CS39A Zooplankton - Feeding, Reproduction, Growth and Molecular Diversity
Date: Tuesday, June 11, 2002
Location: Poster Session - VCC
JunttilaPH, Department of Ecol. and Syst., P.O. Box 17, FIN-00014 University of Helsinki , Helsinki, Finland, pjunttil@mappi.helsinki.fi
Schwenk, K, , Department of Ecol. & Evol., J.W.Goethe-University Frankfurt am Main, Siesmayerstrasse 70, D-60054, Frankfurt am Main, Germany, k.schwenk@zoology.uni-frankfurt.de
Species of the genus Daphnia have been used as model systems in ecotoxicology, quantitative genetics and recently in ecological genetics. However, the systematics and taxonomy of the group is under revision, since recently several molecular DNA studies revealed cryptic species and hybrid complexes. For example, studies of the Hyalodaphnia group presented evidence for a previously unrecognised species: D. umbra, which has been found in Canada and Norway. Our study of 18 ponds in Northern Finland focussed on the genetic and ecological differentiation of D. umbra and D. longispina which are closely related and morphologically similar. We applied previously established species specific mitochondrial (12S rDNA) and nuclear DNA (ITS) markers. We found that D. umbra represents a genetically isolated lineage. Genetic differentiation between D. longispina and D. umbra was in the range of genetic differentiation among other Hyalodaphnia species. D. longispina and D. umbra did not occur in syntopy and no interspecific hybrids were detected. Species were found in different habitat types; D. longispina inhabiting small, shallow and fishless ponds, whereas D. umbra inhabiting larger and deeper ponds containing fish.