Reproduction and development of the freshwater clam Corbicula australis in southeast Australia
Reproduction and development of the freshwater clam Corbicula australis in southeast Australia
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DOI：
10.1023/a:1003986512832
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发表时间：
2000-01-01
期刊：
影响因子：
2.6
通讯作者：
Potts, J
中科院分区：
文献类型：
--
作者：
Byrne, M;Phelps, H;Potts, J
淡水蚌Corbicula australis是澳大利亚东南部水系大型生物群的重要组成部分。在Douglas Park和Menangle的Nepean河对两个种群的繁殖进行了调查，以记录配子发生周期、幼虫形态和确定它们孵化胚胎的时间。australis是同时雌雄同体，在内部半分枝中孕育后代。性腺为卵母细胞，在每个子囊中有生卵区和生精区。精子是双鞭毛的，这是双壳纲中克隆corbicliides所特有的。配子发生是连续的，不表现出季节性模式。相比之下，胚胎的产卵和孵化仅限于一年中温暖的月份。胚胎从10月到5月出现在鳃中。南方棘球蚴是通过改良的幼虫发育而成的，幼虫具有退化的纤毛膜，不用于游泳或捕获颗粒。膜被微绒毛覆盖，这表明在有袋动物环境中，膜上皮可能专门用于营养摄取。南棘蝽每年生产几窝幼崽，幼崽被释放后，足部发育良好。两个种群的繁殖数量不同。这在一定程度上是由于门角蛤的体型较大，也可能反映了该地点生产力的提高。南方蛤具有雌雄同体、自交受精/雄性生殖的潜能、将后代育至匍匐幼虫阶段和高繁殖率等一系列生活史特征，这些特征为这种蛤在易受干扰的沙地生境中的快速定植和种群增长提供了条件。
The freshwater clam Corbicula australis is an important component of the macrobiota of the river systems of southeast Australia. Reproduction of two populations of this clam in the Nepean River at Douglas Park and Menangle was investigated to document the gametogenic cycle, larval morphology and to determine when they incubate embryos. C. australis is a simultaneous hermaphrodite and broods its young in the inner demibranchs. The gonads are ovotestes with oogenic and spermatogenic regions in each ascinus. The sperm are biflagellate, a condition unique in the Bivalvia to clonal corbiculids. Gametogenesis was continuous and did not exhibit a seasonal pattern. In contrast, spawning and incubation of embryos was limited to the warmer months of the year. Embryos were present in the gills from October to May. C. australis develops through a modified veliger larva with a vestigially ciliated velum which is not used for swimming or particle capture. The velum is covered by microvilli and it is suggested that the velar epithelium may be specialised for nutrient uptake in the marsupial environment. C. australis produces several clutches each year and the young are released as advanced juveniles with a well-developed foot. Reproductive output differed between the two populations. This was in part due to the larger size of the clams from Menangle and may also reflect the enhanced productivity at this site. The suite of life history traits exhibited by C. australis: hermaphroditism, potential for self-fertilization/androgenesis, brooding progeny to the crawl-away juvenile stage and a high reproductive output, provide for rapid colonization and population growth in this clam which typically inhabits disturbance prone sandy lotic habitats.