TY - JOUR
T1 - Structural origins of coloration in the spider Phoroncidia rubroargentea Berland, 1913 (Araneae:Theridiidae) from Madagascar
AU - Kariko, Sarah
AU - Timonen, Jaakko V. I.
AU - Weaver, James C.
AU - Gur, Dvir
AU - Marks, Carolyn
AU - Leiserowitz, Leslie
AU - Kolle, Mathias
AU - Li, Ling
N1 - J.V.I.T. was supported by the European Commission through the Seventh Framework Programme (FP7) project DynaSLIPS (project no. 626954). M.K. was support by the National Science Foundation through the ‘Designing Materials to Revolutionize and Engineer our Future’ program (DMREF-1533985). The field research was generously supported by the Fulbright Commission, an Isabella Briggs Travelling Fellowship, Harvard Travelers Club, Douroncouli Foundation and the Museum of Comparative Zoology; expeditions supported by Patagonia, The North Face, Leatherman, York Pack, Easter Seals Headlamps and Timex. Additional expedition support provided by the Institute for the Conservation of Nature. This work was performed in part at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Coordinated Infrastructure Network (NNCI), which is supported by the National Science Foundation under NSF award no. 1541959. CNS is part of Harvard University. Acknowledgements This paper is dedicated to Herbert W. Levi (who passed away during the course of this research) in honour of his early work on Phoroncidia and for mentoring S.J.K. We would like to extend special recognition and thanks to Telo Albert who worked with S.J.K. at Vatoharanana and whose fieldwork was invaluable on several expeditions that resulted in finding the spiders that inspired this study. We thank the government and people of Madagascar, Madagascar Ministry of Forests, Environment and Tourism/ Direction des Eaux et Forêts of the Ministre d’ Etat a L'Agriculture et au Development Rural, the CAFF/CORE oversight committee, the accord of collaboration with Duke University, Ministry of Higher Education and the Department of Water and Forests, and Madagascar National Parks (ANGAP) for making our work in Madagascar possible as well as the arachnofauna. We are grateful for vital logistical and infrastructural support from Madagascar Institut pour la Conservation des Ecosystèmes Tropicaux (MICET), particularly director Benjamin Andriamihaja; and to Centre ValBio, especially Eileen Larney with John Cadle and support personnel. Thanks also to Berthe Rakotosamimanana and Celestine Ravaorinorma for assistance with permits. Thanks to Patricia Wright and Patricia Paladines at the Institute for the Conservation of Tropical Environments (ICTE) and Noel Rowe for vital field and logistical support. Thanks to the RNP research technicians/guides: Emile Rajeriarison, Loret Rasabo, the late Georges Rakotonirina, the late Talata Pierre; and the late Zafy Albert, guardian of Vato: this work would not have been possible without all of you. We acknowledge assistance in the field by Barbara and the late Vince Roth; thanks to Andy Kingman for early fieldwork. Thanks to the team that attempted with robust effort and little luck to find additional P. rubroargentea spiders in Madagascar: William Montag, Telo Albert, and Rahanitriniaina Sahondra Lalao. Also, thanks to Bettina Lengsfeld for sewing special beating sheets and Paul Bertner for use of his field photos. Thanks to Dan Rossman for technical support. Specimens from SJK expeditions were collected under permit no. 017-MEF/DEF/SDN/FFE/AUT from the Ministere des Eaux et Forets of Madagascar. We gratefully acknowledge the Museum of Comparative Zoology's Invertebrate Zoology collections for support: Professor Gonzalo Giribet; Adam Baldinger and Laura Leibensperger, Jennifer Lenihan Trimble and Penny Benson as well as the Ernst Mayr Library staff especially Connie Rinaldo, Robert Young, Mary Sears, Dorothy Barr, April Collins, Ronnie Broadfoot and Dana Fisher. Thanks to Curators Charles Griswold and Lauren Esposito as well as Darrell Ubick and Anthea Carmichael for loaning specimens from the California Academy of Sciences as well as the many curators who assisted with collections searches for Phoroncidia specimens or provided helpful information: Janet Beccaloni, Rudy Jocqué and Didier Van den Spiegel, Zoe Simmons, Karin Sindemark Kronestedt and Elin Sigvaldadottir, Norman Platnick and Louis Sorkin. Thanks to Curator Christine Rollard for her assistance at the Museum National D'Historie Naturelle, Paris. Thanks to Adam Graham and the team at Harvard's Center for Nanoscale Systems. L.L. thanks the Department of Mechanical Engineering at Virginia Tech for support. Thanks to four anonymous reviewers whose comments improved this manuscript.
PY - 2018/2
Y1 - 2018/2
N2 - This study investigates the structural basis for the red, silver and black coloration of the theridiid spider, Phoroncidia rubroargentea (Berland, 1913) from Madagascar. Specimens of this species can retain their colour after storage in ethanol for decades, whereas most other brightly pigmented spider specimens fade under identical preservation conditions. Using correlative optical, structural and chemical analysis, we identify the colour-generating structural elements and characterize their optical properties. The prominent silvery appearance of the spider's abdomen results from regularly arranged guanine microplatelets, similar to those found in other spiders and fish. The microplatelets are composed of a doublet structure twinned about the [02(1) over bar] axis, as suggested by electron diffraction. The red coloration originates from chambered microspheres (approx. 1 mu m in diameter), which contain structured fluorescent material. Co-localization of the red microparticles on top of the reflective guanine microplatelets appears to enhance the red coloration. The spider's thick cuticular layer, which encases its abdomen, varies in its optical properties, being transparent in regions where only guanine reflectors are present, and tanned, exhibiting light absorption where the red microspheres are found. Moreover, colour degradation in some preserved spider specimens that had suffered damage to the cuticular layer suggests that this region of the exoskeleton may play an important role in the stabilization of the red coloration.
AB - This study investigates the structural basis for the red, silver and black coloration of the theridiid spider, Phoroncidia rubroargentea (Berland, 1913) from Madagascar. Specimens of this species can retain their colour after storage in ethanol for decades, whereas most other brightly pigmented spider specimens fade under identical preservation conditions. Using correlative optical, structural and chemical analysis, we identify the colour-generating structural elements and characterize their optical properties. The prominent silvery appearance of the spider's abdomen results from regularly arranged guanine microplatelets, similar to those found in other spiders and fish. The microplatelets are composed of a doublet structure twinned about the [02(1) over bar] axis, as suggested by electron diffraction. The red coloration originates from chambered microspheres (approx. 1 mu m in diameter), which contain structured fluorescent material. Co-localization of the red microparticles on top of the reflective guanine microplatelets appears to enhance the red coloration. The spider's thick cuticular layer, which encases its abdomen, varies in its optical properties, being transparent in regions where only guanine reflectors are present, and tanned, exhibiting light absorption where the red microspheres are found. Moreover, colour degradation in some preserved spider specimens that had suffered damage to the cuticular layer suggests that this region of the exoskeleton may play an important role in the stabilization of the red coloration.
UR - http://www.scopus.com/inward/record.url?scp=85048544522&partnerID=8YFLogxK
U2 - 10.1098/rsif.2017.0930
DO - 10.1098/rsif.2017.0930
M3 - مقالة
SN - 1742-5689
VL - 15
JO - Journal of the Royal Society Interface
JF - Journal of the Royal Society Interface
IS - 139
M1 - 20170930
ER -