Coexistence of both gyroid chiralities in individual butterfly wing scales of Callophrys rubi

Winter B, Butz B, Dieker C, Schroeder-Turk GE, Mecke K, Spiecker E (2015)

Publication Status: Published

Publication Type: Journal article

Publication year: 2015

Journal

Publisher: National Academy of Sciences

Book Volume: 112

Pages Range: 12911-12916

Journal Issue: 42

DOI: 10.1073/pnas.1511354112

Abstract

The wing scales of the Green Hairstreak butterfly Callophrys rubi consist of crystalline domains with sizes of a few micrometers, which exhibit a congenitally handed porous chitin microstructure identified as the chiral triply periodic single-gyroid structure. Here, the chirality and crystallographic texture of these domains are investigated by means of electron tomography. The tomograms unambiguously reveal the coexistence of the two enantiomeric forms of opposite handedness: the left- and right-handed gyroids. These two enantiomers appear with nonequal probabilities, implying that molecularly chiral constituents of the biological formation process presumably invoke a chiral symmetry break, resulting in a preferred enantiomeric form of the gyroid structure. Assuming validity of the formation model proposed by Ghiradella H (1989) J Morphol 202(1): 69-88 and Saranathan V, et al. (2010) Proc Natl Acad Sci USA 107(26): 11676-11681, where the two enantiomeric labyrinthine domains of the gyroid are connected to the extracellular and intra-SER spaces, our findings imply that the structural chirality of the single gyroid is, however, not caused by the molecular chirality of chitin. Furthermore, the wing scales are found to be highly textured, with a substantial fraction of domains exhibiting the < 001 > directions of the gyroid crystal aligned parallel to the scale surface normal. Both findings are needed to completely understand the photonic purpose of the single gyroid in gyroid-forming butterflies. More importantly, they show the level of control that morphogenesis exerts over secondary features of biological nanostructures, such as chirality or crystallographic texture, providing inspiration for biomimetic replication strategies for synthetic self-assembly mechanisms.

Authors with CRIS profile

Additional Organisation(s)

Involved external institutions

Murdoch University Australia (AU)

How to cite

APA:

Winter, B., Butz, B., Dieker, C., Schroeder-Turk, G.E., Mecke, K., & Spiecker, E. (2015). Coexistence of both gyroid chiralities in individual butterfly wing scales of Callophrys rubi. Proceedings of the National Academy of Sciences of the United States of America, 112(42), 12911-12916. https://dx.doi.org/10.1073/pnas.1511354112

MLA:

Winter, Benjamin, et al. "Coexistence of both gyroid chiralities in individual butterfly wing scales of Callophrys rubi." Proceedings of the National Academy of Sciences of the United States of America 112.42 (2015): 12911-12916.

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