scholarly journals Mimicry can drive convergence in structural and light transmission features of transparent wings in Lepidoptera

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Charline Sophie Pinna ◽  
Maëlle Vilbert ◽  
Stephan Borensztajn ◽  
Willy Daney de Marcillac ◽  
Florence Piron-Prunier ◽  
...  
Keyword(s):  
Optical Properties ◽  
Prey Species ◽  
Light Transmission ◽  
Structural Diversity ◽  
Interspecific Interaction ◽  
Fine Tuning ◽  
Microscopy Imaging ◽  
Wing Colour ◽  
Aposematic Signals ◽  
Colour Patterns

Müllerian mimicry is a positive interspecific interaction, whereby co-occurring defended prey species share a common aposematic signal. In Lepidoptera, aposematic species typically harbour conspicuous opaque wing colour patterns with convergent optical properties among co-mimetic species. Surprisingly, some aposematic mimetic species have partially transparent wings, raising the questions of whether optical properties of transparent patches are also convergent, and of how transparency is achieved. Here, we conducted a comparative study of wing optics, micro and nanostructures in neotropical mimetic clearwing Lepidoptera, using spectrophotometry and microscopy imaging. We show that transparency, as perceived by predators, is convergent among co-mimics in some mimicry rings. Underlying micro- and nanostructures are also sometimes convergent despite a large structural diversity. We reveal that while transparency is primarily produced by microstructure modifications, nanostructures largely influence light transmission, potentially enabling additional fine-tuning in transmission properties. This study shows that transparency might not only enable camouflage but can also be part of aposematic signals.

scholarly journals Convergence in light transmission properties of transparent wing areas in clearwing mimetic butterflies

2020 ◽  
Author(s):  
Charline Pinna ◽  
Maëlle Vilbert ◽  
Stephan Borensztajn ◽  
Willy Daney de Marcillac ◽  
Florence Piron-Prunier ◽  
...  
Keyword(s):  
Optical Properties ◽  
Evolutionary Biology ◽  
Light Transmission ◽  
Interspecific Interaction ◽  
Fine Tuning ◽  
Colour Pattern ◽  
Wing Membrane ◽  
Microscopy Imaging ◽  
Transmission Properties ◽  
Aposematic Signals

AbstractMüllerian mimicry is a positive interspecific interaction, whereby co-occurring defended prey species share a common aposematic signal that advertises their defences to predators. In Lepidoptera, aposematic species typically harbour conspicuous opaque wing colour pattern, which have convergent optical properties, as perceived by predators. Surprisingly, some aposematic mimetic species have partially or totally transparent wings, which raises the question of whether optical properties of such transparent areas are also under selection for convergence. To answer this question and to investigate how transparency is achieved in the first place, we conducted a comparative study of optics and structures of transparent wings in neotropical mimetic clearwing Lepidoptera. We quantified transparency by spectrophotometry and characterised clearwing microstructures and nanostructures by microscopy imaging. We show that transparency is convergent among co-mimics in the eyes of predators, despite a large diversity of underlying micro- and nanostructures. Notably, we reveal that nanostructure density largely influences light transmission. While transparency is primarily produced by modification of microstructure features, nanostructures may provide a way to fine-tune the degree of transparency. This study calls for a change of paradigm in transparent mimetic lepidoptera: transparency not only enables camouflage but can also be part of aposematic signals.SignificanceTransparency in animals has long been associated to camouflage, but the existence of aposematic mimetic Lepidoptera with partly transparent wings raises the question of the role of transparency in aposematism. Here, we undertake the first comparative analysis of transparency features in mimetic Lepidoptera. We show that transparency is likely part of the aposematic signal, as light transmission properties are convergent among co-mimics. We also reveal a high diversity of wing structures (scales and wing membrane nanostructures) underlying transparency, which enables fine-tuning the degree of transparency. This study, at the interface between physical optics and evolutionary biology, sheds light on the evolution of transparency in aposematic mimetic lineages and may promote bioinspired applications for transparent materials such as antireflective devices.

scholarly journals Temperature Dependence of Stress and Optical Properties in AlN Films Grown by MOCVD

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 698
Author(s):  
Wenwang Wei ◽  
Yi Peng ◽  
Jiabin Wang ◽  
Muhammad Farooq Saleem ◽  
Wen Wang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Compressive Stress ◽  
Sapphire Substrate ◽  
Light Transmission ◽  
Chemical Vapor ◽  
Biaxial Stress ◽  
X Ray Diffraction ◽  
Patterned Sapphire Substrate ◽  
Transmission Electron ◽  
Nano Patterning

AlN epilayers were grown on a 2-inch [0001] conventional flat sapphire substrate (CSS) and a nano-patterned sapphire substrate (NPSS) by metalorganic chemical vapor deposition. In this work, the effect of the substrate template and temperature on stress and optical properties of AlN films has been studied by using Raman spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-visible spectrophotometer and spectroscopic ellipsometry (SE). The AlN on NPSS exhibits lower compressive stress and strain values. The biaxial stress decreases from 1.59 to 0.60 GPa for AlN on CSS and from 0.90 to 0.38 GPa for AlN on NPSS sample in the temperature range 80–300 K, which shows compressive stress. According to the TEM data, the stress varies from tensile on the interface to compressive on the surface. It can be deduced that the nano-holes provide more channels for stress relaxation. Nano-patterning leads to a lower degree of disorder and stress/strain relaxes by the formation of the nano-hole structure between the interface of AlN epilayers and the substrate. The low crystal disorder and defects in the AlN on NPSS is confirmed by the small Urbach energy values. The variation in bandgap (Eg) and optical constants (n, k) with temperature are discussed in detail. Nano-patterning leads to poor light transmission due to light scattering, coupling, and trapping in nano-holes.

scholarly journals Female butterflies prefer males bearing bright iridescent ornamentation

2007 ◽  
Vol 274 (1613) ◽  
pp. 1043-1047 ◽  
Author(s):  
Darrell J Kemp
Keyword(s):  
Mate Choice ◽  
Driving Force ◽  
Female Mate Choice ◽  
Sex Recognition ◽  
Female Mate ◽  
Wing Colour ◽  
Enclosure Experiments ◽  
Colour Patterns

Butterflies are among nature's most colourful animals, and provide a living showcase for how extremely bright, chromatic and iridescent coloration can be generated by complex optical mechanisms. The gross characteristics of male butterfly colour patterns are understood to function for species and/or sex recognition, but it is not known whether female mate choice promotes visual exaggeration of this coloration. Here I show that females of the sexually dichromatic species Hypolimnas bolina prefer conspecific males that possess bright iridescent blue/ultraviolet dorsal ornamentation. In separate field and enclosure experiments, using both dramatic and graded wing colour manipulations, I demonstrate that a moderate qualitative reduction in signal brightness and chromaticity has the same consequences as removing the signal entirely. These findings validate a long-held hypothesis, and argue for the importance of intra- versus interspecific selection as the driving force behind the exaggeration of bright, iridescent butterfly colour patterns.

Fine-tuning the optical properties of aluminium and lithium quinolates through oligothiophene substituents in 2-position

2004 ◽  
Vol 147 (1-3) ◽  
pp. 175-182 ◽  
Author(s):  
A. Jaafari ◽  
V. Ouzeau ◽  
M. Ely ◽  
F. Rodriguez ◽  
A. Yassar ◽  
...  
Keyword(s):  
Optical Properties ◽  
Fine Tuning

pH-Mediated fine-tuning of optical properties of graphene oxide membranes

Carbon ◽  
2012 ◽  
Vol 50 (9) ◽  
pp. 3233-3239 ◽  
Author(s):  
Wei Lv ◽  
Cong-Hui You ◽  
Sida Wu ◽  
Baohua Li ◽  
Zhen-Ping Zhu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Graphene Oxide ◽  
Fine Tuning ◽  
Oxide Membranes ◽  
Graphene Oxide Membranes

scholarly journals Fine Tuning the Optical Properties of Green to Red Photoconvertible Fluorescent Proteins

2010 ◽  
Vol 98 (3) ◽  
pp. 413a
Author(s):  
Karin Nienhaus ◽  
Virgile Adam ◽  
Dominique Bourgeois ◽  
G. Ulrich Nienhaus
Keyword(s):  
Optical Properties ◽  
Fluorescent Proteins ◽  
Fine Tuning

Viologens: A versatile organic molecule for energy storage applications

2021 ◽  
Author(s):  
Kathiresan Murugavel ◽  
Ambrose Bebin ◽  
Angu Lakhsmi Natarajan ◽  
Deepa Elizabeth Mathew ◽  
D Sujatha ◽  
...  
Keyword(s):  
Energy Storage ◽  
Electrochemical Properties ◽  
Organic Molecule ◽  
Structural Diversity ◽  
Fine Tuning ◽  
Active Materials ◽  
Energy Storage Applications ◽  
Molecular Tailoring

Organic redox compounds illustrate to be a fascinating class of active materials in energy-storage applications. The structural diversity as well as molecular tailoring helps in fine-tuning of the electrochemical properties...

scholarly journals Partial and Total Substitution of Zn by Mg in the Cu2ZnSnS4 Structure

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 578
Author(s):  
Diana M. Mena Romero ◽  
David Victoria Valenzuela ◽  
Cristy L. Azanza Ricardo
Keyword(s):  
Thin Film ◽  
Optical Properties ◽  
Cost Effective ◽  
Energy Conversion Efficiency ◽  
Band Gap Energy ◽  
Fine Tuning ◽  
Secondary Phases ◽  
Solar Absorber ◽  
High Efficient ◽  
Earth Abundant

Cu 2 ZnSnS 4 (CZTS) is a quaternary semiconductor that has emerged as a promising component in solar absorber materials due to its excellent optical properties such as band-gap energy of ca. 1.5 eV and significant absorption coefficient in the order of 10 4 cm − 1 . Nevertheless, the energy conversion efficiency of CZTS-based devices has not reached the theoretical limits yet, possibly due to the existence of antisite defects (such as Cu Zn or Zn Cu ) and secondary phases. Based on electronic similarities with Zn, Mg has been proposed for Zn substitution in the CZTS structure in the design of alternative semiconductors for thin-film solar cell applications. This work aims to study the properties of the CZTS having Mg incorporated in the structure replacing Zn, with the following stoichiometry: x = 0, 0.25, 0.5, 0.75, and 1 in the formula Cu 2 Zn 1 − x Mg x SnS 4 (CZ-MTS). The semiconductor was prepared by the hot injection method, using oleylamine (OLA) as both surfactant and solvent. The presence and concentration of incorporated Mg allowed the fine-tuning of the CZ-MTS semiconductor’s structural and optical properties. Furthermore, it was observed that the inclusion of Mg in the CZTS structure leads to a better embodiment ratio of the Zn during the synthesis, thus reducing the excess of starting precursors. In summary, CZ-MTS is a promising candidate to fabricate high efficient and cost-effective thin-film solar cells made of earth-abundant elements.

scholarly journals Evolutionary fine-tuning of background-matching camouflage among geographical populations in the sandy beach tiger beetle

2020 ◽  
Vol 287 (1941) ◽  
pp. 20202315
Author(s):  
Nayuta Yamamoto ◽  
Teiji Sota
Keyword(s):  
Sequence Data ◽  
Evolutionary Process ◽  
Fine Tuning ◽  
Colour Pattern ◽  
Tiger Beetle ◽  
Background Matching ◽  
Geographical Populations ◽  
Geographical Distances ◽  
The Japanese Archipelago ◽  
Colour Patterns

Background-matching camouflage is a widespread adaptation in animals; however, few studies have thoroughly examined its evolutionary process and consequences. The tiger beetle Chaetodera laetescripta exhibits pronounced variation in elytral colour pattern among sandy habitats of different colour in the Japanese Archipelago. In this study, we performed digital image analysis with avian vision modelling to demonstrate that elytral luminance, which is attributed to proportions of elytral colour components, is fine-tuned to match local backgrounds. Field predation experiments with model beetles showed that better luminance matching resulted in a lower attack rate and corresponding lower mortality. Using restriction site-associated DNA (RAD) sequence data, we analysed the dispersal and evolution of colour pattern across geographical locations. We found that sand colour matching occurred irrespective of genetic and geographical distances between populations, suggesting that locally adapted colour patterns evolved after the colonization of these habitats. Given that beetle elytral colour patterns presumably have a quantitative genetic basis, our findings demonstrate that fine-tuning of background-matching camouflage to local habitat conditions can be attained through selection by visual predators, as predicted by the earliest proponent of natural selection.

Optical Thin Films of Metal Oxides Produced by the Sol-Gel Method for Photovoltaic Applications

2019 ◽  
Vol 293 ◽  
pp. 83-95
Author(s):  
Marek Szindler
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Light Transmission ◽  
Sol Gel ◽  
Thin Layers ◽  
Gel Method ◽  
Sol Gel Method ◽  
Wide Range

The use of thin films in optoelectronic and photovoltaic devices is aimed at improving the physical properties of the substrate material. The modification of the surface of the silicon substrate is thus one of the greatest challenges in research on photovoltaic materials, in order to achieve even greater efficiency or better adapt their properties depending on the application. The technologies of applying layers vary depending on the effect to be obtained and the material from which the layer is formed. In practice, the most common method is chemical vapor deposition and physical vapor deposition, and the most commonly applied optical materials are SiO2, TiO2 and Si3N4.This paper presents the results of investigations on morphology and optical properties of the prepared aluminium oxide thin films. Thin films were prepared with use of sol-gel spin coating method. Surface morphology studies were carried out using an atomic force microscope. To characterize the surface of the thin films, 3D images and histograms of the frequency of individual inequalities were made. In order to characterize the optical properties of Al2O3 thin films, the reflectance and light transmission tests were performed using a spectrophotometer. Optical constants were determined using a spectroscopic ellipsometer. Results and their analysis show that the sol-gel method allows the deposition of homogenous thin films of Al2O3 with the desired geometric characteristics and good optical properties. Uniform, continuous thin layers with a roughness not exceeding a few nanometres were deposited. Their deposition enabled to reduce the reflection of light from the polished substrate below 15% in a wide range (425-800nm) while maintaining high transparencies (over 90%). The obtained results causes that mentioned thin films are good potential material for optics, optoelectronics and photovoltaics.

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