ULTRASTRUCTURAL AND CYTOCHEMICAL STUDIES ON SPERMIOGENESIS OF THE BEETLE CEROTOMA-ARCUATA (COLEOPTERA, CHRYSOMELIDAE)

The spermiogenesis of the beetle Cerotoma arcuata was analysed at the ultrastructural and cytochemical level. Nuclear development involved c hanges in the shape and in the degree of chromatin condensation. Ethan olic-phosphotungstic acid technique suggested the presence of basic pr oteins in the nuclear material. The acrosome showed three-layer and th e inner core presented a filamentous substructure. During morphogenesi s of the acrosome, acid phosphatase activity was found in the Golgi co mplex and proacrosomal vesicle. In the sperm tail an axoneme, two mito chondrial derivatives, an accessory body and two puff-like corpuscles were observed. The axoneme presented a 9+9+2 microtubule pattern and a cid phosphatase and thiamine pyrophosphatase activities were found in the electron-dense fibres. The mitochondrial derivatives showed differ ent shapes and sizes. The structures that appear during spermiogenesis may be involved in the mechanism of cellular motility, protection of the genome, process of sperm-oocyte interaction and can significantly contribute to further phylogenetic studies.