Effects of Chaetogaster limnaei limnaei (Oligochaeta, Tubificidae) on freshwater snail communities
From laboratory studies, the relationship between the oligochaete Chaetogaster limnaei limnaei (CL) and its freshwater snail hosts is known to be context-dependent, ranging from mutualistic to parasitic. We monitored snail communities of seven streams in Germany during three seasons of a year and investigated infestation by CL. Some snail species never were infested. In snail species that were infested, size, substratum type, oxygen concentration and species identity were the most important variables explaining the variance in CL infestation. Independent of individual snail size, Bithynia tentaculata, Ancylus fluviatilis and Acroloxus lacustris showed the highest CL abundances. Across species, CL abundances were highest in large individuals on silty substratum at well-oxygenated sites. Reproductive success of snail populations was estimated from proportion of juveniles in populations. This measure of reproductive success of snail populations was inversely related with CL infestation level. These results suggest that CL infestation affects aquatic snails at the population and community level in the field. Differential infestation levels and different impacts of CL infestation between species lead to an asymmetric distribution of positive and negative effects among all snail species present in a habitat. Thus, CL may be an overlooked agent in structuring snail communities.
KeywordsAquatic molluscs Oligochaete Prevalence Infestation intensity Density-dependent effect Reproductive success
This study used data that were generated at the Long-Term Ecological Research (LTER) site “Rhine-Main-Observatory”. The comments of three anonymous reviewers helped to improve this manuscript.
- AQEM, 2002. Manual for the application of the AQEM system. http://www.aqem.de/index.php.
- Backlund, H. O., 1949. En kommensal som äter sitt värddjurs parasiter. Fauna och flora: populär tidskrift för biologi 44: 38–41.Google Scholar
- Brinkhurst, R. O. & B. G. M. Jamieson, 1971. Aquatic Oligochaeta of the World. Oliver and Boyd, Edinburgh.Google Scholar
- Domisch, S., S. Jähnig, J. P. Simaika, M. Kuemmerlen & S. Stoll, 2015. Application of species distribution models in stream ecosystems: the challenges of spatial and temporal scale, environmental predictors and species occurrence data. Fundamental and Applied Limnology 186: 45–61.Google Scholar
- Früh, D., P. Haase, & S. Stoll, 2015. Temperature drives asymmetric competition between alien and indigenous freshwater snails (Physa acuta vs. Physa fontinalis). PeerJ PrePrints 3: e1227.Google Scholar
- Hijmans, R. J., S. Phillips, J. R. Leathwick, & J. Elith, 2013. Dismo: species distribution modelling. R package version 08-11. http://CRAN.R-project.org/package=dismo.
- Mrazek, A., 1917. The feeding habits of Chaetogaster limnaei. Sbornik Zoologicky 1: 22–23.Google Scholar
- R Development Core Team, 2011. R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna.Google Scholar
- Streit, B., 1974. Populationsdynamik von Chaetogaster limnaei limnaei in einer Population von Ancylus fluviatilis. Archiv für Hydrobiologie Supplement 47: 106–118.Google Scholar
- Streit, B., 1977. Morphometric relationships and feeding habits of two species of Chaetogaster, Ch. limnaei and Ch. diastrophus (Oligochaeta). Archiv für Hydrobiologie Supplement 48: 424–437.Google Scholar
- Vaghin, V., 1946. On the biological species of Chaetogaster limnaei, k. Baer. Doklady Akademii Nauk SSSR 51: 481–484.Google Scholar
- Wagin, V. W. L., 1941. Chaetogaster limnaei K. Baer als Cercarienvertilger. Zoologischer Anzeiger 95: 55–59.Google Scholar
- Young, M. R., 1974. Seasonal variation in the occurrance of Chaetogaster limnaei limnaei Gruffydd (Oligochaeta) in two of its molluscan hosts in the Worcester-Birmingham canal and its relationship with the digenean parasites of these molluscs. Journal of Natural History 8: 529–535.CrossRefGoogle Scholar