Endosymbionts
Parasites and commensals of alien species: distribution, biology and ecology.
DocumentsDate added
We report the results of a two-year study in the Svisloch River (Minsk, Belarus) on the dynamics of infection in Dreissena polymorpha by nematodes and three ciliate species Conchophthirus acuminatus, Ophryoglena sp., and Ancistrumina limnica. Although these endosymbionts were present in most of the samples, their prevalence and infection intensity differed significantly. C. acuminatus and A. limnica infection intensities in both years of the study had a maximum in summer and were positively correlated with water temperature. In contrast, Ophryoglena sp. and nematode infection intensities were considerably lower in summer versus winter and were negatively correlated with temperature. In the first long-term study to monitor the size and reproductive rate of C. acuminatus, we found that mean length was negatively correlated with temperature and that temperature was positively correlated with asexual reproduction, with a peak of cell division in April as water temperatures increased.
[Karatayev AY, Mastitsky SE, Burlakova LE, Molloy DP and Vezhnovets GG (2003) Seasonal dynamics of endosymbiotic ciliates and nematodes in Dreissena polymorpha. Journal of Invertebrate Pathology 83 (1): 73-82]
This study, conducted in the Dnieper-Bug Canal in Belarus, is the first to monitor the seasonal (June-November) dynamics of infection with the parasitic ciliate Ophryoglena sp. in a zebra mussel (Dreissena polymorpha) population. Mean population prevalence and intensity of infection varied, respectively, from 11 to 62% and from 0.9 to 24.1 ciliates/mussel. Mean prevalence was highly correlated with mussel length in mussels <20mm (R2 = 0.97) and was lower in larger mussels. Mean infection intensity in mussels 1-25 mm long was similarly correlated with their size (R2 = 0.98), reached a maximum in the 20-25 mm size-class, and then sharply decreased, thus providing evidence, albeit limited, that high intensity of infection might be lethal. Transinfection of zebra mussels by Ophryoglena sp. was achieved in the laboratory a first for a protozoan parasite of D. polymorpha; from an initial complete lack of infection, mean prevalence and intensity rose, respectively, to 86.7% and 8.3 ciliates/mussel.
[Karatayev AY, Burlakova LE, Molloy DP, Volkova LK and Volosyuk VV (2002) Field and laboratory studies of Ophryoglena sp. (Ciliata: Ophryoglenidae) infection in zebra mussels, Dreissena polymorpha (Bivalvia: Dreissenidae). Journal of Invertebrate Pathology 79: 80-85]
The paper includes data on species composition of chironomid larvae which were encountered in the mantle cavity of zebra mussels (Dreissena polymorpha) within 7 waterbodies in the Republic of Belarus. All were found to be free-living species commonly present in periphyton and/or benthos. A long-term study of the seasonal dynamics of these larvae in Dreissena did not reveal any typical pattern. Our data suppose that chironomids do not have an obligate association with zebra mussels and possibly enter their mantle cavity inadvertently.
[Mastitsky SE and Samoilenko VM (2005) Larvae of chironomids (Insecta, Diptera) encountered in the mantle cavity of zebra mussel, Dreissena polymorpha (Bivalvia, Dreissenidae). Internat Rev Hydrobiol 90(1): 42-50]
The paper contains results of the analysis of consequences of the rapid distribution of zebra mussel and its associated endosymbionts across freshwater ecosystems. Data from Belarusian waterbodies show that at least 32 taxa from 8 classes of animals inhabit the mantle cavity and/or visceral mass of the mollusc. Among these endosymbionts one can find both parasites and commensals which are either obligate or facultative. It is possible to distinguish the following main consequences of spread of Dreissena and its endosymbionts: 1) increase of species richness in a waterbody; 2) extension of number of possible hosts for endosymbionts indigenous for a given waterbody; 3) change for the worse parasitological situation in a waterbody; 4) changes in the behavioral habits of some free-living organisms (nematodes, chironomids, oligochaetes and leeches) and 5) reorganization of trophic chains in the ecosystem of waterbody.
[Mastitsky SE (2003) Eco-parasitological aspects of distribution of zebra mussel (Dreissena polymorpha Pallas). In: Proc. II International conf. "Lake ecosystems: biological processes, anthropogenic transformation, quality of water", Minsk-Naroch, 22-26 September 2003, pp 471-474. Belarusian State University Press, Minsk (in Russian with English summary)]
|
|
