SEM-EDAX: A tool for microanalytical elemental mapping in butterfly wing scales

Scanning Electron Microscopy (SEM) integrated with Energy-Dispersive X-ray Analysis (EDAX) provides an effective approach for investigating the elemental composition of butterfly wing scales at the microscale. Microanalytical studies of butterfly wing scales remain relatively limited, with most previous investigations focusing primarily on their morphological and optical characteristics. To address this gap, the present study provides a comparative assessment of elemental composition and spatial elemental distribution in the wing scales of ten butterfly species, namely Parantica aglea, Acraea terpsicore, Tirumala septentrionis, Mycalesis mineus, Ariadne merione, Cupha erymanthis, Ypthima huebneri, Leptosia nina, Eurema hecabe, and Catopsilia pomona, using SEM-EDAX. The results revealed interspecific differences and regional heterogeneity in elemental composition, with carbon, oxygen, and nitrogen constituting the dominant elements across all species, while trace elements including potassium, aluminium, silicon, chlorine, molybdenum, and sodium, exhibited localized occurrence. Elemental mapping further revealed heterogeneous spatial distribution patterns among different wing regions. The findings highlight the effectiveness of SEM-EDAX as a microanalytical tool for characterizing the compositional heterogeneity of butterfly wing scales and provide a comparative baseline for future studies on butterfly wing structure and composition.