Characteristic of the excretory system in Cassida palaestina Reiche, 1858 (Coleoptera: Chrysomelidae: Cassidinae).

The Malpighian tubules are well-known and studied as the principal excretory organs in most insects. They play a key role in the production of primary urine and osmoregulation. It works with the rectum while regulating the water and salt balance in the body. The distal ends of the tubules are found in contact with the wall of the rectum in insects that feed on dry substances or live in a nearly dry environment and therefore, need to retain water: that is an arrangement known as a cryptonephric system. In this study, Cassida palaestina Reiche, 1858 is a beetle species belonging to the order Coleoptera was used as material, and the morphological features of the Malpighian tubules of this species were examined using light microscopy and scanning electron microscopy. The four cryptonephric Malpighian tubules of C. palaestina are found at the junction of the midgut and hindgut. The apical surface of tubule cells is surrounded by numerous microvilli. The cytoplasm of tubule cells fills with granules of many different sizes. Here, we reported our observations on the cryptonephridial complex in C. palaestina, and this study is almost the first study to examine the structure of the excretory system of the genus Cassida. Insights into the structure of the cryptonephridial complex of this species are compared with the well-studied cryptonephridial complexes of Cucujiformia. The findings were found to be quite similar to those of other species studied in the literature (with the structure of the Malpighian tubules of insects within the same order and from different orders). These data are the basis for future morphological studies. At the same time, the presence or absence of the cryptonephridial complex among species in the Cucujiformia infraorder, which C. palaestina is a part of, helps to understand the phylogenetic relationship.