寄生在鲤鱼及草(鲩)鱼的鱊头槽绦虫的多样性

研究了寄生于鲤鱼及草(鲩)鱼的鱊头槽绦虫(Bothriocephalus acheiloghathi)的多样性.作者在1986-2000年收集材料,遍及中国19个省及自治区.在江苏等5省只收集到其它寄生虫的材料,故结果未列入附录1和2.研究结果表明,鲤鱼及草鱼的寄生鱊头槽绦虫的地理分布截然不同.寄生于鲤鱼的鱊头槽绦虫分布于黄河水系的西北地区及黑龙江水系的东北各省及长江上游的四川、云南和贵州,南方各省的鲤鱼不感染这种绦虫.寄生于草鱼的鱊头槽绦虫分布于沿珠江水系的广东、广西及闽江水系的福建,感染池塘的幼龄草鱼,天然水体中未发现感染阳性的草鱼.交义感染试验表明,寄生在这两种鲤科鱼类的头槽绦虫有极强的宿主特异性,草鱼感染的头槽绦虫一年内大部分时间排出发育完全的胚胎卵,而鲤鱼感染的头槽绦虫排出的虫卵多为早期分裂卵,甚至在盛夏,水温在28℃-30℃的情况下也无例外.虫卵发育程度不同,卵的孵化期也有差异.在同等温度28℃-29℃时,草鱼头槽绦虫虫卵的孵化期为1.69±0.17 d;鲤鱼的头槽绦虫虫卵的孵化期为3.98±0.3 d.此外,种群结构也有明显区别,草鱼的头槽绦虫在繁殖季节,体长＜1 cm的幼虫占种群的主体,年终时绦虫全部从宿主体内消失,生活周期从初染至消敛约1年;鲤鱼的头槽绦虫主体全年皆为孕节成虫,在Ⅱ龄商品鱼中继续繁殖.本研究表明,鲤鱼及草鱼的寄生鱊头槽绦虫显示的多样性是因长期适应不同生活环境从而演化为两个不同的亚种动物学报 53(3):470-480,2007].

Diversity of the Asiatic tapeworm Bothriocephalus acheilognathi parasitizing common carp and grass carp in China

The present study of the tapeworm Bothriocephalus acheilognathi parasitic in common carp and grass carp in China, was carried out from 1986 to 2000, covering 16 provinces and autonomous regions of the country. Distinct diversities are noticed. Worms in common carp are confined to the Yellow River and the Heilongjiang in the north and the upper reach of the Yangtze River in the southwest. Worms in grass carp are found in ponds along the Pearl River in the south, but not in natural waters, and no common carp are found infected in this region. Eggs of worms in grass carp are primarily embryonated but those in common carp are in a state of early cleavage. The hatching period of eggs at 27℃-28℃ is 1.69±0.2 d in grass carp tapeworms and. 3.98±0.3 d in worms in common carp. In grass carp, young worms ＜1 cm dominate in the population during the breeding season and disappear by the end of the year, whereas in common carp the population consists mainly of gravid worms which continue to propagate in the ageⅡcommercial-sized hosts. Evidently, B.acheilognathi parasitic in these two cyprinids are two geographical subspecies owing to long-term adaptation to different environmentsActa Zoologica Sinica 53(3):470-480,2007].