In vivo visualization of butterfly scale cell morphogenesis in Vanessa cardui.

During metamorphosis, the wings of a butterfly sprout hundreds of thousands of scales with intricate microstructures and nano-structures that determine the wings' optical appearance, wetting characteristics, thermodynamic properties, and aerodynamic behavior. Although the functional characteristics of scales are well known and prove desirable in various applications, the dynamic processes and temporal coordination required to sculpt the scales' many structural features remain poorly understood. Current knowledge of scale growth is primarily gained from ex vivo studies of fixed scale cells at discrete time points; to fully understand scale formation, it is critical to characterize the time-dependent morphological changes throughout their development. Here, we report the continuous, in vivo, label-free imaging of growing scale cells of Vanessa cardui using speckle-correlation reflection phase microscopy. By capturing time-resolved volumetric tissue data together with nanoscale surface height information, we establish a morphological timeline of wing scale formation and gain quantitative insights into the underlying processes involved in scale cell patterning and growth. We identify early differences in the patterning of cover and ground scales on the young wing and quantify geometrical parameters of growing scale features, which suggest that surface growth is critical to structure formation. Our quantitative, time-resolved in vivo imaging of butterfly scale development provides the foundation for decoding the processes and biomechanical principles involved in the formation of functional structures in biological materials.

Morfología microestructural dérmica en juveniles de dos especies hermanas de tiburón pala, Sphyrna tiburo y S. vespertina / Dermal microstructural morphology in juveniles of two sister species of bonnethead shark, Sphyrna tiburo and S. vespertina

RESUMEN: Los dentículos dérmicos son estructuras dermales presentes en el grupo de los condrictios, tienen un papel muy importante en su biología y se les ha utilizado como un carácter taxonómico que permiten reconocer grupos o especies. Por lo que en el presente trabajo se compara la morfología dermal de los juveniles de dos especies de tiburones pala, Sphyrna tiburo y S. vespertina, cuyo origen evolutivo está emparentado con el cierre del istmo centroaméricano. Para ello se obtuvieron muestras dermales (1 cm2) de tres regiones corporales y se procesaron para obtener imágenes de alta resolución por medio de Microscopia electrónica de barrido (MEB). Los dentículos de ambas especies tienen un patrón morfológico común, con variaciones en la longitud de las prolongaciones de las crestas, área libre y superposición de los dentículos, y grado de notoriedad de la ornamentación microestructural.

SUMMARY: The dermal denticles are dermal structures present in the group of chondrichthyans, they have a very important role in their biology and they have been used as a taxonomic character that allows to recognize groups or species. Therefore, in the present work, the dermal morphology of the juveniles of two species of shovel sharks, Sphyrna tiburo and S. vespertina, whose evolutionary origin is related to the closure of the Central American isthmus, is compared. For this, dermal samples (1 cm2) from three body regions were obtained and processed to obtain high resolution images by means of scanning electron microscopy (SEM). The denticles of both species have a common morphological pattern, with variations in the length of the ridge extensions, free area and overlapping of the denticles, and the degree of notoriety of the microstructural ornamentation.

A microanatomical and histological study of the scales of the Devonian sarcopterygian Miguashaia bureaui and the evolution of the squamation in coelacanths.

Coelacanths have traditionally been described as morphologically conservative throughout their long evolutionary history, which spans more than 400 million years. After an initial burst during the Devonian, a morphological stasis was long thought to have prevailed since the Carboniferous, as shown by the extant Latimeria. New fossil discoveries have challenged this view, with punctual and sometimes unusual departures from the general coelacanth Bauplan. The dermal skeleton is considered to represent one, if not the main, example of morphological stasis in coelacanth evolution and as a consequence, has remained poorly surveyed. The lack of palaeohistological data on the dermoskeleton has resulted in a poor understanding of the early establishment and evolution of the coelacanth squamation. Here we describe the scales of Miguashaia bureaui from the Upper Devonian of Miguasha, Québec (Canada), revealing histological data for a Palaeozoic coelacanth in great detail and adding to our knowledge on the dermal skeleton of sarcopterygians. Miguashaia displays rounded scales ornamented by tubercules and narrow ridges made of dentine and capped with enamel. At least two generations of superimposed odontodes occur, which is reminiscent of the primitive condition of stem osteichthyans like Andreolepis or Lophosteus, and onychodonts like Selenodus. The middle vascular layer is well developed and shows traces of osteonal remodelling. The basal plate consists of a fully mineralised lamellar bone with a repetitive rotation pattern every five layers indicating a twisted plywood-like arrangement of the collagen plies. Comparisons with the extant Latimeria and other extinct taxa show that these features are consistently conserved across coelacanth evolution with only minute changes in certain taxa. The morphological and histological features displayed in the scales of Miguashaia enable us to draw a comprehensive picture of the onset of the coelacanth squamation and to propose and discuss evolutionary scenarios for the coelacanth dermoskeleton.

Microanalysis of scale morphology in killifish, Aphaniops hormuzensis inhabiting ecologically diverse environments (Cyprinodontiformes; Aphaniidae).

Ecologically, Aphaniops hormuzensis populations occupying diverse environments in southern Iran and showed substantial morphological variation across its range. In this study, three different habitats were chosen and identified as group A (sulfur rich spring), group B (salty River), and group C (urban canal), and scale microstructures and scale shape was inspected among three groups. The SEM imaging indicated that lepidonts were more developed on the scale of larger (group C, SL > 30 mm) than younger fish (group A, SL < 30 mm). We tentatively concluded that lepidonts are formed during scale development so that in the earlier stages of fish development, scales probably do not have lepidont. Also, the size and shape of lepidonts vary between the populations, and their shape and orientation within a given species affected by the fish size rather than the local ecological conditions of habitats. The number of radii was relatively higher in group C (12.58 ± 0.66 in males and 13.00 ± 1.89 in females). Similar to what is mentioned before in the case of lepidont, the inter-population variation in the number of radii seems to be influenced by fish size. Group A (SL < 30 mm) had a relatively large focus diameter (0.14 ± 0.02 in males and 0.36 ± 0.44 in females). It is assumed that the focus size is large at the earlier stage of fish development, but later during the fish growth, and by increasing the scale size, the focus diameter is reduced. In conclusion and agreement with previous studies, scale surface morphology and microstructure could be employed to discriminate certain populations, while scale size and J-indices could not help in distinguishing the populations. It is also proposed that the characteristics of scale morphology in the population-level are influenced by the combination of genetic, and environmental factors, as well as fish development.

General and specific microscopic characteristics of the dorsal tail scales and the spines of the crest in the tuatara Sphenodon pucntatus (Reptilia; Rhynchocephalia; Sphenodontidae).

Dorsal crest scales and those of the tail spines of the tuatara (Sphenodon punctatus) represent different specializations involved in display and protection. Erection of the dorsal crest occurs in males during combat and courtship, but tail spines are not noticeably involved in these activities. In both scale derivatives corneous beta proteins (CBPs, formerly called beta-keratins) and intermediate filaments keratins (IFKs) were determined by immunolabelling. The dermis is dense with few sparse fibrocytes surrounded by collagen bundles, the latter rather randomly oriented in the crest scales. In the tail ridge scales banded collagen I fibrils form more regular, orthogonally aligned bundles of alternating layers with connections to the basal epidermal membrane. A conglomerate of dermal melanonophores and iridophores is present under the epidermis. The iridophores are the likely origin of the whitish colour of the crest. The epidermis shows a thicker beta-layer with serrated/indented corneocytes in the tail scales while the beta layer is reduced in the crest but contains CBPs. A relatively thick mesos layer is present in both scale derivatives, especially in the crest where its role, aside from limiting transpiration, is not known. The alpha-layer is formed by corneocytes with irregular perimeter and sparse desmosomal remnants. The high labelling intensity for CBPs in the beta-layer disappears in the mesos layer but occurs, albeit strongly reduced, in the alpha-layer as in the other body scales. The take-home message is that the dense dermis and its apical beta-layer strengthen mechanically the ridge spines while the crest is mainly supported by the firm but pliable and less dense or regular dermis.

Diverse nanostructures underlie thin ultra-black scales in butterflies.

Recently, it has been shown that animals such as jumping spiders, birds, and butterflies have evolved ultra-black coloration comparable to the blackest synthetic materials. Of these, certain papilionid butterflies have reflectances approaching 0.2%, resulting from a polydisperse honeycomb structure. It is unknown if other ultra-black butterflies use this mechanism. Here, we examine a phylogenetically diverse set of butterflies and demonstrate that other butterflies employ simpler nanostructures that achieve ultra-black coloration in scales thinner than synthetic alternatives. Using scanning electron microscopy, we find considerable interspecific variation in the geometry of the holes in the structures, and verify with finite-difference time-domain modeling that expanded trabeculae and ridges, found across ultra-black butterflies, reduce reflectance up to 16-fold. Our results demonstrate that butterflies produce ultra-black by creating a sparse material with high surface area to increase absorption and minimize surface reflection. We hypothesize that butterflies use ultra-black to increase the contrast of color signals.

Role of Surface Chemistry in the Superhydrophobicity of the Springtail Orchesella cincta (Insecta:Collembola).

Collembola are ancient arthropods living in soil with extensive exposure to dirt, bacteria, and fungi. To protect from the harsh environmental conditions and to retain a layer of air for breathing when submerged in water, they have evolved a superhydrophobic, liquid-repelling cuticle surface. The nonfouling and self-cleaning properties of springtail cuticle make it an interesting target of biomimetic materials design. Recent research has mainly focused on the intricate microstructures at the cuticle surface. Here we study the role of the cuticle chemistry for the Collembola species Orchesella cincta (Collembola, Entomobryidae). O. cincta uses a relatively simple cuticle structure with primary granules arranged to function as plastrons. In contrast to the Collembolan cuticle featuring structures on multiple length scales that is functional irrespective of surface chemistry, we found that the O. cincta cuticle loses its hydrophobic properties after being rinsed with dichloromethane. Sum frequency generation spectroscopy and time-of-flight secondary ion mass spectrometry in combination with high-resolution mass spectrometry show that a nanometer thin triacylglycerol-containing wax layer at the cuticle surface is essential for maintaining the antiwetting properties. Removal of the wax layer exposes chitin, terpenes, and lipid layers in the cuticle. With respect to biomimetic applications, the results show that, combined with a carefully chosen surface chemistry, superhydrophobicity may be achieved using a relatively unsophisticated surface structure rather than a complex, re-entrant surface structure alone.

NEXAFS imaging to characterize the physio-chemical composition of cuticle from African Flower Scarab Eudicella gralli.

The outermost surface of insect cuticle is a high-performance interface that provides wear protection, hydration, camouflage and sensing. The complex and inhomogeneous structure of insect cuticle imposes stringent requirements on approaches to elucidate its molecular structure and surface chemistry. Therefore, a molecular understanding and possible mimicry of the surface of insect cuticle has been a challenge. Conventional optical and electron microscopies as well as biochemical techniques provide information about morphology and chemistry but lack surface specificity. We here show that a near edge X-ray absorption fine structure microscope at the National Synchrotron Light Source can probe the surface chemistry of the curved and inhomogeneous cuticle of the African flower scarab. The analysis shows the distribution of organic and inorganic surface species while also hinting at the presence of aragonite at the dorsal protrusion region of the Eudicella gralli head, in line with its biological function.

'Crystal Macrosetae': Novel Scales and Bristles in Male Arctiine Moths (Lepidoptera: Erebidae: Arctiinae) Filled with Crystallizing Material.

Scales, exoskeletal features characteristic of the Lepidoptera, occur in enormous structural and functional diversity. They cover the wing membranes and other body parts and give butterflies and moths their often stunning appearance. Generally, the patterns made by scales are visual signals for intra- and interspecific communication. In males, scales and/or bristles also make up the androconial organs, which emit volatile signals during courtship. Here, a structurally and putative functionally novel type of scales and bristles is reported: 'crystal macrosetae'. These lack trabeculae and windows, are made up by a very thin and flexible envelope only and contain crystallizing material. In 'crystal scales', there is a flat surface ornamentation of modified ridges, while 'crystal bristles' often show large protrusions. Crystal macrosetae usually cannot be reliably recognized without destruction. Apparently, they serve as containers for large amounts of material that is viscous in living moths, highly hygroscopic, crystallizes when specimens dry up, and can be visualized by scanning electron microscopy. Crystal macrosetae occur in males only, always associated with or making up androconial organs located on various parts of the body, and have numerous forms with diverse surface ornamentation across many species and genera. The newly identified structures and the discovery of crystallizing material in scales and bristles raise many questions and could shed new light on ontogenetic development of macrosetae, and on the biology and physiology as well as the evolution and systematics of Arctiinae. There is evidence that crystal macrosetae occur in other moths too.

Improving catalase stability by its immobilization on grass carp (Ctenopharyngodon idella) scale collagen self-assembly films.

We extracted collagen (CL) from the scales of Ctenopharyngodon idella and fabricated a CL self-assembly film. Catalase (CAT) was immobilized on the films using cross-linking, adsorption, and embedding methods. The activity and operational stability of immobilized CAT were investigated, along with the influence of the concentration of glutaraldehyde (GTA) and of the initial concentration of embedded CAT. The results showed that the CL triple helix remained intact. Differential scanning calorimetry data showed that the thermal stability of CL was significantly improved by neutral salt-induced self-aggregation and GTA cross-linking. The immobilized enzyme had high activity and good operational stability. When the enzyme concentration reached 0.5 mg/mL, immobilized enzyme activity of grass carp scales reached a maximum of 2596 U/g, and after twenty-two uses, enzyme activity remained above 50%, and it could be reused >45 times (CAT = 0.5 mg/mL, GTA = 5%, Temperature = 30 °C, pH = 7). Moreover, the optimum temperature and pH of immobilized CAT were 35 °C and 7, respectively, while the same for free CAT was 30 °C and 7, respectively. This indicated that immobilization of CAT has a protective effect.

Mechanical behavior of ctenoid scales: Joint-like structures control the deformability of the scales in the flatfish Solea solea (Pleuronectiformes).

Ctenoid scales protect the fish body against predators and other environmental impacts. At the same time, they allow for sufficient degree of flexibility to perform species-specific locomotion. The scales of the flatfish Solea solea were chosen to study the specific mechanical behavior and material properties of the ctenoid scales. Using scanning electron microscopy and micro-computed tomography, three-dimensional asymmetric structures of the stacked mineralized ctenial spines in the posterior field, which is a part of the scales exposed to the environment, were examined in detail. Nanoindentations on the surface of the ctenial spines indicated that the elastic modulus and hardness of these mineralized structures are about 14 GPa and 0.4 GPa, respectively. The spines appeared to be connected to each other by means of joint-like structures containing soft tissues. Bending tests showed that the ctenoid scales have two functional zones: a stiff supporting main body and an anisotropically deformable posterior field. While the stiff plate-like main body provides support for the whole scale, the deformable joint-like structures in the ctenial spines increase the deformability of the posterior field in downward bending. During upward bending, however, the spines prevent complete folding of the posterior field by an interlocking effect. STATEMENT OF SIGNIFICANCE: In contrast to the continuously mineralized cycloid scales, ctenoid scales combine two conflicting properties: They are hard to protect the body of fish against predators and other environmental impacts, yet flexible enough to allow for sufficient degree of body bendability for locomotion. To understand the structural background underlying this specific biomechanical feature, here we investigated the scales of the flatfish Solea solea. For the first time, we demonstrated the presence of joint-like structures within the scales, which increase scale deformability during downward bending, but prevent scale deformation during upward bending by interlocking. Our results shed lights on the material-structure-function relationships in ctenoid scales, as well as on their functional adaptations to the specific environment.

Light and transmission electron microscopic structure of skin glands and dermal scales of a caecilian amphibian Gegeneophis ramaswamii, with a note on antimicrobial property of skin gland secretion.

Amphibian skin secretions contain a variety of bioactive compounds that are involved in diverse roles such as communication, homeostasis, defence against predators, pathogens, and so on. Especially, the caecilian amphibians possess numerous cutaneous glands that produce the secretory material, which facilitate survival in their harsh subterranean environment. Inspite of the fact that India has a fairly abundant distribution of caecilian amphibians, there has hardly been any study on their skin and its secretion. Herein, we describe, using light microscopy and electron microscopy, two types of dermal glands, mucous and granular, in Gegeneophis ramaswamii. The mucous glands are filled with mucous materials. The mucous-producing cells are located near the periphery. The granular glands are surrounded by myoepithelial cells. A large number of granules of different sizes are present in the lumen of the granular gland. The granule-producing cells are present near the myoepithelial lining of the gland. There are small flat disk-like dermal scales in pockets in the transverse ridges of the posterior region of the body. Each pocket contains 1-4 scales of various sizes. Scanning electron microscopic (SEM) study of the skin surface showed numerous funnel-shaped glandular openings. The antibacterial activity of the skin secretions was revealed in the test against Escherichia coli, Klebsiella pneumoniae, and Aeromonas hydrophila, all gram-negative bacteria. SEM analyses confirm the membrane damage in bacterial cells on exposure to skin secretions of G. ramaswamii.

Structure and function of skin in the pelagic sea snake, Hydrophis platurus.

We describe and interpret the functional morphology of skin of the Yellow-bellied sea snake, Hydrophis platurus. This is the only pelagic sea snake, and its integument differs from what is known for other species of snakes. In gross appearance, the scales of H. platurus consist of non-overlapping, polygonal knobs with flattened outer surfaces bearing presumptive filamentous sensillae. The deep recesses between scales ('hinge') entrap and wick water over the body surface, with mean retention of 5.1 g/cm of skin surface, similar to that determined previously for the roughened, spiny skin of marine file snakes, Acrochordus granulatus. This feature possibly serves to maintain the skin wet when the dorsal body protrudes above water while floating on calm oceanic slicks where they forage. In contrast with other snakes, including three species of amphibious, semi-marine sea kraits (Laticauda spp.), the outer corneous ß-protein layer consists of a syncytium that is thinner than seen in most other species. The subjacent α-layer is also thin, and lipid droplets and lamellar bodies are seen among the immature, cornifying α-cells. A characteristic mesos layer, comprising the water permeability barrier, is either absent or very thin. These features are possibly related to (1) permeability requirements for cutaneous gas exchange, (2) reduced gradient for water efflux compared with terrestrial environments, (3) less need for physical protection in water compared with terrestrial ground environments, and (4) increased frequency of ecdysis thought to be an anti-fouling mechanism. The lipogenic features of the α-layer possibly compensate for the reduced or absent mesos layer, or produce layers of cells that comprise what functionally might be termed a mesos layer, but where the organization of barrier lipids nonetheless appears less robust than what is characteristically seen in squamates.

Morphological study of the urotergite I process in ten species of the genus Triatoma (Hemiptera, Reduviidae, Triatominae).

The insects of subfamily Triatominae exhibit many morphological features used for taxonomic identification. In some species, however, these features are very similar. The authors have proposed by first time the description of the structure referred as urotergite I process. The objective of the study was analyse the use of urotergite I process in the species of the genus Triatoma as a taxonomic feature that may contribute to the more precise and correct identification of these Trypanosoma cruzi Chagas, 1909 vectors. Scanning electron microscopy (SEM) was used to describe the structure of urotergite I process in ten Triatoma (Hemiptera, Reduviidae, Triatominae) species: Triatoma brasiliensis Neiva, 1911; Triatoma circummaculata Stål, 1859; Triatoma infestans (Klug, 1834); Triatoma maculata (Erichson, 1848); Triatoma pseudomaculata Corrêa & Espínola, 1964; Triatoma rubrovaria (Blanchard, 1843); Triatoma sordida (Stål, 1859); Triatoma tibiamaculata (Pinto, 1926); Triatoma vitticeps (Stål, 1859) and Triatoma wygodzinskyi Lent, 1951. The morphological description of the urotergite I process reflects the taxonomic value of the structure for separating and identifying species of ten specimens of the genus Triatoma. The morphological pattern of the urotergite I process on these ten species was compared, and interspecific variability was observed. We suggest the use of the urotergite I process as a complementary character to identify insects of the subfamily Triatominae. In the future, the use of the urotergite I process in dichotomic keys to identify triatomines may contribute to the improvement of the entomological surveillance of Chagas' disease.

Tailored disorder in calcite organization in tergite cuticle of the supralittoral isopod Tylos europaeus Arcangeli, 1938.

The crustacean cuticle forms skeletal elements consisting of chitin-protein fibrils reinforced by amorphous and crystalline calcium carbonate and phosphate minerals. The edges of skeletal elements are of particular interest. They are subject to repeated strain and stress because they form transitions to the arthrodial membranes connecting them. These allow for relative movements of skeletal elements. In this study, we investigate structure, chemical composition, mineral organization and local mechanical properties of the anterior and posterior edges of the tergite cuticle in the conglobating beach isopod Tylos europaeus and compare these with the protective dorsal region of the tergites. The distribution of mineral phases at the edges resembles that of dorsal regions of the tergites. At the transition with the unmineralized arthrodial membrane the calcite containing distal exocuticle is replaced by epicuticular material and the subjacent cuticular layers containing amorphous calcium carbonate become enriched with amorphous calcium phosphate. At the edges, the local elastic modulus and hardness values are significantly lower compared to dorsal regions of the tergite cuticle, for both, the calcite and the amorphous mineral containing layers. The calcite within the tergite cuticle is assembled in different texture patterns: (i) almost random co-orientation, (ii) almost single crystalline calcite, and (iii) a graded organization. Calcite organization and co-orientation strength is highly variable, not only on very few tens of micrometres, but also between regions with different skeletal functionality. Our results show that besides structure and composition, patterns of calcite organization contribute to the hierarchical architecture and functionality of biological composites.

Multifractal Characterization of Butterfly Wings Scales.

A lot of insect families have physical structures created by evolution for coloration. These structures are a source of ideas for new bio-inspired materials. The aim of this study was to quantitatively characterize the micromorphology of butterfly wings scales using atomic force microscopy and multifractal analysis. Two types of butterflies, Euploea mulciber ("striped blue crow") and Morpho didius ("giant blue morpho"), were studied. The three-dimensional (3D) surface texture of the butterfly wings scales was investigated focusing on two areas: where the perceived colors strongly depend on and where they do not depend on the viewing angle. The results highlight a correlation between the surface coloration and 3D surface microtexture of butterfly wings scales.

Group I chitin deacetylases are essential for higher order organization of chitin fibers in beetle cuticle.

Roles in the organization of the cuticle (exoskeleton) of two chitin deacetylases (CDAs) belonging to group I, TcCDA1 and TcCDA2, as well as two alternatively spliced forms of the latter, TcCDA2a and TcCDA2b, from the red flour beetle, Tribolium castaneum, were examined in different body parts using transmission EM and RNAi. Even though all TcCDAs are co-expressed in cuticle-forming cells from the hardened forewing (elytron) and ventral abdomen, as well as in the softer hindwing and dorsal abdomen, there are significant differences in the tissue specificity of expression of the alternatively spliced transcripts. Loss of either TcCDA1 or TcCDA2 protein by RNAi causes abnormalities in organization of chitinous horizontal laminae and vertical pore canals in all regions of the procuticle of both the hard and soft cuticles. Simultaneous RNAi for TcCDA1 and TcCDA2 produces the most serious abnormalities. RNAi of either TcCDA2a or TcCDA2b affects cuticle integrity to some extent. Following RNAi, there is accumulation of smaller disorganized fibers in both the horizontal laminae and pore canals, indicating that TcCDAs play a critical role in elongation/organization of smaller nanofibers into longer fibers, which is essential for structural integrity of both hard/thick and soft/thin cuticles. Immunolocalization of TcCDA1 and TcCDA2 proteins and effects of RNAi on their accumulation indicate that these two proteins function in concert exclusively in the assembly zone in a step involving the higher order organization of the procuticle.

Photonic crystal micro-pixelation and additive color mixing in weevil scales.

The origin of the brilliant near angle-independent coloration of the weevil Eupholus chevrolati was investigated by a combination of optical and electron microscopy tools, photonic band structure calculations, and color mixing analysis. Optical microscopy and scanning micro-spectroscopy revealed the presence of micrometer-sized red, yellow, green, and blue reflective pixels covering the entire exoskeleton of the weevil. Scanning electron microscopy in combination with focused ion beam milling showed that each micro-pixel consisted of a diamond-based photonic crystal structure and the different reflective colors were the result of different orientations of the photonic crystal. Color mixing analysis was used to study the collective behavior of the reflective micro-pixels. A pointillist, additive color-mixing scheme of the reflective photonic crystal micro-pixels was determined as the origin of the weevil's bright and near angle-independent yellow-green coloration.

A Triassic-Jurassic window into the evolution of Lepidoptera.

On the basis of an assemblage of fossilized wing scales recovered from latest Triassic and earliest Jurassic sediments from northern Germany, we provide the earliest evidence for Lepidoptera (moths and butterflies). The diverse scales confirm a (Late) Triassic radiation of lepidopteran lineages, including the divergence of the Glossata, the clade that comprises the vast multitude of extant moths and butterflies that have a sucking proboscis. The microfossils extend the minimum calibrated age of glossatan moths by ca. 70 million years, refuting ancestral association of the group with flowering plants. Development of the proboscis may be regarded as an adaptive innovation to sucking free liquids for maintaining the insect's water balance under arid conditions. Pollination drops secreted by a variety of Mesozoic gymnosperms may have been non-mutualistically exploited as a high-energy liquid source. The early evolution of the Lepidoptera was probably not severely interrupted by the end-Triassic biotic crisis.

Rainbow peacock spiders inspire miniature super-iridescent optics.

Colour produced by wavelength-dependent light scattering is a key component of visual communication in nature and acts particularly strongly in visual signalling by structurally-coloured animals during courtship. Two miniature peacock spiders (Maratus robinsoni and M. chrysomelas) court females using tiny structured scales (~ 40 × 10 µm2) that reflect the full visual spectrum. Using TEM and optical modelling, we show that the spiders' scales have 2D nanogratings on microscale 3D convex surfaces with at least twice the resolving power of a conventional 2D diffraction grating of the same period. Whereas the long optical path lengths required for light-dispersive components to resolve individual wavelengths constrain current spectrometers to bulky sizes, our nano-3D printed prototypes demonstrate that the design principle of the peacock spiders' scales could inspire novel, miniature light-dispersive components.