Najadicola Ingens (Koenike), A Water‐Mite Parasitic in Fresh‐Water Clams

Abstract

The distribution of Najadicola ingens (Koenike 1895) Piersig 1897, a hydrachnid parasite of freshwater clams in .North America, is known only from a few scattered records. Relatively few specimens have been reported up to the present. Koenike (1895) described the species from specimens found in .dnodonta fragilis Lamarck and Unio complanata (Solander)l and sent to him by Dr. Tyrrell of Ottawa. The collection locality was given only as Canada. Wolcott (1899) collected this mite from ./tnodonta fragilis at "26" Lake, near Charlevoix, Michigan, and Intermediate Lake, Ellsworth, Michigan, from Unio gibbosus Barnes, U. ligamentinus Lamarck, and Anodonta footiana Lea at Grand Rapids, Michigan, and from U. luteolus Lamarck at Long Lake, Kalamazoo, Michigan. He examined 3500 clams representing 60 species from Michigan, Wisconsin, Nebraska, New York, Illinois, Iowa, and Pennsylvania, but found not more than 16 specimens, all from the Michigan localities just mentioned. Wolcott (1918) stated that the species is generally distributed, but did not give additional distribution records. Marshall

Population dynamics of the water mite Unionicola arcuata (Unionicolidae) in the freshwater bivalve Cristaria plicata (Unionidae) in Poyang Lake, eastern China

“…Population biology of water mites in the family Unionicolidae has been commonly observed in relation to bivalve size (Humes & Jamnback 1950, Mitchell 1965, Gordon et al 1979, Dimock 1985. The prevalence of Najadicola ingens was reported to be related in reverse to the sizes of Elliptio complanata and Anodonta cataracta (Humes & Jamnback 1950).…”

“…The prevalence of Najadicola ingens was reported to be related in reverse to the sizes of Elliptio complanata and Anodonta cataracta (Humes & Jamnback 1950). However, no correlation was found between the size of Lampsilis siliquoidea and any parameters of the population biology of Unionicola fossulata (Mitchell 1965).…”

“…The water mite Unionicola arcuata (Wolcott) has been described in several species of freshwater bivalves in China and in other Asian countries, as well as in North America (Imamura 1953, Baker 1982, Vidrine 1986, Wen & Zhu 1999, and has been reported as a parasite in the 'pearl bivalve' C. plicata both in lakes and under culture conditions for pearl production in China. Several other species in the family Unionicolidae have been the focus of ecological investigations (Humes & Jamnback 1950, Conroy 1974, Gordon et al 1979, Dimock 1985, Joy & Hively 1990). However, relatively little is known about the population biology of the water mite U. arcuata.…”

Factors affecting trematode infection rates in freshwater mussels

“…Finally, we investigated whether environmental conditions in the lakes can explain differences in the abundance of parasites among mussel populations. Earlier studies suggest that parasitism among mussels might attain its highest rates in lentic habitats and nutrient-enriched streams (Humes & Jamnback, 1950;Fuller, 1974), but there were no studies directly investigating the links between physicochemical parameters and parasitism. Given the scarcity of data, we generally hypothesized that eutrophic waters with low oxygen supply would worsen the physiological state of duck mussels and result in an increased susceptibility to infections.…”

Parasitic mite and trematode abundance are associated with reduced reproductive output and physiological condition of freshwater mussels

“…Humes & Jamnback (1950) report that gills of Pyganodon cataracta (Say, 1817) that are parasitized by the mite Najadicola ingens (Koenike, 1895) are misshapen and contain a few larvae. Subsequent studies report tissue inflammation and damage resulting from mite feeding in some host mussels but do not demonstrate that high mite densities reduce host mussel condition or fitness (i.e., reproductive output, Baker, 1977;Fisher et al, 2000).…”