pollen aperture number: a generational conflict. Theor Popul Biol 2012; 82:147-57. [PMID: 22796134 DOI: 10.1016/j.tpb.2012.06.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 06/25/2012] [Accepted: 06/29/2012] [Indexed: 10/28/2022]
Abstract
In flowering plants, the haploid phase is reduced to the pollen grain and embryo sac. These reproductive tissues (gametophytes) are actually distinct individuals that have a different genome from the plant (sporophyte), and are more or less independent. The morphology of pollen grains, particularly the openings permitting pollen tube germination (apertures), is crucial for determining the outcome of pollen competition. Many species of flowering plants simultaneously produce pollen grains with different aperture numbers in a single individual (heteromorphism). In this paper, we show that the heteromorphic pollen aperture pattern depends on the genetic control of pollen morphogenesis. This points out a conflict of interest between genes expressed in the sporophyte and genes expressed in the gametophyte. More generally, such a conflict should exist whenever heteromorphism is an ESS resulting from a bet-hedging strategy. For pollen aperture, heteromorphism has been observed in about 40% of angiosperm species, suggesting that conflicting situations are the rule. In this context, the sporo-gametophytic conflict could be one of the factors that led to the reduction of the haploid phase in plants.
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Affiliation(s)
- Irène Till-Bottraud
- Université de Grenoble 1, CNRS, Laboratoire d'Ecologie Alpine, UMR 5553, BP53, F-38041 Grenoble Cedex, France.
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