Butterfly Wing Research Articles

A release from developmental bias accelerates morphological diversification in butterfly eyespots

Development can bias the independent evolution of traits sharing ontogenetic pathways, making certain evolutionary changes less likely. The eyespots commonly found on butterfly wings each have concentric rings of differing colors, and these serially repeated pattern elements have been a focus for evo-devo research. In the butterfly family Nymphalidae, eyespots have been shown to function in startling or deflecting predators and to be involved in sexual selection. Previous work on a model species of Mycalesina butterfly, Bicyclus anynana, has provided insights into the developmental control of the size and color composition of individual eyespots. Experimental evolution has also shown that the relative size of a pair of eyespots on the same wing surface is highly flexible, whereas they are resistant to diverging in color composition, presumably due to the underlying shared developmental process. This fixed color composition has been considered as a prime example of developmental bias with significant consequences for wing pattern evolution. Here, we test this proposal by surveying eyespots across the whole subtribe of Mycalesina butterflies and demonstrate that developmental bias shapes evolutionary diversification except in the genus Heteropsis which has gained independent control of eyespot color composition. Experimental manipulations of pupal wings reveal that the bias has been released through a novel regional response of the wing tissue to a conserved patterning signal. Our study demonstrates that development can bias the evolutionary independence of traits, but it also shows how bias can be released through developmental innovations, thus, allowing rapid morphological change, facilitating evolutionary diversification.

Superhydrophobic Shape Memory Polymer Microarrays with Switchable Directional/Antidirectional Droplet Sliding and Optical Performance.

Bioinspired smart surfaces with switchable wettability and optical performance have aroused much attention in the past few years. However, almost all reported surfaces focused on regulating single surface function. In this work, inspired by the butterfly wings, a novel superhydrophobic surface with shape memory polymer microarrays (SMPAs) was prepared through the integration of three-dimensional printing, replica-molding, and a simple surface treatment. In this superhydrophobic SMPA system, the permanent upright microarrays and temporary tilted microarrays can be reversibly switched owing to the excellent shape memory effect (SME). Accompanied by the structure variations, switchable directional/antidirectional droplet sliding and vivid color conversion as the butterfly wings can be achieved. Moreover, because of the SME, local structure regulation can also be achieved on the surface, and with the help of such an ability, the SMPA was further applied as a multifunctional platform to demonstrate controllable droplet transportation and information storage. This work reports the reversible control of directional/antidirectional droplet sliding and tunable color on a superhydrophobic SMPA, and it is believed that such a smart surface can be potentially applied in many fields, such as microfluidic devices and smart optical chips.

Thermal control strategy of OMEGA SSPS based simultaneous shape and topology optimization of butterfly wing radiator

This paper proposes an innovative thermal control strategy for obtaining optimum layout of Orb-shape Membrane Energy Gathering Array (OMEGA) space solar power station radiator based simultaneous shape and topology optimization. Firstly, a parameter in term of maximum heat dissipation per mass is introduced for the optimal configuration using the Particle Swarm optimization algorithm. Then, analogizing the butterfly wing vein and branch points, a better layout of heat transfer network is inspired to conduct. Based on this, the virtual temperature points are added for completely constructing bionic butterfly wing heat transfer network and the calculation method is derived and discussed in detail. Finally, the derived method is realized through topology optimization method and the validity is verified through comparison of thermal analysis results. Unlike other radiators design, the proposed method optimizes layout of radiator from both two aspects of configuration outside and bionic butterfly wing heat transfer network inside, which is meaningful for the future application.

Morphological and Spatial Diversity of the Discal Spot on the Hindwings of Nymphalid Butterflies: Revision of the Nymphalid Groundplan.

Simple SummaryButterfly wing color patterns are diverse, but they can be understood as modifications of the common scheme called the nymphalid groundplan. The discal spot is relatively small, but it is one of the important components of the nymphalid groundplan. Using many hindwing specimens of the family Nymphalidae, the morphological and spatial diversity of the discal spot was studied. The discal spot is expressed as a small or narrow spot, a pair of parallel bands, a diamond or oval structure, a large dark spot, a few fragmented spots, or a white structure. The discal spot is always located in a central portion of the wing defined by the wing veins, and this portion is sandwiched by a pair of bands of the central symmetry system, another important component of the nymphalid groundplan. On the basis of these results, the present study revises the nymphalid groundplan in minor points; the discal spot is an independent and diverse miniature symmetry system nested within the central symmetry system. Due to the involvement of wing veins to define the locations of the discal spot, the present study suggests the possible developmental dynamics of butterfly color pattern formation that produces color pattern diversity.Diverse butterfly wing color patterns are understood through the nymphalid groundplan, which mainly consists of central, border, and basal symmetry systems and a discal spot. However, the status of the discal spot remains unexplored. Here, the morphological and spatial diversity of the discal spot was studied in nymphalid hindwings. The discal spot is expressed as a small or narrow spot, a pair of parallel bands, a diamond or oval structure, a large dark spot, a few fragmented spots, or a white structure. In some cases, the discal spot is morphologically similar to and integrated with the central symmetry system (CSS). The discal spot is always located in a distal portion of the discal cell defined by the wing veins, which is sandwiched by the distal and proximal bands of the CSS (dBC and pBC) and is rarely occupied by border ocelli. The CSS occasionally has the central band (cBC), which differs from the discal spot. These results suggest that the discal spot is an independent and diverse miniature symmetry system nested within the CSS and that the locations of the discal spot and the CSS are determined by the wing veins at the early stage of wing development.

Classification of Twin Arrangements in Butterfly Martensite Grains and Analysis of Relationship between Twin Arrangement and Butterfly Wing Angle in Medium-Carbon Steel

Classification of Twin Arrangements in Butterfly Martensite Grains and Analysis of Relationship between Twin Arrangement and Butterfly Wing Angle in Medium-Carbon Steel

Light guidance in photonic structures of Morpho butterfly wing scales

In this paper, we investigate the impact of the periodicity along three orthogonal axes of the blue wing scales of Morpho butterflies, whereas most of the previous studies modeled the scale structure only considering one or two photonic crystal dimensions. Moreover, the previous optical studies of these scales focused on the light reflected by the wing, whereas we investigate the light propagation along the lamellae, this direction corresponding to the third dimension of the photonic crystal structure. Simulation results obtained using the finite-element method are compared with measurements and/or literature. These calculations, performed for different scale models and orientations, show that a significant part of the non-reflected light, essentially red and infrared, is guided by the lamellae towards the base of the scales where it can be more easily absorbed and the heat more quickly transferred to the hemolymph. This new phenomenon could contribute to the thermal balance of the insect and further illustrates the multifunctionality of the wings of Lepidoptera.

Highly Sensitive and Selective VOC Vapor Optical Fiber Sensor Using Hierarchical Nanostructures of Butterfly Wing Scales

Volatile organic compound (VOC) is one of the most widely spread and hazardous environmental pollutants. In this work, a VOC vapor optical fiber sensor is proposed and demonstrated based on the multilayer interference and diffraction of Morpho Didius butterfly wing scales. The sensing wing is fabricated and sheathed on the end of the optical fiber probe with a sleeve, while the sensing element could be easily renewed by replacing the sleeve part. It is found that the reflectance spectrum of the butterfly wings changes with varied VOC vapors. By tracing the spectral changes, the categories and concentrations of VOC vapors are investigated experimentally, while the differential reflectance spectrum ΔR is introduced to magnify the subtle differences of the original spectrum. Here, the dichloromethane, acetone, and ethanol vapors are tested, and the maximum sensitivity of the sensor is measured as 3.303E-5%/ppm, 7.762E-5%/ppm, and 2.881E-4%/ppm, respectively. The principal components analysis method is employed to further analyze the ΔR spectrum, and the concentration of varied VOC vapors could be discriminated and identified according to the distribution of the projected points. Considering its advantages including low-cost, easy fabrication, good repeatability, high sensitivity, and selectivity, this wing-based vapor optical fiber sensor has great application potential in the field of air monitoring.

Reversible Structure Engineering of Bioinspired Anisotropic Surface for Droplet Recognition and Transportation.

Surfaces with tunable liquid adhesion have aroused great attention in past years. However, it remains challenging to endow a surface with the capability of droplet recognition and transportation. Here, a bioinspired surface, termed as TMAS, is presented that is inspired by isotropic lotus leaves and anisotropic butterfly wings. The surface is prepared by simply growing a triangular micropillar array on the pre‐stretched thin poly(dimethylsiloxane) (PDMS) film. The regulation of mechanical stress in the PDMS film allows the fine tuning of structural parameters of the micropillar array reversibly, which results in the instantaneous, in situ switching between isotropic and various degrees of anisotropic droplet adhesions, and between strong adhesion and directional sliding of water droplets. TMAS can thus be used for robust droplet transportation and recognition of acids, bases, and their pH strengths. The results here could inspire the design of robust sensor techniques.

From Patterning Genes to Process: Unraveling the Gene Regulatory Networks That Pattern Heliconius Wings

Butterfly wing patterns have emerged as exceptional model systems with which to link the developmental and genetic processes that generate morphological variation with the ecological and evolutionary processes that shape this variation in natural populations. Among butterflies, research on species within the genus Heliconius has provided remarkable opportunities to explore how phenotypic diversity is generated within the context of an extraordinary adaptive radiation. Wing pattern diversity among the 48 species and hundreds of intraspecific variants arose within the last 12-14 million years and includes striking pattern convergence between distantly related species, as well as marked pattern divergence between closely related populations and species. Here, we synthesize recent research aimed at gaining a mechanistic understanding of how this variation is generated. This research integrates decades of controlled crossing experiments, and the discovery of major wing patterning genes (optix, aristaless1, WntA and cortex) with recent functional genetic manipulation using CRISPR/Cas9 targeted mutagenesis. The emerging data provides a rich framework with which to explore the repeatability of evolution, particularly within the context of how natural selection acts on divergent gene regulatory networks to generate both highly convergent, as well as highly divergent phenotypes. Overall, the functional data show that the gene regulatory networks underlying pattern variation diverge rapidly in Heliconius; yet these networks retain enough flexibility so that natural selection can drive the evolution of nearly identical patterns from different developmental genetic starting points. Moreover, for the first time this research is starting to illuminate the links between the genetic changes modulating pattern variation and how they influence the larger gene networks that are ultimately responsible for patterning a butterfly wing. There are still large gaps in our understanding, but current research priorities are well laid out and experimental methodologies are in place to address them. The challenge is to synthesize diverse research strategies into a cohesive picture of morphological evolution.

Discovery of single gyroid structure in self-assembly of block copolymer with inorganic precursors

Triply periodic hyperbolic surfaces have attracted great attention due to their unique geometries and physical properties. Among them, the single gyroid (SG) is of significant interest due to its inherent chirality as well as the potential applications in energy and environmental science. However, the formation of the thermodynamically unstable structure is still unclear. In this work, we show the formation of SG structure in the structural transformation from the cylindrical to shifted double diamond (SDD) scaffold in a self-assembly system of diblock copolymer and silica precursors in solution. It has been found that the cylindrical tubes with zero Gaussian curvature were split and curved into hyperbolic surfaces and extruded to form SG structures and further evolved into the SDD networks. This growth or extrusion process suggests the SG structure is an intermediate phase of the cylindrical and SDD, and this transformation is found similar to the formation of butterfly wing scales (Thecla opisena), which has not been observed in neither the theoretical calculation nor the experimental self-assembly of amphiphilic molecules. We hope the structural relationship may bring new insights in understanding the formation of single networks in the biological system and the creation of new functional materials.

Evolutionary algorithms converge towards evolved biological photonic structures

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.

Convergent Evolution of Broadband Reflectors Underlies Metallic Coloration in Butterflies

Butterfly wings often display structural colors, which are the result of light reflection from chitinous nanostructures that adorn the wing scales. Amongst these structural colors are broadband metallic reflections, which have been previously linked to an ultrathin broadband reflector in the nymphalid butterfly Argyrophorus argenteus. To test if similar optical modes of broadband, specular reflectance have evolved in other butterfly taxa, we characterized the reflective scales of eight species from five Papilionoidea families using microspectrophotometry (MSP), light microscopy in reflected and transmitted modes, and scanning electron microscopy (SEM). In Nymphalidae, Pieridae, and Hesperidae, and Lycaenidae, we find that broadband specularity is due to spatial mixing of densely juxtaposed colorful reflectances that change across microscale distances (e.g. 1-3 µm). These seemingly convergent silver scales are unpigmented, show a continuous upper lamina with reduced windows, and consist of an air-cuticle sandwich of variable thickness, forming an undulatory thin-film. Strikingly, Hypochrysops apelles (Lycaenidae) show a novel mode of silver reflectance with spatial color mixing occurring across the entire proximo-distal length of the scale (>100 µm), transitioning from blue to red hues between the stem and the tip of the scales. Unlike the undulatory type, this reflector shows flat thin-films but this includes a multilayered lower lamina responsible for selective color iridescence in other lycaenids or in sunset moths. Finally, the gold scales of Anteros formosus (Riodinidae) show mixed reflectance in the green-to-red range, seemingly produced by a thin film in the lower lamina. Our comparative study suggests that evolution of metallic broadband reflectance repeatedly involved spatial color mixing and unperforated upper laminae, and is accomplished using at least three types of ultrastructural modifications. Undulatory thin-film systems, based on geometric adjustments of the transverse profile of the upper lamina and scale lumen, are widespread and may have evolved repeatedly from more generic colorless scale morphologies, while lycaenid and riodinid broadband reflectors may be elaborations of pre-existing iridescent states.

Digital Biomimetic Architecture between Art and Dynamic Structure: Case Study—Wings in Flight

Architecture as a multirelated field is influenced and connected by many subjects. Among those subjects, the role of art and natural science is the most dominant frame without ignoring the development of advanced technology. By using technology, the impossible becomes possible such as to capture the body motion of humans as the subject of art and science at the same time. Body motion is a potential research of movement over the time. This does not only involve the aesthetic, but also even more the scientific aspect of a dynamic motion of an organism that can be investigated through a biomimetic approach. In order to understand the biomimetic term, we investigated the physical morphogenesis and geometrical principle of an organism. The term morphogenesis is a process in which the natural system produces and regulates the configuration of a material in space and over time. Based on that, we tried to design a dynamic structure using butterfly’s motion as a subject of study with morphological and biomimetic approaches. Butterflies show a simultaneous aspect of movement over time characterized by fragmentation. This idea also summarizes many aspects of modern art such as portrayal of body movements by futurists, space-time continuum, cinematic freeze frame, and time-lapse photography. A futurist represents a movement that is emphasized on the factors of speed, technology, modernisms, and objects. This indicates an alternative position that may be relevant to the system of butterfly wings. This can only be achieved by utilizing a digital design and its parametric tools that help generate functions and form dynamic structures with high complexity and precision. Throughout the development of the system, there will be many changes to the form which will be constantly tested and evaluated using a series of prototype and visual digital design.

How many scales on the wings? A case study based on Colias crocea (Geoffroy, 1785) (Hexapoda: Lepidoptera, Pieridae)

The covering by scales of the wings of Lepidoptera contributes to multiple functions that are critical for their survival and reproduction. In order to gain a better understanding about their distribution, we have exhaustively studied 4 specimens of Colias crocea (Geoffroy, 1785). We have quantified the sources of variability affecting scale density. The results indicate that the scale covering of butterfly wings may be remarkably heterogeneous, and that the importance of the sources of variability differs between forewings and hindwings. Thus, in forewing the greatest variability occurs between sectors, while in the hindwings it occurs between sides, with a higher density of scales on the underside, considerably higher (almost 19%) than on the upperside. It seems likely that this difference has an adaptive value, as the hindwing underside is more exposed (in resting position) to predators. These results are in contrast with the generally accepted notion that scale covering is uniform and homogeneous. Moreover, the cover scale density is independent of the size of the specimen and therefore an average density of scales can be attributed to this species. According to our measurements C. crocea has 312 scales/mm2 and the total number of scales per individual is about 520,000 on average.

Anterior–Posterior Patterning in Lepidopteran Wings

The color patterns on the wings of butterflies and moths are among the most complex manifestations of pattern formation in nature. The complexities of these patterns arise from the diversification of a conserved set of homologous elements known as the Nymphalid Ground Plan that can change color, shift position, expand, or disappear altogether. Recent work has shown that the anterior-posterior axis of the butterfly wing may also have an important role in the development and evolution of wing-pattern diversity. Here we characterize the anterior-posterior axis by mapping expression domains of key regulatory genes onto the wing. We show that the butterfly wing can be subdivided into four primary regions, with the boundaries of these domains arising at the positions of the M1, M3, and Cu2 wing-veins. We find that the correlation among variation in the border ocelli is strongest for those within the same domain. We show how these domains may be used to determine phenotypic outcomes by surveying the frequency of color boundaries, tail development, and wing shape discontinuities across five major butterfly families: Lycaenidae, Nymphalidae, Papilionidae, Pieridae, and Riodinidae. Of the more than 200 genera we surveyed in this study, color pattern discontinuities emerge most often at the boundary veins M1, M3, and Cu2, and shape discontinuities and tails at veins M3 and Cu2. These findings reveal a hitherto unrecognized mode of evolution of patterning in the Lepidoptera.

Transcription factors underlying wing margin color patterns and pupal cuticle markings in butterflies

BackgroundThe diversity of butterfly color patterns can be attributed to a relatively small number of pattern elements that are homologous across Lepidoptera. Although genes involved in patterning some of these elements have been identified, the development of several major elements remains poorly understood. To identify genes underlying wing pupal cuticle markings and wing margin color patterns, we examined expression of the candidate transcription factors Engrailed/Invected (En/Inv), Distal-less (Dll), Cubitus interruptus (Ci), and Spalt in two nymphalids: Junonia coenia and Bicyclus anynana.ResultsWe found that En/Inv, Dll, and Ci mark domains on the J. coenia last-instar forewing disc that closely correspond to the position and shape of pupal cuticle markings. We also found that Spalt demarcates wing margin color patterns in both J. coenia and B. anynana, and that CRISPR/Cas9 deletions in the spalt gene result in reduction and loss of wing margin color patterns in J. coenia. These data demonstrate a role for spalt in promoting wing margin color patterning, in addition to its previously described role in eyespot patterning.ConclusionOur observations support the model that a core set of regulatory genes are redeployed multiple times, and in multiple roles, during butterfly wing pattern development. Of these genes, spalt is of special interest as it plays a dual role in both eyespot and margin color pattern development.

Multichanneled hierarchical porous nanocomposite CuO/carbonized butterfly wing and its excellent catalytic performance for thermal decomposition of ammonium perchlorate

To meet the requirement of generating more apparent specific heat release at lower temperatures for ammonium perchlorate (AP)‐based composite solid propellants, the development of high‐performance catalysts for improving the thermal decomposition properties of AP still remains essential and challenging. Herein, a novel catalyst, multichanneled hierarchical porous nanocomposite of CuO and carbonized butterfly wing (CuO/CBW), has been prepared through an in‐situ reaction on original butterfly wing scales. Owing to the high active surface area and the good electrical and thermal conductivity, as well as the synergistic effect of CuO nanoparticles (20–25 nm) and CBW, CuO/CBW nanocomposite exhibits excellent catalytic activity for AP thermal decomposition in reducing the high‐temperature decomposition temperature by 88.3°C, lowering the apparent activation energy from 190.0 to 103.1 kJ mol−1 and increasing the heat release from 255 to 1841 J g−1.

Butterfly wing architectures inspire sensor and energy applications.

Natural biological systems are constantly developing efficient mechanisms to counter adverse effects of increasing human population and depleting energy resources. Their intelligent mechanisms are characterized by the ability to detect changes in the environment, store and evaluate information, and respond to external stimuli. Bio-inspired replication into man-made functional materials guarantees enhancement of characteristics and performance. Specifically, butterfly architectures have inspired the fabrication of sensor and energy materials by replicating their unique micro/nanostructures, light-trapping mechanisms and selective responses to external stimuli. These bio-inspired sensor and energy materials have shown improved performance in harnessing renewable energy, environmental remediation and health monitoring. Therefore, this review highlights recent progress reported on the classification of butterfly wing scale architectures and explores several bio-inspired sensor and energy applications.

Antireflective design of Si-based photovoltaics via biomimicking structures on black butterfly scales

The naturally evolved sunlight harvesters are not limited to foliage. Animals also harvest sunlight for light-heat conversion. A typical antireflective and light-trapping scheme has been well demonstrated on thin butterfly scales where solar energy is converted to heat besides being diffracted for surface coloration. Biomimicking scale structures offers a unique route to enhance light harvesting efficiencies happening on manmade solar cells. Herein, we performed a computational investigation of using microstructures on black butterflies for solar cell efficiency enhancement. Scale microstructures were obtained from nine species of black butterflies and employed as coating structures in numerical models built on Si-slabs. Introducing butterfly wing structures not only reduces the light reflection and transmittance but also increases the light absorption within Si-slabs. Surface reflection was decreased down to 10%, and the short-circuit current was increased by 66% correspondingly. An antireflection design strategy is given and hoped to benefit light harvesting in Si-based solar cells eventually.

Biological Activities and GCMS Analysis of the Methanolic Extract of Christia vespertilionis (L.F.) Bakh. F. Leaves

Christia vespertilionis (L.F) Bakh. F. (red butterfly wing) is commonly used as a herbal medicine to treat symptoms of many diseases. The present study aimed to determine the in vitro antimalarial and cytotoxic activities as well as investigate the chemical compositions of the methanolic extract of C. vespertilionis leaves (CVME). The antimalarial activity of CVME against a chloroquine-sensitive (3D7) strain of Plasmodium falciparum was assessed by using a malarial SYBR Green I fluorescence-based (MSF) assay. The cytotoxic effect of CVME on cancerous (MDA-MB-231 and MCF-7) and noncancerous (NIH/3T3) cell lines were evaluated by using methyl tetrazolium (MTT) assay. Chemical constituents of CVME were analysed by using a gas chromatography/mass spectrometry (GCMS). CVME exhibited a moderate antimalarial activity with an IC50 value of 43.87 ± 2.04 µg/mL. CVME is considered as weak cytotoxic and significantly inhibited proliferation of MDA-MB-231 cells with an IC50 value of 37.45 ± 1.05 µg/mL (p<0.05) as compared to standard MCF-7 (IC50>100 μg/mL) and NIH/3T3 cells (IC50>100 μg/mL). This effect is selectively cytotoxic towards certain cancerous cells only. GCMS analysis suggests that CVME potentially contains several pharmacologically bioactive compounds such as tetrahydro-2-methyl- thiophene (61.77%), phytol (8.59%), 10-undecenoic acid (5.00%), 6-methyl heptyl-2-propanoate (4.96%) and 2-(2-benzothiazolylthio)-1-(3,5-dimethylpyrazolyl)-ethanone (2.70%) that might possess antimalarial and cytotoxic activities. It implies that CVME has selective cytotoxic activity against the breast cancer cell line (MDA-MB-231) and possesses an antimalarial activity against the 3D7 malaria parasite, suggesting the presence of bioactive compounds in C. vespertilionis leaves that could be a potential source of phytochemicals with high medicinal value to be used in cancer and malaria treatment.
 
 
 Keywords: Christia vespertilionis, antimalarial activity, anticancer activity, cytotoxic activity, bioactive compounds.