About the Cover

Abstract

Next article FreeAbout the CoverPDFPDF PLUSFull Text Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinked InRedditEmailQR Code SectionsMoreCoverThe cover image is of the brilliantly colored, adult nudibranch Flabellina iodinea. The purple-blue body contrasts richly with the bright orange dorsal extensions, termed cerata. This coloration, coupled with its rhythmically twisting swimming motion, has earned this species the nickname “Spanish shawl.”The shell-less F. iodinea feeds preferentially on the cnidarian hydroid Eudendrium ramosum, from which it obtains the carotenoid astaxanthin that gives the animal its purple, orange, and red pigmented coloration as well as its stinging cells, termed nematocysts. Flabellina iodinea sequesters nematocysts in specialized cells of the cerata for defense. The conspicuously contrasting color pattern of the animal functions to attract would-be predators to the location of these stinging nematocysts and away from the main body, thereby discouraging further predation by those that have learned their lesson!On pages 116–129, S. J. Dearden, A. Ghoshal, D. G. DeMartini, and D. E. Morse show that the pigmented optical appearance of F. iodinea is augmented by dynamically sparkling, brightly reflective stacks of tiny crystals that tumble within vesicles in cells located throughout the epidermis. This tumbling exposes different faces of the small reflective crystals to produce their silvery sparkling appearance. Light and electron microscopy revealed the location and behavior of these sparkling crystals in situ, while purification, thin-layer chromatography, and electron diffraction were used to characterize their crystallographic and molecular structure—composed of the organic metabolites guanine and hypoxanthine. Although similar stacks of such crystals have been found to provide reflectivity in tissues of chameleons, spiders, fish, and other nudibranchs, this is the first discovery of dynamically sparkling, tumbling, crystalline reflectors in any tissue.Credits: Photo, Larry Friesen, Santa Barbara City College. Cover design, Jeannie Harrell, University of Chicago Press. Next article DetailsFiguresReferencesCited by The Biological Bulletin Volume 234, Number 2April 2018 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.1086/698953 © 2018 by The University of Chicago. All rights reserved.PDF download Crossref reports no articles citing this article.