DIFFERENCES IN DEMOGRAPHIC PARAMETERS AMONG ELECTROPHORETIC CLONES OF DAPHNIA-OBTUSA KURZ (CRUSTACEA, CLADOCERA)

In an 18-month electrophoretic study, a Daphnia obtusa population that recently colonized Lake Orta (a large, severely polluted lake in Northern Italy) showed no genetic variation. Populations from other localities were sampled. From clones established by single females, genotype differences were determined by two life table experiments (using Lake Orta and Lake Maggiore water as a culture medium). As expected, in the Lake Orta water the colonizing clone (LO) had longer survival, produced more newborns and had a larger rate of increase than the other clones. In the Lake Maggiore water the LO clone still fared better than the other clones.