Morphological Investigations on the Spermatogenesis of Diamondback Moth,Plutella xylostella(L.)

The spermatogenesis in the diamondback moth,Plutella xylostella(L.)(Lepidoptera:Plu- tellidae)was investigated by light and uhrastructural observations.The results showed that the testis of P.xylostella developed rapidly in the last 4th instar larvae,and mature sperms were detected on day 1 of the 4th stadium.The onset of the apyrene spermatogenesis started in the 4th instar larva or before, while the euprene spermiogenesis occurred in the adult.The dichotomic spermatogenesis of P.xylostel- la occurred in the stage of primary spermatocyte supported by the occurrence of apyrene and eupyrene primary spermatocytes within testis.Every sperm bundles of P.xylostella includes 256 sperms.The length of apyrene sperm is about 20μm long,and eupyrene one is about 12μm long.The chromosome number in mitotic metaphase of spermatogonia of P.xylostella is 30 pairs.