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Lunau K, Dyer AG. The modelling of flower colour: spectral purity or colour contrast as biologically relevant descriptors of flower colour signals for bees depending upon the perceptual task. PLANT BIOLOGY (STUTTGART, GERMANY) 2024. [PMID: 38958933 DOI: 10.1111/plb.13682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 05/07/2024] [Indexed: 07/04/2024]
Abstract
Flower colour is an important mediator of plant-pollinator interactions. While the reflectance of light from the flower surface and background are governed by physical properties, the perceptual interpretation of such information is generated by complex multilayered visual processing. Should quantitative modelling of flower signals strive for repeatable consistency enabled by parameter simplification, or should modelling reflect the dynamic way in which bees are known to process signals? We discuss why colour is an interpretation of spectral information by the brain of an animal. Different species, or individuals within a species, may respond differently to colour signals depending on sensory apparatus and/or individual experience. Humans and bees have different spectral ranges, but colour theory is strongly rooted in human colour perception and many principles of colour vision appear to be common. We discuss bee colour perception based on physiological, neuroanatomical and behavioural evidence to provide a pathway for modelling flower colours. We examine whether flower petals and floral guides as viewed against spectrally different backgrounds should be considered as a simple colour contrast problem or require a more dynamic consideration of how bees make perceptual decisions. We discuss that plants such as deceptive orchids may present signals to exploit bee perception, whilst many plants do provide honest signalling where perceived saturation indicates the probability of collecting nutritional rewards towards the centre of a flower that then facilitates effective pollination.
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Affiliation(s)
- K Lunau
- Faculty of Mathematics and Natural Sciences, Institute of Sensory Ecology, Heinrich-Heine University, Düsseldorf, Germany
| | - A G Dyer
- Department of Physiology, Monash University, Clayton, Australia
- Institut für Entwicklungsbiologie, und Neurobiologie, Johannes Gutenberg Universität, Mainz, Germany
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Barreto E, Boehm MMA, Ogutcen E, Abrahamczyk S, Kessler M, Bascompte J, Dellinger AS, Bello C, Dehling DM, Duchenne F, Kaehler M, Lagomarsino LP, Lohmann LG, Maglianesi MA, Morlon H, Muchhala N, Ornelas JF, Perret M, Salinas NR, Smith SD, Vamosi JC, Varassin IG, Graham CH. Macroevolution of the plant-hummingbird pollination system. Biol Rev Camb Philos Soc 2024. [PMID: 38705863 DOI: 10.1111/brv.13094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 04/19/2024] [Accepted: 04/26/2024] [Indexed: 05/07/2024]
Abstract
Plant-hummingbird interactions are considered a classic example of coevolution, a process in which mutually dependent species influence each other's evolution. Plants depend on hummingbirds for pollination, whereas hummingbirds rely on nectar for food. As a step towards understanding coevolution, this review focuses on the macroevolutionary consequences of plant-hummingbird interactions, a relatively underexplored area in the current literature. We synthesize prior studies, illustrating the origins and dynamics of hummingbird pollination across different angiosperm clades previously pollinated by insects (mostly bees), bats, and passerine birds. In some cases, the crown age of hummingbirds pre-dates the plants they pollinate. In other cases, plant groups transitioned to hummingbird pollination early in the establishment of this bird group in the Americas, with the build-up of both diversities coinciding temporally, and hence suggesting co-diversification. Determining what triggers shifts to and away from hummingbird pollination remains a major open challenge. The impact of hummingbirds on plant diversification is complex, with many tropical plant lineages experiencing increased diversification after acquiring flowers that attract hummingbirds, and others experiencing no change or even a decrease in diversification rates. This mixed evidence suggests that other extrinsic or intrinsic factors, such as local climate and isolation, are important covariables driving the diversification of plants adapted to hummingbird pollination. To guide future studies, we discuss the mechanisms and contexts under which hummingbirds, as a clade and as individual species (e.g. traits, foraging behaviour, degree of specialization), could influence plant evolution. We conclude by commenting on how macroevolutionary signals of the mutualism could relate to coevolution, highlighting the unbalanced focus on the plant side of the interaction, and advocating for the use of species-level interaction data in macroevolutionary studies.
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Affiliation(s)
- Elisa Barreto
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf, 8903, Switzerland
| | - Mannfred M A Boehm
- Biodiversity Research Centre, University of British Columbia, 2212 Main Mall, Vancouver, BC, Canada
| | - Ezgi Ogutcen
- Department of Environment and Biodiversity, Paris Lodron University of Salzburg, Hellbrunner Straße 34, Salzburg, 5020, Austria
| | - Stefan Abrahamczyk
- Nees Institute for Biodiversity of Plant, University of Bonn, Meckenheimer Allee 170, Bonn, 53115, Germany
- State Museum of Natural History Stuttgart, Botany Department, Rosenstein 1, Stuttgart, 70191, Germany
| | - Michael Kessler
- Systematic and Evolutionary Botany, University of Zurich, Zollikerstrasse 107, Zurich, 8008, Switzerland
| | - Jordi Bascompte
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurestrasse 190, Zurich, 8057, Switzerland
| | - Agnes S Dellinger
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, Vienna, 1030, Austria
| | - Carolina Bello
- Department of Environmental Systems Science, Institute of Integrative Biology, ETH Zurich, Universitätstrasse 16, Zurich, 8092, Switzerland
| | - D Matthias Dehling
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf, 8903, Switzerland
- Securing Antarctica's Environmental Future, School of Biological Sciences, Monash University, 25 Rainforest Walk, Clayton, 3800, Victoria, Australia
| | - François Duchenne
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf, 8903, Switzerland
| | - Miriam Kaehler
- Departamento de Botânica, Universidade Federal do Paraná, Avenida Coronel Francisco H. dos Santos 100, Curitiba, 81531-980, Brazil
| | - Laura P Lagomarsino
- Department of Biological Sciences, Shirley C. Tucker Herbarium, Louisiana State University, Life Science Annex Building A257, Baton Rouge, 70803, LA, USA
| | - Lúcia G Lohmann
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Rua do Matão 277, Butantã, São Paulo, 05508-090, Brazil
- Department of Integrative Biology, University and Jepson Herbaria, University of California, Berkeley, 1001 Valley Life Sciences Building, Berkeley, 94720-2465, CA, USA
| | - María A Maglianesi
- Escuela de Ciencias Exactas y Naturales, Universidad Estatal a Distancia, San José, 474-2050, Costa Rica
| | - Hélène Morlon
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, UMR 8197, 46 rue d'Ulm, Paris, 75005, France
| | - Nathan Muchhala
- Department of Biology, University of Missouri - St. Louis, St. Louis, 63121, MO, USA
| | - Juan Francisco Ornelas
- Departamento de Biología Evolutiva, Instituto de Ecología, A.C. (INECOL), Xalapa, Veracruz, 91073, Mexico
| | - Mathieu Perret
- Department of Plant Sciences, Conservatoire et Jardin Botaniques de Genève, University of Geneva, Chem. de l'Impératrice 1, 1292 Pregny-Chambésy, Geneva, Switzerland
| | - Nelson R Salinas
- Pfizer Plant Research Laboratory, New York Botanical Garden, 2900 Southern Blvd., Bronx, New York City, 10458, NY, USA
| | - Stacey D Smith
- Department of Ecology and Evolutionary Biology, University of Colorado-Boulder, 1900 Pleasant St, Boulder, 80302, CO, USA
| | - Jana C Vamosi
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, T2N1N4, AB, Canada
| | - Isabela G Varassin
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf, 8903, Switzerland
- Departamento de Botânica, Universidade Federal do Paraná, Avenida Coronel Francisco H. dos Santos 100, Curitiba, 81531-980, Brazil
| | - Catherine H Graham
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf, 8903, Switzerland
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Lunau K, De Camargo MGG, Brito VLG. Pollen, anther, stamen, and androecium mimicry. PLANT BIOLOGY (STUTTGART, GERMANY) 2024; 26:349-368. [PMID: 38407440 DOI: 10.1111/plb.13628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 01/23/2024] [Indexed: 02/27/2024]
Abstract
Floral colours represent a highly diverse communication signal mainly involved in flower visitors' attraction and guidance, but also flower discrimination, filtering non-pollinators and discouraging floral antagonists. The divergent visual systems and colour preferences of flower visitors, as well as the necessity of cues for flower detection and discrimination, foster the diversity of floral colours and colour patterns. Despite the bewildering diversity of floral colour patterns, a recurrent component is a yellow UV-absorbing floral centre, and it is still not clear why this pattern is so frequent in angiosperms. The pollen, anther, stamen, and androecium mimicry (PASAM) hypothesis suggests that the system composed of the flowers possessing such yellow UV-absorbing floral reproductive structures, the flowers displaying central yellow UV-absorbing structures as floral guides, and the pollen-collecting, as well as pollen-eating, flower visitors responding to such signals constitute the world's most speciose mimicry system. In this review, we call the attention of researchers to some hypothetical PASAM systems around the globe, presenting some fascinating examples that illustrate their huge diversity. We will also present new and published data on pollen-eating and pollen-collecting pollinators' responses to PASAM structures supporting the PASAM hypothesis and will discuss how widespread these systems are around the globe. Ultimately, our goal is to promote the idea that PASAM is a plausible first approach to understanding floral colour patterns in angiosperms.
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Affiliation(s)
- K Lunau
- Faculty of Mathematics and Natural Sciences, Institute of Sensory Ecology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - M G G De Camargo
- Phenology Lab, Department of Biodiversity, Biosciences Institute, UNESP - São Paulo State University, Rio Claro, São Paulo, Brazil
| | - V L G Brito
- Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil
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Ospina-Calvo B, De Gerónimo E, Villarruel FD, Aparicio VC, Ashworth L, Erra-Balsells R, Cabrerizo FM. Distribution of photoactive β-carboline alkaloids across Passiflora caerulea floral organs. Photochem Photobiol 2024; 100:87-100. [PMID: 37448143 DOI: 10.1111/php.13837] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/15/2023] [Accepted: 07/01/2023] [Indexed: 07/15/2023]
Abstract
This study reports valuable information regarding the presence and concentration of a series of photoactive β-carboline (βCs) alkaloids (norharmane, harmane, harmine, harmol, harmaline, and harmalol) and their distribution across the floral age and organs of Passiflora caerulea. UHPLC-MS/MS data reported herein reveal that the βCs' content ranged from 1 to 110 μg kg-1 , depending on the floral organ and age. In certain physiologically relevant organs, such as anthers, βCs' content was one order of magnitude higher than in other organs, suggesting a special role for βCs in this specific organ. βCs' content also varied in a structure-dependent manner. Alkaloids bearing a hydroxyl group at position C(7) of the main βC ring were present at concentrations one order of magnitude higher than other βC derivatives investigated. UV-visible and fluorescence spectroscopy of the flower extracts provided complementary information regarding other biologically relevant groups of chromophores (phenolic/indolic derivatives, flavonoids/carotenes, and chlorophylls). Since flowers are constantly exposed to solar radiation, the presence of photoactive βCs in floral organs may have several (photo)biological implications that are further discussed.
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Affiliation(s)
- Brian Ospina-Calvo
- Instituto Tecnológico de Chascomús (CONICET-UNSAM), Chascomús, Argentina
- Escuela de Bio y Nanotecnologías (UNSAM), San Martin, Argentina
| | - Eduardo De Gerónimo
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Estación Experimental Agropecuaria, Instituto Nacional de Tecnología Agropecuaria, Buenos Aires, Argentina
| | - Fernando D Villarruel
- Instituto Tecnológico de Chascomús (CONICET-UNSAM), Chascomús, Argentina
- Escuela de Bio y Nanotecnologías (UNSAM), San Martin, Argentina
| | - Virgina C Aparicio
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Estación Experimental Agropecuaria, Instituto Nacional de Tecnología Agropecuaria, Buenos Aires, Argentina
| | - Lorena Ashworth
- Instituto Multidisciplinario de Biología Vegetal (IMBIV, CONICET), Universidad Nacional de Córdoba (UNC), Córdoba, Argentina
| | - Rosa Erra-Balsells
- Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón II, 3er P, Ciudad Universitaria, Buenos Aires, Argentina
- CONICET, Universidad de Buenos Aires, Centro de Investigación en Hidratos de Carbono (CIHIDECAR), Facultad de Ciencias Exactas y Naturales, Pabellón II, 3er P, Ciudad Universitaria, Buenos Aires, Argentina
| | - Franco M Cabrerizo
- Instituto Tecnológico de Chascomús (CONICET-UNSAM), Chascomús, Argentina
- Escuela de Bio y Nanotecnologías (UNSAM), San Martin, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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Kang Y, Li Y, Zhang T, Wang P, Liu W, Zhang Z, Yu W, Wang J, Wang J, Zhou Y. Integrated metabolome, full-length sequencing, and transcriptome analyses unveil the molecular mechanisms of color formation of the canary yellow and red bracts of Bougainvillea × buttiana 'Chitra'. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 116:1441-1461. [PMID: 37648415 DOI: 10.1111/tpj.16439] [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: 03/25/2023] [Revised: 08/05/2023] [Accepted: 08/16/2023] [Indexed: 09/01/2023]
Abstract
Bougainvillea is a typical tropical flower of great ornamental value due to its colorful bracts. The molecular mechanism behind color formation is not well-understood. Therefore, this research conducted metabolome analysis, transcriptome analysis, and multi-flux full-length sequencing in two color bracts of Bougainvillea × buttiana 'Chitra' to investigate the significantly different metabolites (SDMs) and differentially expressed genes (DEGs). Overall, 261 SDMs, including 62 flavonoids and 26 alkaloids, were detected, and flavonols and betalains were significantly differentially accumulated among the two bracts. Furthermore, the complete-length transcriptome of Bougainvillea × buttiana was also developed, which contained 512 493 non-redundant isoforms. Among them, 341 210 (66.58%) displayed multiple annotations in the KOG, GO, NR, KEGG, Pfam, Swissprot, and NT databases. RNA-seq findings revealed that 3610 DEGs were identified between two bracts. Co-expression analysis demonstrated that the DEGs and SDMs involved in flavonol metabolism (such as CHS, CHI, F3H, FLS, CYP75B1, kaempferol, and quercetin) and betacyanin metabolism (DODA, betanidin, and betacyanins) were the main contributors for the canary yellow and red bract formation, respectively. Further investigation revealed that several putative transcription factors (TFs) might interact with the promoters of the genes mentioned above. The expression profiles of the putative TFs displayed that they may positively and negatively regulate the structural genes' expression profiles. The data revealed a potential regulatory network between important genes, putative TFs, and metabolites in the flavonol and betacyanin biosynthesis of Bougainvillea × buttiana 'Chitra' bracts. These findings will serve as a rich genetic resource for future studies that could create new color bracts.
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Affiliation(s)
- Yuqian Kang
- Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, School of Tropical Agriculture and Forestry (School of Agricultural and Rural Affairs, School of Rural Revitalization), Hainan University, Haikou, 570228, Hainan, People's Republic of China
| | - Yuxin Li
- Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, School of Tropical Agriculture and Forestry (School of Agricultural and Rural Affairs, School of Rural Revitalization), Hainan University, Haikou, 570228, Hainan, People's Republic of China
| | - Tingting Zhang
- Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, School of Tropical Agriculture and Forestry (School of Agricultural and Rural Affairs, School of Rural Revitalization), Hainan University, Haikou, 570228, Hainan, People's Republic of China
- Xiangyang Academy of Agricultural Sciences, Xiangyang, 441057, Hubei, People's Republic of China
| | - Peng Wang
- Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, School of Tropical Agriculture and Forestry (School of Agricultural and Rural Affairs, School of Rural Revitalization), Hainan University, Haikou, 570228, Hainan, People's Republic of China
| | - Wen Liu
- Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, School of Tropical Agriculture and Forestry (School of Agricultural and Rural Affairs, School of Rural Revitalization), Hainan University, Haikou, 570228, Hainan, People's Republic of China
| | - Zhao Zhang
- Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, School of Tropical Agriculture and Forestry (School of Agricultural and Rural Affairs, School of Rural Revitalization), Hainan University, Haikou, 570228, Hainan, People's Republic of China
| | - Wengang Yu
- Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, School of Tropical Agriculture and Forestry (School of Agricultural and Rural Affairs, School of Rural Revitalization), Hainan University, Haikou, 570228, Hainan, People's Republic of China
| | - Jian Wang
- Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, School of Tropical Agriculture and Forestry (School of Agricultural and Rural Affairs, School of Rural Revitalization), Hainan University, Haikou, 570228, Hainan, People's Republic of China
| | - Jian Wang
- Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, School of Tropical Agriculture and Forestry (School of Agricultural and Rural Affairs, School of Rural Revitalization), Hainan University, Haikou, 570228, Hainan, People's Republic of China
| | - Yang Zhou
- Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, School of Tropical Agriculture and Forestry (School of Agricultural and Rural Affairs, School of Rural Revitalization), Hainan University, Haikou, 570228, Hainan, People's Republic of China
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6
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Bruninga‐Socolar B, Socolar JB, Konzmann S, Lunau K. Pollinator-mediated plant coexistence requires high levels of pollinator specialization. Ecol Evol 2023; 13:e10349. [PMID: 37539071 PMCID: PMC10394160 DOI: 10.1002/ece3.10349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 07/06/2023] [Accepted: 07/10/2023] [Indexed: 08/05/2023] Open
Abstract
In pollen-limited plant communities, the foraging behavior of pollinators might mediate coexistence and competitive exclusion of plant species by determining which plants receive conspecific pollen. A key question is whether realistic pollinator foraging behavior promotes coexistence or exclusion of plant species. We use a simulation model to understand how pollinator foraging behavior impacts the coexistence dynamics of pollen-limited plants. To determine whether pollinators are likely to provide a biologically important coexistence mechanism, we compare our results to bee foraging data from the literature and from a novel experimental analysis. Model results indicate that strong specialization at the level of individual foraging paths is required to promote coexistence. However, few empirical studies have robustly quantified within-bout specialization. Species-level data suggest that foraging behavior is sufficient to permit pollinator-mediated coexistence in species-poor plant communities and possibly in diverse communities where congeneric plants co-occur. Our experiments using bumblebees show that individual-level specialization does exist, but not at levels sufficient to substantially impact coexistence dynamics. The literature on specialization within natural foraging paths suffers from key limitations, but overall suggests that pollinator-mediated coexistence should be rare in diverse plant communities.
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Costa A, Moré M, Sérsic AN, Cocucci AA, Drewniak ME, Izquierdo JV, Coetzee A, Pauw A, Traveset A, Paiaro V. Floral colour variation of Nicotiana glauca in native and non-native ranges: Testing the role of pollinators' perception and abiotic factors. PLANT BIOLOGY (STUTTGART, GERMANY) 2023; 25:403-410. [PMID: 36744723 DOI: 10.1111/plb.13509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
Invasive plants displaying disparate pollination environments and abiotic conditions in native and non-native ranges provide ideal systems to test the role of different ecological factors driving flower colour variation. We quantified corolla reflectance of the ornithophilous South American Nicotiana glauca in native populations, where plants are pollinated by hummingbirds, and in populations from two invaded regions: South Africa, where plants are pollinated by sunbirds, and the Balearic island of Mallorca, where plants reproduce by selfing. Using visual modelling we examined how corolla reflectance could be perceived by floral visitors present in each region. Through Mantel tests we assessed a possible association between flower colour and different abiotic factors. Corolla reflectance variation (mainly along medium to long wavelengths, i.e. human green-yellow to red colours) was greater among studied regions than within them. Flower colour was more similar between South America and South Africa, which share birds as pollinators. Within invaded regions, corolla reflectance variation was lower in South Africa, where populations could not be distinguished from each other by sunbirds, than in Spain, where populations could be distinguished from each other by their occasional visitors. Differences in corolla colour among populations were partially associated with differences in temperature. Our findings suggest that shifts in flower colour of N. glauca across native and invaded ranges could be shaped by changes in both pollination environment and climatic factors. This is the first study on plant invasions considering visual perception of different pollinators and abiotic drivers of flower colour variation.
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Affiliation(s)
- A Costa
- Instituto Multidisciplinario de Biología Vegetal (CONICET-UNC), Córdoba, Argentina
| | - M Moré
- Instituto Multidisciplinario de Biología Vegetal (CONICET-UNC), Córdoba, Argentina
| | - A N Sérsic
- Instituto Multidisciplinario de Biología Vegetal (CONICET-UNC), Córdoba, Argentina
| | - A A Cocucci
- Instituto Multidisciplinario de Biología Vegetal (CONICET-UNC), Córdoba, Argentina
| | - M E Drewniak
- Instituto Multidisciplinario de Biología Vegetal (CONICET-UNC), Córdoba, Argentina
| | - J V Izquierdo
- Instituto Multidisciplinario de Biología Vegetal (CONICET-UNC), Córdoba, Argentina
| | - A Coetzee
- Fitz Patrick Institute of African Ornithology, DSI-NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa
| | - A Pauw
- Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa
| | - A Traveset
- Instituto Mediterráneo de Estudios Avanzados (CSIC, UIB), Mallorca, Balearic Islands, Spain
| | - V Paiaro
- Instituto Multidisciplinario de Biología Vegetal (CONICET-UNC), Córdoba, Argentina
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8
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Mori S, Hasegawa Y, Moriguchi Y. Color strategies of camellias recruiting different pollinators. PHYTOCHEMISTRY 2023; 207:113559. [PMID: 36528119 DOI: 10.1016/j.phytochem.2022.113559] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 12/09/2022] [Accepted: 12/10/2022] [Indexed: 06/17/2023]
Abstract
Most ornithophilous plants have red flowers; this has been associated with 'the bee avoidance hypothesis', in which ornithophilous flowers may bear colors that are less conspicuous to bees than melittophilous flowers. In the genus Camellia, C. rusticana and C. japonica bear red flowers and yet recruit different pollinators; the former is entomophilous, while the latter is ornithophilous. C. japonica is considered to have been speciated from a common ancestor later than C. rusticana, accompanying a pollinator shift from insects to birds. Nevertheless, factors explaining the pollinator difference in camellias remain rudimentary. In this study, the color traits of the two camellias were investigated, to determine their color strategy to allure different pollinators. The behavior of bees towards the two camellias was examined by a two-choice assay. Flower color characteristics of the two camellias were analyzed with diffuse reflectance and fluorescence spectra. Based on the visual sensory system of bees and birds, the achromatic contrast, chromatic contrast, intensity, and spectral purity of the two species were evaluated, testing the bee avoidance hypothesis. Furthermore, the compounds responsible for the fluorescence, likely serving as a visual attractant, were identified by NMR and MS. Bees visited C. rusticana flowers almost exclusively and C. japonica hardly at all. Reflectance spectral data showed that C. rusticana petals are more conspicuous to bees than birds due to a UV-reflection secondary peak; and that C. japonica petals exhibited crucially low chromatic contrast against a leaf background to bees, suggesting them to be almost indistinguishable. On the other hand, C. japonica flowers appeared conspicuous to birds. The anthers of C. rusticana exhibited blue fluorescence derived from two anthranilates, while those of C. japonica did not. The two camellias offer different color strategies to be conspicuous to their respective pollinators, and C. japonica seemed to have evolved to avoid bees. Alterations in these color traits may have played a role in pollinator shift.
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Affiliation(s)
- Shinnosuke Mori
- Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan.
| | - Yoichi Hasegawa
- Forestry and Forest Products Research Institute, Forest Research and Management Organization, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Yoshinari Moriguchi
- Graduate School of Science and Technology, Niigata University, 8050, Ikarashi 2-Nocho, Nishi-ku, Niigata, 950-2181, Japan
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Dujmović M, Radman S, Opačić N, Fabek Uher S, Mikuličin V, Voća S, Šic Žlabur J. Edible Flower Species as a Promising Source of Specialized Metabolites. PLANTS (BASEL, SWITZERLAND) 2022; 11:2529. [PMID: 36235395 PMCID: PMC9570977 DOI: 10.3390/plants11192529] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 09/20/2022] [Accepted: 09/23/2022] [Indexed: 01/22/2023]
Abstract
Eating habits are changing over time and new innovative nutrient-rich foods will play a great role in the future. Awareness of the importance of a healthy diet is growing, so consumers are looking for new creative food products rich in phytochemicals, i.e., specialized metabolites (SM). The consumption of fruits, vegetables and aromatic species occupies an important place in the daily diet, but different edible flower species are still neglected and unexplored. Flowers are rich in SM, have strong antioxidant capacities and also possess significant functional and biological values with favorable impacts on human health. The main aim of this study was to evaluate the content of SM and the antioxidant capacities of the edible flower species: Calendula officinalis L. (common marigold), Tagetes erecta L. (African marigold), Tropaeolum majus L. (nasturtium), Cucurbita pepo L. convar. giromontiina (zucchini) and Centaurea cyanus L. (cornflower). The obtained results showed the highest content of ascorbic acid (129.70 mg/100 g fw) and anthocyanins (1012.09 mg/kg) recorded for cornflower, phenolic compounds (898.19 mg GAE/100 g fw) and carotenoids (0.58 mg/g) for African marigold and total chlorophylls (0.75 mg/g) for common marigold. In addition to the esthetic impression of the food, they represent an important source of SM and thus can have a significant impact if incorporated in the daily diet.
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Affiliation(s)
- Mia Dujmović
- Department of Agricultural Technology, Storage and Transport, University of Zagreb Faculty of Agriculture, Svetošimunska cesta 25, 10000 Zagreb, Croatia
| | - Sanja Radman
- Department of Vegetable Crops, University of Zagreb Faculty of Agriculture, Svetošimunska cesta 25, 10000 Zagreb, Croatia
| | - Nevena Opačić
- Department of Vegetable Crops, University of Zagreb Faculty of Agriculture, Svetošimunska cesta 25, 10000 Zagreb, Croatia
| | - Sanja Fabek Uher
- Department of Vegetable Crops, University of Zagreb Faculty of Agriculture, Svetošimunska cesta 25, 10000 Zagreb, Croatia
| | - Vida Mikuličin
- Department of Agricultural Technology, Storage and Transport, University of Zagreb Faculty of Agriculture, Svetošimunska cesta 25, 10000 Zagreb, Croatia
| | - Sandra Voća
- Department of Agricultural Technology, Storage and Transport, University of Zagreb Faculty of Agriculture, Svetošimunska cesta 25, 10000 Zagreb, Croatia
| | - Jana Šic Žlabur
- Department of Agricultural Technology, Storage and Transport, University of Zagreb Faculty of Agriculture, Svetošimunska cesta 25, 10000 Zagreb, Croatia
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10
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León‐Osper M, Narbona E. Unravelling the mystery of red flowers in the Mediterranean Basin: How to be conspicuous in a place dominated by hymenopteran pollinators. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14166] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Melissa León‐Osper
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide Sevilla España
| | - Eduardo Narbona
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide Sevilla España
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11
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Mundi O, Awa Ii T, Chmel K, Ewome FL, Uceda-Gómez G, Janečková P, Janeček Š. The ornithophily of Impatiens sakeriana does not guarantee a preference by sunbirds. Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blac083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
In recent decades, the tight mutual specialization between nectarivorous birds and ornithophilous plants has been questioned, and instead, high degrees of generalization and interaction asymmetry have been highlighted. Here, we studied interactions among two sunbirds and four plant species in two Mount Cameroon forests, with two plant species from each forest. First, we investigated whether sunbirds differ in frequencies of visitation to target plant species in natural conditions. Second, using a cage experiment, we investigated whether sunbirds prefer various plant species, plants with which they are more familiar and that occur in the habitat where they were caught and/or the only studied ornithophilous plant, Impatiens sakeriana. In natural conditions, the short-billed sunbird, Cinnyris reichenowi, fed more on flowers with shorter tubes than the long-billed sunbird, Cyanomitra oritis. Likewise, sunbirds differed in their experimental preferences. Local plants were generally preferred. This was most obvious in the case of I. sakeriana, which was often visited by both sunbirds, but only in the habitat where it grows naturally. This study supports the importance of associative learning. Together with other studies, we suggest that the signalling traits of flowers with bird pollination syndromes evolved to filter out other visitors rather than to attract bird pollinators.
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Affiliation(s)
- Onella Mundi
- Laboratory of Applied Biology and Ecology, Faculty of Science, University of Dschang , PO Box 67, Dschang, West Region , Cameroon
| | - Taku Awa Ii
- Laboratory of Applied Biology and Ecology, Faculty of Science, University of Dschang , PO Box 67, Dschang, West Region , Cameroon
| | - Kryštof Chmel
- Department of Ecology, Faculty of Science, Charles University , Viničná 7, CZ-128 44 Praha 2 , Czech Republic
| | - Francis Luma Ewome
- Department of Ecology, Faculty of Science, Charles University , Viničná 7, CZ-128 44 Praha 2 , Czech Republic
| | - Guillermo Uceda-Gómez
- Department of Ecology, Faculty of Science, Charles University , Viničná 7, CZ-128 44 Praha 2 , Czech Republic
| | - Petra Janečková
- Department of Ecology, Faculty of Science, Charles University , Viničná 7, CZ-128 44 Praha 2 , Czech Republic
| | - Štěpán Janeček
- Department of Ecology, Faculty of Science, Charles University , Viničná 7, CZ-128 44 Praha 2 , Czech Republic
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12
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van der Kooi CJ, Spaethe J. Caution with colour calculations: spectral purity is a poor descriptor of flower colour visibility. ANNALS OF BOTANY 2022; 130:1-9. [PMID: 35726715 PMCID: PMC9295922 DOI: 10.1093/aob/mcac069] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND The colours of flowers are of key interest to plant and pollination biologists. An increasing number of studies have investigated the importance of saturation of flower colours (often called 'spectral purity' or 'chroma') for visibility to pollinators, but the conceptual, physiological and behavioural foundations for these metrics as well as the calculations used rest on slender foundations. METHODS We discuss the caveats of colour attributes that are derived from human perception, and in particular spectral purity and chroma, as variables in flower colour analysis. We re-analysed seven published datasets encompassing 774 measured reflectance spectra to test for correlations between colour contrast, spectral purity and chroma. MAIN FINDINGS AND CONCLUSIONS We identify several concerns with common calculation procedures in animal colour spaces. Studies on animal colour vision provide no ground to assume that any pollinator perceives (or responds to) saturation, chroma or spectral purity in the way humans do. A re-analysis of published datasets revealed that values for colour contrast between flowers and their background are highly correlated with measures for spectral purity and chroma, which invalidates treating these factors as independent variables as is currently commonplace. Strikingly, spectral purity and chroma - both of which are metrics for saturation and are often used synonymously - are not correlated at all. We conclude that alternative, behaviourally validated metrics for the visibility of flowers to pollinators, such as colour contrast and achromatic contrast, are better in understanding the role of flower colour in plant-pollinator signalling.
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Affiliation(s)
| | - Johannes Spaethe
- Department of Behavioral Physiology and Sociobiology, University of Würzburg, Germany
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13
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Pachpor T, Sonne M, Bhatt A, Parkar K, Shahane S, Mestry P, Kulkarni S, Ogale H, Patwardhan A. Nectar Sugar Composition, Standing Nectar Crop and Floral Visitor Diversity of Three Endemic Plant Species from Western Ghats Biodiversity Hot-Spot of India. Chem Biodivers 2022; 19:e202200001. [PMID: 35578975 DOI: 10.1002/cbdv.202200001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 05/06/2022] [Indexed: 11/11/2022]
Abstract
Plant insect interactions are governed by various factors. Nectar availability and floral nectar composition play a significant role in deciding the pollinator pool that visits a particular plant species. This study investigates nectar sugar composition and volume from three endemic species from Western Ghats of India viz. Canthium dicoccum (Gaertn.) Teijsm. & Binn., Ligustrum perrottetii A. DC., and Wendlandia thyrsoidea (Roth) Steud., in their natural habitats. Our results demonstrate intraspecific variation in nectar sugar composition in these endemic plant species. Fructose, mannose and glucose sugars were found in the nectar of all three species. In addition to these three, arabinose was found in Ligustrum and sucrose in Canthium. Nectar volume showed variations in bagged and unbagged conditions. The highest average nectar quantity was found in Canthium (1.27 μl/flower), followed by Ligustrum (0. 31 μl/flower), and Wendlandia (0.14 μl/flower). Floral visitor diversity with a specific emphasis on butterflies showed the highest number of visitors on Ligustrum i. e., 42 out of 45 total butterfly species across all three plant species. This is the first report of standing nectar crop and nectar-sugar composition data compiled for these plant species.
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Affiliation(s)
- Tejaswini Pachpor
- Annasaheb Kulkarni Department of Biodiversity, M.E.S. Abasaheb Garware College, Pune-411004, Maharashtra, India
| | - Mrunalini Sonne
- Annasaheb Kulkarni Department of Biodiversity, M.E.S. Abasaheb Garware College, Pune-411004, Maharashtra, India
| | - Alap Bhatt
- Annasaheb Kulkarni Department of Biodiversity, M.E.S. Abasaheb Garware College, Pune-411004, Maharashtra, India
| | - Kshitija Parkar
- Annasaheb Kulkarni Department of Biodiversity, M.E.S. Abasaheb Garware College, Pune-411004, Maharashtra, India
| | - Sneha Shahane
- Annasaheb Kulkarni Department of Biodiversity, M.E.S. Abasaheb Garware College, Pune-411004, Maharashtra, India
| | - Pratiksha Mestry
- Annasaheb Kulkarni Department of Biodiversity, M.E.S. Abasaheb Garware College, Pune-411004, Maharashtra, India
| | - Shivani Kulkarni
- Annasaheb Kulkarni Department of Biodiversity, M.E.S. Abasaheb Garware College, Pune-411004, Maharashtra, India
| | - Hemant Ogale
- Research and Action in Natural Wealth Administration (RANWA), 16 Swastishree Society, Ganeshnagar, Kothrud, Pune - 411052, Maharashtra, India
| | - Ankur Patwardhan
- Annasaheb Kulkarni Department of Biodiversity, M.E.S. Abasaheb Garware College, Pune-411004, Maharashtra, India.,Research and Action in Natural Wealth Administration (RANWA), 16 Swastishree Society, Ganeshnagar, Kothrud, Pune - 411052, Maharashtra, India
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14
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Andrino CO, Santana PC, Lovo J, Barbosa-Silva RG, Albuquerque-Lima S, Zappi DC. Anthers in blue: a hidden rhapsody in Amazonian Eriocaulaceae. Ecology 2022; 103:e3636. [PMID: 35050515 DOI: 10.1002/ecy.3636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/11/2021] [Accepted: 11/16/2021] [Indexed: 11/09/2022]
Affiliation(s)
- Caroline O Andrino
- Instituto Tecnológico Vale, R. Boaventura da Silva 955 Nazaré, 66055-090, Belém, PA, Brazil.,Museu Paraense Emílio Goeldi, Campus de Pesquisa Coord. Botânica, Av. Perimetral 1901, Terra Firme, 66077-830, Belém, PA, Brazil
| | - Pamela C Santana
- Departamento de Ecologia, Universidade de São Paulo, São Paulo, Brazil
| | - Juliana Lovo
- Departamento de Sistemática e Ecologia, Universidade Federal da Paraíba, Caixa Postal 5065, Cidade Universitária, João Pessoa, PB, Brazil
| | - Rafael G Barbosa-Silva
- Instituto Tecnológico Vale, R. Boaventura da Silva 955 Nazaré, 66055-090, Belém, PA, Brazil.,Museu Paraense Emílio Goeldi, Campus de Pesquisa Coord. Botânica, Av. Perimetral 1901, Terra Firme, 66077-830, Belém, PA, Brazil
| | - Sinzinando Albuquerque-Lima
- Laboratório de Biologia Floral e Reprodutiva, Centro de Biociências, Universidade Federal de Pernambuco, Avenida Professor Moraes Rego 1235, Cidade Universitária, Recife, PE, Brazil
| | - Daniela C Zappi
- Instituto Tecnológico Vale, R. Boaventura da Silva 955 Nazaré, 66055-090, Belém, PA, Brazil.,Programa de Pós-Graduação em Botânica, Instituto de Ciências Biológicas, Universidade de Brasília, DF, Brazil
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15
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Amorim MD, Maruyama PK, Baronio GJ, Azevedo CS, Rech AR. Hummingbird contribution to plant reproduction in the rupestrian grasslands is not defined by pollination syndrome. Oecologia 2022; 199:1-12. [PMID: 35043254 DOI: 10.1007/s00442-021-05103-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 12/21/2021] [Indexed: 11/24/2022]
Abstract
Floral traits mediate the roles of distinct animals as effective pollinators along a generalization/specialization continuum. Many plant species are visited by different pollinator functional groups and the specific contribution of each group is expected to reflect the set of floral characteristics defined by pollination syndromes. Although considered a highly specialized nectarivorous group, hummingbirds frequently visit flowers lacking apparent specialization to bird pollination. How they contribute to the reproduction of these plants, however, has not been evaluated through field experiments considering multiple non-related plant species simultaneously. Here, we investigated hummingbirds' contributions to the pollination of ten plant species comprising a gradient of adaptation to bird pollination in the Brazilian rupestrian grasslands. We excluded hummingbirds from flowers and evaluated their relative contribution in comparison to insects (mainly bees) on conspecific/heterospecific pollen deposition and fruit set. Floral traits that are typically associated with bird pollination were associated with increased pollen deposition, but not with fruit set in the presence of hummingbirds. With hummingbirds, conspecific and heterospecific pollen deposition increased in most species, while fruit set increased in four plant species with varying degrees of fit to ornithophily. Our results show that assessing the relative contribution of specific pollinator groups may depend on when this contribution is measured, i.e. pollen deposition or fruit set. Considering fruit set, our results indicate that hummingbirds contributed to plant reproduction independently of the fit to bird pollination syndrome. This emphasizes their importance as under-appreciated generalized pollinators in some communities.
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Affiliation(s)
- Marsal D Amorim
- Programa de Pós-Graduação em Biologia Animal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, MG, 39100-000, Brazil. .,Programa de Pós-Graduação em Ecologia, Conservação e Manejo da Vida Silvestre, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil.
| | - Pietro K Maruyama
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil
| | - Gudryan J Baronio
- Programa de Pos-Graduação em Ciência Florestal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Campus JK, Diamantina, MG, 39100-000, Brazil
| | - Cristiano S Azevedo
- Departamento de Evolução, Biodiversidade e Meio Ambiente, Instituto de Ciências Exatas e Biológicas, Campus Morro do Cruzeiro, s/n, Bauxita, Ouro Prêto, MG, CEP: 35400-000, Brazil
| | - André R Rech
- Faculdade Interdisciplinar de Humanidades, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, Minas Gerais, 39100-000, Brazil
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16
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Garcia JE, Hannah L, Shrestha M, Burd M, Dyer AG. Fly pollination drives convergence of flower coloration. THE NEW PHYTOLOGIST 2022; 233:52-61. [PMID: 34460949 DOI: 10.1111/nph.17696] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 08/18/2021] [Indexed: 06/13/2023]
Abstract
Plant-pollinator interactions provide a natural experiment in signal evolution. Flowers are known to have evolved colour signals that maximise their ease of detection by the visual systems of important pollinators such as bees. Whilst most angiosperms are bee pollinated, our understanding on how the second largest group of pollinating insects, flies, may influence flower colour evolution is limited to the use of categorical models of colour discrimination that do not reflect the small colour differences commonly observed between and within flower species. Here we show by comparing flower signals that occur in different environments including total absence of bees, a mixture of bee and fly pollination within one plant family (Orchidaceae) from a single community, and typical flowers from a broad taxonomic sampling of the same geographic region, that perceptually different colours, empirically measured, do evolve in response to different types of insect pollinators. We show evidence of both convergence among fly-pollinated floral colours but also of divergence and displacement of colour signals in the absence of bee pollinators. Our findings give an insight into how both ecological and agricultural systems may be affected by changes in pollinator distributions around the world.
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Affiliation(s)
- Jair E Garcia
- Bio-Inspired Digital Sensing Laboratory, School of Media and Communication, RMIT University, Melbourne, Vic., 3000, Australia
| | - Lea Hannah
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, 2750, Australia
| | - Mani Shrestha
- Department of Disturbance Ecology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, 95447, Germany
- School of Information Technology, Monash University, Clayton, Vic., 3168, Australia
| | - Martin Burd
- School of Biological Sciences, Monash University, Clayton, Vic., 3168, Australia
| | - Adrian G Dyer
- Bio-Inspired Digital Sensing Laboratory, School of Media and Communication, RMIT University, Melbourne, Vic., 3000, Australia
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17
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Lunau K, Scaccabarozzi D, Willing L, Dixon K. A bee's eye view of remarkable floral colour patterns in the south-west Australian biodiversity hotspot revealed by false colour photography. ANNALS OF BOTANY 2021; 128:821-824. [PMID: 34216211 PMCID: PMC8577209 DOI: 10.1093/aob/mcab088] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND AND AIMS Colour pattern is a key cue of bee attraction selectively driving the appeal of pollinators. It comprises the main colour of the flower with extra fine patterns, indicating a reward focal point such as nectar, nectaries, pollen, stamens and floral guides. Such advertising of floral traits guides visitation by the insects, ensuring precision in pollen gathering and deposition. The study, focused in the Southwest Australian Floristic Region, aimed to spot bee colour patterns that are usual and unusual, missing, accomplished by mimicry of pollen and anthers, and overlapping between mimic-model species in floral mimicry cases. METHODS Floral colour patterns were examined by false colour photography in 55 flower species of multiple highly diverse natural plant communities in south-west Australia. False colour photography is a method to transform a UV photograph and a colour photograph into a false colour photograph based on the trichromatic vision of bees. This method is particularly effective for rapid screening of large numbers of flowers for the presence of fine-scale bee-sensitive structures and surface roughness that are not detectable using standard spectrophotometry. KEY RESULTS Bee- and bird-pollinated flowers showed the expected but also some remarkable and unusual previously undetected floral colour pattern syndromes. Typical colour patterns include cases of pollen and flower mimicry and UV-absorbing targets. Among the atypical floral colour patterns are unusual white and UV-reflecting flowers of bee-pollinated plants, bicoloured floral guides, consistently occurring in Fabaceae spp., and flowers displaying a selective attractiveness to birds only. In the orchid genera (Diuris and Thelymitra) that employ floral mimicry of model species, we revealed a surprising mimicry phenomenon of anthers mimicked in turn by model species. CONCLUSION The study demonstrates the applicability of 'bee view' colour imaging for deciphering pollinator cues in a biodiverse flora with potential to be applied to other eco regions. The technique provides an exciting opportunity for indexing floral traits on a biome scale to establish pollination drivers of ecological and evolutionary relevance.
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Affiliation(s)
- Klaus Lunau
- Institute of Sensory Ecology, Heinrich-Heine University Düsseldorf, Germany
| | - Daniela Scaccabarozzi
- School of Molecular and Life Sciences, Curtin University, Perth, Western Australia, Australia
| | - Larissa Willing
- Institute of Sensory Ecology, Heinrich-Heine University Düsseldorf, Germany
| | - Kingsley Dixon
- School of Molecular and Life Sciences, Curtin University, Perth, Western Australia, Australia
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18
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Garcia JE, Dyer AG, Burd M, Shrestha M. Flower colour and size signals differ depending on geographical location and altitude region. PLANT BIOLOGY (STUTTGART, GERMANY) 2021; 23:905-914. [PMID: 34546624 DOI: 10.1111/plb.13326] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 07/18/2021] [Indexed: 06/13/2023]
Abstract
Bees are major pollinators of angiosperms and have phylogenetically conserved colour vision but differ in how various key species use achromatic information that is vital for both flower detection and size processing. We modelled green contrast and colour contrast signals from flowers of different countries where there are well established differences in availability of model bee species along altitudinal gradients. We tested for consistency in visual signals as expected from generalization in pollination principles using phylogenetically informed linear models. Patterns of chromatic contrast, achromatic green contrast and flower size differed among the three floras we examined. In Nepal there is a significant positive correlation between flower size and colour contrast in the subalpine region, but a negative correlation at the lower altitudes. At high elevations in Norway, where pollinators other than bees are common, flower size was positively correlated with colour contrast. At low and medium altitudes in Norway and in Australia, we did not observe a significant relationship between size and colour contrast. We thus find that the relationship between size, green and colour contrast cannot be generalized across communities, thus suggesting that flower visual signal adaptations to local pollinators are not limited to chromatic contrast.
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Affiliation(s)
- J E Garcia
- Bio-Inspired Digital Sensing (BIDs Lab), School of Media and Communication, RMIT University, Melbourne, Victoria, Australia
| | - A G Dyer
- Bio-Inspired Digital Sensing (BIDs Lab), School of Media and Communication, RMIT University, Melbourne, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - M Burd
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - M Shrestha
- Bio-Inspired Digital Sensing (BIDs Lab), School of Media and Communication, RMIT University, Melbourne, Victoria, Australia
- Disturbance Ecology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
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19
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Pollination generalization and reproductive assurance by selfing in a tropical montane ecosystem. Naturwissenschaften 2021; 108:50. [PMID: 34626232 DOI: 10.1007/s00114-021-01764-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 09/22/2021] [Accepted: 09/29/2021] [Indexed: 10/20/2022]
Abstract
Pollination and reproduction are important processes for understanding plant community dynamics. Information regarding pollination and reproduction is urgent for threatened ecosystems, such as tropical montane ecosystems. In tropical mountains, pollination patterns are expected to conform to the reproductive assurance theory (due to low pollinator activity) and old, climatically buffered and infertile landscapes (OCBIL) theory (due to restricted plant range size). For 82 plant species of the Itatiaia National Park (including endemic and endangered species), we evaluated at least one of the following features: pollinator identity, flower color and size, flowering phenology, and pollinator dependence. Most plant species (ca. 60%) were pollinated by two or more functional groups of pollinators (generalized pollination), with high importance of flies as pollinators. There was low pollinator activity overall (less than one visit per flower per hour). Notably, the invasive honeybee Apis mellifera L. performed half of the visits to this entire plant community, suggesting an impact on the native pollinator fauna and consequently on the native flora. Most endemic plants were generalized with white and small flowers, while endangered species were pollination-specialized with colorful and large flowers. Thus, endangered species are susceptible to changes in pollinator fauna. Flowering seasonality reflected the importance of climatic constraints in this environment. One-third of the plant species were autogamous. Our data suggest that pollinator scarcity may have promoted reproductive assurance strategies such as generalization and pollinator independence. Our community-level study highlighted consistent pollination patterns for tropical mountains and emphasized threats for specialized endangered species.
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20
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Narbona E, del Valle JC, Arista M, Buide ML, Ortiz PL. Major Flower Pigments Originate Different Colour Signals to Pollinators. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.743850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Flower colour is mainly due to the presence and type of pigments. Pollinator preferences impose selection on flower colour that ultimately acts on flower pigments. Knowing how pollinators perceive flowers with different pigments becomes crucial for a comprehensive understanding of plant-pollinator communication and flower colour evolution. Based on colour space models, we studied whether main groups of pollinators, specifically hymenopterans, dipterans, lepidopterans and birds, differentially perceive flower colours generated by major pigment groups. We obtain reflectance data and conspicuousness to pollinators of flowers containing one of the pigment groups more frequent in flowers: chlorophylls, carotenoids and flavonoids. Flavonoids were subsequently classified in UV-absorbing flavonoids, aurones-chalcones and the anthocyanins cyanidin, pelargonidin, delphinidin, and malvidin derivatives. We found that flower colour loci of chlorophylls, carotenoids, UV-absorbing flavonoids, aurones-chalcones, and anthocyanins occupied different regions of the colour space models of these pollinators. The four groups of anthocyanins produced a unique cluster of colour loci. Interestingly, differences in colour conspicuousness among the pigment groups were almost similar in the bee, fly, butterfly, and bird visual space models. Aurones-chalcones showed the highest chromatic contrast values, carotenoids displayed intermediate values, and chlorophylls, UV-absorbing flavonoids and anthocyanins presented the lowest values. In the visual model of bees, flowers with UV-absorbing flavonoids (i.e., white flowers) generated the highest achromatic contrasts. Ours findings suggest that in spite of the almost omnipresence of floral anthocyanins in angiosperms, carotenoids and aurones-chalcones generates higher colour conspicuousness for main functional groups of pollinators.
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Saab GDS, Mansano VDF, Nogueira A, Maia IC, Bergamo PJ, Paulino JV. A sophisticated case of division of labour in the trimorphic stamens of the Cassia fistula (Leguminosae) flower. AOB PLANTS 2021; 13:plab054. [PMID: 34512942 PMCID: PMC8420109 DOI: 10.1093/aobpla/plab054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 08/26/2021] [Indexed: 06/13/2023]
Abstract
Buzz-pollinated pollen flowers have pollen as the primary resource for pollinators and must deal with a conflict between the exploitation of pollen grains by bees and pollination success. It has been hypothesized that heterostemony allows division of labour between stamens as a solution to the pollen dilemma. To test the division of labour hypothesis, we chose Cassia fistula, which has a trimorphic androecium and analysed androecium development, pollen grain release mechanisms and visitor behaviour. We explored the reflectance of floral organs and carried out an exclusion experiment to test the attractiveness of each stamen morph to the bee species. Finally, we explored the structural, ultrastructural and functional variation between the pollen grains, including pollen viability across stamen morphs. The differences among the three stamen morphs, which is developed from two whorls of the stamen, are the first evidence of the division of labour in our study system. Large Bombus and Xylocopa bees actively and exclusively exploited the pollen grains from the central poricidal anthers generating pollen deposition on their bodies. The reflectance pattern of floral organs indicated a targeting of these large bees to the central anthers, corroborated by the anther manipulative experiment where only the exclusion of the anthers positioned in the flower centre, especially the intermediate stamens, reduced bee visits. Both results revealed a division of labour, in which the intermediate stamen morph was responsible for both floral attractiveness and pollen resources. Only the largest stamen morph produced germinable pollen grains, highlighting their role as pollinating stamens. The smallest stamen morph has a less clear function, likely representing an economy in pollen production for feeding function. Our findings suggest that the evolution of the trimorphic androecium is associated with division of labour in large pollen flowers and can represent a strong strategy for circumventing the pollen dilemma, optimizing the feeding function by reducing pollen grain investment from central anthers.
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Affiliation(s)
- Gabriella da Silva Saab
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ 21941-902, Brazil
| | - Vidal de Freitas Mansano
- Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, DIPEQ, Rua Pacheco Leão 915, Rio de Janeiro, RJ 22460-030, Brazil
| | - Anselmo Nogueira
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, São Bernardo do Campo, SP 09606-045, Brazil
| | - Isabele Carvalho Maia
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, São Bernardo do Campo, SP 09606-045, Brazil
| | - Pedro Joaquim Bergamo
- Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, DIPEQ, Rua Pacheco Leão 915, Rio de Janeiro, RJ 22460-030, Brazil
- Programa de Pós-Graduação em Ecologia, Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas (Unicamp), Barão Geraldo, Campinas, SP 13083-862, Brazil
| | - Juliana Villela Paulino
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ 21941-902, Brazil
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Ohashi K, Jürgens A, Thomson JD. Trade-off mitigation: a conceptual framework for understanding floral adaptation in multispecies interactions. Biol Rev Camb Philos Soc 2021; 96:2258-2280. [PMID: 34096158 PMCID: PMC8518848 DOI: 10.1111/brv.12754] [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] [Received: 05/03/2020] [Revised: 05/15/2021] [Accepted: 05/18/2021] [Indexed: 11/26/2022]
Abstract
Explanations of floral adaptation to diverse pollinator faunas have often invoked visitor‐mediated trade‐offs in which no intermediate, generalized floral phenotype is optimal for pollination success, i.e. fitness valleys are created. In such cases, plant species are expected to specialize on particular groups of flower visitors. Contrary to this expectation, it is commonly observed that flowers interact with various groups of visitors, while at the same time maintaining distinct phenotypes among ecotypes, subspecies, or congeners. This apparent paradox may be due to a gap in our understanding of how visitor‐mediated trade‐offs could affect floral adaptation. Here we provide a conceptual framework for analysing visitor‐mediated trade‐offs with the hope of stimulating empirical and theoretical studies to fill this gap. We propose two types of visitor‐mediated trade‐offs to address negative correlations among fitness contributions of different visitors: visitor‐mediated phenotypic trade‐offs (phenotypic trade‐offs) and visitor‐mediated opportunity trade‐offs (opportunity trade‐offs). Phenotypic trade‐offs occur when different groups of visitors impose conflicting selection pressures on a floral trait. By contrast, opportunity trade‐offs emerge only when some visitors’ actions (e.g. pollen collection) remove opportunities for fitness contribution by more beneficial visitors. Previous studies have observed disruptive selection due to phenotypic trade‐offs less often than expected. In addition to existing explanations, we propose that some flowers have achieved ‘adaptive generalization’ by evolving features to avoid or eliminate the fitness valleys that phenotypic trade‐offs tend to produce. The literature suggests a variety of pathways to such ‘trade‐off mitigation’. Trade‐off mitigation may also evolve as an adaptation to opportunity trade‐offs. We argue that active exclusion, or floral specialization, can be viewed as a trade‐off mitigation, occurring only when flowers cannot otherwise avoid strong opportunity trade‐offs. These considerations suggest that an evolutionary strategy for trade‐off mitigation is achieved often by acquiring novel combinations of traits. Thus, phenotypic diversification of flowers through convergent evolution of certain trait combinations may have been enhanced not only through adaptive specialization for particular visitors, but also through adaptive generalization for particular visitor communities. Explorations of how visitor‐mediated trade‐offs explain the recurrent patterns of floral phenotypes may help reconcile the long‐lasting controversy on the validity of pollination syndromes.
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Affiliation(s)
- Kazuharu Ohashi
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan.,Department of Biology, Chemical Plant Ecology, Technische Universität Darmstadt, Schnittspahnstrasse 4, 64287 Darmstadt, Germany
| | - Andreas Jürgens
- Department of Biology, Chemical Plant Ecology, Technische Universität Darmstadt, Schnittspahnstrasse 4, 64287 Darmstadt, Germany
| | - James D Thomson
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Harbord St., Toronto, ON, M5S 3G5, Canada
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23
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Monteiro BL, Camargo MGG, Loiola PDP, Carstensen DW, Gustafsson S, Morellato LPC. Pollination in the campo rupestre: a test of hypothesis for an ancient tropical mountain vegetation. Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blaa205] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
The campo rupestre is a Neotropical OCBIL (old, climatically buffered infertile landscape), a grassy-shrub vegetation with high species richness and endemism, characterized by rocky outcrops surrounded by grasslands distributed in South American ancient mountaintops. We tested one OCBIL prediction: the prevalence of long-distance pollinators ensuring cross-pollination across the archipelago-like landscapes of the campo rupestre. We described the pollination systems and tested whether their frequency differed across vegetation types and elevation, focusing on long-distance systems. We performed non-systematic and systematic surveys of plants and plant-pollinator interactions across the elevation gradient and vegetation types. We also reviewed the literature on campo rupestre pollination and applied an accuracy criterion to infer 11 pollination systems. The bee system was split into large bee (long-distance) and small bee (shorter distances) to test the prevalence of long-distance pollination systems. We surveyed 413 pollinator species, mostly bees (220) and flies (69). Among the 636 plant species studied, the bee pollination system was dominant (56%), followed by wind and hummingbird. Wind, small-bee and fly pollination systems increased with elevation, and small-bee and wind pollination systems prevailed in grasslands. Large-bee and hummingbird long-distance pollination systems remained unchanged with elevation and were more frequent in the highly isolated rocky outcrops corroborating the OCBIL theory.
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Affiliation(s)
- Beatriz Lopes Monteiro
- Phenology Laboratory, Department of Biodiversity, Biosciences Institute, UNESP–São Paulo State University, Rio Claro, São Paulo, Brazil
| | - Maria Gabriela Gutierrez Camargo
- Phenology Laboratory, Department of Biodiversity, Biosciences Institute, UNESP–São Paulo State University, Rio Claro, São Paulo, Brazil
| | - Priscilla De Paula Loiola
- Phenology Laboratory, Department of Biodiversity, Biosciences Institute, UNESP–São Paulo State University, Rio Claro, São Paulo, Brazil
| | - Daniel Wisbech Carstensen
- Center for Macroecology, Evolution and Climate, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
| | - Simone Gustafsson
- Center for Macroecology, Evolution and Climate, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
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Roguz K, Hill L, Koethe S, Lunau K, Roguz A, Zych M. Visibility and attractiveness of Fritillaria (Liliaceae) flowers to potential pollinators. Sci Rep 2021; 11:11006. [PMID: 34040041 PMCID: PMC8155214 DOI: 10.1038/s41598-021-90140-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 05/05/2021] [Indexed: 02/04/2023] Open
Abstract
Visual floral characters play an important role in shaping plant-pollinator interactions. The genus Fritillaria L. (Liliaceae), comprising approximately 140 species, is described as displaying a remarkable variety of flower colours and sizes. Despite this variation in visual floral traits of fritillaries, little is known about the potential role of these features in shaping plant-pollinator interactions. Here, we seek to clarify the role of visual attraction in species offering a robust food reward for pollinators early in the spring, which is the case for Fritillaria. We also searched for potential tendencies in the evolution of floral traits crucial for plant-pollinator communication. The generality of species with green and purple flowers may indicate an influence of environmental factors other than pollinators. The flowers of the studied species seem to be visible but not very visually attractive to potential pollinators. The food rewards are hidden within the nodding perianth, and both traits are conserved among fritillaries. Additionally, visual floral traits are not good predictors of nectar properties. When in the flowers, pollinators are navigated by nectar guides in the form of contrasting nectary area colouration. Flower colour does not serve as a phenotypic filter against illegitimate pollinators-red and orange bird-pollinated fritillaries are visible to bees.
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Affiliation(s)
- Katarzyna Roguz
- Botanic Garden, Faculty of Biology, University of Warsaw, Warsaw, Poland.
| | | | - Sebastian Koethe
- Institute of Sensory Ecology, Faculty of Biology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Klaus Lunau
- Institute of Sensory Ecology, Faculty of Biology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Agata Roguz
- National Information Processing Institute, Al. Niepodległości 188 B, 00-608, Warszawa, Poland
| | - Marcin Zych
- Botanic Garden, Faculty of Biology, University of Warsaw, Warsaw, Poland
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25
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Tunes P, Camargo MGG, Guimarães E. Floral UV Features of Plant Species From a Neotropical Savanna. FRONTIERS IN PLANT SCIENCE 2021; 12:618028. [PMID: 34025689 PMCID: PMC8137824 DOI: 10.3389/fpls.2021.618028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
Despite the wide interest in flower colours, only after the end of the nineteenth-century studies started to comprise floral UV reflection, which is invisible to humans but visible to the major groups of pollinators. Many flowers and inflorescences display colour patterns, an important signal for pollinators, promoted by the presence of at least two different colours within flowers or inflorescences, including colours in the UV waveband. For Neotropical savanna plant species, we characterised floral UV features using UV-photography and reflectance measurements. We tested (i) whether floral UV features were constrained by their shared ancestry, (ii) whether floral UV features were associated with pollinators, and (iii) whether floral UV features were associated with floral traits mediating these interactions, including floral resource, type of attraction unit and presence/absence of non-UV colour patterns. Of 80 plant species, ca. 70% were UV-patternless, most of them UV-absorbing. Approximately 30% presented one of three types of UV-patterns: bullseye, contrasting corolla markings oriented toward floral resources or contrasting reproductive structures, which were all considered as floral guides. Floral UV features were phylogenetically constrained and were associated with pollinators, floral resources and attraction unit, but not with non-UV colour patterns. UV-patternless flowers were associated with most of the pollination systems, while UV-patterned flowers were mainly associated with bee-pollination. UV-absorbing flowers comprised the only category with hawkmoth- and butterfly-pollinated flowers, and a high percentage of hummingbird-pollinated species. Nocturnal pollinated species were also commonly UV-absorbing, except for one UV-reflecting bat-pollinated species and one beetle-pollinated species with UV-reflecting stigmas. All types of floral UV features were associated with nectar; however, flowers with contrasting reproductive structures were mainly associated with pollen. There was an association between UV-absorbing species and the presence of inflorescences and intermediate attraction units. Our results evince that phylogenetic relatedness can constraint floral UV features' diversification, but combinations of evolutionary and ecological processes may be expected in this scenario.
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Affiliation(s)
- Priscila Tunes
- Laboratory of Ecology and Evolution of Plant-Animal Interactions, Postgraduate Program in Biological Sciences (Botany), Institute of Biosciences, São Paulo State University, Botucatu, Brazil
| | | | - Elza Guimarães
- Laboratory of Ecology and Evolution of Plant-Animal Interactions, Institute of Biosciences, São Paulo State University, Botucatu, Brazil
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26
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Martins AE, Arista M, Morellato LPC, Camargo MGG. Color signals of bee-pollinated flowers: the significance of natural leaf background. AMERICAN JOURNAL OF BOTANY 2021; 108:788-797. [PMID: 34056706 DOI: 10.1002/ajb2.1656] [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: 05/21/2020] [Accepted: 12/29/2020] [Indexed: 06/12/2023]
Abstract
PREMISE Flower color is a primary pollinator attractant and generally adjusted to the cognitive system of the pollinators. The perception of flower color depends on the visual system of pollinators and also on environmental factors such as light conditions and the background against which flowers are displayed. METHODS Using bee-pollinated Fabaceae species as a model, we analyzed flower color diversity and compared flower color signals considering both the standard green and the natural leaf background of two tropical seasonally dry vegetations-a mountain rupestrian grassland (campo rupestre) and a woody savanna (cerrado)-compared to a nontropical Mediterranean shrubland. RESULTS By using natural background, bees discriminated color for 58% of the flowers in the campo rupestre and for only 43% in cerrado. Both vegetations were surpassed by 75% of bee color discrimination in Mediterranean vegetation. Chromatic contrast and purity were similar among the three vegetation types. Green contrast and brightness were similar between the tropical vegetations but differed from the Mediterranean shrubland. Green contrast differences were lost when using a standard green background, and most variables (purity, green contrast, and brightness) differed according to the background (natural or standard green) in all vegetations. CONCLUSIONS The natural background influenced bee perception of flower color regardless of vegetation. The background of the campo rupestre promoted green contrast for flowers, ensuring flower detection by pollinators and, along with bees, may also act as a selective pressure driving the diversity of flower colors in Fabaceae species. We highlight the importance of considering the natural background coloration when analyzing flower color signals.
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Affiliation(s)
- Amanda E Martins
- Department of Biodiversity, Phenology Lab, São Paulo State University (UNESP), Biosciences Institute, Av 24A, 1515, Rio Claro, São Paulo, 13506-900, Brazil
| | - Montserrat Arista
- Department of Plant Biology and Ecology, Universidad de Sevilla, Seville, 41080, Spain
| | - Leonor Patricia Cerdeira Morellato
- Department of Biodiversity, Phenology Lab, São Paulo State University (UNESP), Biosciences Institute, Av 24A, 1515, Rio Claro, São Paulo, 13506-900, Brazil
| | - Maria Gabriela G Camargo
- Department of Biodiversity, Phenology Lab, São Paulo State University (UNESP), Biosciences Institute, Av 24A, 1515, Rio Claro, São Paulo, 13506-900, Brazil
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27
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Martins AE, Camargo MGG, Morellato LPC. Flowering Phenology and the Influence of Seasonality in Flower Conspicuousness for Bees. FRONTIERS IN PLANT SCIENCE 2021; 11:594538. [PMID: 33664750 PMCID: PMC7921784 DOI: 10.3389/fpls.2020.594538] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 12/28/2020] [Indexed: 05/28/2023]
Abstract
Flowering patterns are crucial to understand the dynamics of plant reproduction and resource availability for pollinators. Seasonal climate constrains flower and leaf phenology, where leaf and flower colors likely differ between seasons. Color is the main floral trait attracting pollinators; however, seasonal changes in the leaf-background coloration affect the perception of flower color contrasts by pollinators. For a seasonally dry woody cerrado community (Brazilian savanna) mainly pollinated by bees, we verified whether seasonality affects flower color diversity over time and if flower color contrasts of bee-pollinated species differ between seasons due to changes in the leaf-background coloration. For 140 species, we classified flower colors based on human-color vision, and for 99 species, we classified flower colors based on bee-color vision (spectral measurements). We described the community's flowering pattern according to the flower colors using a unique 11 years phenological database. For the 43 bee-pollinated species in which reflectance data were also available, we compared flower color diversity and contrasts against the background between seasons, considering the background coloration of each season. Flowering was markedly seasonal, peaking at the end of the dry season (September), when the highest diversity of flower colors was observed. Yellow flowers were observed all year round, whereas white flowers were seasonal, peaking during the dry season, and pink flowers predominated in the wet season, peaking in March. Bee-bluegreen flowers peaked between September and October. Flowers from the wet and dry seasons were similarly conspicuous against their corresponding background. Regardless of flowering season, the yellowish background of the dry season promoted higher flower color contrast for all flower species, whereas the greener background of the wet season promoted a higher green contrast. Temporal patterns of flower colors and color contrasts were related to the cerrado seasonality, but also to bee's activity, visual system, and behavior. Background coloration affected flower contrasts, favoring flower conspicuousness to bees according to the season. Thus, our results provide new insights regarding the temporal patterns of plant-pollinator interactions.
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Affiliation(s)
- Amanda Eburneo Martins
- Phenology Laboratory, Department of Biodiversity, Biosciences Institute, São Paulo State University (UNESP), Rio Claro, Brazil
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28
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Dyer AG, Jentsch A, Burd M, Garcia JE, Giejsztowt J, Camargo MGG, Tjørve E, Tjørve KMC, White P, Shrestha M. Fragmentary Blue: Resolving the Rarity Paradox in Flower Colors. FRONTIERS IN PLANT SCIENCE 2021; 11:618203. [PMID: 33552110 PMCID: PMC7859648 DOI: 10.3389/fpls.2020.618203] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 12/17/2020] [Indexed: 05/05/2023]
Abstract
Blue is a favored color of many humans. While blue skies and oceans are a common visual experience, this color is less frequently observed in flowers. We first review how blue has been important in human culture, and thus how our perception of blue has likely influenced the way of scientifically evaluating signals produced in nature, including approaches as disparate as Goethe's Farbenlehre, Linneaus' plant taxonomy, and current studies of plant-pollinator networks. We discuss the fact that most animals, however, have different vision to humans; for example, bee pollinators have trichromatic vision based on UV-, Blue-, and Green-sensitive photoreceptors with innate preferences for predominantly short-wavelength reflecting colors, including what we perceive as blue. The subsequent evolution of blue flowers may be driven by increased competition for pollinators, both because of a harsher environment (as at high altitude) or from high diversity and density of flowering plants (as in nutrient-rich meadows). The adaptive value of blue flowers should also be reinforced by nutrient richness or other factors, abiotic and biotic, that may reduce extra costs of blue-pigments synthesis. We thus provide new perspectives emphasizing that, while humans view blue as a less frequently evolved color in nature, to understand signaling, it is essential to employ models of biologically relevant observers. By doing so, we conclude that short wavelength reflecting blue flowers are indeed frequent in nature when considering the color vision and preferences of bees.
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Affiliation(s)
- Adrian G. Dyer
- School of Media and Communication, RMIT University, Melbourne, VIC, Australia
| | - Anke Jentsch
- Department of Disturbance Ecology, Bayreuth Center for Ecology and Environmental Research, University of Bayreuth, Bayreuth, Germany
| | - Martin Burd
- School of Biological Sciences, Monash University, Melbourne, VIC, Australia
| | - Jair E. Garcia
- School of Media and Communication, RMIT University, Melbourne, VIC, Australia
| | - Justyna Giejsztowt
- Department of Disturbance Ecology, Bayreuth Center for Ecology and Environmental Research, University of Bayreuth, Bayreuth, Germany
| | - Maria G. G. Camargo
- Phenology Lab, Biosciences Institute, Department of Biodiversity, UNESP – São Paulo State University, São Paulo, Brazil
| | - Even Tjørve
- Inland Norway University of Applied Sciences, Lillehammer, Norway
| | | | - Peter White
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Mani Shrestha
- School of Media and Communication, RMIT University, Melbourne, VIC, Australia
- Faculty of Information Technology, Monash University, Melbourne, VIC, Australia
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29
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Stavenga DG, Leertouwer HL, Dudek B, van der Kooi CJ. Coloration of Flowers by Flavonoids and Consequences of pH Dependent Absorption. FRONTIERS IN PLANT SCIENCE 2021; 11:600124. [PMID: 33488645 PMCID: PMC7820715 DOI: 10.3389/fpls.2020.600124] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/08/2020] [Indexed: 05/13/2023]
Abstract
Flavonoid pigments are key determinants of flower colors. As absorption spectra of flavonoids are known to be severely pH-dependent, cellular pH will play a crucial role in flower coloration. The flavonoids are concentrated in the vacuoles of the flowers' epidermal cells, and thus the pigments' absorption spectra are modulated by the vacuolar pH. Here we study the pH dependence of flavonoid absorption spectra in extracts from flowers of two poppy species Papaver dubium (red) and Meconopsis cambrica (orange), and a white and red Mandevilla sanderi variety. In the red poppy and Mandevilla flowers, absorption spectra of the cyanidin- and pelargonidin-based anthocyanins peak in the blue-green-wavelength range at low pH, but exhibit a distinct bathochromic shift at higher pH. This shift to longer wavelengths is not found for the blue-absorbing nudicaulin derivatives of M. cambrica, which have a similar absorption spectrum at low and high pH. The pH-dependent absorption changes of the white M. sanderi's flavonoid remained restricted to the UV. An analysis of the spectra with logistic functions suggests that the pH-dependent characteristics of the basic states of flavonols and anthocyanins are related. The implications of tuning of pH and pigment absorption spectra for studies on flower color evolution are discussed.
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Affiliation(s)
- Doekele G. Stavenga
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, Netherlands
| | - Hein L. Leertouwer
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, Netherlands
| | - Bettina Dudek
- Research Group Biosynthesis/NMR, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Casper J. van der Kooi
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands
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30
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Soares NC, Maruyama PK, Staggemeier VG, Morellato LPC, Araújo MS. The role of individual variation in flowering and pollination in the reproductive success of a crepuscular buzz-pollinated plant. ANNALS OF BOTANY 2021; 127:213-222. [PMID: 32914162 PMCID: PMC7789112 DOI: 10.1093/aob/mcaa163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 09/05/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND AND AIMS Plant individuals within a population differ in their phenology and interactions with pollinators. However, it is still unknown how individual differences affect the reproductive success of plants that have functionally specialized pollination systems. Here, we evaluated whether plant individual specialization in phenology (temporal specialization) and in pollination (pollinator specialization) affect the reproductive success of the crepuscular-bee-pollinated plant Trembleya laniflora (Melastomataceae). METHODS We quantified flowering activity (amplitude, duration and overlap), plant-pollinator interactions (number of flowers visited by pollinators) and reproductive success (fruit set) of T. laniflora individuals from three distinct locations in rupestrian grasslands of southeastern Brazil. We estimated the degree of individual temporal specialization in flowering phenology and of individual specialization in plant-pollinator interactions, and tested their relationship with plant reproductive success. KEY RESULTS Trembleya laniflora presented overlapping flowering, a temporal generalization and specialized pollinator interactions. Flowering overlap among individuals and populations was higher than expected by chance but did not affect the individual interactions with pollinators and nor their reproductive success. In contrast, higher individual generalization in the interactions with pollinators was related to higher individual reproductive success. CONCLUSIONS Our findings suggest that individual generalization in plant-pollinator interaction reduces the potential costs of specialization at the species level, ensuring reproductive success. Altogether, our results highlight the complexity of specialization/generalization of plant-pollinator interactions at distinct levels of organization, from individuals to populations, to species.
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Affiliation(s)
- Natalia Costa Soares
- Laboratório de Fenologia, Departamento de Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, SP, Brazil
| | - Pietro Kiyoshi Maruyama
- Centro de Síntese Ecológica e Conservação, Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Vanessa Graziele Staggemeier
- Laboratório de Fenologia, Departamento de Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, SP, Brazil
- Departamento de Ecologia, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil
| | - Leonor Patrícia Cerdeira Morellato
- Laboratório de Fenologia, Departamento de Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, SP, Brazil
| | - Márcio Silva Araújo
- Departamento de Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, SP, Brazil
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31
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Tai KC, Shrestha M, Dyer AG, Yang EC, Wang CN. Floral Color Diversity: How Are Signals Shaped by Elevational Gradient on the Tropical-Subtropical Mountainous Island of Taiwan? FRONTIERS IN PLANT SCIENCE 2020; 11:582784. [PMID: 33391297 DOI: 10.5061/dryad.63xsj3v08] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 11/25/2020] [Indexed: 05/27/2023]
Abstract
Pollinators with different vision are a key driver of flower coloration. Islands provide important insights into evolutionary processes, and previous work suggests islands may have restricted flower colors. Due to both species richness with high endemism in tropical-subtropical environments, and potentially changing pollinator distributions with altitude, we evaluated flower color diversity across the mountainous island of Taiwan in a comparative framework to understand the cause of color diversity. We sampled flower color signaling on the tropical-subtropical island of Taiwan considering altitudes from sea level to 3300 m to inform how over-dispersion, random processes or clustering may influence flower signaling. We employed a model of bee color space to plot loci from 727 species to enable direct comparisons to data sets from continental studies representing Northern and Southern Hemispheres, and also a continental mountain region. We observed that flower color diversity was similar to flowers that exist in mainland continental studies, and also showed evidence that flowers predominantly had evolved color signals that closely matched bee color preferences. At high altitudes floras tend to be phylogenetically clustered rather than over-dispersed, and their floral colors exhibited weak phylogenetic signal which is consistent with character displacement that facilitated the co-existence of related species. Overall flower color signaling on a tropical-subtropical island is mainly influenced by color preferences of key bee pollinators, a pattern consistent with continental studies.
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Affiliation(s)
- King-Chun Tai
- Department of Life Science, National Taiwan University, Taipei, Taiwan
- Institute of Ecology and Evolutionary Biology, National Taiwan University, Taipei, Taiwan
| | - Mani Shrestha
- School of Media and Communication, RMIT University, Melbourne, VIC, Australia
| | - Adrian G Dyer
- School of Media and Communication, RMIT University, Melbourne, VIC, Australia
| | - En-Cheng Yang
- Department of Entomology, National Taiwan University, Taipei, Taiwan
| | - Chun-Neng Wang
- Department of Life Science, National Taiwan University, Taipei, Taiwan
- Institute of Ecology and Evolutionary Biology, National Taiwan University, Taipei, Taiwan
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Moré M, Ibañez AC, Drewniak ME, Cocucci AA, Raguso RA. Flower Diversification Across "Pollinator Climates": Sensory Aspects of Corolla Color Evolution in the Florally Diverse South American Genus Jaborosa (Solanaceae). FRONTIERS IN PLANT SCIENCE 2020; 11:601975. [PMID: 33365042 PMCID: PMC7750315 DOI: 10.3389/fpls.2020.601975] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 11/04/2020] [Indexed: 06/12/2023]
Abstract
Flower phenotype may diverge within plant lineages when moving across "pollinator climates" (geographic differences in pollinator abundance or preference). Here we explored the potential importance of pollinators as drivers of floral color diversification in the nightshade genus Jaborosa, taking into account color perception capabilities of the actual pollinators (nocturnal hawkmoths vs. saprophilous flies) under a geographic perspective. We analyzed the association between transitions across environments and perceptual color axes using comparative methods. Our results revealed two major evolutionary themes in Jaborosa: (1) a "warm subtropical sphingophilous clade" composed of three hawkmoth-pollinated species found in humid lowland habitats, with large white flowers that clustered together in the visual space of a model hawkmoth (Manduca sexta) and a "cool-temperate brood-deceptive clade" composed of largely fly-pollinated species with small dark flowers found at high altitudes (Andes) or latitudes (Patagonian Steppe), that clustered together in the visual space of a model blowfly (Lucilia sp.) and a syrphid fly (Eristalis tenax). Our findings suggest that the ability of plants to colonize newly formed environments during Andean orogeny and the ecological changes that followed were concomitant with transitions in flower color as perceived by different pollinator functional groups. Our findings suggest that habitat and pollination mode are inextricably linked in the history of this South American plant lineage.
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Affiliation(s)
- Marcela Moré
- Laboratorio de Ecología Evolutiva y Biología Floral, Instituto Multidisciplinario de Biología Vegetal, CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Ana C. Ibañez
- Laboratorio de Ecología Evolutiva y Biología Floral, Instituto Multidisciplinario de Biología Vegetal, CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - M. Eugenia Drewniak
- Laboratorio de Ecología Evolutiva y Biología Floral, Instituto Multidisciplinario de Biología Vegetal, CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Andrea A. Cocucci
- Laboratorio de Ecología Evolutiva y Biología Floral, Instituto Multidisciplinario de Biología Vegetal, CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Robert A. Raguso
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, United States
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Miola DTB, Ramos VDV, Silveira FAO. A brief history of research in campo rupestre: identifying research priorities and revisiting the geographical distribution of an ancient, widespread Neotropical biome. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa175] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Few ecologists and evolutionary biologists are familiar with the ecology and evolution of the campo rupestre, an ancient azonal peinobiome characterized by a fire-prone, nutrient-impoverished, montane vegetation mosaic, home to thousands of endemics and climate refugia. With the goal of providing a synthetic view of the campo rupestre, we provide a brief historical account of the biological research, revisit its geographical distribution and identify knowledge gaps. The azonal campo rupestre is distributed as isolated and naturally fragmented sky islands, mostly in Central and Eastern Brazil and in the Guyana Shield, with significant areas across the Amazon, Cerrado, Atlantic Forest, Caatinga and Pantanal. Our proposal to elevate campo rupestre to the level of biome is expected to improve communication among scientists and consolidate the use of the term campo rupestre in the ecological and evolutionary literature, as is the case for analogous ecosystems, such as kwongan, fynbos, páramos and tepuis. Based on the identification of knowledge gaps, we propose a research programme comprising ten key topics that can foster our understanding of the ecology and evolution of campo rupestre and, potentially, support conservation strategies.
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Affiliation(s)
- Deise T B Miola
- Rua Itaúna 35, Lj 3. Pará de Minas, Minas Gerais, Brazil
- Departamento de Genética, Ecologia e Evolução, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | - Fernando A O Silveira
- Departamento de Genética, Ecologia e Evolução, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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Aguiar JMRBV, Maciel AA, Santana PC, Telles FJ, Bergamo PJ, Oliveira PE, Brito VLG. Intrafloral Color Modularity in a Bee-Pollinated Orchid. FRONTIERS IN PLANT SCIENCE 2020; 11:589300. [PMID: 33304366 PMCID: PMC7693458 DOI: 10.3389/fpls.2020.589300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/15/2020] [Indexed: 05/11/2023]
Abstract
Flower color has been studied in different ecological levels of organization, from individuals to communities. However, it is unclear how color is structured at the intrafloral level. In bee-pollinated flowers, the unidirectional gradient in color purity and pollen mimicry are two common processes to explain intrafloral color patterns. Considering that floral traits are often integrated, usually reflecting evolutionary modules under pollinator-mediated selection, we hypothesize that such intrafloral color patterns are structured by intrafloral color modules as perceived by bee color vision system. Here, we studied the tropical bee-pollinated orchid Cattleya walkeriana, given its intrafloral color complexity and variation among individuals. Considering bee color vision, we investigated if intrafloral color modules arose among intrafloral patches (tip or base of the sepals, petals, and labellum). We expected a separate color module between the labellum patches (the main attractive structure in orchids) and petals and sepals. We measured the color reflectance and calculated the photoreceptor excitation, spectral purity, hue, and the chromatic contrast of the floral structures in the hexagon color model. Spectral purity (saturation) was higher in the labellum tip in comparison to petals and sepals, generating a unidirectional gradient. Labellum base presented a less saturated yellow UV-absorbing color, which may reflect a pollen mimicry strategy. C. walkeriana presented three intrafloral color modules corresponding to the color of petals and sepals, the color of the labellum tip, and the color of labellum base. These color modules were unrelated to the development of floral structures. Given the importance of intrafloral color patterns in bee attraction and guidance, our results suggest that intrafloral patterns could be the outcome of evolutionary color modularization under pollinator-mediated selection.
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Affiliation(s)
- João Marcelo Robazzi Bignelli Valente Aguiar
- Programa de Pós-Graduação em Entomologia, Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Artur Antunes Maciel
- Programa de Pós-Graduação em Ecologia e Conservação dos Recursos Naturais, Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Brazil
| | - Pamela Cristina Santana
- Programa de Pós-Graduação em Ecologia, Departamento de Ecologia, Universidade de São Paulo, São Paulo, Brazil
| | - Francismeire Jane Telles
- Programa de Pós-Graduação em Ecologia e Conservação dos Recursos Naturais, Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Brazil
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Dellinger AS. Pollination syndromes in the 21 st century: where do we stand and where may we go? THE NEW PHYTOLOGIST 2020; 228:1193-1213. [PMID: 33460152 DOI: 10.1111/nph.16793] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 05/31/2020] [Indexed: 06/12/2023]
Abstract
Pollination syndromes, recurring suites of floral traits appearing in connection with specific functional pollinator groups, have served for decades to organise floral diversity under a functional-ecological perspective. Some potential caveats, such as over-simplification of complex plant-animal interactions or lack of empirical observations, have been identified and discussed in recent years. Which of these caveats do indeed cause problems, which have been solved and where do future possibilities lie? I address these questions in a review of the pollination-syndrome literature of 2010 to 2019. I show that the majority of studies was based on detailed empirical pollinator observations and could reliably predict pollinators based on a few floral traits such as colour, shape or reward. Some traits (i.e. colour) were less reliable in predicting pollinators than others (i.e. reward, corolla width), however. I stress that future studies should consider floral traits beyond those traditionally recorded to expand our understanding of mechanisms of floral evolution. I discuss statistical methods suitable for objectively analysing the interplay of system-specific evolutionary constraints, pollinator-mediated selection and adaptive trade-offs at microecological and macroecological scales. I exemplify my arguments on an empirical dataset of floral traits of a neotropical plant radiation in the family Melastomataceae.
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Roguz K, Gallagher MK, Senden E, Bar-Lev Y, Lebel M, Heliczer R, Sapir Y. All the Colors of the Rainbow: Diversification of Flower Color and Intraspecific Color Variation in the Genus Iris. FRONTIERS IN PLANT SCIENCE 2020; 11:569811. [PMID: 33154761 PMCID: PMC7588356 DOI: 10.3389/fpls.2020.569811] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 09/15/2020] [Indexed: 06/01/2023]
Abstract
Floral color plays a key role as visual signaling and is therefore of great importance in shaping plant-pollinator interactions. Iris (Iridaceae), a genus comprising over 300 species and named after the Greek goddess of the colorful rainbow, is famous for its dazzling palette of flower colors and patterns, which vary considerably both within and among species. Despite the large variation of flower color in Iris, little is known about the phylogenetic and ecological contexts of floral color. Here, we seek to resolve the evolution of flower color in the genus Iris in a macroevolutionary framework. We used a phylogenetic analysis to reconstruct the ancestral state of flower color and other pollination-related traits (e.g., the presence of nectar and mating system), and also tracked the evolution of color variation. We further explored weather floral trait transitions are better explained by environmental or pollinator-mediated selection. Our study revealed that the most recent common ancestor likely had monomorphic, purple flowers, with a crest and a spot on the fall. The flowers were likely insect-pollinated, nectar-rewarding, and self-compatible. The diversity of floral traits we see in modern irises, likely represents a trade-off between conflicting selection pressures. Whether shifts in these flower traits result from abiotic or biotic selective agents or are maintained by neutral processes without any selection remains an open question. Our analysis serves as a starting point for future work exploring the genetic and physiological mechanisms controlling flower coloration in the most color-diverse genus Iris.
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Affiliation(s)
- Katarzyna Roguz
- The Botanical Garden, School of Plant Sciences, Tel Aviv University, Tel Aviv, Israel
- Botanic Garden, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - M. Kate Gallagher
- The Botanical Garden, School of Plant Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Esther Senden
- The Botanical Garden, School of Plant Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Yamit Bar-Lev
- The Botanical Garden, School of Plant Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Merav Lebel
- The Botanical Garden, School of Plant Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Roni Heliczer
- The Botanical Garden, School of Plant Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Yuval Sapir
- The Botanical Garden, School of Plant Sciences, Tel Aviv University, Tel Aviv, Israel
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Lunau K, Gerten S. Selective attraction in bird-pollinated flowers. A commentary on: 'Red flowers differ in shades between pollination systems and across continents'. ANNALS OF BOTANY 2020; 126:iv-v. [PMID: 32856689 PMCID: PMC7539357 DOI: 10.1093/aob/mcaa144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
This article comments on: Zhe Chen, Yang Niu, Chang-Qiu Liu and Hang Sun, Red flowers differ in shades between pollination systems and across continents, Annals of Botany, Volume 126, Issue 5, 9 October 2020, Pages 837–848, https://doi.org/10.1093/aob/mcaa103
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Affiliation(s)
- Klaus Lunau
- Institute of Sensory Ecology, Heinrich-Heine University, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Sarah Gerten
- Institute of Sensory Ecology, Heinrich-Heine University, Universitätsstr. 1, D-40225 Düsseldorf, Germany
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Shrestha M, Garcia JE, Burd M, Dyer AG. Australian native flower colours: Does nectar reward drive bee pollinator flower preferences? PLoS One 2020; 15:e0226469. [PMID: 32525873 PMCID: PMC7289428 DOI: 10.1371/journal.pone.0226469] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 05/18/2020] [Indexed: 11/18/2022] Open
Abstract
Colour is an important signal that flowering plants use to attract insect pollinators like bees. Previous research in Germany has shown that nectar volume is higher for flower colours that are innately preferred by European bees, suggesting an important link between colour signals, bee preferences and floral rewards. In Australia, flower colour signals have evolved in parallel to the Northern hemisphere to enable easy discrimination and detection by the phylogenetically ancient trichromatic visual system of bees, and native Australian bees also possess similar innate colour preferences to European bees. We measured 59 spectral signatures from flowers present at two preserved native habitats in South Eastern Australia and tested whether there were any significant differences in the frequency of flowers presenting higher nectar rewards depending upon the colour category of the flower signals, as perceived by bees. We also tested if there was a significant correlation between chromatic contrast and the frequency of flowers presenting higher nectar rewards. For the entire sample, and for subsets excluding species in the Asteraceae and Orchidaceae, we found no significant difference among colour categories in the frequency of high nectar reward. This suggests that whilst such relationships between flower colour signals and nectar volume rewards have been observed at a field site in Germany, the effect is likely to be specific at a community level rather than a broad general principle that has resulted in the common signalling of bee flower colours around the world.
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Affiliation(s)
- Mani Shrestha
- Bio-Inspired Digital Lab (BIDS-Lab), Schools of Media and Communication, RMIT University, Melbourne, Australia
| | - Jair E. Garcia
- Bio-Inspired Digital Lab (BIDS-Lab), Schools of Media and Communication, RMIT University, Melbourne, Australia
| | - Martin Burd
- School of Biological Sciences, Monash University, Melbourne, Australia
| | - Adrian G. Dyer
- Bio-Inspired Digital Lab (BIDS-Lab), Schools of Media and Communication, RMIT University, Melbourne, Australia
- * E-mail:
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Pollinator divergence and pollination isolation between hybrids with different floral color and morphology in two sympatric Penstemon species. Sci Rep 2020; 10:8126. [PMID: 32415216 PMCID: PMC7229217 DOI: 10.1038/s41598-020-64964-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 04/27/2020] [Indexed: 11/08/2022] Open
Abstract
Differential visitation of pollinators due to divergent floral traits can lead to reproductive isolation via assortative pollen flow, which may ultimately be a driving force in plant speciation, particularly in areas of overlap. We evaluate the effects of pollinator behavioral responses to variation of intraspecific floral color and nectar rewards, on reproductive isolation between two hybrid flower color morphs (fuchsia and blue) and their parental species Penstemon roseus and P. gentianoides with a mixed-pollination system. We show that pollinators (bumblebees and hummingbirds) exhibit different behavioral responses to fuchsia and blue morphs, which could result from differential attraction or deterrence. In addition to differences in color (spectral reflectance), we found that plants with fuchsia flowers produced more and larger flowers, produced more nectar and were more visited by pollinators than those with blue flowers. These differences influenced the foraging behavior and effectiveness as pollinators of both bumblebees and hummingbirds, which contributed to reproductive isolation between the two hybrid flower color morphs and parental species. This study demonstrates how differentiation of pollination traits promotes the formation of hybrid zones leading to pollinator shifts and reproductive isolation. While phenotypic traits of fuchsia and red flowers might encourage more efficient hummingbird pollination in a mixed-pollination system, the costs of bumblebee pollination on plant reproduction could be the drivers for the repeated shifts from bumblebee- to hummingbird-mediated pollination.
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Dorin A, Shrestha M, Herrmann M, Burd M, Dyer AG. Automated calculation of spectral-reflectance marker-points to enable analysis of plant colour-signalling to pollinators. MethodsX 2020; 7:100827. [PMID: 32257838 PMCID: PMC7125344 DOI: 10.1016/j.mex.2020.100827] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 01/25/2020] [Indexed: 11/30/2022] Open
Abstract
A spectral reflectance curve for a coloured surface can be constructed from a set of radiation reflectance value measurements made across the spectrum at discrete wavelengths. The curve gives an indication of the pattern of light entering the eye of an organism viewing an illuminated object. Marker points represent the positions along a reflectance curve at which sharp transitions in reflectance occur, these being potentially important to visual perception, for instance by insects discriminating between two flowers, each of a different colour. Consequently, methods of marker point analysis have been applied in several studies evaluating flower colours. These studies have sometimes required researchers to place marker points on reflectance curves by eye, or they have used algorithms written as unreleased software. To automate the process systematically and provide open access, we implemented special-purpose software in C++. Below we provide a summary of the approach adopted in our implementation and made available online in a port to TypeScript. The main benefits of our method are summarized as being:Automation and repeatability. Standardisation, cross-platform compatibility and Open Access. Interactive exploration of the effects of parameter variation.
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Affiliation(s)
- Alan Dorin
- Faculty of Information Technology, Monash University, Australia
| | - Mani Shrestha
- Bio-Inspired Digital Sensing-Lab, School of Media and Communication, RMIT, Australia
| | | | - Martin Burd
- School of Biological Sciences, Monash University, Australia
| | - Adrian G Dyer
- Bio-Inspired Digital Sensing-Lab, School of Media and Communication, RMIT, Australia
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Ogutcen E, Durand K, Wolowski M, Clavijo L, Graham C, Glauser G, Perret M. Chemical Basis of Floral Color Signals in Gesneriaceae: The Effect of Alternative Anthocyanin Pathways. FRONTIERS IN PLANT SCIENCE 2020; 11:604389. [PMID: 33381138 PMCID: PMC7767864 DOI: 10.3389/fpls.2020.604389] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 11/23/2020] [Indexed: 05/14/2023]
Abstract
Changes in floral pigmentation can have dramatic effects on angiosperm evolution by making flowers either attractive or inconspicuous to different pollinator groups. Flower color largely depends on the type and abundance of pigments produced in the petals, but it is still unclear whether similar color signals rely on same biosynthetic pathways and to which extent the activation of certain pathways influences the course of floral color evolution. To address these questions, we investigated the physical and chemical aspects of floral color in the Neotropical Gesnerioideae (ca. 1,200 spp.), in which two types of anthocyanins, hydroxyanthocyanins, and deoxyanthocyanins, have been recorded as floral pigments. Using spectrophotometry, we measured flower reflectance for over 150 species representing different clades and pollination syndromes. We analyzed these reflectance data to estimate how the Gesnerioideae flowers are perceived by bees and hummingbirds using the visual system models of these pollinators. Floral anthocyanins were further identified using high performance liquid chromatography coupled to mass spectrometry. We found that orange/red floral colors in Gesnerioideae are produced either by deoxyanthocyanins (e.g., apigenidin, luteolinidin) or hydroxyanthocyanins (e.g., pelargonidin). The presence of deoxyanthocyanins in several lineages suggests that the activation of the deoxyanthocyanin pathway has evolved multiple times in the Gesnerioideae. The hydroxyanthocyanin-producing flowers span a wide range of colors, which enables them to be discriminated by hummingbirds or bees. By contrast, color diversity among the deoxyanthocyanin-producing species is lower and mainly represented at longer wavelengths, which is in line with the hue discrimination optima for hummingbirds. These results indicate that Gesnerioideae have evolved two different biochemical mechanisms to generate orange/red flowers, which is associated with hummingbird pollination. Our findings also suggest that the activation of the deoxyanthocyanin pathway has restricted flower color diversification to orange/red hues, supporting the potential constraining role of this alternative biosynthetic pathway on the evolutionary outcome of phenotypical and ecological diversification.
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Affiliation(s)
- Ezgi Ogutcen
- Conservatoire et Jardin botaniques de la Ville de Genève, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Karine Durand
- Conservatoire et Jardin botaniques de la Ville de Genève, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Marina Wolowski
- Institute of Natural Sciences, Federal University of Alfenas, Alfenas, Brazil
| | - Laura Clavijo
- Instituto de Ciencias Naturales, National University of Colombia, UNAL, Bogotá, Colombia
| | - Catherine Graham
- Swiss Federal Research Institute (WSL), Birmensdorf, Switzerland
| | - Gaétan Glauser
- Neuchatel Platform of Analytical Chemistry, University of Neuchatel, Neuchâtel, Switzerland
| | - Mathieu Perret
- Conservatoire et Jardin botaniques de la Ville de Genève, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
- *Correspondence: Mathieu Perret,
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Coimbra G, Araujo C, Bergamo PJ, Freitas L, Rodríguez-Gironés MA. Flower Conspicuousness to Bees Across Pollination Systems: A Generalized Test of the Bee-Avoidance Hypothesis. FRONTIERS IN PLANT SCIENCE 2020; 11:558684. [PMID: 33072143 PMCID: PMC7542005 DOI: 10.3389/fpls.2020.558684] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 09/02/2020] [Indexed: 05/14/2023]
Abstract
Flower signals of bee- and bird-pollinated plants have converged via pollinator-mediated evolution, driven by the visual system of their respective pollinators. For bird flowers, sensory exclusion of less effective bees is also important and such exclusion is also mediated by floral morphological filters. Likewise, other systems based on pollination by red-sensitive insects are also associated with red flowers displaying lower short-wavelength secondary peaks of reflectance, which decreases detectability to animals that are less sensitive to red, such as bees. These flowers often also present long tubes. Here, we tested a generalization of the bee-avoidance hypothesis in order to assess if it holds only for bird flowers or for other non-bee pollination systems as well. For this, we compared flower contrasts and spectral purity in bee visual systems as proxies for conspicuousness among four kinds of pollination systems: bee-visited flowers, insect-visited flowers (including bees and other insects), non-bee insect flowers (flowers visited by red-sensitive insects such as flies, butterflies and beetles, but not bees), and bird-visited flowers. We also assessed the association between conspicuousness to bees and flower depth, used as a proxy for morphological exclusion of bees. Overall, flower conspicuousness to bees differed only between insect (all three groups) and bird flowers, due to lower visual signals for the latter. This suggests that bee sensory exclusion via color signals is exclusive to bird flowers, while non-bee insect flowers might use other sensory channels to exclude bees, such as olfactory signals. Visual bee avoidance might be a mechanism exclusive to plants pollinated by specific guilds of red-sensitive insects not well represented in our sample. We also found a negative association between flower conspicuousness to bees and flower depth, suggesting an interplay of morphological and spectral traits in discouraging bee visits. Our results support the bee-avoidance hypothesis exclusively for bird flowers and an overall association between lower visual signals to bees and long tubes.
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Affiliation(s)
- Gabriel Coimbra
- Jardim Botânico do Rio de Janeiro, Rio de Janeiro, Brazil
- *Correspondence: Gabriel Coimbra,
| | - Carina Araujo
- Jardim Botânico do Rio de Janeiro, Rio de Janeiro, Brazil
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Tai KC, Shrestha M, Dyer AG, Yang EC, Wang CN. Floral Color Diversity: How Are Signals Shaped by Elevational Gradient on the Tropical-Subtropical Mountainous Island of Taiwan? FRONTIERS IN PLANT SCIENCE 2020; 11:582784. [PMID: 33391297 PMCID: PMC7773721 DOI: 10.3389/fpls.2020.582784] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 11/25/2020] [Indexed: 05/14/2023]
Abstract
Pollinators with different vision are a key driver of flower coloration. Islands provide important insights into evolutionary processes, and previous work suggests islands may have restricted flower colors. Due to both species richness with high endemism in tropical-subtropical environments, and potentially changing pollinator distributions with altitude, we evaluated flower color diversity across the mountainous island of Taiwan in a comparative framework to understand the cause of color diversity. We sampled flower color signaling on the tropical-subtropical island of Taiwan considering altitudes from sea level to 3300 m to inform how over-dispersion, random processes or clustering may influence flower signaling. We employed a model of bee color space to plot loci from 727 species to enable direct comparisons to data sets from continental studies representing Northern and Southern Hemispheres, and also a continental mountain region. We observed that flower color diversity was similar to flowers that exist in mainland continental studies, and also showed evidence that flowers predominantly had evolved color signals that closely matched bee color preferences. At high altitudes floras tend to be phylogenetically clustered rather than over-dispersed, and their floral colors exhibited weak phylogenetic signal which is consistent with character displacement that facilitated the co-existence of related species. Overall flower color signaling on a tropical-subtropical island is mainly influenced by color preferences of key bee pollinators, a pattern consistent with continental studies.
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Affiliation(s)
- King-Chun Tai
- Department of Life Science, National Taiwan University, Taipei, Taiwan
- Institute of Ecology and Evolutionary Biology, National Taiwan University, Taipei, Taiwan
| | - Mani Shrestha
- School of Media and Communication, RMIT University, Melbourne, VIC, Australia
- *Correspondence: Mani Shrestha, ;
| | - Adrian G. Dyer
- School of Media and Communication, RMIT University, Melbourne, VIC, Australia
| | - En-Cheng Yang
- Department of Entomology, National Taiwan University, Taipei, Taiwan
| | - Chun-Neng Wang
- Department of Life Science, National Taiwan University, Taipei, Taiwan
- Institute of Ecology and Evolutionary Biology, National Taiwan University, Taipei, Taiwan
- Chun-Neng Wang,
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Chen KH, Lu JY, Wang CN. Effective pollination of Aeschynanthus acuminatus (Gesneriaceae) by generalist passerines, in sunbird-absent East Asia. Sci Rep 2019; 9:17552. [PMID: 31772181 PMCID: PMC6879542 DOI: 10.1038/s41598-019-53035-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 10/23/2019] [Indexed: 11/30/2022] Open
Abstract
Aeschynanthus (Gesneriaceae), a genus comprising approximately 160 species in subtropical Southeast Asia, has red, tubular flowers, typical of a sunbird pollination syndrome. A. acuminatus, the species that is distributed extending to the northern edge of the genus, where the specialized nectarivorous sunbirds are absent, possesses reddish-green flowers and a wide-open corolla tube, flowering time shifts from summer to winter and the species achieves high fruiting success. This atypical flower led us to investigate the pollination biology of this species. Three species of generalist passerines, Grey-cheeked Fulvetta (Alcippe morrisonia, Sylviidae), White-eared Sibia (Heterophasia auricularis, Leiothrichidae) and Taiwan Yuhina (Yuhina brunneiceps, Zosteropidae), were recorded visiting A. acuminatus flowers. Pollination effectiveness was quantified via conspecific pollen presence on stigmas and natural fruit set. The significantly high natural fruit set (60%) and conspecific pollen transfer rate (94%) indicate high reproductive success facilitated by the accurate pollen placement on the birds. The existence of copious (61 µL) and highly diluted (7%) hexose-dominant nectar, together with a major reflectance peak of corolla lobe in the long-wavelength red color spectrum, is consistent with the pollination syndrome of generalist passerines. The high pollination effectiveness of A. acuminatus due to the recruitment of generalist passerines as pollinators, and the specializations of floral traits to match generalist bird pollination, appear crucial in the successful colonization on islands such as Taiwan that lack specialized bird pollinators.
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Affiliation(s)
- Kai-Hsiu Chen
- Department of Life Science, National Taiwan University, Taipei, 10617, Taiwan
| | - Jing-Yi Lu
- Department of Life Science, National Taiwan University, Taipei, 10617, Taiwan
| | - Chun-Neng Wang
- Department of Life Science, National Taiwan University, Taipei, 10617, Taiwan.
- Institute of Ecology and Evolutionary Biology, National Taiwan University, Taipei, 10617, Taiwan.
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Mark D. Rausher. THE NEW PHYTOLOGIST 2019; 223:1712-1713. [PMID: 31385359 DOI: 10.1111/nph.16021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
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Color preference and spatial distribution of glaphyrid beetles suggest a key role in the maintenance of the color polymorphism in the peacock anemone (Anemone pavonina, Ranunculaceae) in Northern Greece. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:735-743. [DOI: 10.1007/s00359-019-01360-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 07/02/2019] [Accepted: 07/15/2019] [Indexed: 10/26/2022]
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Dyer AG, Shrestha M. Assessment of floral colour signals at a community through the eyes of the birds and bees. THE NEW PHYTOLOGIST 2019; 222:648-650. [PMID: 30895650 DOI: 10.1111/nph.15724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Affiliation(s)
- Adrian G Dyer
- Bio-inspired Digital Sensing (BIDS) Lab, School of Media and Communication, RMIT University, Melbourne, VIC, 3001, Australia
| | - Mani Shrestha
- Bio-inspired Digital Sensing (BIDS) Lab, School of Media and Communication, RMIT University, Melbourne, VIC, 3001, Australia
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