Iridescences Serge Berthier Iridescences The Physical Colors of Insects Serge Berthier Institut des Nano-Sciences de Paris UMR CNRS - Universit´ePierre et Marie Curie Universit´eDenis Diderot 4 Place Jussieu Paris, 75252 France Translator Capucine Lafait 7 Rue Christian Dewet Paris, 75012 France Library of Congress Control Number: 2006925252 ISBN-10: 0-387-34119-6 e-ISBN-10: 0-387-34120-X ISBN-13: 978-0-387-34119-4 e-ISBN-13: 978-0-387-34120-0 Printed on acid-free paper. C 2007 Springer Science+Business Media, LLC All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer Science+Business Media, LLC, 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. 987654321 springer.com About the Author Serge Berthier teaches physics at the Denis Diderot-Paris 7 University and researches biologic structures, colors and biomimetism at the Institut des NanoSciences de Paris (Pierre and Marie Curie-Paris 6 University and CNRS). He teaches solid state optics in the post-graduate degree “Optics and Material” and the post-graduate research degree “Optics and Photonic” for the Denis Diderot University. He also teaches electromagnetism and laser physics to undergraduates at the Paris-Jussieu Institut of Technology. v Foreword Here is a book to recommend for various reasons. First of all, let us note that the first chapter introduces the reader into a reflection on the physical explanation of an observation. The origin of butterfly colors has interested a great physics experimenter, A.A. Michelson, Nobel Prize in 1907, thought it proceeded from selective reflection over butterfly wings and defended this idea during his whole life. The book he wrote in 1927 at the age of 75 and which contains all of the conclusions of his work, ends with a chapter entitled “metallic colors of birds and insects”. At the same time, another great physicist, Lord Raleigh, claimed that observed colors were caused by light interferences. How is it possible to defend two different explanations for similar observations? Simply because the knowledge of the objects observed was inappropriate. Here is a simple case which shows how a scientific explanation can evolve with the knowledge of the object observed. S. Berthier’s book beautifully shows that it is possible to teach physics in relation with biology, which makes the latter certainly more attracting and lively. One is here offered an optics course through a treatise on Lepidoptera and Coleopteron colors. This shows that it is possible to teach physics in a “painless” way. Lastly, the conclusion underlines that the study of butterfly iridescence entice researchers to find ways to apply the same principles to textiles. It also highlights that Butterflies and Cincidelidae’s properties could be used to ensure the identification and protection of bank notes. As founder of the laboratory in which S. Berthier works, I am very happy and proud to present this book. Its author has a gift for pedagogy and this book is fascinating at all levels. It should interest young people, as young as high school seniors, but also every people who likes to learn and understand nature further. This book succeeds in being concise and clear, but also in making one marvel. It is also a step forward as concerns pluridisciplinarity. I wish that it is successful, as it deserves, and I congratulate the author. Florin Abeles Professor Emeritus of Pierre et Marie University, Paris. vi Acknowledgments Part of this book is a new, improved, and substantially modified version of the first book, Butterfly Colors or the Imperative Beauty. I won’t mention again all the people who contributed to the first book. They will recognize their contribution in the present work that made up Imperative Beauty and was the basis of Iridescence. I would like to thank them once again, the pupils, students, and teachers who gave a reason for being to these publications. I thank my colleague and friend Michel Perreau for his uncompromising correcting of the first book and making pertinent remarks about the present book, which were very useful to me. Other people took over, furthering and widening the scope of the first exploratory work. A schoolboy also whose stay was too short: Antoine Baillet. Thank you, my dear Antoine! Spadework, exalting at first but also quite laborious, was performed joyfully and contentedly by Aur´elie Tournie and Marius Knoch, students at the Institut Universitaire de technologie (IUT) Paris-Jussieu, and Mathieu Gueguen at IUT of Annecy. They made a great number of the most beautiful of the photonic microscopy photos presented here. I thank them for their patience and congratulate them for succeeding in conciliating scientific rigor and artistic sensitivity. Postgraduate students focused more on applications. Passing from quality to quantity does not always prove uplifting. If their conclusions have only a small place in the present book, they still made the latter possible in terms of logistics. Thanks to Jean Druille and Loic Ledernez, students of the Optics and Materials Master at the University Denis Diderot in Paris. We aimed at widening the scope of the study of iridescence beyond physics and butterflies in the present publication, which is beyond our qualifications. That is why we relied on the work of specialists, especially Pr. Henri Descimon, of Marseille University, on pigments. He also provided us with a certain number of photos illustrating his conclusions. I want to respectfully thank him. I would also like to thank my friend Emanuel Fritsch of the Institut des Mat´eriaux de Nantes for photos of opals, as well as Philippe Lalanne of the Institut d’Optique d’Orsay, my colleague of the Optics and Photonic post-graduate degree, for the calculations of electromagnetic fields diffracted by the Morphos. These research works were performed at the “color and biomimetism” group of the Labora- toire d’Optique des Solides—Universit´e Pierre et Marie Curie, Paris. I thank all the staff of the laboratory, beginning with its director, Jacques Lafait, for his unbreakable support. Some people directly contributed to this work, like Claude Sella, who suggested I should use ionic thinning on elytrons, thus allowing me to distinguish “in relief” chitin sticks. These elytrons had first un- dergone optical polishing in our crystallography workshop in Michelle Jacquet’s expert hands, who I friendlily thank. A special thanks to Eric Charron, who performed spectogoniometric measurements and established Morphos diffraction maps, as well as to those who patiently and kindly tried to pacify my relationship with computers and get me out of the incredible messes I get myself in: Claude Naud and G´erard Vuye. vii viii Acknowledgments Most of the scanning electron microscopy photos were taken by St´ephaneBorensztein at the Laboratoire de Physique des Liquides et Electrochimie´ at the University Pierre and Marie Curie. Transmission electronic or photonic microscopy sections of scales and alary membranes were made at the Laboratoire de Biologie Marine at the same university. Thanks to Jean-Pierre Lechair and Ghislaine Fr´ebourg for welcoming me and for their beautiful work. I was about to forget my friend and official supplier of butterflies and other insects, Claude Nature. You can go to his shop 6, rue des Chantiers in the 5th in Paris to get a good dose of marvel and good spirits. Lastly,authors are unbearable persons. Thanks to my children, Val´erianand Juliette, for putting up with my unavailability and sudden changes of moods with so much kindness and humor. Annie Fontaine had her share, and in addition, she patiently and rigorously—and tactfully, authors being touchy persons—corrected proofs. Thank you for the warmth and tenderness you gave me. Contents 1 Iridescence ...................................................................................................... 1 About the Book................................................................................................. 5 2 Why Colors...................................................................................................... 7 Variations in Colors ........................................................................................... 9 Colors: Another Classification............................................................................. 10 Mimicry........................................................................................................... 10 3 Lepidoptera Description and Scales of Observation.............................................. 14 Outlining a Classification ................................................................................... 14 Summary Description of Butterflies...................................................................... 15 Description of the Wings .................................................................................... 20 4 Coleoptera Description and Observation Scales................................................... 40 Coleoptera ......................................................................................................