引文信息：
Mingxia Sun, Weihao Meng, Haiwei Yin, Lingjie Fan, Lei Shi, Gregory S. Watson, Jolanta A. Watson, Jingxia Wang, Lei Jiang & Aiping Liang. Dynamic Color Regulation of the Lycaenid Butterfly Wing Scales. Journal of Bionic Engineering，2024，21（5），2395- 2408.Dynamic Color Regulation of the Lycaenid Butterfly Wing Scales
1 Tianjin Key Laboratory of Conservation and Utilization of Animal Diversity, College of Life Sciences, Tianjin Normal University, Tianjin, 300387, China.
2 Laboratory of Bioinspired-Smart Interface Sciences, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
3 Shanghai Ideaoptics Corporation, Shanghai, 200433, China.
4 Key Laboratory of Micro & Nano Photonic Structures (MOE) and Key Laboratory of Surface Physics, Department of Physics, Fudan University, Shanghai, 200433, China.
5 School of Science, Technology and Engineering, University of the Sunshine Coast, Fraser Coast Campus, Hervey Bay, QLD, 4655, Australia.
6 Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
Abstract
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.
Fig. W1 Arrangement of wing surface scales of lycaenid butterflies. (a) Plebejus argyrognomon, (b) Polyommatus erotides. (a1-a4, b1-b4) Schematics, micrographs and images show the three layers of scales stacked on the wing with a handle stemmed into a single tubular follicle extruding out of the wing cuticle in differently title angles of the three layers of scales relative to wing cuticle. ●, CS, cover scale. ▲, GS, ground scale. ★, AS, androconia scale.
Fig. W2 Reflectance spectra of single scales on wings of lycaenid butterflies in the visible wavelength range of 390–760 nm. (a1-a4) Plebejus argyrognomon, (b1-b4) Polyommatus erotides. (a1, b1) CS, cover scale, (a2, b2) GS, ground scale and (a3, b3) AS, androconia scale. (a4, b4) The reflection intensity of single CS, GS and AS at the wavelength of about 390 nm and 445 nm as the incident angle changing from − 20° to 30°. The inset in the upper middle shows the direction of wing tip aligned with that of the incident angle, which changed from − 20° to 30° with a step of 5°. Red arrows show the peaks at approximately 390 nm in (a1, a3) and 445 nm in (b1, b3).
Fig. W3 SEM images of the wing scale of lycaenid butterflies. (a1- a3) Plebejus argyrognomon, (b1-b3) Polyommatus erotides. (a1) When the wings were erected downwards, only the tip of CSs are visible. (a2) When the wings were erected upwards, the CSs prominently bend. (b1) When the wings were erected upwards, the CSs and ASs prominently bend. (b2) The GS is flexible as well. (a3, b3) The backsides of all scales are decorated with wavelike structures. CS, cover scale. GS, ground scale. AS, androconia scale.
Fig. W4 Optical micrographs of the left wings rotating in four directions relative to the butterfly body axis, as shown in the diagrams (a, b). (a1-a10) Plebejus argyrognomon, (b1-b10) Polyommatus erotides. The dash lines illustrate the original and rotated positions of the wings from 0° to 60°. The wing’s position at 0° is the horizontal plane, which is always perpendicular to the plumb line. (a1-a4, b1-b4) When the wing rotates downward (wing tip tilting down) relative to the butterfly longitudinal body axis, the wing color brightened. (a5-a8, b5-b8) When the wing rotates upward (wing tip tilting up) relative to the butterfly longitudinal body axis, the wing turned brown. (a9, b9) When the wing rotates downward (wing costal margin tilting down) relative to the butterfly transversal body axis, the wing color became slightly paler. (a10, b10) When the wing rotates upward (wing costal margin tilting up) relative to the butterfly transversal body axis, the wing color became paler (a10) or even whiter (b10). Angles 0°, 15°, 30°, 45° and 60° on the bottom left of each optical photo are the angles the wing rotation, angles 20°, 30°, 35° and 35° on the upper right of (a9, a10, b9, b10) are the titled angles of the scales relative to their original positions.
全文链接：https://rdcu.be/dU9AA
