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Cardoso JCF, Johnson SD, Oliveira PE. Incomplete resupination during floral development leads to pollination failure in a slipper orchid. Plant Biol (Stuttg) 2024; 26:34-40. [PMID: 37856560 DOI: 10.1111/plb.13587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 09/24/2023] [Indexed: 10/21/2023]
Abstract
In many families, plants undergo floral resupination by twisting through approximately 180° during floral development so that the flower is effectively positioned upside down. In most orchids, resupination results in the median petal (i.e., the labellum) becoming lowermost, which plays a crucial role in pollination by serving as a landing platform or as a trapping device, or both. Incomplete resupination is predicted to lead to reduced pollination, although tests of this assumption are still lacking. We investigated the effect of resupination using Phragmipedium vittatum, a rare lady's slipper orchid whose specialized labellum forms a trapping device. First, we surveyed the natural occurrence of incomplete resupination. Then we manipulated flowers into non- (≈0°), half- (≈90°), and fully resupinate (≈180°) positions to test the effect of orientation on pollen smear removal and deposition by pollinators (female hoverflies). We found that ca. 10% of flowers in the natural population were not fully resupinate, being either non- (upward, 0-60°) or half-resupinate (sideward, 60-120°). The change in orientation prevented the effectiveness of pollination by hoverflies since no pollen smear removal or deposition were found in flowers from non- and half-resupinate treatments. Although these flowers still attracted hoverflies, they were not trapped effectively. As this orchid is incapable of autonomous self-pollination, flowers that do not resupinate fail to set fruits. These results highlight the importance of correct floral orientation provided by resupination to ensure pollination in orchids and other resupinate flowers.
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Affiliation(s)
- J C F Cardoso
- Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil
- Departamento de Biodiversidade Evolução e Meio Ambiente, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brazil
| | - S D Johnson
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - P E Oliveira
- Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil
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2
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Barberis M, Calabrese D, Galloni M, Nepi M. Secondary Metabolites in Nectar-Mediated Plant-Pollinator Relationships. Plants (Basel) 2023; 12:plants12030550. [PMID: 36771634 PMCID: PMC9920422 DOI: 10.3390/plants12030550] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/17/2023] [Accepted: 01/19/2023] [Indexed: 06/01/2023]
Abstract
In recent years, our understanding of the complex chemistry of floral nectar and its ecological implications for plant-pollinator relationships has certainly increased. Nectar is no longer considered merely a reward for pollinators but rather a plant interface for complex interactions with insects and other organisms. A particular class of compounds, i.e., nectar secondary compounds (NSCs), has contributed to this new perspective, framing nectar in a more comprehensive ecological context. The aim of this review is to draft an overview of our current knowledge of NSCs, including emerging aspects such as non-protein amino acids and biogenic amines, whose presence in nectar was highlighted quite recently. After considering the implications of the different classes of NSCs in the pollination scenario, we discuss hypotheses regarding the evolution of such complex nectar profiles and provide cues for future research on plant-pollinator relationships.
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Affiliation(s)
- Marta Barberis
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy
| | - Daniele Calabrese
- Department of Life Sciences, University of Siena, Via P.A. Mattioli 4, 53100 Siena, Italy
| | - Marta Galloni
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy
| | - Massimo Nepi
- Department of Life Sciences, University of Siena, Via P.A. Mattioli 4, 53100 Siena, Italy
- National Biodiversity Future Centre (NBFC), 90123 Palermo, Italy
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3
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Pyke GH, Ren ZX, Trunschke J, Lunau K, Wang H. Changes in floral nectar are unlikely adaptive responses to pollinator flight sound. Ecol Lett 2020; 23:1421-1422. [PMID: 32578293 DOI: 10.1111/ele.13403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 09/04/2019] [Accepted: 09/16/2019] [Indexed: 11/30/2022]
Abstract
Under noiseless experimental conditions, sugar concentration of secreted floral nectar may increase after flower exposure to nearby sounds of pollinator flight (Veits et al. 2019). However, we reject the argument that this represents adaptive plant behaviour, and consider that the appealing analogy between a flower and human ear is unjustified.
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Affiliation(s)
- Graham H Pyke
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, CN-650201, Kunming, China.,Department of Biological Sciences, Macquarie University, Ryde, NSW, 2109, Australia
| | - Zong-Xin Ren
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, CN-650201, Kunming, China
| | - Judith Trunschke
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, CN-650201, Kunming, China
| | - Klaus Lunau
- Institute of Sensory Ecology, Heinrich-Heine-University, Dusseldorf, Germany
| | - Hong Wang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, CN-650201, Kunming, China
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4
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Scaccabarozzi D, Cozzolino S, Guzzetti L, Galimberti A, Milne L, Dixon KW, Phillips RD. Masquerading as pea plants: behavioural and morphological evidence for mimicry of multiple models in an Australian orchid. Ann Bot 2018; 122:1061-1073. [PMID: 30184161 PMCID: PMC6266105 DOI: 10.1093/aob/mcy166] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/12/2018] [Indexed: 05/03/2023]
Abstract
Background and Aims While there is increasing recognition of Batesian floral mimicry in plants, there are few confirmed cases where mimicry involves more than one model species. Here, we test for pollination by mimicry in Diuris (Orchidaceae), a genus hypothesized to attract pollinators via mimicry of a range of co-occurring pea plants (Faboideae). Methods Observations of pollinator behaviour were made for Diuris brumalis using arrays of orchid flowers. An analysis of floral traits in the co-flowering community and spectral reflectance measurements were undertaken to test if Di. brumalis and the pea plants showed strong similarity and were likely to be perceived as the same by bees. Pollen removal and fruit-set were recorded at 18 sites over two years to test if fitness of Di. brumalis increased with the abundance of the model species. Key Results Diuris brumalis shares the pollinator species Trichococolletes capillosus and T. leucogenys (Hymenoptera: Colletidae) with co-flowering Faboideae from the genus Daviesia. On Di. brumalis, Trichocolletes exhibited the same stereotyped food-foraging and mate-patrolling behaviour that they exhibit on Daviesia. Diuris and pea plants showed strong morphological similarity compared to the co-flowering plant community, while the spectral reflectance of Diuris was similar to that of Daviesia spp. Fruit-set and pollen removal of Di. brumalis was highest at sites with a greater number of Daviesia flowers. Conclusions Diuris brumalis is pollinated by mimicry of co-occurring congeneric Faboideae species. Evidence for mimicry of multiple models, all of which share pollinator species, suggests that this may represent a guild mimicry system. Interestingly, Di. brumalis belongs to a complex of species with similar floral traits, suggesting that this represents a useful system for investigating speciation in lineages that employ mimicry of food plants.
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Affiliation(s)
- Daniela Scaccabarozzi
- Department of Environment and Agriculture, Curtin University, Bentley, WA, Australia
- Department of Biology, University of Naples Federico II, Complesso Universitario MSA, Naples, Italy
- Kings Park and Botanic Garden, The Botanic Garden and Parks Authority, West Perth, WA, Australia
| | - Salvatore Cozzolino
- Department of Biology, University of Naples Federico II, Complesso Universitario MSA, Naples, Italy
| | - Lorenzo Guzzetti
- Università degli Studi di Milano-Bicocca, ZooPlantLab, Dipartimento di Biotecnologie e Bioscienze, Piazza della Scienza, Milano, Italy
| | - Andrea Galimberti
- Università degli Studi di Milano-Bicocca, ZooPlantLab, Dipartimento di Biotecnologie e Bioscienze, Piazza della Scienza, Milano, Italy
| | - Lynne Milne
- School of Earth and Planetary Sciences, Curtin University, Bentley, WA, Australia
| | - Kingsley W Dixon
- Department of Environment and Agriculture, Curtin University, Bentley, WA, Australia
| | - Ryan D Phillips
- Kings Park and Botanic Garden, The Botanic Garden and Parks Authority, West Perth, WA, Australia
- Evolution, Ecology and Genetics, Research School of Biology, The Australian National University, Canberra, ACT, Australia
- Department of Ecology, Environment and Evolution, La Trobe University, Vic., Australia
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5
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Phillips RD, Peakall R. An experimental evaluation of traits that influence the sexual behaviour of pollinators in sexually deceptive orchids. J Evol Biol 2018; 31:1732-1742. [PMID: 30144355 DOI: 10.1111/jeb.13370] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 08/20/2018] [Indexed: 12/20/2022]
Abstract
Pollination by sexual deception of male insects is perhaps one of the most remarkable cases of mimicry in the plant kingdom. However, understanding the influence of floral traits on pollinator behaviour in sexually deceptive plants is challenging, due to the risk of confounding changes in floral odour when manipulating morphology. Here, we investigated the floral traits influencing the sexual response of male Zaspilothynnus nigripes (Tiphiidae) wasps, a pollinator of two distantly related sexually deceptive orchids with contrasting floral architecture, Caladenia pectinata and Drakaea livida. In D. livida, the chemical sexual attractant is emitted from the labellum, whereas in C. pectinata, it is produced from the distal sepal tips, allowing manipulative experiments. When controlling for visual cues, there was no difference in long-distance attraction, although the floral odour of D. livida induced copulation more frequently than that of C. pectinata. The role of colour in pollinator sexual attraction was equivocal, indicating that colour may not be a strong constraint on the initial evolution of sexual deception. The frequency of wasp visitors landing on C. pectinata decreased when the amount of floral odour was reduced, but attempted copulation rates were enhanced when the source of floral odour was associated with the labellum. These latter variables may represent axes of selection that operate across many sexually deceptive species. Nonetheless, the observed variation in floral traits suggests flexibility among species in how sexual deception can be achieved.
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Affiliation(s)
- Ryan D Phillips
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia.,Kings Park and Botanic Garden, The Botanic Garden and Parks Authority, West Perth, WA, Australia.,Department of Ecology, Environment & Evolution, La Trobe University, Bundoora, VIC, Australia
| | - Rod Peakall
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
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6
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Ye ZM, Jin XF, Wang QF, Yang CF, Inouye DW. Nectar replenishment maintains the neutral effects of nectar robbing on female reproductive success of Salvia przewalskii (Lamiaceae), a plant pollinated and robbed by bumble bees. Ann Bot 2017; 119:1053-1059. [PMID: 28158409 PMCID: PMC5604579 DOI: 10.1093/aob/mcw285] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Accepted: 12/19/2016] [Indexed: 05/24/2023]
Abstract
Background and Aims It has been suggested that the dynamics of nectar replenishment could differ for flowers after being nectar robbed or visited legitimately, but further experimental work is needed to investigate this hypothesis. This study aimed to assess the role of nectar replenishment in mediating the effects of nectar robbing on pollinator behaviour and plant reproduction. Methods Plant-robber-pollinator interactions in an alpine plant, Salvia przewalskii , were studied. It is pollinated by long-tongued Bombus religiosus and short-tongued B. friseanus , but robbed by B. friseanus . Nectar production rates for flowers after they were either robbed or legitimately visited were compared, and three levels of nectar robbing were created to detect the effects of nectar robbing on pollinator behaviour and plant reproduction. Key Results Nectar replenishment did not differ between flowers that had been robbed or legitimately visited. Neither fruit set nor seed set was significantly affected by nectar robbing. In addition, nectar robbing did not significantly affect visitation rate, flowers visited within a plant per foraging bout, or flower handling time of the legitimate pollinators. However, a tendency for a decrease in relative abundance of the pollinator B. religiosus with an increase of nectar robbing was found. Conclusions Nectar robbing did not affect female reproductive success because nectar replenishment ensures that pollinators maintain their visiting activity to nectar-robbed flowers. Nectar replenishment might be a defence mechanism against nectar robbing to enhance reproductive fitness by maintaining attractiveness to pollinators. Further studies are needed to reveal the potential for interference competition among bumble bees foraging as robbers and legitimate visitors, and to investigate variation of nectar robbing in communities with different bumble bee species composition.
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Affiliation(s)
- Zhong-Ming Ye
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China
- Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention, Jiangxi Institute of Soil and Water Conservation, Nanchang 330029, China
| | - Xiao-Fang Jin
- Institute of Ecology and Environmental Science, Nanchang Institute of Technology, Nanchang 330099, China
| | - Qing-Feng Wang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China
| | - Chun-Feng Yang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China
| | - David W. Inouye
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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7
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Fisogni A, Rossi M, Sgolastra F, Bortolotti L, Bogo G, de Manincor N, Quaranta M, Galloni M. Seasonal and annual variations in the pollination efficiency of a pollinator community of Dictamnus albus L. Plant Biol (Stuttg) 2016; 18:445-454. [PMID: 26573095 DOI: 10.1111/plb.12417] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 11/11/2015] [Indexed: 06/05/2023]
Abstract
The interplay between insect and plant traits outlines the patterns of pollen transfer and the subsequent plant reproductive fitness. We studied the factors that affect the pollination efficiency of a pollinator community of Dictamnus albus L. by evaluating insect behaviour and morphological characteristics in relation to flowering phenology. In order to extrapolate the pollinator importance of single taxa and of the whole pollinator guild, we calculated an index distinguishing between potential (PPI) and realized (RPI) pollinator importance. Although the pollinator species spectrum appeared rather constant, we found high intra- and inter-annual variability of pollinator frequency and importance within the insect community. Flower visitation rate strictly depended on insect abundance and on the overlap between their flying period and flower blooming. All the pollinators visited flowers from the bottom to the top of the racemes, excluding intra-plant geitonogamous pollination, and most of them showed high pollen fidelity. Only medium large-sized bees could contact the upward bending stiles while feeding on nectar, highlighting a specialisation of the plant towards bigger pollinators. Moreover, we found evidence of functional specialisation, since all pollinators were restricted to a single taxonomic group (order: Hymenoptera; superfamily: Apoidea). Both the PPI and RPI indices indicate Habropoda tarsata as the most important pollinator of D. albus. Following hand cross-pollination experiments we revealed the presence of pollination limitation in 1 of the 3 years of field study. We discuss this result in relation to flowering abundance and to possible mismatches of phenological periods between plants and insects.
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Affiliation(s)
- A Fisogni
- Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Bologna, Bologna, Italy
| | - M Rossi
- Istituto di Bioscienze e Biorisorse, Consiglio Nazionale delle Ricerche, Portici (NA), Italy
| | - F Sgolastra
- Dipartimento di Scienze Agrarie, Università di Bologna, Bologna, Italy
| | - L Bortolotti
- Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria - Unità di Ricerca di Apicoltura e Bachicoltura (CRA-API), Bologna, Italy
| | - G Bogo
- Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Bologna, Bologna, Italy
- Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria - Unità di Ricerca di Apicoltura e Bachicoltura (CRA-API), Bologna, Italy
| | - N de Manincor
- Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Bologna, Bologna, Italy
| | - M Quaranta
- Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria - Centro di Ricerca per l'Agrobiologia e la Pedologia (CRA-ABP), Florence, Italy
| | - M Galloni
- Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Bologna, Bologna, Italy
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Brock MT, Lucas LK, Anderson NA, Rubin MJ, Markelz RJC, Covington MF, Devisetty UK, Chapple C, Maloof JN, Weinig C. Genetic architecture, biochemical underpinnings and ecological impact of floral UV patterning. Mol Ecol 2016; 25:1122-40. [PMID: 26800256 DOI: 10.1111/mec.13542] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 12/17/2015] [Accepted: 12/22/2015] [Indexed: 11/29/2022]
Abstract
Floral attraction traits can significantly affect pollinator visitation patterns, but adaptive evolution of these traits may be constrained by correlations with other traits. In some cases, molecular pathways contributing to floral attraction are well characterized, offering the opportunity to explore loci potentially underlying variation among individuals. Here, we quantify the range of variation in floral UV patterning (i.e. UV 'bulls-eye nectar guides) among crop and wild accessions of Brassica rapa. We then use experimental crosses to examine the genetic architecture, candidate loci and biochemical underpinnings of this patterning as well as phenotypic manipulations to test the ecological impact. We find qualitative variation in UV patterning between wild (commonly lacking UV patterns) and crop (commonly exhibiting UV patterns) accessions. Similar to the majority of crops, recombinant inbred lines (RILs) derived from an oilseed crop × WI fast-plant® cross exhibit UV patterns, the size of which varies extensively among genotypes. In RILs, we further observe strong statistical-genetic and QTL correlations within petal morphological traits and within measurements of petal UV patterning; however, correlations between morphology and UV patterning are weak or nonsignificant, suggesting that UV patterning is regulated and may evolve independently of overall petal size. HPLC analyses reveal a high concentration of sinapoyl glucose in UV-absorbing petal regions, which, in concert with physical locations of UV-trait QTLs, suggest a regulatory and structural gene as candidates underlying observed quantitative variation. Finally, insects prefer flowers with UV bulls-eye patterns over those that lack patterns, validating the importance of UV patterning in pollen-limited populations of B. rapa.
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Affiliation(s)
- Marcus T Brock
- Department of Botany, University of Wyoming, Laramie, WY, 82071, USA
| | - Lauren K Lucas
- Department of Biology, Utah State University, Logan, UT, 84322, USA
| | - Nickolas A Anderson
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Matthew J Rubin
- Department of Botany, University of Wyoming, Laramie, WY, 82071, USA
| | - R J Cody Markelz
- Department of Plant Biology, University of California, Davis, CA, 95616, USA
| | - Michael F Covington
- Department of Plant Biology, University of California, Davis, CA, 95616, USA
| | - Upendra K Devisetty
- Department of Plant Biology, University of California, Davis, CA, 95616, USA
| | - Clint Chapple
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Julin N Maloof
- Department of Plant Biology, University of California, Davis, CA, 95616, USA
| | - Cynthia Weinig
- Department of Botany, University of Wyoming, Laramie, WY, 82071, USA.,Department of Molecular Biology, University of Wyoming, Laramie, WY, 82071, USA
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9
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Lerdau MT. Minding (and bridging) the gap between evolutionary ecology and atmospheric biogeochemistry in a study of plant pollinator behaviour. New Phytol 2016; 209:11-12. [PMID: 26625344 DOI: 10.1111/nph.13752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- Manuel T Lerdau
- Department of Environmental Sciences, University of Virginia, Clark Hall, Charlottesville, VA, 22904-4123, USA
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10
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Essenberg CJ. FLOBOTS: ROBOTIC FLOWERS FOR BEE BEHAVIOUR EXPERIMENTS. J Pollinat Ecol 2015; 15:1-5. [PMID: 25722755 PMCID: PMC4338914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023] Open
Abstract
Studies of pollinator foraging behaviour often require artificial flowers that can refill themselves, allowing pollinators to forage for long periods of time under experimental conditions. Here I describe a design for inexpensive flowers that can refill themselves upon demand and that are easy enough to set up and clean that they can be used in arrays of 30 or more flowers. I also summarize of a variety of artificial flower designs developed by other researchers.
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11
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Yang CF, Wang QF, Guo YH. Pollination in a patchily distributed lousewort is facilitated by presence of a co-flowering plant due to enhancement of quantity and quality of pollinator visits. Ann Bot 2013; 112:1751-1758. [PMID: 24131615 PMCID: PMC3838553 DOI: 10.1093/aob/mct228] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 08/09/2013] [Indexed: 06/02/2023]
Abstract
BACKGROUND AND AIMS Plants surrounded by individuals of other co-flowering species may suffer a reproductive cost from interspecific pollen transfer (IPT). However, differences in floral architecture may reduce or eliminate IPT. METHODS A study was made of Pedicularis densispica (lousewort) and its common co-flowering species, Astragalus pastorius, to compare reproductive and pollination success of lousewort plants from pure and mixed patches. Floral architecture and pollinator behaviour on flowers of the two plants were compared along with the composition of stigmatic pollen load of the louseworts. The extent of pollen limitation of plants from pure and mixed patches was also explored through supplemental pollination with self- and outcross pollen (PLs and PLx). KEY RESULTS Mixed patches attracted many more nectar-searching individuals of Bombus richardsi. These bumble-bees moved frequently between flowers of the two species. However, they pollinated P. densispica with their dorsum and A. pastorius with their abdomen. This difference in handling almost completely eliminated IPT. Lousewort plants from mixed patches yielded more seeds, and seeds of higher mass and germinability, than those from pure patches. Moreover, louseworts from mixed patches had lower PLs and PLx compared with those from pure patches. CONCLUSIONS Differences in floral architecture induced differences in pollinator behaviour that minimized IPT, such that co-flowering plants significantly enhanced quantity and quality of pollinator visits for the lousewort plants in patchy habitat. These findings add to our understanding of the mechanisms of pollination facilitation.
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Affiliation(s)
- Chun-Feng Yang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, The Chinese Academy of Sciences, Wuhan 430074, China
| | - Qing-Feng Wang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, The Chinese Academy of Sciences, Wuhan 430074, China
| | - You-Hao Guo
- College of Life Sciences, Wuhan University, Wuhan 430072, China
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Ings TC, Chittka L. Predator crypsis enhances behaviourally mediated indirect effects on plants by altering bumblebee foraging preferences. Proc Biol Sci 2009; 276:2031-6. [PMID: 19324797 PMCID: PMC2677241 DOI: 10.1098/rspb.2008.1748] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Accepted: 02/03/2009] [Indexed: 11/12/2022] Open
Abstract
Predators of pollinators can influence pollination services and plant fitness via both consumptive (reducing pollinator density) and non-consumptive (altering pollinator behaviour) effects. However, a better knowledge of the mechanisms underlying behaviourally mediated indirect effects of predators is necessary to properly understand their role in community dynamics. We used the tripartite relationship between bumblebees, predatory crab spiders and flowers to ask whether behaviourally mediated effects are localized to flowers harbouring predators, or whether bees extend their avoidance to entire plant species. In a tightly controlled laboratory environment, bumblebees (Bombus terrestris) were exposed to a random mixture of equally rewarding yellow and white artificial flowers, but foraging on yellow flowers was very risky: bees had a 25 per cent chance of receiving a simulated predation attempt by 'robotic' crab spiders. As bees learnt to avoid 'dangerous' flowers, their foraging preferences changed and they began to visit fewer yellow flowers than expected by chance. Bees avoided spider-free yellow flowers as well as dangerous yellow flowers when spiders were more difficult to detect (the colour of yellow spiders was indistinguishable from that of yellow flowers). Therefore, this interaction between bee learning and predator crypsis could lead flower species harbouring cryptic predators to suffer from reduced reproductive success.
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Affiliation(s)
- Thomas C Ings
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.
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13
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Mitchell RJ, Irwin RE, Flanagan RJ, Karron JD. Ecology and evolution of plant-pollinator interactions. Ann Bot 2009; 103:1355-63. [PMID: 19482881 PMCID: PMC2701755 DOI: 10.1093/aob/mcp122] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 04/27/2009] [Accepted: 05/01/2009] [Indexed: 05/08/2023]
Abstract
BACKGROUND Some of the most exciting advances in pollination biology have resulted from interdisciplinary research combining ecological and evolutionary perspectives. For example, these two approaches have been essential for understanding the functional ecology of floral traits, the dynamics of pollen transport, competition for pollinator services, and patterns of specialization and generalization in plant-pollinator interactions. However, as research in these and other areas has progressed, many pollination biologists have become more specialized in their research interests, focusing their attention on either evolutionary or ecological questions. We believe that the continuing vigour of a synthetic and interdisciplinary field like pollination biology depends on renewed connections between ecological and evolutionary approaches. SCOPE In this Viewpoint paper we highlight the application of ecological and evolutionary approaches to two themes in pollination biology: (1) links between pollinator behaviour and plant mating systems, and (2) generalization and specialization in pollination systems. We also describe how mathematical models and synthetic analyses have broadened our understanding of pollination biology, especially in human-modified landscapes. We conclude with several suggestions that we hope will stimulate future research. This Viewpoint also serves as the introduction to this Special Issue on the Ecology and Evolution of Plant-Pollinator Interactions. These papers provide inspiring examples of the synergy between evolutionary and ecological approaches, and offer glimpses of great accomplishments yet to come.
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Affiliation(s)
- Randall J. Mitchell
- Department of Biology, Program in Integrated Biosciences, University of Akron, Akron, OH 44325, USA
| | - Rebecca E. Irwin
- Department of Biology, Dartmouth College, Hanover, New Hampshire 03755, USA
| | - Rebecca J. Flanagan
- Department of Biological Sciences, P.O. Box 413, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
| | - Jeffrey D. Karron
- Department of Biological Sciences, P.O. Box 413, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
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Whelan RJ, Ayre DJ, Beynon FM. The birds and the bees: pollinator behaviour and variation in the mating system of the rare shrub Grevillea macleayana. Ann Bot 2009; 103:1395-401. [PMID: 19403627 PMCID: PMC2701754 DOI: 10.1093/aob/mcp091] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
BACKGROUND AND AIMS In Australia, honey-bees have invaded systems that evolved without social insect pollinators, where many plants are adapted to vertebrate pollination. Behavioural differences between pollinators are likely to influence mating patterns, but few studies have examined this empirically in long-lived, woody, perennials. It was shown previously that outcrossing rates in Grevillea macleayana vary among populations. Here tests were conducted to determine whether the behaviour of birds and honey-bees differed between a population previously found to be highly outcrossed and two inbreeding populations. METHODS Visit frequencies and movement patterns of the visitors to inflorescences at three sites over two seasons were compared. A caging experiment was used to test the effects of excluding birds on pollen removal from newly opened flowers and on pollen deposition on stigmas that had been washed clean. KEY RESULTS Honey-bees were the most frequent visitors overall, but honeyeaters were more frequent visitors in the population previously found to have a high outcrossing rate than they were in either of the other populations. More visits by honeyeaters were from distant plants. Pollen removal did not vary greatly among sites, and was not affected by bird exclusion; however, more pollen was deposited on the stigmas of cleaned pollen presenters in the population previously observed to be highly outcrossing than in the other two. This high level of pollen deposition was reduced by experimental bird exclusion. CONCLUSIONS Honey-bees were the most frequent visitors, by an order of magnitude, and excluding vertebrates revealed that bees were removing most of the pollen but deposited fewer pollen grains on stigmas. Birds were more frequent visitors at the site previously found to be outcrossing than the other two sites, and they moved further between plants and visited fewer inflorescences on a plant during a foraging bout than bees did. These characteristics of bird visits to G. macleayana would be sufficient to produce significant variation in outcrossing rates among sites.
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