Article | Published:

Disorder in convergent floral nanostructures enhances signalling to bees

Nature volume 550, pages 469474 (26 October 2017) | Download Citation

Abstract

Diverse forms of nanoscale architecture generate structural colour and perform signalling functions within and between species. Structural colour is the result of the interference of light from approximately regular periodic structures; some structural disorder is, however, inevitable in biological organisms. Is this disorder functional and subject to evolutionary selection, or is it simply an unavoidable outcome of biological developmental processes? Here we show that disordered nanostructures enable flowers to produce visual signals that are salient to bees. These disordered nanostructures (identified in most major lineages of angiosperms) have distinct anatomies but convergent optical properties; they all produce angle-dependent scattered light, predominantly at short wavelengths (ultraviolet and blue). We manufactured artificial flowers with nanoscale structures that possessed tailored levels of disorder in order to investigate how foraging bumblebees respond to this optical effect. We conclude that floral nanostructures have evolved, on multiple independent occasions, an effective degree of relative spatial disorder that generates a photonic signature that is highly salient to insect pollinators.

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Acknowledgements

We thank M. Dorling for plant and bee care; P. Cunha for advice on e-beam lithography; and B. Wilts, J. Baumberg, R. Bateman, N. Cunniffe, N. Walker-Hale, L. Chittka, H. Whitney and M. Kolle for discussion. We acknowledge the collections at Cambridge University Botanic Garden and the Royal Botanic Gardens, Kew. This work was funded by the Leverhulme Trust (F/09741/G to B.J.G. and U.S.), BBSRC (DTG studentship to A.R. and the David Phillips fellowship (BB/K014617/1) (76933) to S.V.), the European Research Council ((ERC-2014-STG H2020 639088) to S.V.), the Herchel Smith fund (to E.M.), EU Marie Curie actions (NanoPetals to E.M. and B.J.G.), EPSRC (EP/G037221/1 to R.M.), the Winton Fund for the Physics of Sustainability and the Cambridge Trust CHESS (to T.W.), the Adolphe Merkle Foundation and the Swiss National Science Foundation (National Center of Competence in Research Bio-Inspired Materials) (U.S.). We thank the EU for funding under Marie Curie Actions I.T.N. PlaMatSu (722842) to U.S., S.V. and B.J.G.

Author information

Author notes

    • Edwige Moyroud
    •  & Tobias Wenzel

    These authors contributed equally to this work.

Affiliations

  1. Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK

    • Edwige Moyroud
    • , Alison Reed
    • , Greg Mellers
    • , Patrick Killoran
    • , M. Murphy Westwood
    •  & Beverley J. Glover
  2. Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK

    • Tobias Wenzel
    •  & Ullrich Steiner
  3. Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK

    • Rox Middleton
    •  & Silvia Vignolini
  4. Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK

    • Paula J. Rudall
    •  & Hannah Banks
  5. Adolphe Merkle Institute, Chemin des Verdiers 4, CH1700 Fribourg, Switzerland

    • Ullrich Steiner

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Contributions

B.J.G., S.V., U.S., P.J.R. and E.M. conceived and led the project. B.J.G., S.V., U.S., E.M. and T.W. designed experiments. E.M., S.V., A.R. and M.M.W. surveyed collections and performed SEM imaging. E.M., H.B. and G.M. performed TEM imaging. S.V., R.M. and T.W. performed optical measurements. T.W. extracted striation parameters, ran finite-difference time-domain simulations, manufactured artificial gratings and conducted cross-sectional SEM. E.M. and P.K. performed bee behavioural experiments. B.J.G., E.M., T.W., S.V., U.S. and P.J.R. wrote the manuscript. All authors commented before submission.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Silvia Vignolini or Beverley J. Glover.

Reviewer Information Nature thanks D. Deheyn and the other anonymous reviewer(s) for their contribution to the peer review of this work.

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https://doi.org/10.1038/nature24285

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