Imaging scatterometry and microspectrophotometry of lycaenid butterfly wing scales with perforated multilayers

We studied the structural as well as spatial and spectral reflectance characteristics of the wing scales of lycaenid butterfly species, where the scale bodies consist of perforated multilayers. The extent of the spatial scattering profiles was measured with a newly built scatterometer. The width of the reflectance spectra, measured with a microspectrophotometer, decreased with the degree of perforation, in agreement with the calculations based on multilayer theory.

Download Full-text

Modeling the Reflectance Changes Induced by Vapor Condensation in Lycaenid Butterfly Wing Scales Colored by Photonic Nanoarchitectures

Nanomaterials ◽

10.3390/nano9050759 ◽

2019 ◽

Vol 9 (5) ◽

pp. 759 ◽

Cited By ~ 5

Author(s):

Géza I. Márk ◽

Krisztián Kertész ◽

Gábor Piszter ◽

Zsolt Bálint ◽

László P. Biró

Keyword(s):

Photonic Band Gap ◽

Ethanol Vapor ◽

Vapor Condensation ◽

Reflectance Spectra ◽

Structural Color ◽

Vapor Concentration ◽

Butterfly Species ◽

Air Voids ◽

Lycaenid Butterfly ◽

Wing Scales

Gas/vapor sensors based on photonic band gap-type materials are attractive as they allow a quick optical readout. The photonic nanoarchitectures responsible for the coloration of the wing scales of many butterfly species possessing structural color exhibit chemical selectivity, i.e., give vapor-specific optical response signals. Modeling this complex physical-chemical process is very important to be able to exploit the possibilities of these photonic nanoarchitectures. We performed measurements of the ethanol vapor concentration-dependent reflectance spectra of the Albulina metallica butterfly, which exhibits structural color on both the dorsal (blue) and ventral (gold-green) wing sides. Using a numerical analysis of transmission electron microscopy (TEM) images, we revealed the details of the photonic nanoarchitecture inside the wing scales. On both sides, it is a 1D + 2D structure, a stack of layers, where the layers contain a quasi-ordered arrangement of air voids embedded in chitin. Next, we built a parametric simulation model that matched the measured spectra. The reflectance spectra were calculated by ab-initio methods by assuming variable amounts of vapor condensed to liquid in the air voids, as well as vapor concentration-dependent swelling of the chitin. From fitting the simulated results to the measured spectra, we found a similar swelling on both wing surfaces, but more liquid was found to concentrate in the smaller air voids for each vapor concentration value measured.

Download Full-text

Orientation-Dependent Reflection of Structurally Coloured Butterflies

Biomimetics ◽

10.3390/biomimetics5010005 ◽

2020 ◽

Vol 5 (1) ◽

pp. 5

Author(s):

Sigrid Zobl ◽

Bodo D. Wilts ◽

Willi Salvenmoser ◽

Peter Pölt ◽

Ille C. Gebeshuber ◽

...

Keyword(s):

Orientation Dependence ◽

Butterfly Species ◽

Butterfly Wing ◽

Step Size ◽

Photonic Structures ◽

Light Interference ◽

Important Input ◽

Individual Scale ◽

The Individual ◽

Wing Scales

The photonic structures of butterfly wing scales are widely known to cause angle-dependent colours by light interference with nanostructures present in the wing scales. Here, we quantify the relevance of the horizontal alignment of the butterfly wing scales on the wing. The orientation-dependent reflection was measured at four different azimuth angles, with a step size of 90°, for ten samples—two of different areas of the same species—of eight butterfly species of three subfamilies at constant angles of illumination and observation. For the observed species with varying optical structures, the wing typically exhibits higher orientation-dependent reflections than the individual scale. We find that the measured anisotropy is caused by the commonly observed grating structures that can be found on all butterfly wing scales, rather than the local photonic structures. Our results show that the technique employed here can be used to quickly evaluate the orientation-dependence of the reflection and hence provide important input for bio-inspired applications, e.g., to identify whether the respective structure is suitable as a template for nano-imprinting techniques.

Download Full-text

Spectrally tuned structural and pigmentary coloration of birdwing butterfly wing scales

Journal of The Royal Society Interface ◽

10.1098/rsif.2015.0717 ◽

2015 ◽

Vol 12 (111) ◽

pp. 20150717 ◽

Cited By ~ 23

Author(s):

Bodo D. Wilts ◽

Atsuko Matsushita ◽

Kentaro Arikawa ◽

Doekele G. Stavenga

Keyword(s):

Electron Microscopy ◽

Mate Recognition ◽

Butterfly Species ◽

Butterfly Wing ◽

Spectral Filter ◽

Ecological Processes ◽

The World ◽

Wing Patterns ◽

Small Genus ◽

Wing Scales

The colourful wing patterns of butterflies play an important role for enhancing fitness; for instance, by providing camouflage, for interspecific mate recognition, or for aposematic display. Closely related butterfly species can have dramatically different wing patterns. The phenomenon is assumed to be caused by ecological processes with changing conditions, e.g. in the environment, and also by sexual selection. Here, we investigate the birdwing butterflies, Ornithoptera , the largest butterflies of the world, together forming a small genus in the butterfly family Papilionidae. The wings of these butterflies are marked by strongly coloured patches. The colours are caused by specially structured wing scales, which act as a chirped multilayer reflector, but the scales also contain papiliochrome pigments, which act as a spectral filter. The combined structural and pigmentary effects tune the coloration of the wing scales. The tuned colours are presumably important for mate recognition and signalling. By applying electron microscopy, (micro-)spectrophotometry and scatterometry we found that the various mechanisms of scale coloration of the different birdwing species strongly correlate with the taxonomical distribution of Ornithoptera species.

Download Full-text

Surface-Enhanced Raman Spectroscopy for Molecule Characterization: HIM Investigation into Sources of SERS Activity of Silver-Coated Butterfly Scales

Nanomaterials ◽

10.3390/nano11071741 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1741

Author(s):

Hiroyuki Takei ◽

Kazuki Nagata ◽

Natalie Frese ◽

Armin Gölzhäuser ◽

Takayuki Okamoto

Keyword(s):

Raman Spectroscopy ◽

Surface Enhanced Raman Spectroscopy ◽

Metal Nanostructures ◽

Butterfly Species ◽

Sers Substrate ◽

Butterfly Wing ◽

Sers Substrates ◽

Surface Enhanced ◽

Surface Enhanced Raman ◽

Wing Scales

Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for obtaining structural information of molecules in solution at low concentrations. While commercial SERS substrates are available, high costs prevent their wide-spread use in the medical field. One solution is to prepare requisite noble metal nanostructures exploiting natural nanostructures. As an example of biomimetic approaches, butterfly wing scales with their intricate nanostructures have been found to exhibit exquisite SERS activity when coated with silver. Selecting appropriate scales from particular butterfly species and depositing silver of certain thicknesses leads to significant SERS activity. For morphological observations we used scanning electron microscopes as well as a helium ion microscope, highly suitable for morphological characterization of poorly conducting samples. In this paper, we describe a protocol for carrying out SERS measurements based on butterfly wing scales and demonstrate its LOD with a common Raman reporter, rhodamine 6 G. We also emphasize what special care is necessary in such measurements. We also try to shed light on what makes scales work as SERS substrates by carefully modifying the original nanostructures. Such a study allows us to either use scales directly as a raw material for SERS substrate or provides an insight as to what nanostructures need to be recreated for synthetic SERS substrates.

Download Full-text

A High-Transmission, Multiple Antireflective Surface Inspired from Bilayer 3D Ultrafine Hierarchical Structures in Butterfly Wing Scales

Small ◽

10.1002/smll.201502454 ◽

2015 ◽

Vol 12 (6) ◽

pp. 713-720 ◽

Cited By ~ 30

Author(s):

Zhiwu Han ◽

Zhengzhi Mu ◽

Bo Li ◽

Shichao Niu ◽

Junqiu Zhang ◽

...

Keyword(s):

Hierarchical Structures ◽

Butterfly Wing ◽

High Transmission ◽

Wing Scales

Download Full-text

Brilliant iridescence of Morpho butterfly wing scales is due to both a thin film lower lamina and a multilayered upper lamina

Journal of Comparative Physiology A ◽

10.1007/s00359-016-1084-1 ◽

2016 ◽

Vol 202 (5) ◽

pp. 381-388 ◽

Cited By ~ 23

Author(s):

M. A. Giraldo ◽

D. G. Stavenga

Keyword(s):

Thin Film ◽

Butterfly Wing ◽

Morpho Butterfly ◽

Wing Scales

Download Full-text

Evolution of the wave: aerodynamic and aposematic functions of butterfly wing motion

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2006.0261 ◽

2007 ◽

Vol 274 (1612) ◽

pp. 913-917 ◽

Cited By ~ 16

Author(s):

Robert B Srygley

Keyword(s):

Beat Frequency ◽

Warning Signal ◽

Colour Pattern ◽

Butterfly Species ◽

Wing Beat ◽

Butterfly Wing ◽

Motion Cues ◽

Wing Beat Frequency ◽

Wing Motion ◽

Heliconius Cydno

Many unpalatable butterfly species use coloration to signal their distastefulness to birds, but motion cues may also be crucial to ward off predatory attacks. In previous research, captive passion-vine butterflies Heliconius mimetic in colour pattern were also mimetic in motion. Here, I investigate whether wing motion changes with the flight demands of different behaviours. If birds select for wing motion as a warning signal, aposematic butterflies should maintain wing motion independently of behavioural context. Members of one mimicry group ( Heliconius cydno and Heliconius sapho ) beat their wings more slowly and their wing strokes were more asymmetric than their sister-species ( Heliconius melpomene and Heliconius erato , respectively), which were members of another mimicry group having a quick and steady wing motion. Within mimicry groups, wing beat frequency declined as its role in generating lift also declined in different behavioural contexts. In contrast, asymmetry of the stroke was not associated with wing beat frequency or behavioural context—strong indication that birds process and store the Fourier motion energy of butterfly wings. Although direct evidence that birds respond to subtle differences in butterfly wing motion is lacking, birds appear to generalize a motion pattern as much as they encounter members of a mimicry group in different behavioural contexts.

Download Full-text