TESTIS MORPHOLOGY AND SPERMATOGENESIS IN 2 SPECIES OF ELENCHUS (STREPSIPTERA, ELENCHIDAE)

Testes ultrastructure and spermatogenesis were studied in two species of Strepsiptera (Insecta), namely, Elenchus tenuicornis and E. japonic us, using light and electron microscopy. In both species, the testis i s paired and consists of several large irregularly shaped follicles. E ach follicle consists of a single clone of germ cells surrounded by a thin epithelium. During the larval and pupal stages, all the germ cell s of each testis develop synchronously, and at eclosion, the gonads co ntain solely mature sperm. One of the most interesting findings is the morphogenesis of a large nuclear vesicle bounded by the fenestrate pa rr of the nuclear envelope. This vesicle contains an electron-dense sp herical structure, the chromatoid body. At the end of spermiogenesis, both the nuclear vesicle and its chromatoid body are eliminated with t he excess cytoplasm. Large drops of residual cytoplasm containing seve ral nuclear vesicles are present in the lumen of the testis and inside the cytoplasm of phagocytic cells. (C) 1998 Elsevier Science Ltd. All rights reserved.