ULTRASTRUCTURE STUDY ON THE TESTICULAR SHEATHS OF SPODOPTERA MAURITIA BOISD. (LEPIDOPTERA: NOCTUIDAE)
Ultrastructural studies have demonstrated that th e larval testes are covered by a sheath consisting of two cellular layers, the outer tunica externa and inner tunica interna. The two layers are bounded by an outer basal lamina and an inner basal lamina. Tunica externa is thinner than tunica interna, contains numerous vacuoles and rough endoplasmic reticulum. The tunica interna is homogenous and contains numerous glycogen particles, lipid droplets, abundant mitochondria, numerous vacuoles, few pigment granules and ce ntrally located nuclei with dense chromatin clusters. In the pupal testes, the membra na communis covers the tunica externa, but in larval testes sheath this layer is altogether absent. The cells of membrana communis are larger in size, with a prominent nucleus. Cytoplasm is homogenous with numerous glycog en droplets and mitochondria. Reduction in thickness of external layer is seen with sparse endoplasmic reticulum and few mitochondrial accumulations. The tunica interna contains abundant glycogen deposits, few lipid incl usion, mitochondria and network of channels filled with flocculent material. The cytoplasm is electron de nse.The Tissue of tunica interna exhibited high secretory activity.