Histomorphology Structure of the Gastric Caecum, Midgut, and Malpighian Tubules in Adult Flatheaded Pine Borer <i>Chalcophora mariana</i> (Linnaeus, 1758) (Coleoptera: Buprestidae)

ABSTRACT The pine weevil is one of the largest species in the jewel beetle (Buprestidae) family found in Central Europe and Turkey. Chalcophora mariana is generally considered a secondary guest and primarily develops in weakened, decaying, or recently dead pine trees. Its larvae burrow into the wood tissue by tunnelling beneath the bark; in healthy trees, rather than causing sudden death, they lead to wood decay and a decline in lumber quality. To date, no study has examined the gastric caecum, midgut, and Malpighian tubules of C. mariana . Therefore, in this study, the histomorphology structure of C. mariana 's gastric caecum, midgut, and Malpighian tubules was examined in detail using light microscopy and scanning electron microscopy. C. mariana possesses a pair of gastric caecum. Histological sections show that the gastric caecum has a narrow, star‐shaped lumen, and the lumen itself contains long microvilli. In C. mariana , tracheae arranged at regular intervals and round regenerative crypts were observed on the outer surface of the midgut. Histological sections revealed a single‐layered cylindrical epithelium with long microvilli extending from the apical surface. The Malpighian tubules are arranged in three pairs and connect proximally to the hindgut. In histological sections, single‐layered cuboidal epithelial systems and round cells located in the center are conspicuous; microvilli structures are also observed in the visible apical cells. These findings provide important basic morphological data for future comparative and phylogenetic studies on the histomorphology of the gastric caecum, midgut, and Malpighian tubules in the order Coleoptera.