Multi-instrumental techniques for evaluating butterfly structural colors: A case study on Polyommatus bellargus (Rottemburg, 1775) (Lepidoptera: Lycaenidae: Polyommatinae). (March 2021)

• Record Type: Journal Article
• Authors: Kertész, Krisztián; Bálint, Zsolt; Piszter, Gábor; Horváth, Zsolt Endre; Biró, László Péter
• Is Part Of: Arthropod structure & development. Volume 61(2021)
• Publication Date: 2021-03
• Subjects: Color measurement -- Spectroscopy -- Photonic crystal -- Butterfly -- Wing color -- Individual wing scale; Arthropoda -- Morphology -- Periodicals; Arthropoda -- Anatomy -- Periodicals; Arthropoda -- Cytology -- Periodicals; Arthropods -- growth & development -- Periodicals; 595
• DOI: 10.1016/j.asd.2020.101010
• Languages: English
• ISSNs: 1467-8039

Abstract

Abstract: Color is an important communication channel for day-flying butterflies. Chemical (pigmentary) coloration is often supplemented by physical color generated by photonic nanostructures. These nanoarchitectures – which are characteristic for a given species – exhibit wavelength ranges in which light propagation is forbidden. The photonic nanoarchitectures are located in the lumen of the wing scales and are developed individually by each scale during metamorphosis. This self-assembly process is governed by the genes in the nucleus of the scale producing cell. It is crucial to establish well-defined measurement methods for the unambiguous characterization and comparison of colors generated in such a complex manner. Owing to the intricate architecture ordered at multiple levels (from centimeters to tens of nanometers), the precise quantitative determination of butterfly wing coloration is not trivial. In this paper, we present an overview of several optical spectroscopy measurement methods and illustrate techniques for processing the obtained data, using the species Polyommatus bellargus as a test case, the males of which exhibit a variation in their blue structural color that is easily recognizable to the naked eye. The benefits and drawbacks of these optical methods are discussed and compared. Furthermore, the origin of the color differences is explained in relation to differences in the wing scale nanomorphology revealed by electron microscopy. This in turn is tentatively associated with the unusually large genetic drift reported for this species in the literature. Highlights: Butterfly wing coloration has pigmented and structural backgrounds. Lycaenid butterfly dorsal wing surface has often well determined structural color. Polyommatus bellargus males possess a wide array of hue in blue coloration. Multi instrumental approach is necessary to understand this optical diversity. The used methods are complementary and focus on different levels.