家蚕幼虫体壁内陷体的发现与研究

THE DISCOVERY AND RESEARCH IN BODY WALL INVAGINATED TISSUE OF BOMBYX MORI LARVAE WU

经解剖观察，发现家蚕幼虫生殖芽神经中或赫氏腺内存在一种椭球形或球形多层结构的体壁内陷体（ＢＩＴ），５０％以上ＢＩＴ有刚毛结构；层次构造有１～５级；分布位置有原种型和杂交种（Ｆ２）型之分；中系品种多有发生，日系品种偶见发生，中日杂交一代种不发生；雄蚕发生率极显著高于雌蚕；３～５龄蚕发生率和个体发生量差异不明显；秋蚕潮发生率显著高于春蚕期；高温催青饲育发生率增高；从３～５龄蚕ＢＩＴ结构持征推断其在胚胎期形成。

Dissection ando6servation showed that there was a kind of ellipse or ball shapebody wall invaginated tissue(BIT)in sexual gemroa nerve or Herold's gland of Bombyxmori larvae,Many dissecting tests showed that more than 50%of BIT has bristles.Itsstructure could be divided into 1～5 layers.Its position was different on larvae ofparental stock and hybrid(F2).It happened a lot in varieties of Chinese strain and littlein those of Japanese strain;It did not happen in the hybird(F1)of Japanese strain× Chi-nese strain.The occurrence was extremely significantly higher in male silkworms thanin female ones:It had no obvious difference in happening rate and number in silkwormsof 3～5ages. The happening rate in autumn rearing was higher than in spring rearing.The rate was increased when temperature was high during incubation and rearing. Fromthe characters of BIT structure of 3rd～5th instar larvae,it could be inferred that it isformed in embryonic period.