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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.
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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
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2
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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.
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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
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3
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Sinha SK, Dolai A, Roy AB, Manna S, Das A. The Flower Colour Influences Spontaneous Nectaring in Butterflies: a Case Study with Twenty Subtropical Butterflies. NEOTROPICAL ENTOMOLOGY 2023; 52:1027-1040. [PMID: 37819480 DOI: 10.1007/s13744-023-01086-6] [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: 11/14/2022] [Accepted: 09/14/2023] [Indexed: 10/13/2023]
Abstract
Butterflies have a wide spectrum of colour vision, and changes in flower colour influence both the visiting and nectaring (the act of feeding on flower nectar) events of them. However, the spontaneous behavioural response of butterflies while foraging on real flowers is less characterised in wild conditions. Hence, this study intends to investigate flower colour affinity in wild butterflies in relation to nectaring frequency (NF) and nectaring duration (ND). Six distinct flower colours were used to study spontaneous nectaring behaviour in 20 species of subtropical butterflies. Both NF and ND greatly varied in the flower colours they offered. Yellow flowers were frequently imbibed by butterflies for longer durations, followed by orange, while red, pink, white and violet flowers were occasionally nectared in shorter bouts. Though butterflies have a general tendency to nectar on multiple flower colours, the Nymphalids were more biased towards nectaring on yellow flowers, but Papilionids preferred both yellow and orange, while the Pierids were likely to display an equal affinity for yellow, orange and violet flowers as their first order of preference. Even if the blooms are associated with higher nectar concentrations or a significant grade reward, the butterfly may prefer to visit different-coloured flowers instead. Flower colour choice appears to be a generalist phenomenon for butterflies, but their specialist visiting nature was also significant. Nymphalid representatives responded to a wider variety of floral colour affinities than Pierid and Papilionid species. The colour preference of butterflies aids in the identification of flowers during foraging and influences subsequent foraging decisions, which ultimately benefits pollination success. The current information will support the preservation and conservation of butterflies in their natural habitats.
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Affiliation(s)
- Sumit Kumar Sinha
- Entomology Laboratory, Department of Zoology, University of Calcutta, Calcutta, West Bengal, India
| | - Avishek Dolai
- Entomology Laboratory, Department of Zoology, University of Calcutta, Calcutta, West Bengal, India
| | | | - Sourav Manna
- Semiochemical and lipid laboratory, Department of Life Science, Presidency University, Kolkata, West Bengal, India
| | - Amlan Das
- Entomology Laboratory, Department of Zoology, University of Calcutta, Calcutta, West Bengal, India.
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4
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Chapman KM, Richardson FJ, Forster CY, Middleton EJT, White TE, Burke PF, Latty T. Artificial flowers as a tool for investigating multimodal flower choice in wild insects. Ecol Evol 2023; 13:e10687. [PMID: 38020672 PMCID: PMC10659823 DOI: 10.1002/ece3.10687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 10/10/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023] Open
Abstract
Flowers come in a variety of colours, shapes, sizes and odours. Flowers also differ in the quality and quantity of nutritional reward they provide to entice potential pollinators to visit. Given this diversity, generalist flower-visiting insects face the considerable challenge of deciding which flowers to feed on and which to ignore. Working with real flowers poses logistical challenges due to correlations between flower traits, maintenance costs and uncontrolled variables. Here, we overcome this challenge by designing multimodal artificial flowers that varied in visual, olfactory and reward attributes. We used artificial flowers to investigate the impact of seven floral attributes (three visual cues, two olfactory cues and two rewarding attributes) on flower visitation and species richness. We investigated how flower attributes influenced two phases of the decision-making process: the decision to land on a flower, and the decision to feed on a flower. Artificial flowers attracted 890 individual insects representing 15 morphospecies spanning seven arthropod orders. Honeybees were the most common visitors accounting for 46% of visitors. Higher visitation rates were driven by the presence of nectar, the presence of linalool, flower shape and flower colour and was negatively impacted by the presence of citral. Species richness was driven by the presence of nectar, the presence of linalool and flower colour. For hymenopterans, the probability of landing on the artificial flowers was influenced by the presence of nectar or pollen, shape and the presence of citral and/or linalool. The probability of feeding increased when flowers contained nectar. For dipterans, the probability of landing on artificial flowers increased when the flower was yellow and contained linalool. The probability of feeding increased when flowers contained pollen, nectar and linalool. Our results demonstrate the multi-attribute nature of flower preferences and highlight the usefulness of artificial flowers as tools for studying flower visitation in wild insects.
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Affiliation(s)
- Kathryn M. Chapman
- School of Life and Environmental SciencesThe University of SydneySydneyNew South WalesAustralia
| | - Freya J. Richardson
- School of Life and Environmental SciencesThe University of SydneySydneyNew South WalesAustralia
- Sydney Institute of AgricultureThe University of SydneySydneyNew South WalesAustralia
| | - Caitlyn Y. Forster
- School of Life and Environmental SciencesThe University of SydneySydneyNew South WalesAustralia
| | - Eliza J. T. Middleton
- School of Life and Environmental SciencesThe University of SydneySydneyNew South WalesAustralia
| | - Thomas E. White
- School of Life and Environmental SciencesThe University of SydneySydneyNew South WalesAustralia
| | - Paul F. Burke
- UTS Business School and Centre for Business Intelligence and Data AnalyticsUniversity of Technology SydneySydneyNew South WalesAustralia
| | - Tanya Latty
- School of Life and Environmental SciencesThe University of SydneySydneyNew South WalesAustralia
- Sydney Institute of AgricultureThe University of SydneySydneyNew South WalesAustralia
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5
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Scaccabarozzi D, Lunau K, Guzzetti L, Cozzolino S, Dyer AG, Tommasi N, Biella P, Galimberti A, Labra M, Bruni I, Pattarini G, Brundrett M, Gagliano M. Mimicking orchids lure bees from afar with exaggerated ultraviolet signals. Ecol Evol 2023; 13:e9759. [PMID: 36726874 PMCID: PMC9884568 DOI: 10.1002/ece3.9759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 12/22/2022] [Accepted: 01/04/2023] [Indexed: 02/03/2023] Open
Abstract
Flowers have many traits to appeal to pollinators, including ultraviolet (UV) absorbing markings, which are well-known for attracting bees at close proximity (e.g., <1 m). While striking UV signals have been thought to attract pollinators also from far away, if these signals impact the plant pollinia removal over distance remains unknown. Here, we report the case of the Australian orchid Diuris brumalis, a nonrewarding species, pollinated by bees via mimicry of the rewarding pea plant Daviesia decurrens. When distant from the pea plant, Diuris was hypothesized to enhance pollinator attraction by exaggeratedly mimicking the floral ultraviolet (UV) reflecting patterns of its model. By experimentally modulating floral UV reflectance with a UV screening solution, we quantified the orchid pollinia removal at a variable distance from the model pea plants. We demonstrate that the deceptive orchid Diuris attracts bee pollinators by emphasizing the visual stimuli, which mimic the floral UV signaling of the rewarding model Daviesia. Moreover, the exaggerated UV reflectance of Diuris flowers impacted pollinators' visitation at an optimal distance from Da. decurrens, and the effect decreased when orchids were too close or too far away from the model. Our findings support the hypothesis that salient UV flower signaling plays a functional role in visual floral mimicry, likely exploiting perceptual gaps in bee neural coding, and mediates the plant pollinia removal at much greater spatial scales than previously expected. The ruse works most effectively at an optimal distance of several meters revealing the importance of salient visual stimuli when mimicry is imperfect.
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Affiliation(s)
- Daniela Scaccabarozzi
- School of Pharmaceutical Science and TechnologyTianjin UniversityTianjinChina
- School of Molecular and Life SciencesCurtin UniversityBentleyWestern AustraliaAustralia
| | - Klaus Lunau
- Institute of Sensory EcologyHeinrich‐Heine University DüsseldorfDüsseldorfGermany
| | - Lorenzo Guzzetti
- ZooPlantLab, Dipartimento di Biotecnologie e BioscienzeUniversity of Milano – BicoccaMilanItaly
| | | | - Adrian G. Dyer
- Bio‐Inspired Digital Sensing Lab, School of Media and CommunicationRMIT UniversityMelbourneVictoriaAustralia
- Department of Physiology and Neuroscience Program, Biomedicine Discovery InstituteMonash UniversityClaytonVictoriaAustralia
| | - Nicola Tommasi
- ZooPlantLab, Dipartimento di Biotecnologie e BioscienzeUniversity of Milano – BicoccaMilanItaly
| | - Paolo Biella
- ZooPlantLab, Dipartimento di Biotecnologie e BioscienzeUniversity of Milano – BicoccaMilanItaly
| | - Andrea Galimberti
- ZooPlantLab, Dipartimento di Biotecnologie e BioscienzeUniversity of Milano – BicoccaMilanItaly
| | - Massimo Labra
- ZooPlantLab, Dipartimento di Biotecnologie e BioscienzeUniversity of Milano – BicoccaMilanItaly
| | - Ilaria Bruni
- ZooPlantLab, Dipartimento di Biotecnologie e BioscienzeUniversity of Milano – BicoccaMilanItaly
| | - Giorgio Pattarini
- Department of Mathematics and PhysicsUniversity of StavangerStavangerNorway
| | - Mark Brundrett
- School of Biological SciencesUniversity of Western AustraliaPerthWestern AustraliaAustralia
| | - Monica Gagliano
- Biological Intelligence (BI) Lab, Faculty of Sciences & EngineeringSouthern Cross UniversityLismoreNew South WalesAustralia
- Sydney Environment Institute (SEI)The University of SydneyCamperdownNew South WalesAustralia
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6
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Dexheimer AF, Outomuro D, Dunlap AS, Morehouse NI. Spectral sensitivities of the orchid bee Euglossa dilemma. JOURNAL OF INSECT PHYSIOLOGY 2023; 144:104464. [PMID: 36481409 DOI: 10.1016/j.jinsphys.2022.104464] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
Diurnal pollinators often rely on color cues to make decisions when visiting flowers. Orchid bees are major tropical pollinators, with most studies of their pollination behavior to date focusing on scent collection and chemical ecology. The objective of this study was to measure their spectral sensitivities to preliminarily characterize color vision in the orchid bee Euglossa dilemma and compare it to the known spectral sensitivity of other closely related bees. We compared E. dilemma's spectral sensitivities and opsin protein sequences to four closely related corbiculate bees. E. dilemma appears to have trichromatic vision, with spectral sensitivity peaks in the ultraviolet, blue, and green wavelengths (347 ± 0.957 (SE) nm, 429 ± 6.570 nm, and 537 ± 1.183 nm, respectively), similar to other measured bees. We found no differences between male and female E. dilemma visual systems despite neuroanatomical and behavioral differences reported in the literature. The lambda maxes of the ultraviolet-sensitive photoreceptors appeared to be the most conserved among the bees we compared. Meanwhile, both the lambda maxes of the blue photoreceptors and the blue opsin proteins sequences were the least conserved. Our results open up new possibilities for the study of color vision and color-mediated pollination behaviors in orchid bees.
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Affiliation(s)
- Andreia F Dexheimer
- Department of Biology, University of Missouri -St. Louis, 1 University Blvd, St. Louis, MO 63121, USA; Whitney R. Harris World Ecology Center, 1 University Blvd, St. Louis, MO 63121, USA; Center for STEM Research, Education & Outreach, Southern Illinois University Edwardsville, 1 Hairpin Dr, Edwardsville, IL 62026, USA.
| | - David Outomuro
- Department of Biological Sciences, University of Pittsburgh, 4200 Fifth Ave, Pittsburgh, PA 15260, USA; Department of Biological Sciences, University of Cincinnati, 2600 Clifton Ave, Cincinnati, OH 45221, USA
| | - Aimee S Dunlap
- Department of Biology, University of Missouri -St. Louis, 1 University Blvd, St. Louis, MO 63121, USA; Whitney R. Harris World Ecology Center, 1 University Blvd, St. Louis, MO 63121, USA
| | - Nathan I Morehouse
- Department of Biological Sciences, University of Cincinnati, 2600 Clifton Ave, Cincinnati, OH 45221, USA
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7
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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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8
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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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9
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Koethe S, Reinartz L, Heard TA, Garcia JE, Dyer AG, Lunau K. Comparative psychophysics of Western honey bee (Apis mellifera) and stingless bee (Tetragonula carbonaria) colour purity and intensity perception. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:641-652. [PMID: 36269403 PMCID: PMC9734212 DOI: 10.1007/s00359-022-01581-y] [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: 06/02/2022] [Revised: 09/13/2022] [Accepted: 09/28/2022] [Indexed: 12/14/2022]
Abstract
Bees play a vital role as pollinators worldwide and have influenced how flower colour signals have evolved. The Western honey bee, Apis mellifera (Apini), and the Buff-tailed bumble bee, Bombus terrestris (Bombini) are well-studied model species with regard to their sensory physiology and pollination capacity, although currently far less is known about stingless bees (Meliponini) that are common in pantropical regions. We conducted comparative experiments with two highly eusocial bee species, the Western honey bee, A. mellifera, and the Australian stingless bee, Tetragonula carbonaria, to understand their colour preferences considering fine-scaled stimuli specifically designed for testing bee colour vision. We employed stimuli made of pigment powders to allow manipulation of single colour parameters including spectral purity (saturation) or colour intensity (brightness) of a blue colour (hue) for which both species have previously shown innate preferences. Both A. mellifera and T. carbonaria demonstrated a significant preference for spectrally purer colour stimuli, although this preference is more pronounced in honey bees than in stingless bees. When all other colour cues were tightly controlled, honey bees receiving absolute conditioning demonstrated a capacity to learn a high-intensity stimulus significant from chance expectation demonstrating some capacity of plasticity for this dimension of colour perception. However, honey bees failed to learn low-intensity stimuli, and T. carbonaria was insensitive to stimulus intensity as a cue. These comparative findings suggest that there may be some common roots underpinning colour perception in bee pollinators and how they interact with flowers, although species-specific differences do exist.
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Affiliation(s)
- Sebastian Koethe
- Institute of Sensory Ecology, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Lara Reinartz
- Institute of Sensory Ecology, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | | | - Jair E. Garcia
- School of Media and Communication, RMIT University, Building 5.2.36, City Campus, GPO Box 2476, Melbourne, VIC 3001 Australia
| | - Adrian G. Dyer
- School of Media and Communication, RMIT University, Building 5.2.36, City Campus, GPO Box 2476, Melbourne, VIC 3001 Australia ,Department of Physiology, Monash University, Melbourne, 3800 Australia ,Institute of Developmental Biology and Neurobiology, Johannes Gutenberg Universität, Mainz, Germany
| | - Klaus Lunau
- Institute of Sensory Ecology, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
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10
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Muñoz-Galicia D, Castillo-Guevara C, Lara C. Innate and learnt color preferences in the common green-eyed white butterfly ( Leptophobia aripa): experimental evidence. PeerJ 2021; 9:e12567. [PMID: 34909282 PMCID: PMC8638565 DOI: 10.7717/peerj.12567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 11/08/2021] [Indexed: 11/20/2022] Open
Abstract
Background Learning abilities help animals modify their behaviors based on experience and innate sensory biases to confront environmental unpredictability. In a food acquisition context, the ability to detect, learn, and switch is fundamental in a wide range of insect species facing the ever-changing availability of their floral rewards. Here, we used an experimental approach to address the innate color preferences and learning abilities of the common green-eyed white butterfly (Leptophobia aripa). Methods In Experiment 1, we conducted innate preference choice-tests to determine whether butterflies had a strong innate color preference and to evaluate whether color preferences differed depending on the array of colors offered. We faced naïve butterflies to artificial flowers of four colors (quadruple choice-test): yellow, pink, white, and red; their choices were assessed. In Experiment 2, we examined the ability of this butterfly species to associate colors with rewards while exploring if the spectral reflectance value of a flower color can slow or accelerate this behavioral response. Butterflies were first trained to be fed from artificial yellow flowers inserted in a feeder. These were later replaced by artificial flowers with a similar (blue) or very different (white) spectral reflectance range. Each preference test comprised a dual-choice test (yellow vs blue, yellow vs white). Results Butterflies showed an innate strong preference for red flowers. Both the number of visits and the time spent probing these flowers were much greater than the pink, white, and yellow color flowers. Butterflies learn to associate colors with sugar rewards. They then learned the newly rewarded colors as quickly and proficiently as if the previously rewarded color was similar in spectral reflectance value; the opposite occurs if the newly rewarded color is very different than the previously rewarded color. Conclusions Our findings suggest that common green-eyed white butterflies have good learning abilities. These capabilities may allow them to respond rapidly to different color stimulus.
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Affiliation(s)
- Deysi Muñoz-Galicia
- Centro de Investigación en Ciencias Biológicas, Universidad Autónoma de Tlaxcala, San Felipe, Ixtacuixtla, Tlaxcala, Mexico
| | - Citlalli Castillo-Guevara
- Centro de Investigación en Ciencias Biológicas, Universidad Autónoma de Tlaxcala, San Felipe, Ixtacuixtla, Tlaxcala, Mexico
| | - Carlos Lara
- Centro de Investigación en Ciencias Biológicas, Universidad Autónoma de Tlaxcala, San Felipe, Ixtacuixtla, Tlaxcala, Mexico
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11
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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.
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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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13
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Howard SR, Prendergast K, Symonds MRE, Shrestha M, Dyer AG. Spontaneous choices for insect-pollinated flower shapes by wild non-eusocial halictid bees. J Exp Biol 2021; 224:271069. [PMID: 34318316 DOI: 10.1242/jeb.242457] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 07/22/2021] [Indexed: 11/20/2022]
Abstract
The majority of angiosperms require animal pollination for reproduction, and insects are the dominant group of animal pollinators. Bees are considered one of the most important and abundant insect pollinators. Research into bee behaviour and foraging decisions has typically centred on managed eusocial bee species, including Apis mellifera and Bombus terrestris. Non-eusocial bees are understudied with respect to foraging strategies and decision making, such as flower preferences. Understanding whether there are fundamental foraging strategies and preferences that are features of insect groups can provide key insights into the evolution of flower-pollinator co-evolution. In the current study, Lasioglossum (Chilalictus) lanarium and Lasioglossum (Parasphecodes) sp., two native Australian generalist halictid bees, were tested for flower shape preferences between native insect-pollinated and bird-pollinated flowers. Each bee was presented with achromatic images of either insect-pollinated or bird-pollinated flowers in a circular arena. Both native bee species demonstrated a significant preference for images of insect-pollinated flowers. These preferences are similar to those found in A. mellifera, suggesting that flower shape preference may be a deep-rooted evolutionary occurrence within bees. With growing interest in the sensory capabilities of non-eusocial bees as alternative pollinators, the current study also provides a valuable framework for further behavioural testing of such species.
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Affiliation(s)
- Scarlett R Howard
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Burwood, VIC 3125, Australia
| | - Kit Prendergast
- School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Matthew R E Symonds
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Burwood, VIC 3125, Australia
| | - Mani Shrestha
- Disturbance Ecology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, 95440 Bayreuth, Germany.,Faculty of Information Technology, Monash University, Clayton, VIC 3800, Australia
| | - Adrian G Dyer
- School of Media and Communication, RMIT University, Melbourne, VIC 3000, Australia.,Department of Physiology, Monash University, Clayton, VIC 3800, Australia
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14
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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: 3] [Impact Index Per Article: 1.0] [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.
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15
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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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16
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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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17
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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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18
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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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Balamurali GS, Rose S, Somanathan H, Kodandaramaiah U. Complex multi-modal sensory integration and context specificity in colour preferences of a pierid butterfly. J Exp Biol 2020; 223:jeb223271. [PMID: 32414875 DOI: 10.1242/jeb.223271] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 05/11/2020] [Indexed: 11/20/2022]
Abstract
Innate colour preferences in insects were long considered to be a non-flexible representation of a floral 'search image' guiding them to flowers during initial foraging trips. However, these colour preferences have recently been shown to be modulated by multi-sensory integration of information. Using experiments on the butterfly Catopsilia pomona (common emigrant), we demonstrate that cross-modal integration of information not only affects colour preferences but also colour learning, and in a sex-specific manner. We show that spontaneous colour preference in this species is sexually dimorphic, with males preferring both blue and yellow while females prefer yellow. With minimal training (two training sessions), both males and females learned to associate blue with reward, but females did not learn green. This suggests that the aversion to green, in the context of foraging, is stronger in females than in males, probably because green is used as a cue to find oviposition sites in butterflies. However, females learned green after extensive training (five training sessions). Intriguingly, when a floral odour was present along with green during training, female colour preference during the subsequent choice tests resembled their innate preference (preference for yellow). Our results show that multi-sensory integration of information can influence preference, sensory bias, learning and memory in butterflies, thus modulating their behaviour in a context-specific manner.
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Affiliation(s)
- G S Balamurali
- IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala 695551, India
| | - Saloni Rose
- IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala 695551, India
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Hema Somanathan
- IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala 695551, India
| | - Ullasa Kodandaramaiah
- IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala 695551, India
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20
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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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21
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Koethe S, Fischbach V, Banysch S, Reinartz L, Hrncir M, Lunau K. A Comparative Study of Food Source Selection in Stingless Bees and Honeybees: Scent Marks, Location, or Color. FRONTIERS IN PLANT SCIENCE 2020; 11:516. [PMID: 32435253 PMCID: PMC7218124 DOI: 10.3389/fpls.2020.00516] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
In social bees, the choice of food sources is based on several factors, including scent marks, color, and location of flowers. Here, we used similar setups, in which two stingless bee species, Melipona subnitida and Plebeia flavocincta, and the Western honeybee, Apis mellifera, were tested regarding the importance of chemical cues, color cues, and location-dependent cues for foraging behavior. It was determined whether workers chose food sources according to (1) scent marks deposited by conspecifics, (2) the color hue of a food source, (3) the trained location or the proximity of a food source to the hive. All three species preferred the scent-marked over an unmarked feeder that was presented simultaneously, but M. subnitida showed a weaker preference compared to the other species. When trained to blue feeders all three bee species preferred blue, but A. mellifera showed the strongest fidelity. The training to yellow feeders led to less distinct color choices. Only workers of M. subnitida mostly orientated at the training position and the close proximity to the nest. Whether the distance of a feeding site influenced the choice was dependent on the tested parameter (color or scent marks) and the species. Workers of M. subnitida preferably visited the feeder closer to the nest during the scent mark trials, but choose randomly when tested for color learning. Worker honeybees preferred the closer feeding site if trained to yellow, but not if trained to blue, and preferred the more distant feeder during the scent mark trials. Workers of P. flavocincta preferred the closer feeder if trained to blue or yellow, and preferred the more distant feeder during the scent mark trials. The disparity among the species corresponds to differences in body size. Smaller bees are known for reduced visual capabilities and might rely less on visual parameters of the target such as color hue, saturation, or brightness but use scent cues instead. Moreover, the dim-light conditions in forest habitats might reduce the reliability of visual orientation as compared to olfactory orientation. Honeybees showed the most pronounced orientation at floral color cues.
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Affiliation(s)
- Sebastian Koethe
- Institute of Sensory Ecology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Vivian Fischbach
- Institute of Sensory Ecology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sarah Banysch
- Institute of Sensory Ecology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Lara Reinartz
- Institute of Sensory Ecology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Michael Hrncir
- Departamento de Biociências, Universidade Federal Rural do Semi-Árido, Mossoró, Brazil
- Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Klaus Lunau
- Institute of Sensory Ecology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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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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23
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Shrestha M, Dyer AG, Garcia JE, Burd M. Floral colour structure in two Australian herbaceous communities: it depends on who is looking. ANNALS OF BOTANY 2019; 124:221-232. [PMID: 31008511 PMCID: PMC6758583 DOI: 10.1093/aob/mcz043] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 03/14/2019] [Indexed: 05/03/2023]
Abstract
BACKGROUND AND AIMS Pollinator-mediated interactions between plant species may affect the composition of angiosperm communities. Floral colour signals should play a role in these interactions, but the role will arise from the visual perceptions and behavioural responses of multiple pollinators. Recent advances in the visual sciences can be used to inform our understanding of these perceptions and responses. We outline the application of appropriate visual principles to the analysis of the annual cycle of floral colour structure in two Australian herbaceous communities. METHODS We used spectrographic measurements of petal reflectance to determine the location of flowers in a model of hymenopteran colour vision. These representations of colour perception were then translated to a behaviourally relevant metric of colour differences using empirically calibrated colour discrimination functions for four hymenopteran species. We then analysed the pattern of colour similarity in terms of this metric in samples of co-flowering plants over the course of a year. We used the same method to analyse the annual pattern of phylogenetic relatedness of co-flowering plants in order to compare colour structure and phylogenetic structure. KEY RESULTS Co-flowering communities at any given date seldom had colour assemblages significantly different from random. Non-random structure, both dispersion and clustering, occurred occasionally, but depended on which bee observer is considered. The degree of colour similarity was unrelated to phylogenetic similarity within a co-flowering community. CONCLUSIONS Perceived floral colour structure varied with the sensory capabilities of the observer. The lack of colour structure at most sample dates, particularly the rarity of strong dispersion, suggests that plants do not use chromatic signals primarily to enable bees to discriminate between co-flowering species. It is more likely that colours make plants detectable in a complex landscape.
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Affiliation(s)
- Mani Shrestha
- School of Biological Sciences, Monash University, Melbourne, Australia
- School of Media and Communication, RMIT University, Melbourne, Australia
| | - Adrian G Dyer
- School of Media and Communication, RMIT University, Melbourne, Australia
- Department of Physiology, Monash University, Melbourne, Australia
- For correspondence. E-mail
| | - Jair E Garcia
- School of Media and Communication, RMIT University, Melbourne, Australia
| | - Martin Burd
- School of Biological Sciences, Monash University, Melbourne, Australia
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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: 2.2] [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]
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25
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de Camargo MGG, Lunau K, Batalha MA, Brings S, de Brito VLG, Morellato LPC. How flower colour signals allure bees and hummingbirds: a community-level test of the bee avoidance hypothesis. THE NEW PHYTOLOGIST 2019; 222:1112-1122. [PMID: 30444536 DOI: 10.1111/nph.15594] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 11/08/2018] [Indexed: 05/07/2023]
Abstract
Colour signals are the main floral trait for plant-pollinator communication. Owing to visual specificities, flower visitors exert different selective pressures on flower colour signals of plant communities. Although they evolved to attract pollinators, matching their visual sensitivity and colour preferences, floral signals may also evolve to avoid less efficient pollinators and antagonistic flower visitors. We evaluated evidence for the bee avoidance hypothesis in a Neotropical community pollinated mainly by bees and hummingbirds, the campo rupestre. We analysed flower reflectance spectra, compared colour variables of bee-pollinated flowers (bee-flowers; 244 species) and hummingbird-pollinated flowers (hummingbird-flowers; 39 species), and looked for evidence of bee sensorial exclusion in hummingbird-flowers. Flowers were equally contrasting for hummingbirds. Hummingbird-flowers were less conspicuous to bees, reflecting mainly long wavelengths and avoiding red-blind visitors. Bee-flowers reflected more short wavelengths, were more conspicuous to bees (higher contrasts and spectral purity) than hummingbird-flowers and displayed floral guides more frequently, favouring flower attractiveness, discrimination and handling by bees. Along with no phylogenetic signal, the differences in colour signal strategies between bee- and hummingbird-flowers are the first evidence of the bee avoidance hypothesis at a community level and reinforce the role of pollinators as a selective pressure driving flower colour diversity.
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Affiliation(s)
- Maria Gabriela Gutierrez de Camargo
- Departamento de Botânica, Laboratório de Fenologia, Instituto de Biociências, UNESP-Universidade Estadual Paulista, 13506-900, Rio Claro, São Paulo, Brasil
| | - Klaus Lunau
- Department Biology, Institute of Sensory Ecology, Heinrich-Heine-University Düsseldorf, 40225, Düsseldorf, Germany
| | - Marco Antônio Batalha
- Department of Botany, Federal University of São Carlos, 13565-905, São Carlos, São Paulo, Brazil
| | - Sebastian Brings
- Department Biology, Institute of Sensory Ecology, Heinrich-Heine-University Düsseldorf, 40225, Düsseldorf, Germany
| | | | - Leonor Patrícia Cerdeira Morellato
- Departamento de Botânica, Laboratório de Fenologia, Instituto de Biociências, UNESP-Universidade Estadual Paulista, 13506-900, Rio Claro, São Paulo, Brasil
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Hannah L, Dyer AG, Garcia JE, Dorin A, Burd M. Psychophysics of the hoverfly: categorical or continuous color discrimination? Curr Zool 2019; 65:483-492. [PMID: 31413720 PMCID: PMC6688577 DOI: 10.1093/cz/zoz008] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 02/26/2019] [Indexed: 12/12/2022] Open
Abstract
There is increasing interest in flies as potentially important pollinators. Flies are known to have a complex visual system, including 4 spectral classes of photoreceptors that contribute to the perception of color. Our current understanding of how color signals are perceived by flies is based on data for the blowfly Lucilia sp., which after being conditioned to rewarded monochromatic light stimuli, showed evidence of a categorical color visual system. The resulting opponent fly color space has 4 distinct categories, and has been used to interpret how some fly pollinators may perceive flower colors. However, formal proof that flower flies (Syrphidae) only use a simple, categorical color process remains outstanding. In free-flying experiments, we tested the hoverfly Eristalis tenax, a Batesian mimic of the honeybee, that receives its nutrition by visiting flowers. Using a range of broadband similar–dissimilar color stimuli previously used to test color perception in pollinating hymenopteran species, we evaluated if there are steep changes in behavioral choices with continuously increasing color differences as might be expected by categorical color processing. Our data revealed that color choices by the hoverfly are mediated by a continuous monotonic function. Thus, these flies did not use a categorical processing, but showed evidence of a color discrimination function similar to that observed in several bee species. We therefore empirically provide data for the minimum color distance that can be discriminated by hoverflies in fly color space, enabling an improved understanding of plant–pollinator interactions with a non-model insect species.
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Affiliation(s)
- Lea Hannah
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia.,Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales 2753, Australia
| | - Adrian G Dyer
- School of Media and Communication, RMIT University, Melbourne, Victoria 3001, Australia.,Department of Physiology, Monash University, Clayton, Victoria 3800, Australia
| | - Jair E Garcia
- School of Media and Communication, RMIT University, Melbourne, Victoria 3001, Australia
| | - Alan Dorin
- Faculty of Information Technology, Monash University, Clayton, Victoria 3800, Australia
| | - Martin Burd
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
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van der Kooi CJ, Dyer AG, Kevan PG, Lunau K. Functional significance of the optical properties of flowers for visual signalling. ANNALS OF BOTANY 2019; 123:263-276. [PMID: 29982325 PMCID: PMC6344213 DOI: 10.1093/aob/mcy119] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 06/06/2018] [Indexed: 05/20/2023]
Abstract
BACKGROUND Flower coloration is a key enabler for pollinator attraction. Floral visual signals comprise several components that are generated by specific anatomical structures and pigmentation, and often have different functions in pollinator attraction. Anatomical studies have advanced our understanding of the optical properties of flowers, and evidence from behavioural experiments has elucidated the biological relevance of different components of floral visual signals, but these two lines of research are often considered independently. SCOPE Here, we review current knowledge about different aspects of the floral visual signals, their anatomical and optical properties, and their functional significance in plant-pollinator visual signalling. We discuss common aspects, such as chromatic and achromatic contrast, hue, saturation and brightness, as well as less common types of visual signals, including gloss, fluorescence, polarization and iridescence in the context of salience of floral colour signals and their evolution, and highlight promising avenues for future research.
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Affiliation(s)
- Casper J van der Kooi
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, the Netherlands
- For correspondence. E-mail
| | - Adrian G Dyer
- School of Media and Communication, RMIT University, Melbourne, Australia
| | - Peter G Kevan
- School of Environmental Sciences, University of Guelph, Guelph, Canada
| | - Klaus Lunau
- Institute of Sensory Ecology, Heinrich-Heine-University, Dusseldorf, Germany
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Kemp JE, Bergh NG, Soares M, Ellis AG. Dominant pollinators drive non-random community assembly and shared flower colour patterns in daisy communities. ANNALS OF BOTANY 2019; 123:277-288. [PMID: 29992277 PMCID: PMC6344215 DOI: 10.1093/aob/mcy126] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 06/13/2018] [Indexed: 05/20/2023]
Abstract
Background and Aims As most plants rely on pollination for persistence in communities, pollination interactions should be important determinants of plant community assembly. Here, trait and phylogenetic null modelling approaches were combined with pollinator interaction networks to elucidate the processes structuring flower colour assembly patterns in Asteraceae communities in Namaqualand, South Africa. Methods Plant species were assigned to flower colour pattern categories (CPCs) that incorporate the complexity of the bulls-eye colour pattern, using pollinator vision models. Null models were used to assess whether daisy communities exhibit clustering (driven by filtering, facilitation or convergence) or overdispersion (driven by competitive exclusion or character displacement) of CPCs. Next, flower visitor networks were constructed for communities with non-random CPC assembly to confirm the functional role of pollinators in determining floral trait assembly. Key Results Plant species are unevenly distributed across CPCs, the majority of which are not phylogenetically conserved, suggesting that certain CPCs have a selective advantage. Clustering of CPCs in communities is more frequent than overdispersion, and this does not reflect non-random phylogenetic assembly. In most communities at least one CPC is overrepresented relative to null assemblages. Interaction networks show that each community has a single dominant pollinator that strongly interacts with the overrepresented CPC, suggesting a role for pollinator preferences in driving clustered assembly of CPCs within daisy communities. Conclusion This novel approach, which demonstrates non-random assembly of complex flower colour patterns and corroborates their functional association with particular pollinators, provides strong evidence that pollinators influence plant community assembly. Results suggest that in some community contexts the benefits of pollinator sharing outweigh the costs of heterospecific pollen transfer, generating clustered assembly. They also challenge the perception of generalized pollination in daisies, suggesting instead that complex daisy colour patterns represent a pollination syndrome trait linked to specific fly pollinators.
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Affiliation(s)
- Jurene E Kemp
- Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa
| | - Nicola G Bergh
- The Compton Herbarium, Kirstenbosch Research Centre, South African National Biodiversity Institute, Newlands, Cape Town, South Africa
- The Bolus Herbarium, Department of Biological Sciences, H.W. Pearson Building, University of Cape Town, Rondebosch, Cape Town, South Africa
| | - Muri Soares
- The Bolus Herbarium, Department of Biological Sciences, H.W. Pearson Building, University of Cape Town, Rondebosch, Cape Town, South Africa
| | - Allan G Ellis
- Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa
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Howard SR, Shrestha M, Schramme J, Garcia JE, Avarguès-Weber A, Greentree AD, Dyer AG. Honeybees prefer novel insect-pollinated flower shapes over bird-pollinated flower shapes. Curr Zool 2018; 65:457-465. [PMID: 31413718 PMCID: PMC6688580 DOI: 10.1093/cz/zoy095] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 12/04/2018] [Indexed: 11/18/2022] Open
Abstract
Plant–pollinator interactions have a fundamental influence on flower evolution. Flower color signals are frequently tuned to the visual capabilities of important pollinators such as either bees or birds, but far less is known about whether flower shape influences the choices of pollinators. We tested European honeybee Apis mellifera preferences using novel achromatic (gray-scale) images of 12 insect-pollinated and 12 bird-pollinated native Australian flowers in Germany; thus, avoiding influences of color, odor, or prior experience. Independent bees were tested with a number of parameterized images specifically designed to assess preferences for size, shape, brightness, or the number of flower-like shapes present in an image. We show that honeybees have a preference for visiting images of insect-pollinated flowers and such a preference is most-likely mediated by holistic information rather than by individual image parameters. Our results indicate angiosperms have evolved flower shapes which influence the choice behavior of important pollinators, and thus suggest spatial achromatic flower properties are an important part of visual signaling for plant–pollinator interactions.
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Affiliation(s)
- Scarlett R Howard
- Bio-inspired Digital Sensing (BIDS) Lab, School of Media and Communication, RMIT University, Melbourne, Victoria 3000, Australia
| | - Mani Shrestha
- Bio-inspired Digital Sensing (BIDS) Lab, School of Media and Communication, RMIT University, Melbourne, Victoria 3000, Australia.,Faculty of Information Technology, Monash University, Melbourne, Victoria 3800, Australia
| | - Juergen Schramme
- Institute of Developmental Biology and Neurobiology (iDn), Johannes Gutenberg University, Mainz 55122, Germany
| | - Jair E Garcia
- Bio-inspired Digital Sensing (BIDS) Lab, School of Media and Communication, RMIT University, Melbourne, Victoria 3000, Australia
| | - Aurore Avarguès-Weber
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse 31400, France
| | - Andrew D Greentree
- ARC Centre of Excellence for Nanoscale BioPhotonics, School of Science, RMIT University, Melbourne, Victoria 3000, Australia
| | - Adrian G Dyer
- Bio-inspired Digital Sensing (BIDS) Lab, School of Media and Communication, RMIT University, Melbourne, Victoria 3000, Australia.,Department of Physiology, Monash University, Clayton, Victoria 3800, Australia
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30
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Koethe S, Banysch S, Alves-dos-Santos I, Lunau K. Spectral purity, intensity and dominant wavelength: Disparate colour preferences of two Brazilian stingless bee species. PLoS One 2018; 13:e0204663. [PMID: 30265685 PMCID: PMC6162086 DOI: 10.1371/journal.pone.0204663] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 09/12/2018] [Indexed: 11/18/2022] Open
Abstract
Bees use floral colour as a major long distance orientation cue. While it is known for bumblebees and honeybees that dominant wavelength (≙ colour hue), colour contrast and spectral purity (≙ saturation) are crucial for flower detection and discrimination, only little is known about colour preferences in stingless bees (Meliponini). In this experiment freely flying workers of two Brazilian species of stingless bees-Partamona helleri and Melipona bicolor-were tested for colour preferences concerning the colour parameters dominant wavelength, spectral purity and intensity (≙ brightness). Each individual bee had to perform 57 tests, in which a definite series of dual choices between colour stimuli varying in intensity, spectral purity or dominant wavelength were presented. The results show that P. helleri chose colours of higher spectral purity and preferred bluish colours, while M. bicolor made generalized colour choices. Intensity did not influence the colour choice of any bee species. The results of P. helleri are consistent with findings for honeybees and bumblebees, while colour preferences in M. bicolor seem to be absent.
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Affiliation(s)
- Sebastian Koethe
- Institute of Sensory Ecology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Sarah Banysch
- Institute of Sensory Ecology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Isabel Alves-dos-Santos
- Laboratório de Abelhas, Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo – USP, São Paulo, São Paulo, Brazil
| | - Klaus Lunau
- Institute of Sensory Ecology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
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31
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Understanding innate preferences of wild bee species: responses to wavelength-dependent selective excitation of blue and green photoreceptor types. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2018; 204:667-675. [DOI: 10.1007/s00359-018-1269-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/27/2018] [Accepted: 05/29/2018] [Indexed: 10/14/2022]
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Yilmaz A, Dyer AG, Rössler W, Spaethe J. Innate colour preference, individual learning and memory retention in the ant Camponotus blandus. ACTA ACUST UNITED AC 2018; 220:3315-3326. [PMID: 28931719 DOI: 10.1242/jeb.158501] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 06/29/2017] [Indexed: 01/05/2023]
Abstract
Ants are a well-characterized insect model for the study of visual learning and orientation, but the extent to which colour vision is involved in these tasks remains unknown. We investigated the colour preference, learning and memory retention of Camponotus blandus foragers under controlled laboratory conditions. Our results show that C. blandus foragers exhibit a strong innate preference for ultraviolet (UV, 365 nm) over blue (450 nm) and green (528 nm) wavelengths. The ants can learn to discriminate 365 nm from either 528 nm or 450 nm, independent of intensity changes. However, they fail to discriminate between 450 nm and 528 nm. Modelling of putative colour spaces involving different numbers of photoreceptor types revealed that colour discrimination performance of individual ants is best explained by dichromacy, comprising a short-wavelength (UV) receptor with peak sensitivity at about 360 nm, and a long-wavelength receptor with peak sensitivity between 470 nm and 560 nm. Foragers trained to discriminate blue or green from UV light are able to retain the learned colour information in an early mid-term (e-MTM), late mid-term (l-MTM), early long-term (e-LTM) and late long-term (l-LTM) memory from where it can be retrieved after 1 h, 12 h, 24 h, 3 days and 7 days after training, indicating that colour learning may induce different memory phases in ants. Overall, our results show that ants can use chromatic information in a way that should promote efficient foraging in complex natural environments.
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Affiliation(s)
- Ayse Yilmaz
- Department of Behavioral Physiology & Sociobiology (Zoology II), Biozentrum, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Adrian G Dyer
- Department of Physiology, Monash University, Clayton, VIC 3168, Australia.,School of Media and Communication, Royal Melbourne Institute of Technology, Melbourne, VIC 3000, Australia
| | - Wolfgang Rössler
- Department of Behavioral Physiology & Sociobiology (Zoology II), Biozentrum, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Johannes Spaethe
- Department of Behavioral Physiology & Sociobiology (Zoology II), Biozentrum, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
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Biocommunication between Plants and Pollinating Insects through Fluorescence of Pollen and Anthers. J Chem Ecol 2018; 44:591-600. [PMID: 29717395 DOI: 10.1007/s10886-018-0958-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 03/23/2018] [Accepted: 04/09/2018] [Indexed: 10/17/2022]
Abstract
Flowering plants attract pollinators via various stimuli such as odor, color, and shape. Factors determining the foraging behavior of pollinators remain a major theme in ecological and evolutionary research, although the floral traits and cognitive ability of pollinators have been investigated for centuries. Here we show that the autofluorescence emitted from pollen and anthers under UV irradiation may act as another attractant for flower-visiting insects. We have identified fluorescent compounds from pollen and anthers of five plant species as hydroxycinnamoyl derivatives. The fluorescent compounds are also shown to quench UV energy and exhibit antioxidant activity, indicating a function as protectants of pollen genes from UV-induced damage. A two-choice assay using honeybees in the field demonstrated that they perceived the blue fluorescence emitted from the fluorescent compounds and were attracted to it. This result suggested that the fluorescence from pollen and anthers serves as a visual cue to attract pollinators under sunlight.
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Souto-Vilarós D, Vuleta A, Jovanović SM, Budečević S, Wang H, Sapir Y, Imbert E. Are pollinators the agents of selection on flower colour and size in irises? OIKOS 2018. [DOI: 10.1111/oik.04501] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Daniel Souto-Vilarós
- ISEM, Univ. de Montpellier, CNRS, IRD, EPHE; Montpellier France
- Faculty of Science, Biology center, Univ. of South Bohemia, Branišovská 1760; CZ-37005 České Budějovice Czech Republic
| | - Ana Vuleta
- Dept of Evolutionary Biology; “Siniša Stanković” Inst. for Biological Research, Univ. of Belgrade; Belgrade Serbia
| | - Sanja Manitašević Jovanović
- Dept of Evolutionary Biology; “Siniša Stanković” Inst. for Biological Research, Univ. of Belgrade; Belgrade Serbia
| | - Sanja Budečević
- Dept of Evolutionary Biology; “Siniša Stanković” Inst. for Biological Research, Univ. of Belgrade; Belgrade Serbia
| | - Hui Wang
- ISEM, Univ. de Montpellier, CNRS, IRD, EPHE; Montpellier France
- College of life sciences, Northwest A&F Univ.; Yangling Shaanxi China
| | - Yuval Sapir
- The Botanical Garden, School of Plant Sciences and Food Security, Tel Aviv Univ.; Ramat Aviv Tel Aviv Israel
| | - Eric Imbert
- ISEM, Univ. de Montpellier, CNRS, IRD, EPHE; Montpellier France
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Balamurali GS, Nicholls E, Somanathan H, Hempel de Ibarra N. A comparative analysis of colour preferences in temperate and tropical social bees. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2018; 105:8. [PMID: 29294192 PMCID: PMC5750331 DOI: 10.1007/s00114-017-1531-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 11/15/2017] [Accepted: 12/12/2017] [Indexed: 11/17/2022]
Abstract
The spontaneous occurrence of colour preferences without learning has been demonstrated in several insect species; however, the underlying mechanisms are still not understood. Here, we use a comparative approach to investigate spontaneous and learned colour preferences in foraging bees of two tropical and one temperate species. We hypothesised that tropical bees utilise different sets of plants and therefore might differ in their spontaneous colour preferences. We tested colour-naive bees and foragers from colonies that had been enclosed in large flight cages for a long time. Bees were shortly trained with triplets of neutral, UV-grey stimuli placed randomly at eight locations on a black training disk to induce foraging motivation. During unrewarded tests, the bees' responses to eight colours were video-recorded. Bees explored all colours and displayed an overall preference for colours dominated by long or short wavelengths, rather than a single colour stimulus. Naive Apis cerana and Bombus terrestris showed similar choices. Both inspected long-wavelength stimuli more than short-wavelength stimuli, whilst responses of the tropical stingless bee Tetragonula iridipennis differed, suggesting that resource partitioning could be a determinant of spontaneous colour preferences. Reward on an unsaturated yellow colour shifted the bees' preference curves as predicted, which is in line with previous findings that brief colour experience overrides the expression of spontaneous preferences. We conclude that rather than determining foraging behaviour in inflexible ways, spontaneous colour preferences vary depending on experimental settings and reflect potential biases in mechanisms of learning and decision-making in pollinating insects.
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Affiliation(s)
- G S Balamurali
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, India
- Centre for Research in Animal Behaviour, Department of Psychology, University of Exeter, Exeter, EX4 4QG, UK
| | - Elizabeth Nicholls
- Centre for Research in Animal Behaviour, Department of Psychology, University of Exeter, Exeter, EX4 4QG, UK
- School of Life Sciences, University of Sussex, Brighton, Falmer, BN1 9QG, UK
| | - Hema Somanathan
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, India
| | - Natalie Hempel de Ibarra
- Centre for Research in Animal Behaviour, Department of Psychology, University of Exeter, Exeter, EX4 4QG, UK.
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Streinzer M, Huber W, Spaethe J. Body size limits dim-light foraging activity in stingless bees (Apidae: Meliponini). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2016; 202:643-55. [PMID: 27495990 PMCID: PMC5023731 DOI: 10.1007/s00359-016-1118-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 07/28/2016] [Accepted: 07/29/2016] [Indexed: 12/02/2022]
Abstract
Stingless bees constitute a species-rich tribe of tropical and subtropical eusocial Apidae that act as important pollinators for flowering plants. Many foraging tasks rely on vision, e.g. spatial orientation and detection of food sources and nest entrances. Meliponini workers are usually small, which sets limits on eye morphology and thus quality of vision. Limitations are expected both on acuity, and thus on the ability to detect objects from a distance, as well as on sensitivity, and thus on the foraging time window at dusk and dawn. In this study, we determined light intensity thresholds for flight under dim light conditions in eight stingless bee species in relation to body size in a Neotropical lowland rainforest. Species varied in body size (0.8-1.7 mm thorax-width), and we found a strong negative correlation with light intensity thresholds (0.1-79 lx). Further, we measured eye size, ocelli diameter, ommatidia number, and facet diameter. All parameters significantly correlated with body size. A disproportionately low light intensity threshold in the minute Trigonisca pipioli, together with a large eye parameter P eye suggests specific adaptations to circumvent the optical constraints imposed by the small body size. We discuss the implications of body size in bees on foraging behavior.
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Affiliation(s)
- Martin Streinzer
- Department of Evolutionary Biology, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090, Vienna, Austria.
- Department of Neurobiology, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090, Vienna, Austria.
| | - Werner Huber
- Department of Botany and Biodiversity Research, Faculty of Life Sciences, University of Vienna, Rennweg 14, 1030, Vienna, Austria
| | - Johannes Spaethe
- Department of Evolutionary Biology, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090, Vienna, Austria
- Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
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Stingless bees (Meliponini): senses and behavior. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2016; 202:597-601. [PMID: 27518819 DOI: 10.1007/s00359-016-1117-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 07/22/2016] [Indexed: 10/21/2022]
Abstract
Stingless bees (Hymenoptera, Apidae, Meliponini) are by far the largest group of eusocial bees on Earth. Due to the diversity of evolutionary responses to specific ecological challenges, the Meliponini are well suited for comparative studies of the various adaptations to the environment found in highly eusocial bees. Of particular interest are the physiological mechanisms underlying the sophisticated cooperative and collective actions of entire colonies, which form the basis of the ecological success of the different bee species under the particular conditions prevailing in their respective environment. The present Special Issue of the Journal of Comparative Physiology A provides a sample of the exciting diversity of sensorial and behavioral adaptations in stingless bees, particularly concerning (1) the sensory bases for foraging, (2) chemical communication, and (3) the behavioral ecology of foraging.
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Koethe S, Bossems J, Dyer AG, Lunau K. Colour is more than hue: preferences for compiled colour traits in the stingless bees Melipona mondury and M. quadrifasciata. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2016; 202:615-27. [DOI: 10.1007/s00359-016-1115-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 07/21/2016] [Accepted: 07/22/2016] [Indexed: 12/01/2022]
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Dyer AG, Streinzer M, Garcia J. Flower detection and acuity of the Australian native stingless bee Tetragonula carbonaria Sm. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2016; 202:629-39. [DOI: 10.1007/s00359-016-1107-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 06/14/2016] [Accepted: 06/16/2016] [Indexed: 10/21/2022]
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