Microscopy Reveals Midgut and Malpighian Tubule Structure of Beetle Oxythyrea funesta

Researchers have mapped the fine structure of the digestive and excretory organs of the scarab beetle Oxythyrea funesta, using stereo, light, and scanning electron microscopy to document the midgut and Malpighian tubules in detail. The study, published in BMC Zoology, provides a morphological baseline for this species, which the authors say can support comparative work across the family Scarabaeidae and, ultimately, the development of selective pest management strategies.

In insects, the midgut is the primary organ where chemical digestion and nutrient absorption take place, while the Malpighian tubules remove metabolic waste and maintain osmoregulation.

The examination showed that the digestive tract of O. funesta is divided into three sections, with the midgut lying between the foregut and hindgut. The midgut proved to be the longest region, extending as a straight, tube-like structure from the foregut and forming two annular structures toward the hindgut.

Histologically, the midgut is characterized by a single-layered cylindrical epithelium, a thin muscle layer, and a peritrophic membrane within the lumen. The epithelial cells show apocrine secretion, and regenerative cells are present at the base of the epithelium. Under the scanning electron microscope, secretory vesicles could be seen in the lumen, along with short microvilli extending from the apical surface of the epithelial cells.

The Malpighian tubules, by contrast, are a pair of long, tubular structures with flat surfaces that run from the midgut to the hindgut. Light and scanning electron microscopy of these tubules revealed microvilli extending from the apical surface of a single-layered cuboidal epithelium whose cells carry round nuclei.

The authors state that the study aims to characterize the midgut and Malpighian tubules of O. funesta in a way that supports comparative studies within Scarabaeidae and future work on selective pest management. Because the article was shared early to provide faster access to peer-reviewed, accepted research, it is citable and carries a permanent DOI, though the version is subject to further edits before the final Version of Record.

Similar morphological and histological studies have been published on other beetles and insects, including work on the midgut and Malpighian tubules of Copris felschei, the alimentary canal and associated structures of Pyrrhocoris apterus, and the ultrastructure of midgut, Malpighian tubules, testis, and ovariole in the superworm Zophobas morio.

For O. funesta, the new description links gross anatomy, histology, and surface ultrastructure in a single account: a long, straight midgut with annular junctions, an apocrinally secreting cylindrical epithelium protected by a peritrophic membrane, and paired Malpighian tubules lined with cuboidal epithelium bearing apical microvilli. These features now provide a documented reference point for future anatomical and applied studies on this scarab species.

Subject of Research: Morphology of the midgut and Malpighian tubules of the scarab beetle Oxythyrea funesta examined by light and scanning electron microscopy

Article Title: A morphological study on the midgut and Malpighian tubules of Oxythyrea funesta (Poda, 1761) (Coleoptera: Scarabaeidae) using light and scanning electron microscopy

Article References: Çağlar, Ü., Arslan, H., Özyurt Koçakoğlu, N., & Candan, S. (2026). A morphological study on the midgut and Malpighian tubules of Oxythyrea funesta (Poda, 1761) (Coleoptera: Scarabaeidae) using light and scanning electron microscopy. BMC Zoology. https://doi.org/10.1186/s40850-026-00292-0

Image Credits: AI Generated

DOI: 10.1186/s40850-026-00292-0

Keywords: Oxythyrea funesta, Scarabaeidae, Coleoptera, midgut, Malpighian tubules, insect morphology, histology, scanning electron microscopy, peritrophic membrane, apocrine secretion, digestive system, excretory system