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Conductive hydrogels are regarded as an optimal flexible electronic material. Nevertheless, simultaneously achieving excellent mechanical and conductive properties in hydrogels necessitates attention. The high mechanical properties of hydrogels were achieved by employing a strategy that involves constructing a nano-structure network inspired by the highly ordered structure of dragonfly wings. The conductivity and anti-freezing of the hydrogel were enhanced through the construction of a conductive mechanism, achieved by combining ions with nano-particles. The hydrogel exhibits outstanding properties, including anti-freezing, ultra-stretchable (6000 %), impressive conductivity (16.2 S m -1 ), a transparency level of up to 91.2 %, and excellent sensitivity in strain sensors. Regulation of the hydrogel matrix's topology and the formation of bionic nano-structures synergistically establish the hydrogel's ultra-stretching and energy dissipation mechanism. The high conductivity of the hydrogel is achieved by constructing a synergistic conduction pathway, which incorporates nano-particles and ions. Under the stretching-induced effect of hydrogel, it facilitates a more efficient path for conduction, thereby enhancing its conductivity and sensing sensitivity under significant strains. Subsequently, this hydrogel was successfully applied to wearable sensor technology, demonstrating surprisingly remarkably prompt non-delayed sensing performance even at low-temperatures. It presents abundant opportunities for expanding the application of hydrogels in flexible electronics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In order to guide manufacturers or consumers to choose frozen chicken wings (CWS) reasonably for roasting, the changes of sensory quality and physicochemical properties of CWS with different freezing storage time (0-12 months) after roasting were studied. The results showed that juiciness, fat flavor, meat flavor, and saltiness were the most important dominant attributes of roasted CWS, and their dominance rate gradually decreased from the ninth month. Increased (P < 0.05) TBARS value and water loss result in poor juiciness. According to the results of GC-IMS, the decrease of the dominant rate of meaty may be related to the decrease of the contents of 2-ethyl-5-methylpyrazine, benzene and thiazole. In addition, the accumulation of 1-octen-3-ol, n-hexanol, and hexanal caused by long-term freezing (> 9 months) give chicken wings a fishy and metallic taste. Therefore, CWS that have been frozen for more than 9 months are not ideal ingredients for roasting., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Thermochromic materials have been widely investigated due to their relevance in technological applications, including anti-counterfeiting materials, fashion accessories, displays, and temperature sensors. While many organisms exhibit color changes, few studies have explored the potential of the responsive natural materials for temperature sensing, especially given the often limited and irreversible nature of these changes in live specimens. Here, it is shown that the hindwings of the blue-winged grasshopper Coloracris azureus can act as a reversible, power-free bio-thermometer, transitioning from blue to purple/red in a 30-100°C temperature range. Using microspectrophotometry, light microscopy and Raman microscopy, it is found that the blue color of the wings originates from pigmentary coloration, based on a complex of astaxanthin and proteins. The thermochromic shift from blue to red, induced by a temperature increase, is attributed to a denaturation of this carotenoprotein complex, upon which astaxanthin is released. This process is reversible upon a subsequent temperature decrease. The color changes are both swift and consistent upon temperature change, making the grasshopper's wings suitable as direct visual sensors on thermally dynamic, curved surfaces. The potential possibilities of sustainable, power-free temperature sensors or microthermometers based on biomaterials are demonstrated., (© 2024 The Authors. Small published by Wiley‐VCH GmbH.)

Freezing is a commonly used method for long-term storage of chicken wing products, of which disadvantages are mainly the product damage caused in the process. The aim of this study was to improve the freezing quality of chicken wings with a combination of phosphorus-free water retaining agent (WRA) and high-voltage electrostatic field (HVEF). The effect of WRA acting at different HVEF intensities (0, 1, 3, and 5 kV/cm) on the quality attributes of frozen chicken wings was investigated in 0, 7, 14, 21, 28 and 35 days of frozen storage. The results showed that WRA had functional properties of significantly improving the water holding capacity (WHC), color and texture properties, and fat stability of frozen chicken wing samples. The application of HVEF on this basis helped to promote the absorption of WRA and inhibit oxidative deterioration of chicken wing samples during frozen storage. Meanwhile, the combination of HVEF at 3 kV/cm was more prominent in terms of improvement in WHC, moisture content, color, protein secondary structure and microstructure integrity. This advantage had been consistently maintained with the extension of storage time. Overall, WRA combined with HVEF of 3 kV/cm can be used as an effective strategy to improve the freezing quality of chicken wing samples and has the potential to maintain the frozen chicken wing samples quality for a long time., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Pheromone communication is widespread among animals. Since it is often involved in mate choice, pheromone production is often tightly controlled. Although male sex pheromones (MSPs) and anti-aphrodisiacs have been studied in some Heliconius butterfly species, little is known about the factors affecting their production and release in these long-lived butterflies. Here, we investigate the effect of post-eclosion age on chemical blends from pheromone-emitting tissues in Heliconius atthis and Heliconius charithonia, exhibiting respectively free-mating and pupal-mating strategies that are hypothesised to differently affect the timing of their pheromone emissions. We focus on two different tissues: the wing androconia, responsible for MSPs used in courtship, and the genital tip, the production site for anti-aphrodisiac pheromones that affect post-mating behaviour. Gas chromatography-mass spectrometric analysis of tissue extracts from virgin males and females of both species from day 0 to 8 post-eclosion demonstrates the following. Some ubiquitous fatty acid precursors are already detectable at day 0. The complexity of the chemical blends increases with age regardless of tissue or sex. No obvious difference in the time course of blend production was evident between the two species, but female tissues in H. charithonia were more affected by age than in H. atthis. We suggest that compounds unique to male androconia and genitals and whose amount increases with age are potential candidates for future investigation into their roles as pheromones. While this analysis revealed some of the complexity in Heliconius chemical ecology, the effects of other factors, such as the time of day, remain unknown., (© 2024. The Author(s).)

A great number of butterfly species in the warmer climate have evolved to exhibit fascinating optical properties on their wing scales which can both regulate the wing temperature and exhibit structural coloring in order to increase their chances of survival. In particular, the Archaeoprepona demophon dorsal wing demonstrates notable radiative cooling performance and iridescent colors based on the nanostructure of the wing scale that can be characterized by the nanoporous matrix with the periodic nanograting structure on the top matrix surface. Inspired by the natural species, we demonstrate a multifunctional biomimetic film that reconstructs the nanostructure of the Archaeoprepona demophon wing scales to replicate the radiative cooling and structural coloring functionalities. We resorted to the SiO 2 sacrificial template-based solution process to mimic the random porous structure and laser-interference lithography to reproduce the nanograting architecture of the butterfly wing scale. As a result, the biomimetic structure of the nanograted surface on top of the porous film demonstrated desirable heat transfer and optical properties for outstanding radiative cooling performance and iridescent structural coloring. In this regard, the film is capable of inducing the maximum temperature drop of 8.45 °C, and the color gamut of the biomimetic film can cover 91.8% of the standardized color profile (sRGB).

Heliconius erato is a neotropical butterfly species that is part of a complex mimicry ring, with colorful wing patterns. For intraspecific communication, males use pheromones that are released from two different scent-emitting structures. Scent glands located near the abdominal claspers of males, containing antiaphrodisiac pheromones, release a highly complex mixture of compounds that is transferred to females during mating, rendering them unattractive to other males. On the other hand, androconia, scent-emitting scale areas on the wings of male butterflies, release a structurally more restricted set of compounds that likely serves an aphrodisiac role. We report here on two structurally related compounds that are the major androconial constituents, produced in high amounts and are not volatile due to their high molecular mass. Their structures were established by extensive analysis of mass, infrared, and NMR spectra, as well as microderivatization reactions of the natural extract. After establishing synthetic access, the compounds were unequivocally identified as two unusual head and tail oxidized terpenoids, (4 E ,8 E ,12 E )-4,8,12-trimethyl-16-oxoheptadeca-4,8,12-trien-1-yl oleate ( 1 ) and stearate ( 2 ). Although behavioral assays are necessary to fully comprehend their role in the chemical communication of the species, hypotheses for their use by the butterflies are also discussed.

With more than 1400 chiropteran species identified to date, bats comprise one-fifth of all mammalian species worldwide. Many studies have associated viral zoonoses with 45 different species of bats in the EU, which cluster within 5 families of bats. For example, the Serotine bats are infected by European Bat 1 Lyssavirus throughout Europe while Myotis bats are shown infected by coronavirus, herpesvirus and paramyxovirus. Correct host species identification is important to increase our knowledge of the ecology and evolutionary pattern of bat viruses in the EU. Bat species identification is commonly determined using morphological keys. Morphological determination of bat species from bat carcasses can be limited in some cases, due to the state of decomposition or nearly indistinguishable morphological features in juvenile bats and can lead to misidentifications. The overall objective of our study was to identify insectivorous bat species using molecular biology tools with the amplification of the partial cytochrome b gene of mitochondrial DNA. Two types of samples were tested in this study, bat wing punches and bat faeces. A total of 163 bat wing punches representing 22 species, and 31 faecal pellets representing 7 species were included in the study. From the 163 bat wing punches tested, a total of 159 were genetically identified from amplification of the partial cyt b gene. All 31 faecal pellets were genetically identified based on the cyt b gene. A comparison between morphological and genetic determination showed 21 misidentifications from the 163 wing punches, representing ~12.5% of misidentifications of morphological determination compared with the genetic method, across 11 species. In addition, genetic determination allowed the identification of 24 out of 25 morphologically non-determined bat samples. Our findings demonstrate the importance of a genetic approach as an efficient and reliable method to identify bat species precisely., Competing Interests: No authors have competing interests.

The supramolecular chirality of the hindwing of Anomala albopilosa (male) was investigated using a microscopic vibrational circular dichroism (VCD) system, denoted as MultiD-VCD. The source of intense infrared (IR) light for the system was a quantum cascade laser. Two-dimensional maps of IR and VCD spectra were taken by scanning the surface area (ca. 2 mm × 2 mm) of the insect hindwing tissue. The spectra ranged from 1500 to 1700 cm -1 , and the maps have a spatial resolution of 100 μm. The distribution of proteins, including their supramolecular structures, was analyzed from the location-dependent spectral shape of the VCD bands assigned to amides I and II. The results revealed that the hindwing consists of segregated domains of proteins with different secondary structures: an α-helix (in one part of the membrane), a hybrid of α-helix and β-sheet (in another part of the membrane), and a coil (in a vein).

Structures with variable stiffness have received increasing attention in the fields of robotics, aerospace, structural, and biomedical engineering. This is because they not only adapt to applied loads, but can also combine mutually exclusive properties. Here inspired by insect wings, the concept of "triple stiffness" is introduced and applied to engineering systems that exhibit three distinct deformability regimes. By implementing "flexible joints," "mechanical stoppers," and "buckling zones," structures are engineered to be not only load-bearing and durable, but also impact-resistant. To practice the performance of the design concept in real-life applications, the developed structures are integrated into 3D printed airplane wing models that withstood collisions without failure. The concept developed here opens new avenues for the development of structural elements that are load-bearing, durable, and impact-resistant at the same time., (© 2021 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Scales are symbolic characteristic of Lepidoptera; however, nothing is known about the contribution of cuticular proteins (CPs) to the complex patterning of lepidopteran scales. This is because scales are resistant to solubilization, thus hindering molecular studies. Here we succeeded in dissolving developing wing scales from Bombyx mori, allowing analysis of their protein composition. We identified a distinctive class of histidine rich (His-rich) CPs (6%-45%) from developing lepidopteran scales by LC-MS/MS. Functional studies using RNAi revealed CPs with different histidine content play distinct and critical roles in constructing the microstructure of the scale surface. Moreover, we successfully synthesized films in vitro by crosslinking a 45% His-rich CP (BmorCPR152) with laccase2 using N-acetyl- dopamine or N-β-alanyl-dopamine as the substrate. This molecular study of scales provides fundamental information about how such a fine microstructure is constructed and insights into the potential application of CPs as new biomaterials.

Silver nanoparticles (AgNPs) are among the most widely synthesized and used nanoparticles (NPs). AgNPs have been traditionally synthesized from plant extracts, cobwebs, microorganisms, etc. However, their synthesis from wing extracts of common insect; Mang mao which is abundantly available in most of the Asian countries has not been explored yet. We report the synthesis of AgNPs from M. mao wings extract and its antioxidant and antimicrobial activity. The synthesized AgNPs were spherical, 40-60 nm in size and revealed strong absorption plasmon band around at 430 nm. Highly crystalline nature of these particles as determined by Energy-dispersive X-ray analysis and X-ray diffraction further confirmed the presence of AgNPs. Hydrodynamic size and zeta potential of AgNPs were observed to be 43.9 nm and -7.12 mV, respectively. Fourier-transform infrared spectroscopy analysis revealed the presence of characteristic amide proteins and aromatic functional groups. Thin-layer chromatography (TLC) and Gas chromatography-mass spectroscopy (GC-MS) analysis revealed the presence of fatty acids in the wings extract that may be responsible for biosynthesis and stabilization of AgNPs. Further, SDS-PAGE of the insect wing extract protein showed the molecular weight of 49 kDa. M. mao silver nanoparticles (MMAgNPs) exhibit strong antioxidant, broad-range antibacterial and antifungal activities, (66.8 to 87.0%), broad-range antibacterial and antifungal activities was found with maximum zone of inhibition against Staphylococcus aureus MTCC 96 (35±0.4 mm) and Fusarium oxysporum f. sp. ricini (86.6±0.4) which signifies their biomedical and agricultural potential., Competing Interests: The authors have read the journal’s policy and have the following competing interests: YK is a Director and owner of Kalam Biotech Pvt. Ltd. This does not alter our adherence to PLOS ONE policies on sharing data and materials. There are no patents, products in development or marketed products associated with this research to declare.

Many natural surfaces, including the wings of cicada insects, have shown to display bactericidal properties as a result of surface topography. Moreover, the size and distribution of the surface features (on the nano- and microscale) are known to influence the efficacy of the surface at inhibiting bacterial cell growth. While these types of natural surfaces illustrate the effect of structure on the bactericidal activity, a deeper understanding can be achieved by creating surfaces of different feature sizes. This is essential in order to understand the effects of changes of surface topography on bacteria-surface interactions. To this end, we have performed a series of replica molding processes of the wings of the Megapomponia Intermedia cicada to prepare wing replicas in polyethylene glycol (PEG), which possess the topographical features of the wing surface, with a minimum loss of feature resolution. Atomic force microscopy characterization of these patterned surfaces in both air and aqueous environments shows that by controlling the swelling characteristics of the PEG, we can control the ultimate swollen dimensions of the nanopillar structures on the surface of PEG. As a result, by using a single wing with an average nanopillar height of 220 nm, different patterned PEG samples with nanopillar heights ranging from 180 to 307 nm were produced.

The pierid butterfly Colias croceus (Geoffroy in Fourcroy, 1785), established in the Azores archipelago, is polymorphic with six forms, C. croceus f. croceus ♂ and ♀, C. c. f. cremonae ♂ and ♀, C. c. f. helice ♀, and C. c. f. cremonaehelice ♀. We investigated the optical mechanisms underlying the wing colouration of the butterflies by performing spectrophotometry and imaging scatterometry of the variously coloured wing areas and scales. The scale colouration is primarily due to wavelength-selective absorption of incident light by pterins expressed in granular beads in the wing scales, but thin film reflections of the scales' lower lamina and scale stacking also contribute. Three forms (croceus ♂ and ♀ and helice ♀) are consistent with the patterns of the well-known 'alba' polymorphism. We postulate the coexistence of a second polymorphism, 'cremonae', to understand the three other forms (cremonae ♂ and ♀, and cremonaehelice ♀), which are characterized by the absence of red pigment, presumably due to the differential blocking of erythropterin expression., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This article is a reflection on the themes of the Faraday Discussion meeting on 'Biological and bio-inspired optics' held from 20 to 22 July 2020. It is a personal perspective on the nature of this field as a broad and interdisciplinary field that has led to a sound understanding of the material properties of biological nanostructured and optical materials. The article describes how the nature of the field and the themes of the conference are reflected in particular in work on the 3D bicontinuous biophotonic nanostructures known as single gyroids and in bicontinuous structures more broadly. Such single gyroid materials are found for example in the butterfly Thecla opisena, where the questions of biophotonic response, of bio-inspired optics, of the relationship between structure and function, and of the relationship between natural and synthetic realisations are closely interlinked. This multitude of facets of research on single gyroid structures reflects the beauty of the broader field of biophotonics, namely as a field that lives through embracing the serendipitous discovery of the biophotonic marvels that nature offers to us as seeds for in-depth analysis and understanding. The meandering nature of its discoveries, and the need to accept the slowness that comes from exploration of intellectually new or foreign territory, mean that the field shares some traits with biological evolution itself. Looking into the future, I consider that a closer engagement with living tissue and with the biological questions of function and formation, rather than with the materials science of biological materials, will help ensure the continuing great success of this field.

Nature features a plethora of extraordinary photonic architectures that have been optimized through natural evolution in order to more efficiently reflect, absorb or scatter light. While numerical optimization is increasingly and successfully used in photonics, it has yet to replicate any of these complex naturally occurring structures. Using evolutionary algorithms inspired by natural evolution and performing particular optimizations (maximize reflection for a given wavelength, for a broad range of wavelength or maximize the scattering of light), we have retrieved the most stereotypical natural photonic structures. Whether those structures are Bragg mirrors, chirped dielectric mirrors or the gratings on top of Morpho butterfly wings, our results indicate how such regular structures might have spontaneously emerged in nature and to which precise optical or fabrication constraints they respond. Comparing algorithms show that recombination between individuals, inspired by sexual reproduction, confers a clear advantage that can be linked to the fact that photonic structures are fundamentally modular: each part of the structure has a role which can be understood almost independently from the rest. Such an in silico evolution also suggests original and elegant solutions to practical problems, as illustrated by the design of counter-intuitive anti-reflective coatings for solar cells.

The central shaft of a bird's flight feather bears most of the aerodynamic load during flight and exhibits some remarkable mechanical properties. The shaft comprises two parts, the calamus and the rachis. The calamus is at the base of the shaft, while the rachis is the longer upper part which supports the vanes. The shaft is composed of a fibrous outer cortex, and an inner foam-like core. Recent nanoindentation experiments have indicated that reduced modulus values, E r , for the inner and outer regions of the cortex can vary, with the E r values of the inner region slightly greater than those of the outer region. In this work, Raman spectroscopy is used to investigate the protein secondary structures in the inner and outer regions of the feather cortex. Analysis of the Amide I region of Raman spectra taken from four birds (Swan, Gull, Mallard and Kestrel) shows that the β-sheet structural component decreases between the inner and outer region, relative to the protein side-chain components. This finding is consistent with the proposal that E r values are greater in the inner region than the outer region. This work has shown that Raman spectroscopy can be used effectively to study the change in protein secondary structure between the inner and outer regions of a feather shaft., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Many biological surfaces of animals and plants (e.g., bird feathers, insect wings, plant leaves, etc.) are superhydrophobic with rough surfaces at different length scales. Previous studies have focused on a simple drop-bouncing behavior on biological surfaces with low-speed impacts. However, we observed that an impacting drop at high speeds exhibits more complicated dynamics with unexpected shock-like patterns: Hundreds of shock-like waves are formed on the spreading drop, and the drop is then abruptly fragmented along with multiple nucleating holes. Such drop dynamics result in the rapid retraction of the spreading drop and thereby a more than twofold decrease in contact time. Our results may shed light on potential biological advantages of hypothermia risk reduction for endothermic animals and spore spreading enhancement for fungi via wave-induced drop fragmentation., Competing Interests: The authors declare no competing interest., (Copyright © 2020 the Author(s). Published by PNAS.)

Multilayer thin-film structures in the wings of a butterfly; Papilio crino produce a colourful iridescence from reflected light. In this investigation, scanning electron microscope images show both the concave cover scales and pigmented air-chamber ground scales. The microstructures with the concavities retroreflect incident light, thus causing the double reflection. This gives rise to both the colour mixing and polarisation conversion clearly depicted in the optical images. The result of the numerical and theoretical analysis via the CIELAB, and optical reflection and transmission of light through the multilayer stacks with the use of transfer method show that the emerging colouration on the Papilio crino is structural and is due to the combination of colours caused by multiple bounces within the concavities. The butterfly wing structure can be used as the template for designing the photonic device.

With the function of mediating intercellular communication between cells, extracellular vesicles (EVs) have been intently studied for their physiopathology and clinical application values. However, efficient EV isolation from biological fluids remains a significant challenge. To address this, this work constructs a new microvortex chip that can isolate EVs efficiently by integrating the lipid nanoprobe modified Morpho Menelaus (M. Menelaus) butterfly wing into microfluidic chip. M. Menelaus wing is well known for its orderly arranged periodic nanostructures and can generate microvortex when liquid passes through it, leading to increased interaction between EVs and M. Menelaus wing. In addition, the nanoprobe containing lipid tails can be inserted into EVs through their lipid bilayer membrane structure. Based on the described properties, high-throughput enrichment of EVs with over 70% isolation efficiency was realized. Moreover, it was demonstrated that the nanoprobe system based on M. Menelaus wing enabled downstream biological analysis of nucleic acids and proteins in EVs. Microvortex chips showed potential application value in efficient EV isolation for biomedical research and cancer diagnosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financialinterestsor personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In diverse organisms, nanostructures that coherently scatter light create structural color, but how such structures are built remains mysterious. We investigate the evolution and genetic regulation of butterfly scale laminae, which are simple photonic nanostructures. In a lineage of buckeye butterflies artificially selected for blue wing color, we found that thickened laminae caused a color shift from brown to blue. Deletion of the optix patterning gene also altered color via lamina thickening, revealing shared regulation of pigments and lamina thickness. Finally, we show how lamina thickness variation contributes to the color diversity that distinguishes sexes and species throughout the genus Junonia . Thus, quantitatively tuning one dimension of scale architecture facilitates both the microevolution and macroevolution of a broad spectrum of hues. Because the lamina is an intrinsic component of typical butterfly scales, our findings suggest that tuning lamina thickness is an available mechanism to create structural color across the Lepidoptera., Competing Interests: RT, FA, NP No competing interests declared, (© 2020, Thayer et al.)

Photonic crystals are some of the more spectacular realizations that periodic arrays can change the behavior of electromagnetic waves. In nature, so-called structural colors appear in insects and even plants. Some species create beautiful color patterns as part of biological behavior such as reproduction or defense mechanisms as a form of biomimetics. The interaction between light and matter occurs at the surface, producing diffraction, interference and reflectance, and light transmission is possible under suitable conditions. In particular, there are two Colombian butterflies, Morpho cypris and Greta oto, that exhibit iridescence phenomena on their wings, and in this work, we relate these phenomena to the photonic effect. The experimental and theoretical approaches of the optical response visible region were studied to understand the underlying mechanism behind the light-matter interaction on the wings of these Colombian butterflies. Our results can guide the design of novel devices that use iridescence as angular filters or even for cosmetic purposes.

Background: Bird plumage exhibits a diversity of colors that serve functional roles ranging from signaling to camouflage and thermoregulation. However, birds must maintain a balance between evolving colorful signals to attract mates, minimizing conspicuousness to predators, and optimizing adaptation to climate conditions. Examining plumage color macroevolution provides a framework for understanding this dynamic interplay over phylogenetic scales. Plumage evolution due to a single overarching process, such as selection, may generate the same macroevolutionary pattern of color variation across all body regions. In contrast, independent processes may partition plumage and produce region-specific patterns. To test these alternative scenarios, we collected color data from museum specimens of an ornate clade of birds, the Australasian lorikeets, using visible-light and UV-light photography, and comparative methods. We predicted that the diversification of homologous feather regions, i.e., patches, known to be involved in sexual signaling (e.g., face) would be less constrained than patches on the back and wings, where new color states may come at the cost of crypsis. Because environmental adaptation may drive evolution towards or away from color states, we tested whether climate more strongly covaried with plumage regions under greater or weaker macroevolutionary constraint., Results: We found that alternative macroevolutionary models and varying rates best describe color evolution, a pattern consistent with our prediction that different plumage regions evolved in response to independent processes. Modeling plumage regions independently, in functional groups, and all together showed that patches with similar macroevolutionary models clustered together into distinct regions (e.g., head, wing, belly), which suggests that plumage does not evolve as a single trait in this group. Wing patches, which were conserved on a macroevolutionary scale, covaried with climate more strongly than plumage regions (e.g., head), which diversified in a burst., Conclusions: Overall, our results support the hypothesis that the extraordinary color diversity in the lorikeets was generated by a mosaic of evolutionary processes acting on plumage region subsets. Partitioning of plumage regions in different parts of the body provides a mechanism that allows birds to evolve bright colors for signaling and remain hidden from predators or adapt to local climatic conditions.

Simpler and biocompatible greener approaches for the assembly of nanoparticles (NPs) have been the focus lately which have minimum environmental damage and often entails the use of natural biomolecules to synthesize NPs. Such greener synthesis of nanoparticles has capitalized on the use of microbes, fungi, and plants using biological resources. In this study, Periplaneta americana (American cockroach) wings' extract (chitin-rich) is studied as a novel biomaterial for the first time to synthesize silver NPs (less than 50 nm); chitin is the second most abundant polymer after cellulose on earth. The physicochemical properties of these NPs were analyzed using UV-visible spectroscopy, X-ray diffraction, and transmission electron microscopy (TEM). The insecticidal effect of ensuing NPs was examined on the mortality of Aphis gossypii under laboratory conditions; 48 h after treatments of A. gossypii with silver NPs (100 μg/ml), the mortality rate in treated aphids was about 40% (an average), while an average percentage of losses in the control sample was about 10%. These results indicate the lethal effect of green-synthesized silver NPs on A. gossypii, in vitro. Greener synthesis of silver nanoparticles using American cockroach wings and their insecticidal activities.

Pseudogymnoascus destructans is the causative agent of a fungal infection of bats known as white-nose syndrome (WNS). Since its discovery in 2006, it has been responsible for precipitous declines of several species of cave-dwelling North American bats. While numerous advancements in the understanding of the disease processes underlying WNS have been made in recent years, there are still many aspects of WNS, particularly with respect to pathogen virulence, that remain unknown. In this preliminary investigation, we sought to further elucidate the disease cycle by concentrating on the pathogen, with specific focus on its ability to utilize lipids that compose bat wing sebum and are found in wing membranes, as a substrate for energy and growth. In vitro growth experiments were conducted with the three most common fatty acids that comprise bat sebum: oleic, palmitic, and stearic acids. None of the fatty acids were observed to contribute a significant difference in mean growth from controls grown on SDA, although morphological differences were observed in several instances. Additionally, as an accompaniment to the growth experiments, bat wing explants from Perimyotis subflavus and Eptesicus fuscus were fluorescently stained to visualize the difference in distribution of 16- and 18-carbon chain fatty acids in the wing membrane. Which substrates contribute to the growth of P. destructans is important to understanding the progressive impact P. destructans has on bat health through the course of the disease cycle.

Photonic nanoarchitectures in the wing scales of butterflies and moths are capable of fast and chemically selective vapor sensing due to changing color when volatile vapors are introduced to the surrounding atmosphere. This process is based on the capillary condensation of the vapors, which results in the conformal change of the chitin-air nanoarchitectures and leads to a vapor-specific optical response. Here, we investigated the optical responses of the wing scales of several butterfly and moth species when mixtures of different volatile vapors were applied to the surrounding atmosphere. We found that the optical responses for the different vapor mixtures fell between the optical responses of the two pure solvents in all the investigated specimens. The detailed evaluation, using principal component analysis, showed that the butterfly-wing-based sensor material is capable of differentiating between vapor mixtures as the structural color response was found to be characteristic for each of them.

Cicada wings, covered with arranged nanostructures, were widely studied owing to their high transparency and low reflection. However, limited by technologies, their exquisite surface structures and multifunctional features were not inherited and applied by most artificial materials adequately. Here, the excellent optical properties of the cicada wing were investigated in detail experimentally and theoretically. Besides, a flexible self-cleaning broadband antireflective film inspired by the cicada wing has been successfully fabricated by a well-designed biological template method and sol-gel process. The cicada wing ( Megapomponia intermedia) was selected as the original template directly, and a SiO 2 negative replica was obtained by a sol-gel process. Then, chemical corrosion was used to remove the original template, retaining the pure negative replica. Subsequently, the polymethyl methacrylate (PMMA) positive replica could be rebuilt after another sol-gel process. Compared with a flat PMMA film, the average reflectivity of the structured PMMA film over the visible region was reduced from 10 to 2%. Besides, the bio-inspired film with a thickness of 0.18 mm exhibited satisfactory comprehensive performances with low reflectance (≤2%) in most of the visible region, as well as superhydrophobic property and perfect flexibility. Our results offered a quick and simple method to rebuild the nanostructured functional materials, promoting the practical applications of the bionic nanostructured materials. Meanwhile, the modified biomimetic fabrication method provides a solution for rebuilding exquisite biological materials and designing multifunctional surfaces. Moreover, the multifunctional antireflective film with wider universality will exhibit an enormous potential application value in optical communications, photoelectric devices, flexible display screens, and antidazzle glasses.

Three-dimensional (3D) cell spheroids have a demonstrated value for in vitro biological research and therapeutics development. Attempts to this technique focus on the development of effective methods for fabricating cell spheroids. Here, inspired by the heterogeneously textured wettability bumps (with hydrophilic peaks and hydrophobic bases) of Stenocara beetle, we present a biotemplated substrate with wettable hydrogel arrays for culturing the cell spheroids. The biotemplates were Morpho butterfly wings with chitin and protein components, which could provide a natural superhydrophobic surface without any modification. The droplet microarrays could be formed for cell spheroid culture on this bioinspired wing substrate by using the hydrogel patterns to hanging droplets. The hanging drop culture method on hydrogel-covered wings has the advantages of high speed, uniform size, and controllable diameter for the formation of 3D cell spheroids. It was demonstrated that drugs produced distinct responses in the 3D cell spheroids compared to conventional two-dimensional cell cultures. As the presented system does not require complex instruments and chemical modifications, our method can simply construct the desired wettability substrates with high biocompatibility for cell culture, drug testing, and other biomedical applications.

The waxy epicuticle of dragonfly wings contains a unique nanostructured pattern that exhibits bactericidal properties. In light of emerging concerns of antibiotic resistance, these mechano-bactericidal surfaces represent a particularly novel solution by which bacterial colonization and the formation of biofilms on biomedical devices can be prevented. Pathogenic bacterial biofilms on medical implant surfaces cause a significant number of human deaths every year. The proposed mechanism of bactericidal activity is through mechanical cell rupture; however, this is not yet well understood and has not been well characterized. In this study, we used giant unilamellar vesicles (GUVs) as a simplified cell membrane model to investigate the nature of their interaction with the surface of the wings of two dragonfly species, Austrothemis nigrescens and Trithemis annulata, sourced from Victoria, Australia, and the Baix Ebre and Terra Alta regions of Catalonia, Spain. Confocal laser scanning microscopy and cryo-scanning electron microscopy techniques were used to visualize the interactions between the GUVs and the wing surfaces. When exposed to both natural and gold-coated wing surfaces, the GUVs were adsorbed on the surface, exhibiting significant deformation, in the process of membrane rupture. Differences between the tensile rupture limit of GUVs composed of 1,2-dioleoyl- sn-glycero-3-phosphocholine and the isotropic tension generated from the internal osmotic pressure were used to indirectly determine the membrane tensions, generated by the nanostructures present on the wing surfaces. These were estimated as being in excess of 6.8 mN m -1 , the first experimental estimate of such mechano-bactericidal surfaces. This simple model provides a convenient bottom-up approach toward understanding and characterizing the bactericidal properties of nanostructured surfaces.

To protect themselves, insects cover their bodies with what is called cuticular lipid. The cuticular lipid of an American cockroach has a unique lipid content; the most abundant is a cis-alkadiene, cis, cis-6,9-heptacosadiene, amounting to about 70%, which is followed by a branched alkane 3-methylpentacosane. In order to clarify the structural features of the unique lipid composition below the critical temperature, the cuticular lipid was studied by Fourier transform infrared (FTIR) spectroscopy in combination with an attenuated total reflection (ATR) sampling technique. The infrared spectra measured on an extracted lipid sample at 20 °C suggested that the lipid keeps an appreciable level of conformational and lateral packing regularity, in spite of a high cis-unsaturated lipid content, and also a highly disordered condition around the methyl terminals and cis-olefin groups. The CH 2 scissoring and the CH 2 rocking regions showed the characteristics of the O⊥ subcell. The same characteristics were observed also by in situ measurements on a forewing of the American cockroach. Combining the spectral features of these bands and the physicochemical properties of each component, it can be inferred that saturated lipids form highly ordered domains within the liquid containing the cis, cis-diene as the main component. For comparison, the cuticular lipid of a male cricket, which consisted of many different hydrocarbons, including 15% of unsaturated hydrocarbons, showed a lower regularity both in the conformation and in the lateral packing of hydrocarbon chains. These results imply that not only the degree of cis-unsaturation but also the chemical structure diversity of hydrocarbons are the important factors to determine the physicochemical properties of cuticular lipid.

The wings of moths and butterflies are densely covered in scales that exhibit intricate shapes and sculptured nanostructures. While certain butterfly scales create nanoscale photonic effects, moth scales show different nanostructures suggesting different functionality. Here we investigate moth-scale vibrodynamics to understand their role in creating acoustic camouflage against bat echolocation, where scales on wings provide ultrasound absorber functionality. For this, individual scales can be considered as building blocks with adapted biomechanical properties at ultrasonic frequencies. The 3D nanostructure of a full Bunaea alcinoe moth forewing scale was characterized using confocal microscopy. Structurally, this scale is double layered and endowed with different perforation rates on the upper and lower laminae, which are interconnected by trabeculae pillars. From these observations a parameterized model of the scale's nanostructure was formed and its effective elastic stiffness matrix extracted. Macroscale numerical modeling of scale vibrodynamics showed close qualitative and quantitative agreement with scanning laser Doppler vibrometry measurement of this scale's oscillations, suggesting that the governing biomechanics have been captured accurately. Importantly, this scale of B. alcinoe exhibits its first three resonances in the typical echolocation frequency range of bats, suggesting it has evolved as a resonant absorber. Damping coefficients of the moth-scale resonator and ultrasonic absorption of a scaled wing were estimated using numerical modeling. The calculated absorption coefficient of 0.50 agrees with the published maximum acoustic effect of wing scaling. Understanding scale vibroacoustic behavior helps create macroscopic structures with the capacity for broadband acoustic camouflage., Competing Interests: The authors declare no conflict of interest.

A characteristic feature of the giant owl butterfly, i.e. Caligo memnon , is its big wing eyespot. This feature could serve as deceiving functionality for the butterfly against predators. As evidenced by scanning electron microscope (SEM) image on black part of eyespot, the scales on wing eyespot contain nanostructured ridges and cross-ribs. Applying direct measurement, statistical method, and Fourier analysis, the authors evidence that these nanostructures display order-disorder in their shape and position. The autocorrelation of SEM image provides average values of characteristic periods of the order-disorder nanostructures together with an estimation of corresponding correlation lengths. Linecuts obtained from the Fourier transform of SEM image were also analysed with the Hosemann function to extract similar information. These analyses indicate that the nanostructured order-disorder may contribute to blackness on wing eyespot. The authors thus conclude that the blackness on wing eyespot of C. memnon could be attributed to contributions from both the nanostructured order-disorder and melanin pigment.

The Palearctic-African migratory circuit has been typically associated with birds. Very few insects are known to endure annual trans-Saharan circuits, but the Painted Lady butterfly ( Vanessa cardui ) is an exception. While it was demonstrated that this species massively migrates from Europe to the Afrotropics during the autumn, the existence of a reverse migration from the Afrotropics to Europe in the early spring remains hypothetical. Here, we analysed wing stable hydrogen isotope values (δ 2 H) of V. cardui migrants collected from February to April across the circum-Mediterranean region. We assessed their region of natal origin by comparing their wing isotope signature predicted δ 2 H values (isoscape). The results unambiguously demonstrate a sub-Saharan origin for many individuals, especially those collected in February, representing the first tangible evidence for a reverse northwards trans-Saharan migration in spring. This work supports the view that the Afrotropics (mostly exploited from September to February) is key in the V. cardui Palearctic-African population dynamics. This species relies on both temperate and tropical habitats to complete their multigenerational cycle, an unprecedented adaptation for butterflies and for most migratory insects. Such a migratory circuit has strong parallelisms with those of migratory birds., (© 2018 The Author(s).)

Insects represent the majority of known animal species and exploit a variety of fascinating nanotechnological concepts. We investigated the wings of the damselfly Calopteryx haemorrhoidalis, whose males have dark pigmented wings and females have slightly pigmented wings. We used scanning electron microscopy (SEM) and nanoscale synchrotron X-ray fluorescence (XRF) microscopy analysis for characterizing the nanostructure and the elemental distribution of the wings, respectively. The spatially resolved distribution of the organic constituents was examined by synchrotron Fourier transform infrared (s-FTIR) microspectroscopy and subsequently analyzed using hierarchical cluster analysis. The chemical distribution across the wing was rather uniform with no evidence of melanin in female wings, but with a high content of melanin in male wings. Our data revealed a fiber-like structure of the hairs and confirmed the presence of voids close to its base connecting the hairs to the damselfly wings. Within these voids, all detected elements were found to be locally depleted. Structure and elemental contents varied between wing membranes, hairs and veins. The elemental distribution across the membrane was rather uniform, with higher Ca, Cu and Zn levels in the male damselfly wing membranes.

Laser-ablation electrospray ionization (LAESI) imaging mass spectrometry (IMS) is an emerging bioanalytical tool for direct imaging and analysis of biological tissues. Performing ionization in an ambient environment, this technique requires little sample preparation and no additional matrix, and can be performed on natural, uneven surfaces. When combined with optical microscopy, the investigation of biological samples by LAESI allows for spatially resolved compositional analysis. We demonstrate here the applicability of LAESI-IMS for the chemical analysis of thin, desiccated biological samples, specifically Neotibicen pruinosus cicada wings. Positive-ion LAESI-IMS accurate ion-map data was acquired from several wing cells and superimposed onto optical images allowing for compositional comparisons across areas of the wing. Various putative chemical identifications were made indicating the presence of hydrocarbons, lipids/esters, amines/amides, and sulfonated/phosphorylated compounds. With the spatial resolution capability, surprising chemical distribution patterns were observed across the cicada wing, which may assist in correlating trends in surface properties with chemical distribution. Observed ions were either (1) equally dispersed across the wing, (2) more concentrated closer to the body of the insect (proximal end), or (3) more concentrated toward the tip of the wing (distal end). These findings demonstrate LAESI-IMS as a tool for the acquisition of spatially resolved chemical information from fragile, dried insect wings. This LAESI-IMS technique has important implications for the study of functional biomaterials, where understanding the correlation between chemical composition, physical structure, and biological function is critical. Graphical abstract Positive-ion laser-ablation electrospray ionization mass spectrometry coupled with optical imaging provides a powerful tool for the spatially resolved chemical analysis of cicada wings.

The iridescent wings of the Chalcopterix rutilans damselfly (Rambur) (Odonata, Polythoridae) are investigated with focused ion beam/scanning electron microscopy, transmission electron microscopy, and time-of-flight secondary ion mass spectrometry. The electron microscopy images reveal a natural photonic crystal as the source of the varying colors. The photonic crystal has a consistent number and thickness (∼195 nm) of the repeat units on the ventral side of the wing, which is consistent with the red color visible from the bottom side of the wing in all regions. The dorsal side of the wing shows strong color variations ranging from red to blue depending on the region. In the electron microscopy images, the dorsal side of the wing exhibits varied number and thicknesses of the repeat units. The repeat unit spacings for the red, yellow/green, and blue regions are approximately 195, 180, and 145 nm, respectively. Three-dimensional analysis of the natural photonic crystals by time-of-flight secondary ion mass spectrometry reveals that changes in the relative levels of Na, K, and eumelanin are responsible for the varying dielectric constant needed to generate the photonic crystal. The photonic crystal also appears to be assembled with a chemical tricomponent layer structure due to the enhancement of the CH 6 N 3 + species at every other interface between the high/low dielectric constant layers.

The elytral surface of dung beetles is generally accepted to be self-cleaning due to its anti-adhesive properties. In this article, the wettability and adhesive properties of elytral surface (intact and treated with Acetone and Ethanol) of the beetle Geotrupes stercorarius were characterized. Since these properties are influenced by the surface structure and chemistry, the micro- and nanostructure of the elytra were observed using scanning electron microscopy and the surface roughness were estimated with white light interferometery, whereas the water contact angle and adhesion force of the elytra were evaluated using contact angle measurement device and force transducer, respectively. The results show that the microstructure of the elytra changed greatly after different chemical treatments and the changes in wettability were mainly related to the changes of elytra roughness after treatments. The differences in adhesion force between differently treated elytra and wet sand indicate that the molecular polarity of the elytral surface is decisive for its anti-adhesive (self-cleaning) property.

The neurogenesis and neuronal functions in insect wing have been understudied mainly due to technical hindrances that have prevented electrophysiology studies for decades. The reason is that the nano-architecture of the wing chemosensory bristles hampers the receptors accessibility of odorants/tastants to receptors in fixed setup, whereas in nature, the wing flapping mixes these molecules in bristle lymph. In this report, we analyzed the transcriptome of the wing tissue of two species phylogenetically strongly divergent: Drosophila melanogaster a generic model for diptera order (complete metamorphosis) and the aphid acyrthosiphon pisum, representative of hemiptera order (incomplete metamorphosis) for which a conditional winged/wingless polyphenism is under control of population density and resources. The transcriptome shows that extensive gene networks involved in chemosensory perception are active in adult wing for both species. Surprisingly, the specific transcripts of genes that are commonly found in eye were present in Drosophila wing but not in aphid. The analysis reveals that in the aphid conditional wing, expressed genes show strong similarities with those in the gut epithelia. This suggests that the epithelial cell layer between the cuticle sheets is persistent at least in young aphid adult, whereas it disappears after emergence in Drosophila. Despite marked differences between the two transcriptomes, the results highlight the probable universalism of wing chemosensory function in the holometabolous and hemimetabolous orders of winged insects.

Chitin, a polymer of N-acetyl-D-glucosamine (GlcNAc), is a major structural component in chitin-containing organism including crustaceans, insects and fungi. Mammals express two chitinases, chitotriosidase (Chit1) and acidic mammalian chitinase (AMCase). Here, we report that pig AMCase is stable in the presence of other digestive proteases and functions as chitinolytic enzyme under the gastrointestinal conditions. Quantification of chitinases expression in pig tissues using quantitative real-time PCR showed that Chit1 mRNA was highly expressed in eyes, whereas the AMCase mRNA was predominantly expressed in stomach at even higher levels than the housekeeping genes. AMCase purified from pig stomach has highest activity at pH of around 2-4 and remains active at up to pH 7.0. It was resistant to robust proteolytic activities of pepsin at pH 2.0 and trypsin and chymotrypsin at pH 7.6. AMCase degraded polymeric chitin substrates including mealworm shells to GlcNAc dimers. Furthermore, we visualized chitin digestion of fly wings by endogenous AMCase and pepsin in stomach extract. Thus, pig AMCase can function as a protease resistant chitin digestive enzyme at broad pH range present in stomach as well as in the intestine. These results indicate that chitin-containing organisms may be a sustainable feed ingredient in pig diet.

Neotropical Heliconius butterflies are members of various mimicry rings characterized by diverse colour patterns. In the present study we investigated whether a similar diversity is observed in the chemistry of volatile compounds present in male wing androconia. Recent research has shown that these androconia are used during courting of females. Three to five wild-caught male Heliconius individuals of 17 species and subspecies were analyzed by GC/MS. Most of the identified compounds originate from common fatty acids precursors, including aldehydes, alcohols, acetates or esters preferentially with a C 18 and C 20 chain, together with some alkanes. The compounds occurred in species-specific mixtures or signatures. For example, octadecanal is characteristic for H. melpomene, but variation in composition between the individuals was observed. Cluster analysis of compound occurrence in individual bouquets and analyses based on biosynthetic motifs such as functional group, chain length, or basic carbon-backbone modification were used to reveal structural patterns. Mimetic pairs contain different scent bouquets, but also some compounds in common, whereas sympatric species, both mimetic and non-mimetic, have more distinct compound compositions. The compounds identified here may play a role in mate choice thus helping maintain species integrity in a butterfly genus characterized by pervasive interspecific gene flow.

Wings of flying insects are part of the cuticle which forms the exoskeleton. The primary molecular components of cuticle are protein, chitin, and lipid. How these components interact with one another to form the exoskeleton is not completely understood. The difficulty in characterizing the cuticle arises because it is insoluble and noncrystalline. These properties severely limit the experimental tools that can be used for molecular characterization. Solid-state nuclear magnetic resonance experiments have been used in the past to characterize the exoskeleton of beetles and have found that chitin and protein make comparable contributions to the molecular matrix. However, little work has been done to characterize the components of the wing, which includes vein and membrane. In this work, solid-state NMR was used to characterize the wing of the 17-year cycle cicada (Magicicada cassini) that appeared in northern West Virginia during the summer of 2016. The NMR results show noticeable differences between the molecular components of the vein and membrane.

The red flour beetle Tribolium castaneum has become the second most important insect model organism and is frequently used in developmental biology, genetics and pest-associated research. Consequently, the methodological arsenal increases continuously, but many routinely applied techniques for Drosophila melanogaster and other insect species are still unavailable. For example, a protocol for non-lethal genotyping has not yet been adapted but is particularly useful when individuals with known genotypes are required for downstream experiments. In this study, we present a workflow for non-lethal genotyping of T. castaneum adults based on extracting genomic DNA from wing tissue. In detail, we describe a convenient procedure for wing dissection and a custom method for wing digestion that allows PCR-based genotyping of up to fifty adults in less than an afternoon with a success rate of about 86%. The amount of template is sufficient for up to ten reactions while viability and fertility of the beetles are preserved. We prove the applicability of our protocol by genotyping the white / scarlet gene pair alleles from the black-eyed San Bernadino wild-type and white-eyed Pearl recessive mutant strains spanning four generations. Non-lethal genotyping has the potential to improve and accelerate many workflows: Firstly, during the establishment process of homozygous cultures or during stock keeping of cultures that carry recessively lethal alleles, laborious test crossing is replaced by non-lethal genotyping. Secondly, in genome engineering assays, non-lethal genotyping allows the identification of appropriate founders before they are crossed against wild-types, narrowing the efforts down to only the relevant individuals. Thirdly, non-lethal genotyping simplifies experimental strategies, in which genotype and behavior should be correlated, since the genetic configuration of potential individuals can be determined before the actual behavior assays is performed.

The ability to takeoff quickly and accelerate away from predators is crucial to bird survival. Crude oil can disrupt the fine structure and function of feathers, and here we tested for the first time how small amounts of oil on the trailing edges of the wings and tail of Western sandpipers (Calidris mauri) affected takeoff flight performance. In oiled birds, the distance travelled during the first 0.4s after takeoff was reduced by 29%, and takeoff angle was decreased by 10° compared to unoiled birds. Three-axis accelerometry indicated that oiled sandpipers produced less mechanical power output per wingbeat during the initial phase of flight. Slower and lower takeoff would make oiled birds more likely to be targeted and captured by predators, reducing survival and facilitating the exposure of predators to oil. Whereas the direct mortality of heavily-oiled birds is often obvious and can be quantified, our results show that there are significant sub-lethal effects of small amounts crude oil on feathers, which must be considered in natural resource injury assessments for birds., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Many insect species sequester compounds acquired from their host plants for defense against natural enemies. The distribution of these compounds is likely to affect both their efficacy as defenses, and their costs. In this study we examined the distribution of sequestered iridoid glycosides (IGs) in two congeneric species of nymphalid butterfly, Euphydryas anicia and E. phaeton, and found that the pattern of localization of IGs differed between the two species. Although IG concentrations were quite high in the heads of both species, the relative concentrations in wings and abdomens differed substantially. Euphydryas anicia had relatively high IG concentrations in their abdomens and low IG concentrations in their wings, whereas the reverse was true in E. phaeton. We interpret these results in light of two current hypotheses regarding where sequestered chemicals should be localized: that they should be found in wings, which would allow non-lethal sampling by predators; and that their distribution is constrained by the distribution of tissue types to which sequestered compounds bind. We also offer the third hypothesis, that costs of storage may differ among body parts, and that the localization of compounds may reflect a cost-reduction strategy. Results from E. phaeton were consistent with all three of these non-mutually exclusive hypotheses, whereas results from E. anicia were only consistent with the notion that tissue bias among body parts plays a role in IG distribution. The finding that these two congeneric butterflies exhibit different patterns of IG localization suggests that they have been shaped by different selection regimes.

In previous studies, chitin-based films were produced from chitin nanofibers in dust form and fully characterized. However, chitin films naturally present in many organisms have not been isolated and characterized. Herein, structurally intact chitin films were successfully extracted from the dorsal pronotum and the wing of cockroach. Despite using the same extraction procedure, important differences were observed. Especially, hydrophobicity, transparency, antifungal and antibacterial biofilm activities of wing chitin film were recorded notably higher than those of chitin film from the dorsal pronotum. However, better mechanical properties were observed for chitin film from the dorsal pronotum. Notably, among the tested bacteria, two common pathogens could not form biofilms on the surface of the films. This study clearly demonstrated natural chitin films obtained from an insect can provide a new perspective to chitin-based applications where chitin films with high thermal stability, transparency, resistance to bacterial biofilm formation and antifungal activity are needed., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The integument protects the organism against penetration of xenobiotics and water that would potentially interfere with homeostasis. In insects that play key roles in a variety of agricultural and ecological habitats, this inward barrier has barely been investigated. In order to advance knowledge in this field, we studied integumental barrier (cuticle) permeability in the two global pests Trialeurodes vaporariorum (greenhouse whitefly) and Cimex lectularius (bedbug), applying a simple dye-penetration assay. In agreement with our recent findings in Drosophila melanogaster , we show that the surface of these insects is regionalised. We also show that, in contrast to the single barrier in D. melanogaster , two barriers with distinct temperature-sensitive and lipid-based physico-chemical material properties act in parallel to protect these insects against penetration of hydrophilic molecules. These findings imply the existence of unexplored mechanisms by which the cuticle acts as a protective coat against the penetration of water and xenobiotics, including pollutants and insecticides., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2017. Published by The Company of Biologists Ltd.)

pH sensor is an important and practical device with a wide application in environmental protection field and biomedical industries. An efficient way to enhance the practicability of intelligent polymer composed pH sensor is to subtilize the three-dimensional microstructure of the materials, adding measurable features to visualize the output signal. In this work, C. rubi wing scales were combined with pH-responsive smart polymer polymethylacrylic acid (PMAA) through polymerization to achieve a colour-tunable pH sensor with nature gyroid structure. Morphology and reflection characteristics of the novel composites, named G-PMAA, are carefully investigated and compared with the original biotemplate, C. rubi wing scales. The most remarkable property of G-PMAA is a single-value corresponding relationship between pH value and the reflection peak wavelength (λ max ), with a colour distinction degree of 18 nm/pH, ensuring the accuracy and authenticity of the output. The pH sensor reported here is totally reversible, which is able to show the same results after several detection circles. Besides, G-PMAA is proved to be not influenced by the detection angle, which makes it a promising pH sensor with superb sensitivity, stability, and angle-independence., Competing Interests: The authors declare no competing financial interests.

The nanostructures on the wings of Idea malabarica (Moore, 1877) were analysed using scanning electron microscopy, energy dispersive X-ray spectroscopy, atomic force microscopy, Fourier transform-infrared spectroscopy, and reflectance measurements. The chemical and morphological analyses revealed the chitin-based intricate nanostructures. The influence of the nanostructures on the wetting characteristics of the wing was investigated using optical imaging. Applying the Maxwell-Garnet approximation to the porosities within the nanostructures, the refractive indices, which relate the reflectance response, were estimated. It was concluded that the colour seen on the wings of the Idea malabarica originate from the nanostructural configurations of the chitin-based structures and the embedded pigment.

Structural coloration variability was investigated in two Blue butterfly species that are common in Hungary. The males of Polyommatus icarus (Common Blue) and Plebejus argus (Silver-studded Blue) use their blue wing coloration for conspecific recognition. Despite living in the same type of habitat, these two species display differences in prezygotic mating strategy: the males of P. icarus are patrolling, while P. argus males have sedentary behavior. Therefore, the species-specific photonic nanoarchitecture, which is the source of the structural coloration, may have been subjected to different evolutionary effects. Despite the increasing interest in photonic nanoarchitectures of biological origin, there is a lack of studies focused on the biological variability of structural coloration that examine a statistically relevant number of individuals from the same species. To investigate possible structural color variation within the same species in populations separated by large geographical distances, climatic differences, or applied experimental conditions, one has to be able to compare these variations to the normal biological variability within a single population. The structural coloration of the four wings of 25 male individuals (100 samples for each species) was measured and compared using different light-collecting setups: perpendicular and with an integrating sphere. Significant differences were found in the near UV wavelength region that are perceptible by these polyommatine butterflies but are invisible to human observers. The differences are attributed to the differences in the photonic nanoarchitecture in the scales of these butterflies. Differences in the intensity of structural coloration were also observed and were tentatively attributed to the different prezygotic mating strategies of these insects. Despite the optical complexity of the scale covered butterfly wings, for sufficiently large sample batches, the averaged normal incidence measurements and the averaged measurements using an integrating sphere are in agreement., Competing Interests: The authors have declared that no competing interests exist.

The painted lady, Vanessa cardui, is a migratory butterfly that performs an annual multi-generational migration between Europe and North Africa. Its seasonal appearance south of the Sahara in autumn is well known and has led to the suggestion that it results from extremely long migratory flights by European butterflies to seasonally exploit the Sahel and the tropical savannah. However, this possibility has remained unproven. Here, we analyse the isotopic composition of butterflies from seven European and seven African countries to provide new support for this hypothesis. Each individual was assigned a geographical natal origin, based on its wing stable hydrogen isotope (δ 2 H w ) value and a predicted δ 2 H w basemap for Europe and northern Africa. Natal assignments of autumn migrants collected south of the Sahara confirmed long-distance movements (of 4000 km or more) starting in Europe. Samples from Maghreb revealed a mixed origin of migrants, with most individuals with a European origin, but others having originated in the Sahel. Therefore, autumn movements are not only directed to northwestern Africa, but also include southward and northward flights across the Sahara. Through this remarkable behaviour, the productive but highly seasonal region south of the Sahara is incorporated into the migratory circuit of V. cardui., (© 2016 The Author(s).)