This is the first report of branchiobdellids (Annelida: Clitellata) from Maine. Twenty-seven aquatic sites were surveyed in Aroostook County, Maine and two species of crayfish were collected. Cambarus bartonii bartonii occurred in all but two sites and supported three species of branchiobdellids, Bdellodrilus illuminatus, Cambarincola fallax, and Xironogiton instabilis; in most cases, specimens of all three species occurred on the same host. Bdellodrilus illuminatus was restricted to the branchial chambers, X. instabilis to the chelipeds, and C. fallax to the oral and ventral surfaces of the body. Specimens of Orconectes virilis were collected from two sites and only supported B. illuminatus. The reported distribution of branchiobdellid worms on the North American continent extends north from Costa Rica into southern Canada (Holt, 1973). Early reports of geographical occurrence were reviewed in a monograph by Goodnight (1940). Subsequently, our knowledge of branchiobdellid taxonomy and distribution has been greatly extended (for reviews see Holt, 1965, 1968, 1975). However, information on ecology and interactions of host/branchiobdellid associations are less well understood (Bishop, 1968; Hobbs et al., 1967; McManus, 1960; Young, 1966). In the northeastern United States, only the state of New York and adjacent surrounding areas have received attention (reviewed by Hoffman, 1963). This investigation was undertaken to ascertain the species distribution of branchiobdellids in Aroostook County, Maine as a preliminary step to future studies of their ecology and physiology. MATERIALS AND METHODS Each collection site (Table I) was sampled by kick-searching the bottom once during the period from mid-June to mid-September 1985 for up to 30 min; a maximum of six crayfish was taken from each site. The crayfish were placed in 10% formalin for subsequent identification (Crocker, 1979; Pennak, 1978) and examination for the presence, and then identification, of branchiobdellid worms (Hoffman, 1963; Holt, 1974; Pennak, 1978). Identification was enhanced by staining specimens with alum carmine, dehydration in graded ethanol solutions, clearing in xylene, and mounting in Canada balsam (Humason, 1979). The number of individuals representing each branchiobdellid species was noted; such notations included specimens from the host and in the 1 We thank Prof. Denton W. Crocker, for identification of crayfish species, and Prof. Perry C. Holt and Dr. A. M. Gorman for reading the manuscript. This investigation was supported by National Science Foundation Grant PCM 83-16396 and a Faculty Research Grant-in-aid from the University of Maine at Presque Isle to S.R.G. TRANS. AM. MICROSC. SOC., 106(1): 85-88. 1987. ? Copyright, 1987, by the American Microscopical Society, Inc. This content downloaded from 157.55.39.58 on Thu, 23 Jun 2016 05:34:39 UTC All use subject to http://about.jstor.org/terms TRANS. AM. MICROSC. SOC. bottom debris from the collecting jars. One crayfish from each collection site was retained as a taxonomic reference specimen. Additional crayfish specimens were collected and maintained in the laboratory; movements and distributions of their branchiobdellid symbionts were observed.
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