背瘤丽蚌繁殖特征及钩介幼虫形态

Reproductive traits and glochidium Morphology of Lamprotula leai(Gray)

2004～2007年间,对鄱阳湖背瘤丽蚌(Lamprotula leai)种群组成、繁殖特性和钩介幼虫形态进行了研究。从背瘤丽蚌种群壳长组成看,优势壳长组为41～70mm,占总个体数的74.93%,年龄范围3～6龄。和历史资料比较,鄱阳湖背瘤丽蚌种群趋于小型化,低龄化。背瘤丽蚌主要繁殖特征为:雌雄异体,自然种群性比为11;最小性成熟个体雄性38mm,雌性34mm。繁殖周期为1年1次,繁殖期为2月中旬至5月,3～4月初为妊娠高峰期。繁殖力为115～504千粒/个(均值(328.09±145.73)千粒/个)。背瘤丽蚌育儿囊为四鳃型,钩介幼虫侧面观为半椭圆形,无壳钩,具4对感觉毛。

The population structure,reproductive traits and glochidium morphology of Lamprotula leai （Gray） in Poyang lake Jiangxi province were studied during January 2004 to May 2007.It was found that the distribution of shell length classes tended to be younger and smaller.The shell length of 41-70 mm and the age of 3-6 years accounted for 74.93％ and 60％ of the population respectively.L.leai were dioecious,and the sexual ratio of females to males was about 1 ∶ 1.The usual reproductive period was the middle of February to the end of April,peaking at March to early April;Gravid individuals were very sensitive to the changing of the environment.They could abort by water temperature changes sharply or catching rudely.Four demibranchia of the gills of females could develop into marsupium;Mature glochidia were nonhooked with 4 pairs of sensory hairs.The potential fecundity was 115 000-504 000 per individual （the average value was 328 090±145 730 per individual）.