Interclonal differences in age-specific performance in Daphnia magna

Clonal organisms are often characterized by indeterminate growth and it is more likely in these organisms that delayed senescence evolves. Daphnia is characterized by both clonality and indeterminate growth, yet evidence for its senescence has been collected. In addition, differences in the dynamics of age-specific parameters were seen between environmentally developed phenotypes within a genotype as well as between genotypes, including between sister species. The aim of the present study was to test for interclonal differences within a species and to examine the course of basic life history and age-specific fitness parameters throughout life of Daphnia magna females originating from two different habitats, pond and lake. Clones differed in size at subsequent reproductions, but this did not result in differences in fecundity, although number of offspring in a clutch increased both with size and age of a female. There were also interclonal differences in lifespan and age-specific measures of fitness, but apart from lifespan, habitat of origin did not have significant effects on life history traits.