Wing Color Research Articles

The Relevance of Flash Coloration Against Avian Predation in a Morpho Butterfly: A Field Experiment in a Tropical Rainforest

ABSTRACTThe flash coloration hypothesis postulates that otherwise cryptically colored animals suddenly displaying conspicuous colors during movement confuse predators, reducing capture. Morpho helenor butterflies have contrasting colors on dorsal (iridescent blue) and ventral (brown) wing surfaces, resulting in sequential blue “flashes” during flight. We tested whether this flashing pattern reduces avian predation on M. helenor in Atlantic rainforest by changing the flashing effect in three experiments. In Experiment 1, we added a blue band to the ventral wing. In Experiment 2, we covered the dorsal wing's blue band with a brown band. Control groups in each experiment were painted such that wing color patterns remained unaltered. Survivorship was evaluated through mark‐recapture censuses and beak marks on the wings. Results show that survivorship of treated butterflies in Experiment 1 decrease markedly compared to unaltered control individuals, while survivorship of treated butterflies in Experiment 2 did not differ compared to control individuals. In Experiment 3, we detected scant predation on treated (blue band added to ventral wing) and control butterflies (brown band added to ventral wing) on the forest floor (wings closed), corroborating that flash coloration is an important protective mechanism during flight. Our field experiments provide the first evidence, to our knowledge, that flash coloration in bright blue Morpho butterflies is an effective defense mechanism against avian predators in a tropical rainforest.

Interactions between sexual signaling and wing size drive ecology and evolution of wing colors in Odonata

Insect coloration has evolved in response to multiple pressures, and in Odonata (dragonflies and damselflies) a body of work supports a role of wing color in a variety of visual signals and potentially in thermoregulation. Previous efforts have focused primarily on melanistic coloration even though wings are often multicolored, and there has yet to be comprehensive comparative analyses of wing color across broad geographic regions and phylogenetic groups. Percher vs. flier flight-style, a trait with thermoregulatory and signaling consequences, has not yet been studied with regard to color. We used a new color clustering approach to quantify color across a dataset of over 8,000 odonate wing images representing 343 Nearctic species. We then utilized phylogenetically informed Bayesian zero-inflated mixture models to test how color varies with mean ambient temperature, body size, sex and flight-style. We found that wing coloration clustered into two groups across all specimens - light brown-yellow and black-dark brown - with black-dark brown being a much more cohesive grouping. Male perchers have a greater proportion of black-dark brown color on their wings as do species with longer wings. In colder climates, odonates were more likely to have black-dark brown color present, but we found no relationship between the proportion of black and temperature. Light brown-yellow showed similar scaling with wing length, but no relationship with temperature. Our results suggest that black-dark brown coloration may have a limited role in thermoregulation, while light brown-yellow does not have such a role. We also find that the odonate sexes are divergent in wing color in percher species only, suggesting a strong role for color in signaling in more territorial males. Our research contributes to an understanding of complex interactions driving ecological and evolutionary dynamics of color in animals.

Nanostructural Influence on Optical and Thermal Properties of Butterfly Wing Scales Across Forest Vertical Strata.

Butterfly wing scales feature complex nanostructures that influence wing coloration and various mechanical and optical properties. This configuration plays a key role in ecological interactions, flight conditions, and thermoregulation, facilitated by interactions with environmental electromagnetic energy. In tropical forests, butterflies occupy distinct vertical habitats, experiencing significant light and temperature variations. While wing nanostructures have been widely studied, their variation across different vertical flight preferences remains underexplored. This study investigates the wing nanostructures of 12 tropical butterfly species from the Nymphalidae family, focusing on their optical, morphological, and thermal properties across different forest strata. We analyzed the optical response through diffuse reflectance in the UV, Vis, and NIR ranges, correlating these findings with nanostructural configuration and thermal stability using thermogravimetric analysis (TGA). Our results reveal a significant correlation between flight stratification and wing optical responses, alongside distinct nanostructural features within each stratum. This study demonstrates the variability in butterfly wing nanostructures along the vertical stratification of the forest to cope with environmental conditions, raising new questions for future research on eco-evolutionary flight and thermal adaptations. Additionally, this underscores the importance of understanding how these structural adaptations influence butterfly interactions with their environment and their evolutionary success across different forest strata.

3D Printing of Hierarchical Structures Made of Inorganic Silicon-Rich Glass Featuring Self-Forming Nanogratings.

Hierarchical structures are abundant in nature, such as in the superhydrophobic surfaces of lotus leaves and the structural coloration of butterfly wings. They consist of ordered features across multiple size scales, and their advantageous properties have attracted enormous interest in wide-ranging fields including energy storage, nanofluidics, and nanophotonics. Femtosecond lasers, which are capable of inducing various material modifications, have shown promise for manufacturing tailored hierarchical structures. However, existing methods, such as multiphoton lithography and three-dimensional (3D) printing using nanoparticle-filled inks, typically involve polymers and suffer from high process complexity. Here, we demonstrate the 3D printing of hierarchical structures in inorganic silicon-rich glass featuring self-forming nanogratings. This approach takes advantage of our finding that femtosecond laser pulses can induce simultaneous multiphoton cross-linking and self-formation of nanogratings in hydrogen silsesquioxane. The 3D printing process combines the 3D patterning capability of multiphoton lithography and the efficient generation of periodic structures by the self-formation of nanogratings. We 3D-printed micro-supercapacitors with large surface areas and a high areal capacitance of 1 mF/cm2 at an ultrahigh scan rate of 50 V/s, thereby demonstrating the utility of our 3D printing approach for device applications in emerging fields such as energy storage.

The Ultramorphology and Sexual Dimorphism of Antennae and Sensilla in the Pale Grass Blue, Pseudozizeeria maha (Lepidoptera: Lycaenidae).

The pale grass blue, Pseudozizeeria maha, is a small lycaenid butterfly widely distributed across Asia. Due to its exclusively diurnal lifestyle and conspicuous sexual dimorphism in wing coloration, vision has traditionally been regarded as the primary sensory system driving various behaviors. However, non-visual sensory systems related to sex-specific behavioral responses, such as antennae, have received far less attention. This study investigated the morphological characteristics and sensilla types of the antennae in adult P. maha using scanning electron microscopy, with a focus on potential sexual dimorphism. The antennae of adult P. maha are clavate, with no significant sexual differences in overall morphology. Six types of antennal sensilla were identified: Böhm bristles, sensilla squamiformia, sensilla trichodea, sensilla chaetica, sensilla basiconica, and sensilla coeloconica, with no sexual dimorphism observed in their morphological types or dimensions. Remarkably, the sensilla coeloconica exhibit significant sexual dimorphism, with a more prominent presence in females. This finding suggests that female P. maha may rely more on olfactory cues for some sex-specific behaviors, such as oviposition site selection.

The potential of roadside verges as insect habitat: Road salt has few effects on monarch butterfly performance and migration

AbstractRoadside habitat has been touted as a conservation opportunity for insect pollinators, including the declining monarch butterfly. The spectacular monarch migration is under threat from the loss of habitat and the decline of their milkweed host plants. In the northern part of their range, roadsides could potentially produce millions of monarchs annually due to high densities of milkweed; however, roadside milkweed can accumulate chemicals from roads, such as sodium from road salt. Controlled lab studies have shown mixed effects of sodium on monarch development: small increases can be beneficial as sodium is an important micronutrient in brain and muscle development, but large increases can sometimes decrease survival. It is unclear how dietary sodium affects performance in ecologically relevant conditions and the migration itself. In this experiment, we raised monarchs outdoors, in migration‐inducing conditions, on milkweed sprayed with three levels of sodium chloride. We released 2464 tagged monarchs and held an additional 246 for further lab assays. While our recovery rates to the wintering grounds were low (N = 7 individuals), individuals from all three sodium chloride treatments made it to Mexico. Butterflies reared on control milkweed and low salt concentrated sodium in their tissues, while those on high salt diets excreted sodium, suggesting high salt levels were above a physiological optimum. There were no effects of treatment on wing coloration, survival, body size, immunity, or parasite prevalence. Taken together, our results suggest that monarchs are robust to levels of sodium in milkweeds found along roadsides, which is promising with respect to the toxicity of roadside plants.

Antibody-Mediated Protein Knockdown Reveals Distal-less Functions for Eyespots and Parafocal Elements in Butterfly Wing Color Pattern Development.

One of the important genes for eyespot development in butterfly wings is Distal-less. Its function has been evaluated via several methods, including CRISPR/Cas9 genome editing. However, functional inhibition may be performed at the right time at the right place using a different method. Here, we used a novel protein delivery method for pupal wing tissues in vivo to inactivate a target protein, Distal-less, with a polyclonal anti-Distal-less antibody using the blue pansy butterfly Junonia orithya. We first demonstrated that various antibodies including the anti-Distal-less antibody were delivered to wing epithelial cells in vivo in this species. Treatment with the anti-Distal-less antibody reduced eyespot size, confirming the positive role of Distal-less in eyespot development. The treatment eliminated or deformed a parafocal element, suggesting a positive role of Distal-less in the development of the parafocal element. This result also suggested the integrity of an eyespot and its corresponding parafocal element as the border symmetry system. Taken together, these findings demonstrate that the antibody-mediated protein knockdown method is a useful tool for functional assays of proteins, such as Distal-less, expressed in pupal wing tissues, and that Distal-less functions for eyespots and parafocal elements in butterfly wing color pattern development.

Ultraviolet signaling in a butterfly is preferred by females and conveys male genetic quality.

Indicator models of sexual selection posit that females choose males on the basis of traits that reveal male genetic quality and thereby enjoy increased offspring production. Here, we report that females of the butterfly Eurema hecabe receive indirect benefits from choosing males based on their ultraviolet (UV) wing coloration, a heritable and condition-dependent trait in this species. We first used a large laboratory-bred pedigree to demonstrate a per-family association between inbreeding and male UV trait value. Females exerted choice for UV-bright males within this protocol, and the average male UV trait value increased over six consecutive generations, presumably due to such selection and despite an increasing rate of pedigree-wide inbreeding. We then experimentally imposed a standard strength of inbreeding upon lines of divergent male UV trait values. Inbreeding depressed the siring performance of low UV treatment males more severely and resulted in a marginal reduction of their UV brightness, which rebounded sharply following subsequent outcrossing. These findings are consistent with the ornament-based signaling of genetic quality as a function of underlying individual-level mutational load.

Current evidence of climate-driven colour change in insects and its impact on sexual signals.

The colours of insects function in intraspecific communication such as sexual signalling, interspecific communication such as protection from predators, and in physiological processes, such as thermoregulation. The expression of melanin-based colours is temperature-dependent and thus likely to be impacted by a changing climate. However, it is unclear how climate change drives changes in body and wing colour may impact insect physiology and their interactions with conspecifics (e.g. mates) or heterospecific (e.g. predators or prey). The aim of this review is to synthesise the current knowledge of the consequences of climate-driven colour change on insects. Here, we discuss the environmental factors that affect insect colours, and then we outline the adaptive mechanisms in terms of phenotypic plasticity and microevolutionary response. Throughout we discuss the impact of climate-related colour change on insect physiology, and interactions with con-and-heterospecifics.

The flashy escape: support for dynamic flash coloration as anti-predator defence.

Dynamic flash coloration is a type of antipredator coloration where intermittently appearing colour patterns in moving animals misdirect predator attacks by obscuring the precise location and trajectory of the moving prey. Birds and butterflies with differing dorsoventral wing coloration or iridescent surface structures may potentially benefit from such effects. However, we lack an understanding of what makes for an effective dynamic flash colour design and how much it benefits the carrier. Here, we test the effect of colour flashing using small passerine birds preying upon colourful, moving, virtual 'prey' stimuli on a touchscreen. We show that at fast speeds, green-to-blue flashing colour patterns can reduce the likelihood of pecks hitting the target, induce greater error in targeting accuracy and increase the number of pecks at a stimulus relative to similarly coloured non-flashing targets. Our results support the idea that dynamic flash coloration can deflect predatory attacks at fast speeds, but the effect may be the opposite when moving slowly.

A new species to the genus Neopheosia Matsumura, 1920 (Lepidoptera, Notodontidae) from India

A new species of notodontid moth, Neopheosia melaniata sp. nov. is described with illustration. This new species is closely allied to N. fasciata Moore, 1888 (type species) and completely conforms to the characterization of genus Neopheosia Matsumura. The wing coloration, distinct discal spot on forewing and genitalic features make it distinct. The taxonomic account of N. fasicata Moore is included.

Dynamic Color Regulation of the Lycaenid Butterfly Wing Scales

Butterfly coloration originates from the finely structured scales grown on the underlying wing cuticle. Most researchers who study butterfly scales are focused on the static optic properties of cover scales, with few works referring to dynamic optical properties of the scales. Here, the dynamic coloration effect of the multiple scales was studied based on the measurements of varying-angle reflection and the characterization of scale flexibility in two species of Lycaenid, Plebejus argyrognomon with violet wings and Polyommatus erotides with blue wings. We explored the angle-dependent color changeability and the color-mediating efficiency of wing scales. It was found that the three main kinds of flexible scales (cover, ground and androconia scales) were asynchronously bent during wing rotation, which caused the discoloration effect. The three layers of composite scales broaden the light signal when compared to the single scale, which may be of great significance to the recognition of insects. Specifically, the androconia scales were shown to strongly contribute to the overall wing coloration. The cover scale coloration was ascribed to the coherence scattering resulted from the short-range order at intermediate spatial frequencies from the 2D Fourier power spectra. Our findings are expected to deepen the understanding of the complex characteristics of biological coloration and to provide new inspirations for the fabrication of biomimetic flexible discoloration materials.

Description of a new Pheosia from Sichuan and Gansu, China (Lepidoptera, Notodontidae)

A new species of the genus Pheosia Hübner, 1819, Pheosia mayri sp. n., from Sichuan and Gansu Provinces in China is described. The new species is compared with Chinese Pheosia gelupka Gaede, 1934 and Pheosia buddhista (Püngeler, 1899). The two differ in wing coloration, male and, especially, female genitalia. Adults of both sexes, their genitalia and map of collecting sites are illustrated.

Species Delimitation of Some Melanargia Species (Lepidoptera, Nymphalidae, Satyrinae) in The Southeastern Anatolia Region Based On The mtCOI Gene

Among the Palearctic species, butterflies of the genus Melanargia are known for their black and white wing patterns. The morphological character polarization of this genus is full of varying combinations of subgenus, species complex, and subspecies status. Its taxonomy is open to debate, especially in species and subspecies categories, with definitions mostly based on wing color. In recent years, cryptic species, phenotypically masked species, and species with intense intraspecific variation have been identified through the determination of lineages under the leadership of molecular systematics. The mtCOI gene, which is especially described as a species signature, is an important DNA barcode used for Lepidoptera. In the presented study, the mtCOI gene sequence of the populations of Melanargia larissa, M.grumi, M.hylata, M.syriaca, and M.russiae species in the southeastern Anatolia region was determined for the first time. To determine the boundaries of these species, gene characterization and genetic distances were carried out according to the Kimura-2 Parameter, and putative species analyses were carried out by the ABGD method. Trees were constructed with Maximum likelihood and Bayesian inference algorithms to determine the phylogenetic relationships between species of the genus. In light of these analyses, it has been shown that the genetic distance of morphological species M. larissa, M. grumi, M.hylata, and M. syriaca is not at the species level and that M.larissa maintains its species status according to the principle of priority. In addition, the M.russiae population presented in this study forms a monophyletic clade with other populations of the same species in the phylogenetic tree, proving that this taxon is a stable species.

Succession and seasonality drive tropical butterfly assembly after an extreme hurricane

AbstractThe composition and biodiversity of insect community assemblages are mediated by a complex set of biotic and abiotic factors. Among these factors are forest structure and atmospheric variables (like temperature and humidity), which are heavily influenced by frequent hurricane activity in the Caribbean. Despite this, changes in Caribbean insect assemblages as forests recover from hurricane disturbance are poorly documented. Butterflies represent a charismatic model taxon in biodiversity and conservation, and are thus an ideal subject for exemplifying these shifts in insect abundances and diversity across ecological succession. Here, we monitored butterfly communities in two Puerto Rican forests differing in structure (i.e., canopy height, tree size) to assess butterfly diversity, abundances, and community level wing traits (size and color) over 1 year, beginning 6 months after Hurricane Maria. Monthly sampling over the course of 1 year revealed no relationships between abundances and canopy openness or humidity; instead, species abundances fluctuated seasonally and were nonlinearly correlated with temperature. In contrast, wing size and color were linearly correlated with abiotic variables. Specifically, wings were larger in cooler and more open conditions. Wing color saturation and brightness were negatively correlated with humidity. Our results suggest that, first, a functional approach may provide better insight into the factors mediating species responses to disturbances. Second, further disentangling abundance seasonality from impacts of extreme disturbances necessitates long‐term monitoring.Abstract in Spanish is available with online material.

The quantitative genetic basis of variation in sexual versus non-sexual butterfly wing colouration: autosomal, Z-linked, and maternal effects.

Viability indicator traits are expected to be integrated extensively across the genome yet sex-limited to ensure that any benefits are sexually concordant. Understanding how such expectations are accommodated requires elucidating the quantitative genetic architecture of candidate traits in and across the sexes. Here we applied an animal modelling approach to partition the autosomal, allosomal, and direct maternal bases of variation in sexual versus non-sexual dorsal wing colouration in the butterfly Eurema hecabe. The sexual colour trait-coherently scattered ultraviolet that is under strong directional selection due to female choice-is brighter and more expansive in males, and overlays non-sexual pigmentary yellow markings that otherwise dominate both wing surfaces in each sex. Our modelling estimated high and sexually equivalent autosomal variances for ultraviolet reflectance (furnishing h2 ~ 0.58 overall and ~0.75 in males), accompanied by smaller but generally significant Z-linked and maternal components. By contrast, variation in non-sexual yellow was largely attributed to Z-linked sources. Intersexual genetic correlations based upon the major source of variation in each trait were high and not different from 1.0, implying regulation by a pool of genes common to each sex. An expansive autosomal basis for ultraviolet is consistent with its hypothesized role as a genome-wide viability indicator and ensures that both sons and daughters will inherit their father's attractiveness.

KEANEKARAGAMAN CAPUNG (ORDO: ODONATA) DI KAWASAN WISATA SEMARA RATIH DESA TARO, GIANYAR-BALI

Dragonfly is an insect with an interesting morphology and is often found in areas that are still beautiful and unpolluted, making it an environmental bioindicator.. This research was conducted to determine the diversity of dragonfly species and environmental factors that could influence their existence. The study was carried out in January-February 2023 using the exploratory method. Samples were taken from three station points in the morning and evening five times. The captured dragonfly samples were then identified by observing their morphological characters such as body shape, color pattern on the thorax and abdomen, wing venation, and wing color pattern. Environmental factors of temperature, humidity and altitude where measured every sampling site. The results obtain ten species of dragonflies were found, namely Copera marginipes, Agriocnemis pygmaea, Agriocnemis femina, Ischnura senegalensis, Orthetrum testaceum, Orthetrum sabina, Potamarcha congener, Neurothemis ramburii, Neurothemis terminata. The diversity index obtained was in the medium category with almost even distribution and no dominating species were found. Environmental conditions support the existence of dragonflies in Semara Ratih, Taro Tourism Village, Gianyar-Bali so that in the future it can be used as a tourist attraction in the area. Keywords: dragonfly, identification, morphological characters, habitat, Taro

Phylogenomics of the geometrid tribe Palyadini (Lepidoptera: Geometridae) reveals contrasting patterns of phylogenetic signal in wing colour characters.

Next generation sequencing techniques currently represent a practical and efficient way to infer robust evolutionary hypotheses. Palyadini is a small Neotropical tribe of geometrid moths composed of six genera that feature strikingly colourful wings. Here, we investigated patterns of evolution and amount of phylogenetic signal contained in various colour characters featured in the wings of members of this tribe by (i) inferring a robust phylogenetic hypothesis using ultraconserved elements (UCEs), and afterwards, (ii) mapping the morphological characters onto the molecular topology under a parsimonious ancestral character optimization. Our matrix, obtained with 60% completeness, includes 754 UCE loci and 73 taxa (64 ingroup, nine outgroup). Maximum likelihood and parsimony generated largely identical topologies with strongly supported nodes, except for one node inside the genus Opisthoxia. According to our topology, most wing colour characters are reconstructed as homoplastic, particularly at the tribe level, but five of the seven provide evidence supporting common ancestry at the genus level. Our results emphasize, once again, that no character system is infallible, and that more research is necessary to take our understanding of the evolution of wing colour in moths to a level comparable with the knowledge we have for butterflies.

Morphological and molecular evidence for considering Xylocopa nigrocincta as the senior synonym of Xylocopa suspecta (Apidae: Xylocopini)

Xylocopa nigrocincta Smith, 1854, and Xylocopa suspecta Moure & Camargo, 1988, are two nominal species within the subgenus Neoxylocopa and have a sympatric geographic distribution in South America. While X. nigrocincta is recognized by the presence of reddish metasomatic bands, X. suspecta is entirely black. Although morphologically distinct in terms of metasomal band colour, other morphological characters suggest that both species could be the same evolutionary entity and therefore synonymous. The aim of this research was to review both nigrocincta and suspecta morphotypes using an integrative approach (morphological and molecular) to evaluate if they are truly two different evolutionary lineages. Females of both species were obtained from field collections and museums, representing a large part of their morphotype distribution. Additional diagnostic characters of the external morphology were investigated, such as metasomal band colour, metasomal punctuation, wing colours, and apical regions of the basitibial plate. Mitochondrial gene sequences (COI and CytB) were used for phylogenetic reconstructions. Our results showed that both nigrocincta and suspecta morphotypes are undistinguished based on morphology, although the metasomal band colour, together with the geographic distribution, revealed the presence of three distinct morphogroups, including an intermediate one with a variable number of reddish bands. Nonetheless, the three morphogroups are not supported by molecular data and therefore represent intra-specific variations. In conclusion, our results do not support the hypothesis that the two nominal species are distinct evolutionary lineages, and we propose a synonym between X. nigrocincta and X. suspecta.

Pervasive mimicry in flight behavior among aposematic butterflies

Flight was a key innovation in the adaptive radiation of insects. However, it is a complex trait influenced by a large number of interacting biotic and abiotic factors, making it difficult to unravel the evolutionary drivers. We investigate flight patterns in neotropical heliconiine butterflies, well known for mimicry of their aposematic wing color patterns. We quantify the flight patterns (wing beat frequency and wing angles) of 351 individuals representing 29 heliconiine and 9 ithomiine species belonging to ten color pattern mimicry groupings. For wing beat frequency and up wing angles, we show that heliconiine species group by color pattern mimicry affiliation. Convergence of down wing angles to mimicry groupings is less pronounced, indicating that distinct components of flight are under different selection pressures and constraints. The flight characteristics of the Tiger mimicry group are particularly divergent due to convergence with distantly related ithomiine species. Predator-driven selection for mimicry also explained variation in flight among subspecies, indicating that this convergence can occur over relatively short evolutionary timescales. Our results suggest that the flight convergence is driven by aposematic signaling rather than shared habitat between comimics. We demonstrate that behavioral mimicry can occur between lineages that have separated over evolutionary timescales ranging from <0.5 to 70 My.