Hierarchical morphogenesis of swallowtail butterfly wing scale nanostructures.

The study of color patterns in the animal integument is a fundamental question in biology, with many lepidopteran species being exemplary models in this endeavor due to their relative simplicity and elegance. While significant advances have been made in unraveling the cellular and molecular basis of lepidopteran pigmentary coloration, the morphogenesis of wing scale nanostructures involved in structural color production is not well understood. Contemporary research on this topic largely focuses on a few nymphalid model taxa (e.g., Bicyclus, Heliconius), despite an overwhelming diversity in the hierarchical nanostructural organization of lepidopteran wing scales. Here, we present a time-resolved, comparative developmental study of hierarchical scale nanostructures in Parides eurimedes and five other papilionid species. Our results uphold the putative conserved role of F-actin bundles in acting as spacers between developing ridges, as previously documented in several nymphalid species. Interestingly, while ridges are developing in P. eurimedes, plasma membrane manifests irregular mesh-like crossribs characteristic of Papilionidae, which delineate the accretion of cuticle into rows of planar disks in between ridges. Once the ridges have grown, disintegrating F-actin bundles appear to reorganize into a network that supports the invagination of plasma membrane underlying the disks, subsequently forming an extruded honeycomb lattice. Our results uncover a previously undocumented role for F-actin in the morphogenesis of complex wing scale nanostructures, likely specific to Papilionidae.

Alignment of crystal orientations of the multi-domain photonic crystals in Parides sesostris wing scales.

It is known that the wing scales of the emerald-patched cattleheart butterfly, Parides sesostris, contain gyroid-type photonic crystals, which produce a green structural colour. However, the photonic crystal is not a single crystal that spreads over the entire scale, but it is separated into many small domains with different crystal orientations. As a photonic crystal generally has band gaps at different frequencies depending on the direction of light propagation, it seems mysterious that the scale is observed to be uniformly green under an optical microscope despite the multi-domain structure. In this study, we have carefully investigated the structure of the wing scale and discovered that the crystal orientations of different domains are not perfectly random, but there is a preferred crystal orientation that is aligned along the surface normal of the scale. This finding suggests that there is an additional factor during the developmental process of the microstructure that regulates the crystal orientation.

Electromagnetic characterization of millimetre-scale replicas of the gyroid photonic crystal found in the butterfly Parides sesostris.

We have used three-dimensional stereolithography to synthetically replicate the gyroid photonic crystal (PC) structure that occurs naturally in the butterfly Parides sesostris. We have experimentally characterized the transmission response of this structure in the microwave regime at two azimuthal angles (ϕ) over a comprehensive range of polar angles (θ). We have modelled its electromagnetic response using the finite-element method (FEM) and found excellent agreement with experimental data. Both theory and experiment show a single relatively broad transmission minimum at normal incidence (θ = 0°) that comprises several narrow band resonances which separate into clearly identifiable stop-bands at higher polar angles. We have identified the specific effective geometric planes within the crystal, and their associated periodicities that give rise to each of these stop-bands. Through extensive theoretical FEM modelling of the gyroid PC structure, using varying filling fractions of material and air, we have shown that a gyroid PC with material volume fraction of 40 per cent is appropriate for optimizing the reflected bandwidth at normal incidence (for a refractive index contrast of 1.56). This is the same gyroid PC material volume fraction used by the butterfly P. sesostris itself to produce its green structurally coloured appearance. This infers further optimization of this biological PC beyond that of its lattice constant alone.

APROXIMACIÓN AL ESTUDIO DE LA INTERACCIÓN ENTRE Aristolochia maxima Y LARVAS DE LAS MARIPOSAS Battus polydamas polydamas Y Parides panares erythrus MEDIADA POR ÁCIDOS ARISTOLÓQUICOS / Approach to the Interaction Studies of Aristolochia maxima and the Caterpillars of Butterflies Battus polydamas polydamas and Parides panares erythrus

Las mariposas de la tribu Troidini (Lepidoptera: Papilionidae) capturan los ácidos aristolóquicos (AAs) provenientes de su alimentación larval en plantas de Aristolochiaceae para su protección. En este estudio se detectó la presencia de los ácidos aristóloquicos I y II (AAI y AAII) en hojas jóvenes de Aristolochia maxima (Aristolochiaceae) y en larvas de las mariposas Battus polydamas polydamas y Parides panares erythrus (Papilionidae, Papilioninae) por Cromatografía Líquida de Alta Eficiencia (CLAE). De acuerdo con los resultados de los perfiles cromatógraficos por CLAE, el AAI fue el ácido aristolóquico mayoritario encontrado tanto en las larvas como en las hojas jóvenes de la planta, seguido por cantidades menores del AAII. Estos resultados permiten afirmar que la interacción plantaanimal entre las mariposas de las especies B. polydamas y P. panares y las plantas de A. maxima, está mediada, por los ácidos aristóloquicos I y II.

Most butterflies of the tribe Troidini (Lepidoptera: Papilionidae) sequester aristolochic acids (AA) for their protection. These acids are derived from their host plants family Aristolochiaceae upon which they feed on during their larval stages. Using analytical High Performance Liquid Chromatography (HPLC) methods we were able to detect the presence of aristolochic acids I and II both in the young leaves of Aristolochia maxima (Aristolochiaceae) and in the caterpillars of the butterflies Battus polydamas polydamas and Parides panares erythrus (Papilionidae, Papilioninae). Aristolochic acid I was the major constituent found, followed by lesser amounts of Aristoloquic acid II. These results confirm that the hostanimal interaction among butterflies of the studied species and A. maxima plants is mediated, by aristolochic acids.

Population biology of Parides anchises nephalion (Papilionidae) in a coastal site in Southeast Brazil

A population of Parides anchises nephalion was studied during seven months in SE Brazil. The population size was about 10-20 individuals (with theoretic maximum near 60 individuals), with small variations in some months. Sex ratio was male biased, with males dominating in all months. The age structure was not stable, with an increase in new individuals before the population peak in December. The residence time was 14.1 ± 8.2 days for males and 9.0 ± 3.6 to females, with the maximum registered of 30 days. Males can travel distances of up to 400 m, but most individuals were always recaptured in the same site. The mean forewing length was greater in females. The population features agree with those found in other species of Parides in other neotropical sites.

Uma população de Parides anchises nephalion foi estudada ao longo de sete meses no Sudeste do Brasil. O tamanho populacional variou em torno de 10-20 indivíduos (com um máximo teórico próximo a 60 indivíduos), com pequenas variações em alguns meses. A razão sexual foi desviada para excesso de machos, com estes sendo dominantes em todos os meses. A estrutura etária não foi estável, com um aumento dos indivíduos novos antes do pico populacional em dezembro. O tempo de residência foi de 14,1 ± 8,2 dias para machos e 9,0 ± 3,6 dias para fêmeas, com um máximo registrado de 30 dias. Os machos podem se deslocar por distâncias superiores a 400 m, entretanto, a maioria dos indivíduos foi recapturada sempre no mesmo local. O comprimento médio das asas anteriores foi maior nas fêmeas. As características da população estão de acordo com aquelas descritas para outras espécies de Parides em outros sítios Neotropicais.