The Testis Development and Spermatogenesis in Spodoptera litura (Lepidoptera: Noctuidae)

The testis development and spermatogenesis in Spodoptera litura from larvae to adults were studied with the methods of anatomical observation, paraffin tissue sectioning and testes staining with hematoxylin-eosin as well as microscope photography. The results of the study indicated that the two testes began to fuse at the prepupae stage and merged into one at the pupal stage. At the adult stage, the volume of testes gradually decreased with the discharge of sperm. There were two types of spermatids, eupyrene sperms and apyrene sperms, in the spermatogenesis of Spodoptera litura. Both eupyrene and apyrene spermatogenesis went through the periods of spermatogonium cyst, spermatocyte cyst and spermatid cyst. A major difference in spermiogenesis is that nuclear deformation happened in eupyrene sperms but not in apyrene sperms, and the nucleus of apyrene sperms was abandoned in the later period but kept in eupyrene sperms. In conclusion, the major developmental stages of eupyrene sperms started from the sixth larval stage to pupal stage, while apyrene sperms developed mainly at the pupal stage. The results of this study can provide a basis for further research on sperm development of Spodoptera litura and pest-control with the reproductive control approach.