Cone David K, Marcogliese David J, Barse Ann M, Burt Michael D B
Department of Biology, Saint Mary's University, Halifax, Nova Scotia, Canada, B3H 3C3.
J Parasitol. 2006 Feb;92(1):52-7. doi: 10.1645/GE-590R.1.
Membership and richness of infracommunities and component communities of myxozoan fauna of the banded killifish (Fundulus diaphanus) from freshwater localities in Ontario, Quebec, New York State, New Brunswick, Nova Scotia, and Maryland were studied. Five species of parasites were found: Myxobolus diaphanus (Fantham, Porter, and Richardson, 1940) (connective tissue throughout the body and head), Myxobolus funduli (Kudo, 1918) (interlamellar), Myxobolus neurophilus (Guilford, 1963) (optic tectum of the brain), Myxobolus sp. (connective tissue, typically adjacent to vertebrae), and Sphaerospora sp. (kidney tubules). The most abundant species locally and regionally was M. diaphanus, occurring at prevalences of 14.2 to 93.3% at 6 of 9 localities. Myxobolus funduli and Myxobolus sp. were at 3 and 2 localities respectively, while M. neurophilus and Sphaerospora each occurred at single localities. Four of the 5 myxozoans appear to be specific to fundulids, the exception being M. neurophilus, which is typically a parasite of Perca flavescens. Mean infracommunity richness was 0-1.2. Component community richness was 0-3 species. The fauna is similar in composition to that described from the spottail shiner (Notropis hudsonius) in the Great Lakes in being dominated by histozoic myxobolids and in having maximum prevalence at any single locality correlate positively with geographical distribution. Moreover, mean infracommunity richness was correlated with percentage of hosts infected with any species at a locality, and maximum infracommunity richness was correlated with component community richness. Probably because fewer species of myxozoans of fundulids occur in the regional pool, myxozoan communities encountered in the present study are generally less rich than those described from N. hudsonius. It appears that dispersal of relatively resilient myxospores through such a mechanism as piscivory effectively distributes these parasites over the landscape, while the more delicate actinospores serve to ensure colonization by amplifying species' prevalence at a specific locality and thereby contributing to initial establishment. As such, these types of myxozoans, though they are autogenic, having their entire life cycle normally completed within the aquatic environment, behave more like allogenic parasites that rely on birds and mammals as definitive hosts.
对来自安大略省、魁北克省、纽约州、新不伦瑞克省、新斯科舍省和马里兰州淡水区域的带状鳉鱼（Fundulus diaphanus）体内粘孢子虫动物群落的小群落和组分群落的组成及丰富度进行了研究。共发现了5种寄生虫：透明粘体虫（Myxobolus diaphanus）（Fantham、Porter和Richardson，1940年）（遍布全身和头部的结缔组织）、Funduli粘体虫（Myxobolus funduli）（Kudo，1918年）（片层间）、嗜神经粘体虫（Myxobolus neurophilus）（Guilford，1963年）（脑视顶盖）、粘体虫属（Myxobolus sp.）（结缔组织，通常邻近椎骨）和球孢虫属（Sphaerospora sp.）（肾小管）。在当地和区域内最丰富的物种是透明粘体虫，在9个地点中的6个地点，其感染率为14.2%至93.3%。Funduli粘体虫和粘体虫属分别出现在3个和2个地点，而嗜神经粘体虫和球孢虫属均只出现在单个地点。这5种粘孢子虫中有4种似乎是鳉鱼特有的，嗜神经粘体虫除外，它通常是黄鲈（Perca flavescens）的寄生虫。小群落的平均丰富度为0 - 1.2。组分群落的丰富度为0 - 3种。该动物群落的组成与五大湖地区的尾斑亮鲦（Notropis hudsonius）体内描述的群落相似，以组织内寄生的粘体虫为主，且在任何单个地点的最高感染率与地理分布呈正相关。此外，小群落的平均丰富度与当地感染任何物种的宿主百分比相关，小群落的最大丰富度与组分群落的丰富度相关。可能是因为鳉鱼的粘孢子虫种类在区域库中较少，本研究中遇到的粘孢子虫群落通常比尾斑亮鲦体内描述的群落丰富度更低。看来，相对有弹性的粘孢子通过诸如食鱼等机制传播，有效地将这些寄生虫分布在整个区域，而更为脆弱的放射孢子则通过在特定地点增加物种的感染率来确保定殖，并因此有助于初始建立。因此，这些类型的粘孢子虫虽然是自生的，其整个生命周期通常在水生环境中完成，但它们的行为更像是依赖鸟类和哺乳动物作为终末宿主的异源寄生虫。
