1
|
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; 26:896-910. [PMID: 38958933 DOI: 10.1111/plb.13682] [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: 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.
Collapse
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
| |
Collapse
|
2
|
Wong DCJ, Wang Z, Perkins J, Jin X, Marsh GE, John EG, Peakall R. The road less taken: Dihydroflavonol 4-reductase inactivation and delphinidin anthocyanin loss underpins a natural intraspecific flower colour variation. Mol Ecol 2024:e17334. [PMID: 38651763 DOI: 10.1111/mec.17334] [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: 11/14/2023] [Revised: 02/22/2024] [Accepted: 03/20/2024] [Indexed: 04/25/2024]
Abstract
Visual cues are of critical importance for the attraction of animal pollinators, however, little is known about the molecular mechanisms underpinning intraspecific floral colour variation. Here, we combined comparative spectral analysis, targeted metabolite profiling, multi-tissue transcriptomics, differential gene expression, sequence analysis and functional analysis to investigate a bee-pollinated orchid species, Glossodia major with common purple- and infrequent white-flowered morphs. We found uncommon and previously unreported delphinidin-based anthocyanins responsible for the conspicuous and pollinator-perceivable colour of the purple morph and three genetic changes underpinning the loss of colour in the white morph - (1) a loss-of-function (LOF; frameshift) mutation affecting dihydroflavonol 4-reductase (DFR1) coding sequence due to a unique 4-bp insertion, (2) specific downregulation of functional DFR1 expression and (3) the unexpected discovery of chimeric Gypsy transposable element (TE)-gene (DFR) transcripts with potential consequences to the genomic stability and post-transcriptional or epigenetic regulation of DFR. This is one of few known cases where regulatory changes and LOF mutation in an anthocyanin structural gene, rather than transcription factors, are important. Furthermore, if TEs prove to be a frequent source of mutation, the interplay between environmental stress-induced TE evolution and pollinator-mediated selection for adaptive colour variation may be an overlooked mechanism maintaining floral colour polymorphism in nature.
Collapse
Affiliation(s)
- Darren C J Wong
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Zemin Wang
- State Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou, China
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou, China
| | - James Perkins
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Xin Jin
- State Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou, China
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou, China
| | - Grace Emma Marsh
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Emma Grace John
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Rod Peakall
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| |
Collapse
|
3
|
Shrestha M, Tai KC, Dyer AG, Garcia JE, Yang EC, Jentsch A, Wang CN. Flower colour and size-signals vary with altitude and resulting climate on the tropical-subtropical islands of Taiwan. FRONTIERS IN PLANT SCIENCE 2024; 15:1304849. [PMID: 38362451 PMCID: PMC10867191 DOI: 10.3389/fpls.2024.1304849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 01/09/2024] [Indexed: 02/17/2024]
Abstract
The diversity of flower colours in nature provides quantifiable evidence for how visitations by colour sensing insect pollinators can drive the evolution of angiosperm visual signalling. Recent research shows that both biotic and abiotic factors may influence flower signalling, and that harsher climate conditions may also promote salient signalling to entice scarcer pollinators to visit. In parallel, a more sophisticated appreciation of the visual task foragers face reveals that bees have a complex visual system that uses achromatic vision when moving fast, whilst colour vision requires slower, more careful inspection of targets. Spectra of 714 native flowering species across Taiwan from sea level to mountainous regions 3,300 m above sea level (a.s.l.) were measured. We modelled how the visual system of key bee pollinators process signals, including flower size. By using phylogenetically informed analyses, we observed that at lower altitudes including foothills and submontane landscapes, there is a significant relationship between colour contrast and achromatic signals. Overall, the frequency of flowers with high colour contrast increases with altitude, whilst flower size decreases. The evidence that flower colour signaling becomes increasingly salient in higher altitude conditions supports that abiotic factors influence pollinator foraging in a way that directly influences how flowering plants need to advertise.
Collapse
Affiliation(s)
- Mani Shrestha
- Department of Disturbance Ecology and Vegetation Dynamics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - King-Chun Tai
- Department of Life Science, National Taiwan University, Taipei, Taiwan
- Institute of Ecology and Evolutionary Biology, National Taiwan University, Taipei, Taiwan
| | - Adrian G. Dyer
- Department of Physiology, Monash University, Clayton, VIC, Australia
| | - Jair E. Garcia
- Melbourne Data Analytics Platform, The University of Melbourne, Melbourne, VIC, Australia
| | - En-Cheng Yang
- Department of Entomology, National Taiwan University, Taipei, Taiwan
| | - Anke Jentsch
- Department of Disturbance Ecology and Vegetation Dynamics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Chun-Neng Wang
- Department of Life Science, National Taiwan University, Taipei, Taiwan
- Institute of Ecology and Evolutionary Biology, National Taiwan University, Taipei, Taiwan
| |
Collapse
|
4
|
Mochizuki K, Okamoto T, Chen KH, Wang CN, Evans M, Kramer AT, Kawakita A. Adaptation to pollination by fungus gnats underlies the evolution of pollination syndrome in the genus Euonymus. ANNALS OF BOTANY 2023; 132:319-333. [PMID: 37610846 PMCID: PMC10583214 DOI: 10.1093/aob/mcad081] [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: 01/22/2023] [Accepted: 07/04/2023] [Indexed: 08/25/2023]
Abstract
BACKGROUND AND AIMS Dipteran insects are known pollinators of many angiosperms, but knowledge on how flies affect floral evolution is relatively scarce. Some plants pollinated by fungus gnats share a unique set of floral characters (dark red display, flat shape and short stamens), which differs from any known pollination syndromes. We tested whether this set of floral characters is a pollination syndrome associated with pollination by fungus gnats, using the genus Euonymus as a model. METHODS The pollinator and floral colour, morphology and scent profile were investigated for ten Euonymus species and Tripterygium regelii as an outgroup. The flower colour was evaluated using bee and fly colour vision models. The evolutionary association between fungus gnat pollination and each plant character was tested using a phylogenetically independent contrast. The ancestral state reconstruction was performed on flower colour, which is associated with fungus gnat pollination, to infer the evolution of pollination in the genus Euonymus. KEY RESULTS The red-flowered Euonymus species were pollinated predominantly by fungus gnats, whereas the white-flowered species were pollinated by bees, beetles and brachyceran flies. The colour vision analysis suggested that red and white flowers are perceived as different colours by both bees and flies. The floral scents of the fungus gnat-pollinated species were characterized by acetoin, which made up >90 % of the total scent in three species. Phylogenetically independent contrast showed that the evolution of fungus gnat pollination is associated with acquisition of red flowers, short stamens and acetoin emission. CONCLUSIONS Our results suggest that the observed combination of floral characters is a pollination syndrome associated with the parallel evolution of pollination by fungus gnats. Although the role of the red floral display and acetoin in pollinator attraction remains to be elucidated, our finding underscores the importance of fungus gnats as potential contributors to floral diversification.
Collapse
Affiliation(s)
- Ko Mochizuki
- Botanical Gardens, Graduate School of Science, The University of Tokyo, 3-7-1 Hakusan, Bunkyo-ku, Tokyo, Japan
| | - Tomoko Okamoto
- Faculty of Applied Biological Sciences, Gifu University, Yanagido 1-1, Gifu, Japan
| | - Kai-Hsiu Chen
- Department of Ecology and Evolution, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Chun-Neng Wang
- Department of Life Science, Institute of Ecology and Evolutionary Biology, National Taiwan University, Taipei 10617, Taiwan
| | - Matthew Evans
- Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL 60022, USA
| | - Andrea T Kramer
- Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL 60022, USA
| | - Atsushi Kawakita
- Botanical Gardens, Graduate School of Science, The University of Tokyo, 3-7-1 Hakusan, Bunkyo-ku, Tokyo, Japan
| |
Collapse
|
5
|
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
| |
Collapse
|
6
|
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: 3.0] [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.
Collapse
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
| |
Collapse
|
7
|
Streinzer M, Neumayer J, Spaethe J. Flower Color as Predictor for Nectar Reward Quantity in an Alpine Flower Community. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.721241] [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] Open
Abstract
Entomophilous plants have evolved colorful floral displays to attract flower visitors to achieve pollination. Although many insects possess innate preferences for certain colors, the underlying proximate and ultimate causes for this behavior are still not well understood. It has been hypothesized that the floral rewards, e.g., sugar content, of plants belonging to a particular color category correlate with the preference of the flower visitors. However, this hypothesis has been tested only for a subset of plant communities worldwide. Bumble bees are the most important pollinators in alpine environments and show a strong innate preference for (bee) “UV-blue” and “blue” colors. We surveyed plants visited by bumble bees in the subalpine and alpine zones (>1,400 m a.s.l.) of the Austrian Alps and measured nectar reward and spectral reflectance of the flowers. We found that the majority of the 105 plant samples visited by bumble bees fall into the color categories “blue” and “blue-green” of a bee-specific color space. Our study shows that color category is only a weak indicator for nectar reward quantity; and due to the high reward variance within and between categories, we do not consider floral color as a reliable signal for bumble bees in the surveyed habitat. Nevertheless, since mean floral reward quantity differs between categories, naïve bumble bees may benefit from visiting flowers that fall into the innately preferred color category during their first foraging flights.
Collapse
|
8
|
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: 12] [Impact Index Per Article: 3.0] [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.
Collapse
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
| |
Collapse
|
9
|
Comparative psychophysics of colour preferences in two species of non-eusocial Australian native halictid bees. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 207:657-666. [PMID: 34241711 DOI: 10.1007/s00359-021-01504-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 05/17/2021] [Accepted: 05/19/2021] [Indexed: 10/20/2022]
Abstract
Colour signalling by flowers appears to be the main plant-pollinator communication system observed across many diverse species and locations worldwide. Bees are considered one of the most important insect pollinators; however, native non-eusocial bees are often understudied compared to managed eusocial species, such as honeybees and bumblebees. Here, we tested two species of native Australian non-eusocial halictid bees on their colour preferences for seven different broadband colours with bee-colour-space dominant wavelengths ranging from 385 to 560 nm and a neutral grey control. Lasioglossum (Chilalictus) lanarium demonstrated preferences for a UV-absorbing white (455 nm) and a yellow (560 nm) stimulus. Lasioglossum (Parasphecodes) sp. showed no colour preferences. Subsequent analyses showed that green contrast and spectral purity had a significant positive relationship with the number of visits by L. lanarium to stimuli. Colour preferences were consistent with other bee species and may be phylogenetically conserved and linked to how trichromatic bees processes visual information, although the relative dearth of empirical evidence on different bee species currently makes it difficult to dissect mechanisms. Past studies and our current results suggest that both innate and environmental factors might both be at play in mediating bee colour preferences.
Collapse
|
10
|
Garcia JE, Rohr DH, Dyer AG. Colour Discrimination From Perceived Differences by Birds. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.639513] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The ability of visual generalists to see and perceive displayed colour signals is essential to understanding decision making in natural environments. Whilst modelling approaches have typically considered relatively simple physiological explanations of how colour may be processed, data on key bee species reveals that colour is a complex multistage perception largely generated by opponent neural representations in a brain. Thus, a biologically meaningful unit of colour information must consider the psychophysics responses of an animal engaged in colour decision making. We extracted previously collected psychophysics data for a Violet-Sensitive (VS) bird, the pigeon (Columba livia), and used a non-linear function that reliably represents the behavioural choices of hymenopteran and dipteran pollinators to produce the first behaviourally validated and biologically meaningful representation of how VS birds use colour information in a probabilistic way. The function describes how similar or dis-similar spectral information can lead to different choice behaviours in birds, even though all such spectral information is above discrimination threshold. This new representation of bird vision will enable enhanced modelling representations of how bird vision can sense and use colour information in complex environments.
Collapse
|
11
|
Luo H, Xiao H, Liang Y, Liu N, Turner C, Tan S, Chen X, Xiong D, Yang B. Batesian mimicry in the nonrewarding saprophytic orchid Danxiaorchis yangii. Ecol Evol 2021; 11:2524-2534. [PMID: 33767819 PMCID: PMC7981215 DOI: 10.1002/ece3.7193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 11/17/2020] [Accepted: 12/21/2020] [Indexed: 11/08/2022] Open
Abstract
Batesian mimicry, a type of deceptive pollination, is a complicated strategy used by nonrewarding plants to attract pollinators, but some hypotheses concerning this have not been systematically verified. In order to show in detail a case of Batesian mimicry on saprophytic orchid Danxiaorchis yangii, the ecological relationship between Danxiaorchis yangii, Lysimachia alfredi and Dufourea spp. was explored. Lysimachia alfredi could provide a reward to Dufourea sp., whereas Danxiaorchis yangii not. The floral morphology and geographical distribution of these two plants were highly overlapping, and the fruit set rate of Danxiaorchis yangii was significantly positively correlated with the number of nearby L. alfredi individuals. In a glass cylinder experiment, Danxiaorchis yangii and L. alfredi attracted Dufourea spp. through visual signals, but the insect could not distinguish between flowers of the two plants before landing on flowers. The ultraviolet reflection spectra of flowers between the two plant species were highly similar. In the hexagonal color models constructed according to the visual characteristics of bees, the flower color signals of these two plant species highly overlap, indicating that the visual signals of the flowers of the two plants to the pollinator were greatly similar. All of these results provided evidence that Danxiaorchis yangii simulated the visual signals of L. alfredi through Batesian mimicry, thereby deceptively attracting Dufourea spp.
Collapse
Affiliation(s)
- Huolin Luo
- Jiangxi Key Laboratory of Plant ResourcesSchool of Life ScienceNanchang UniversityNanchangChina
| | - Hanwen Xiao
- Jiangxi Key Laboratory of Plant ResourcesSchool of Life ScienceNanchang UniversityNanchangChina
| | - Yuelong Liang
- Jiangxi Jiulianshan National Nature ReserveGanzhouChina
| | - Nannan Liu
- Jiangxi Key Laboratory of Plant ResourcesSchool of Life ScienceNanchang UniversityNanchangChina
| | - Cassidy Turner
- College of Health SolutionsArizona State UniversityScottsdaleAZUSA
| | - Shaolin Tan
- Jiangxi Key Laboratory of Plant ResourcesSchool of Life ScienceNanchang UniversityNanchangChina
| | - Xinghui Chen
- Jiangxi Key Laboratory of Plant ResourcesSchool of Life ScienceNanchang UniversityNanchangChina
| | - Dongjin Xiong
- Jiangxi Key Laboratory of Plant ResourcesSchool of Life ScienceNanchang UniversityNanchangChina
| | - Boyun Yang
- Jiangxi Key Laboratory of Plant ResourcesSchool of Life ScienceNanchang UniversityNanchangChina
| |
Collapse
|
12
|
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: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [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.
Collapse
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
| |
Collapse
|
13
|
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: 0.6] [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.
Collapse
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
| |
Collapse
|
14
|
Competition and pollen wars: simulations reveal the dynamics of competition mediated through heterospecific pollen transfer by non-flower constant insects. THEOR ECOL-NETH 2020. [DOI: 10.1007/s12080-020-00490-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
15
|
Garcia JE, Phillips RD, Peter CI, Dyer AG. Changing How Biologists View Flowers-Color as a Perception Not a Trait. FRONTIERS IN PLANT SCIENCE 2020; 11:601700. [PMID: 33329670 PMCID: PMC7710862 DOI: 10.3389/fpls.2020.601700] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 10/23/2020] [Indexed: 05/31/2023]
Abstract
Studying flower color evolution can be challenging as it may require several different areas of expertise, ranging from botany and ecology through to understanding color sensing of insects and thus how they perceive flower signals. Whilst studies often view plant-pollinator interactions from the plant's perspective, there is growing evidence from psychophysics studies that pollinators have their own complex decision making processes depending on their perception of color, viewing conditions and individual experience. Mimicry of rewarding flowers by orchids is a fascinating system for studying the pollinator decision making process, as rewarding model flowering plants and mimics can be clearly characterized. Here, we focus on a system where the rewardless orchid Eulophia zeyheriana mimics the floral color of Wahlenbergia cuspidata (Campanulaceae) to attract its pollinator species, a halictid bee. Using recently developed psychophysics principles, we explore whether the color perception of an insect observer encountering variable model and mimic flower color signals can help explain why species with non-rewarding flowers can exist in nature. Our approach involves the use of color discrimination functions rather than relying on discrimination thresholds, and the use of statistical distributions to model intraspecific color variations. Results show that whilst an experienced insect observer can frequently make accurate discriminations between mimic and rewarding flowers, intraspecific signal variability leads to overlap in the perceived color, which will frequently confuse an inexperienced pollinator. This new perspective provides an improved way to incorporate pollinator decision making into the complex field of plant-pollinator interactions.
Collapse
Affiliation(s)
- Jair E. Garcia
- Bio-Inspired Digital Sensing Laboratory (BIDS Lab), School of Media and Communication, RMIT University, Melbourne, VIC, Australia
| | - Ryan D. Phillips
- Department of Ecology, Environment and Evolution, La Trobe University, Bundoora, VIC, Australia
- Department of Biodiversity, Conservation, and Attractions, Kings Park Science, Perth, WA, Australia
- Department of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Craig I. Peter
- Department of Botany, Rhodes University, Grahamstown, South Africa
| | - Adrian G. Dyer
- Bio-Inspired Digital Sensing Laboratory (BIDS Lab), School of Media and Communication, RMIT University, Melbourne, VIC, Australia
| |
Collapse
|
16
|
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: 2.2] [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.
Collapse
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:
| |
Collapse
|
17
|
Schnaitmann C, Pagni M, Reiff DF. Color vision in insects: insights from Drosophila. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:183-198. [PMID: 32020291 PMCID: PMC7069916 DOI: 10.1007/s00359-019-01397-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 12/12/2019] [Accepted: 12/17/2019] [Indexed: 02/07/2023]
Abstract
Color vision is an important sensory capability that enhances the detection of contrast in retinal images. Monochromatic animals exclusively detect temporal and spatial changes in luminance, whereas two or more types of photoreceptors and neuronal circuitries for the comparison of their responses enable animals to differentiate spectral information independent of intensity. Much of what we know about the cellular and physiological mechanisms underlying color vision comes from research on vertebrates including primates. In insects, many important discoveries have been made, but direct insights into the physiology and circuit implementation of color vision are still limited. Recent advances in Drosophila systems neuroscience suggest that a complete insect color vision circuitry, from photoreceptors to behavior, including all elements and computations, can be revealed in future. Here, we review fundamental concepts in color vision alongside our current understanding of the neuronal basis of color vision in Drosophila, including side views to selected other insects.
Collapse
Affiliation(s)
- Christopher Schnaitmann
- Department for Animal Physiology and Neurobiology, Institute of Biology I, Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
| | - Manuel Pagni
- Department for Animal Physiology and Neurobiology, Institute of Biology I, Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
| | - Dierk F Reiff
- Department for Animal Physiology and Neurobiology, Institute of Biology I, Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany.
| |
Collapse
|
18
|
LeCroy KA, Arceo-Gómez G, Koski MH, Morehouse NI, Ashman TL. Floral Color Properties of Serpentine Seep Assemblages Depend on Community Size and Species Richness. FRONTIERS IN PLANT SCIENCE 2020; 11:602951. [PMID: 33488651 PMCID: PMC7820368 DOI: 10.3389/fpls.2020.602951] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 12/02/2020] [Indexed: 05/14/2023]
Abstract
Functional traits, particularly those that impact fitness, can shape the ecological and evolutionary relationships among coexisting species of the same trophic level. Thus, examining these traits and properties of their distributions (underdispersion, overdispersion) within communities can provide insights into key ecological interactions (e.g., competition, facilitation) involved in community assembly. For instance, the distribution of floral colors in a community may reflect pollinator-mediated interactions between sympatric plant species, and the phylogenetic distribution of color can inform how evolutionary contingencies can continue to shape extant community assemblages. Additionally, the abundance and species richness of the local habitat may influence the type or strength of ecological interactions among co-occurring species. To evaluate the impact of community size and species richness on mechanisms shaping the distribution of ecologically relevant traits, we examined how floral color (defined by pollinator color vision models) is distributed within co-flowering assemblages. We modeled floral reflectance spectra of 55 co-flowering species using honeybee (Apis mellifera) and syrphid fly (Eristalis tenax) visual systems to assess the distributions of flower color across 14 serpentine seep communities in California. We found that phylogenetic relatedness had little impact on the observed color assemblages. However, smaller seep communities with lower species richness were more overdispersed for flower color than larger, more species-rich communities. Results support that competitive exclusion could be a dominant process shaping the species richness of flower color in smaller-sized communities with lower species richness, but this is less detectable or overwhelmed by other processes at larger, more speciose communities.
Collapse
Affiliation(s)
- Kathryn A. LeCroy
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, United States
- Department of Environmental Sciences, University of Virginia, Charlottesville, VA, United States
- *Correspondence: Kathryn A. LeCroy,
| | - Gerardo Arceo-Gómez
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, United States
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN, United States
| | - Matthew H. Koski
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, United States
- Department of Biological Sciences, Clemson University, Clemson, SC, United States
| | - Nathan I. Morehouse
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, United States
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Tia-Lynn Ashman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, United States
| |
Collapse
|
19
|
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: 1.8] [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.
Collapse
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,
| |
Collapse
|
20
|
Arnold SEJ, Chittka L. Flower colour diversity seen through the eyes of pollinators. A commentary on: 'Floral colour structure in two Australian herbaceous communities: it depends on who is looking'. ANNALS OF BOTANY 2019; 124:viii-ix. [PMID: 31214687 PMCID: PMC6758570 DOI: 10.1093/aob/mcz107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
This article comments on: Mani Shrestha, Adrian G. Dyer, Jair E. Garcia and Martin Burd. 2019. Floral colour structure in two Australian herbaceous communities: it depends on who is looking. Annals of Botany 124(2): 221–232.
Collapse
Affiliation(s)
- Sarah E J Arnold
- Natural Resources Institute, University of Greenwich, Chatham Maritime, Kent, UK
| | - Lars Chittka
- Department of Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
- Corresponding author details: Lars Chittka,
| |
Collapse
|
21
|
Colour preferences of Tetragonula carbonaria Sm. stingless bees for colour morphs of the Australian native orchid Caladenia carnea. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:347-361. [DOI: 10.1007/s00359-019-01346-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 05/08/2019] [Accepted: 05/13/2019] [Indexed: 01/09/2023]
|