Dissertation Research: Larval Brooding by the Freshwater Mussel Anodonta cataracta

淡水球虫贻贝的生活史在双壳类中是不典型的，既包括自由生活的成虫，也包括寄生的幼虫--钩虫。受精后，发育中的胚胎被孵化在母亲鳃的水管中，在那里它们可能会停留几个月，然后被释放到水柱中，并寄生在鱼身上。这项研究的主要目的是评估发生在育苗的雌性白内障无齿蚌鳃内的形态和生理变化，这是一种北卡罗来纳州丰富的淡水贻贝。在孵化过程中，贻贝的四个鳃中有两个长满了近一百万条钩虫，导致鳃膨胀到非孵化大小的30倍。拟议研究的主要目标包括量化有袋类鳃内发生的形态变化，比较孵化和非孵化贻贝的泵送和过滤动力学，确定孵化对贻贝摄氧量和氧气提取效率的影响，以及评估负责灌溉有袋类和非有袋类鳃的纤毛的活动。这些结果将为更全面地了解白内障吸虫的生殖生物学，特别是球囊孵化和释放对成年雌性的生理和鳃形态的影响提供了更全面的了解。这些信息也可用于管理和养护其他淡水双壳类，包括受威胁和濒危物种。

The life cycle of freshwater unionid mussels is atypical among bivalves and involves both a free-living adult and a parasitic larva, the glochidium. Following fertilization, developing embryos are incubated in the water tubes of the mother's gills where they may remain for several months before being released into the water column and becoming parasitic on fish. The principal objective of this study is to assess the morphological and physiological changes that occur within the gills of brooding female Anodonta cataracta, an abundant freshwater mussel in North Carolina. During brooding, two of the mussel's four gills become packed with nearly a million glochidia, causing the gills to swell to up to thirty times their non-brooding size. The major goals of the proposed research include quantifying the morphological changes that occur within the marsupial gills, comparing the pumping and filtration dynamics of brooding and non-brooding mussels, determining the effect of brooding on oxygen uptake and oxygen extraction efficiency of mussels, and assessing the activity of the cilia responsible for irrigation both the marsupial and non-marsupial gills. The results will provide a more complete understanding of the reproductive biology of A. cataracta, especially the effect of glochidial brooding and release on the physiology and gill morphology of adult females. This information also may have application for the management and conservation of other freshwater bivalves including threatened and endangered species.