Specimen preparation for X-ray micro-computed tomography of forest pests

Abstract

X-ray micro-computed tomography (XCT) is an X-ray-based three-dimensional (3D) imaging technique that enables non-destructive imaging of both external and internal structures. It is widely used for studying biological specimens such as animals and plants. In this review, we discuss various specimen preparation methods for the technique, particularly focusing on forest pests, with six representative cases. Specimen preparation methods for forest pests can be broadly categorized into three groups based on mounting types: (i) simple mounting, (ii) liquid-cell mounting, and (iii) dry-cell mounting. The simple mounting method is particularly suitable for adult beetles due to their exoskeleton. The dehydration process minimizes specimen movement during scanning, ensuring better imaging quality. In the case of liquid-cell mounting, the specimen is immersed in a liquid medium for scanning, which effectively preserves the soft tissues of larvae and pupae. The dry-cell mounting does not involve fixation or dehydration and is particularly useful for analyzing immobilized specimens. To enhance the quality of 3D images, selecting an appropriate preparation method is essential. Since forest pests display varying sizes and types, the choice of preparation method should be based on the specific characteristics of the specimens of interest and research objectives. This review provides valuable insights for researchers and practitioners seeking to identify the most suitable and effective mounting method for XCT scanning of forest pests.