双齿围沙蚕的生活史

Life history of clam worm Perinereis aibuhitensis

为系统了解双齿围沙蚕Perinereis aibuhitensis的生活史,通过人工培育方法观察了其胚胎和幼虫发育全过程,并通过解剖观察了卵的发生及正常个体变态为生殖态异沙蚕体的过程。结果表明:双齿围沙蚕的受精卵采取螺旋型卵裂,形成实心囊胚,经原肠胚后发育为担轮幼虫、疣足幼虫、稚沙蚕和成体沙蚕;卵的发育在体腔内经历卵原细胞期、小生长初级卵母细胞期、大生长初级卵母细胞期和成熟初级卵母细胞期后排出体外,并在受精后进一步形成次级卵母细胞和卵细胞;当正常个体变态为异沙蚕体时,会发生体长明显缩短、腹部变白、眼睛变大和疣足变薄等变化,异沙蚕体繁殖后死亡;研究过程中还观察到幼虫循环系统的发生和红斑等现象。本研究结果可为全面掌握双齿围沙蚕的生活史及开展人工养殖业提供基础数据。

Morphological changes were daily observed in clamd worm Perinereis aibuhitensis farmed in a clam worm culture base during metamorphosis under a binocular microscope and oogenesis,development of embryos and larvae and difference between normal individuals and reproductive bodies were investigated by means of anatomical observation to understand the life history of clam worm and to promote the development of artificial breeding industry.Results showed that fertilized eggs developed to trochophore,nectochaete,and juvenile by spiral cleavage,and solid gastrula,and mature clam worm.The oogonium developed in body cavity and into mature primary oocytes through long-term growth period,and then mature primary oocytes were released from the body and further formed into secondary oocyte and ovum after fertilization.When normal individuals were changed into reproductive bodies,changes into such shortening body,whitening of abdomen,enlargement of eyes and thinning of verruca feet occured.Heteronereis were dead after reproduction.The occurrence of larval circulatory system,and erythema was also observed.