Spermiogenesis in Palembus dermestoides (Coleptera: Tenebrionidae) with emphasis on the formation of mitochondrial derivatives

ABSTRACT

The testes of Palembus dermestoides are formed by six follicles coated and interconnected by a peritoneal sheath. Long, cylindrical and slightly twisted spermatophores were observed. Spermiogenesis followed the usual sequence for insects. During spermiogenesis, the nucleus was transferred to the cell periphery and the mitochondria were grouped at the posterior pole of the cell. Two mitochondrial derivatives and two paracrystalline electrondense bodies were present close to the axoneme. The mitochondrial derivatives were surrounded by a single row of microtubules in immature spermatozoa. The axoneme had the typical 9+9+2 microtubular pattern of insects.