Ecological differences between genotypes in a natural population of daphnia magna

Abstract

Large changes in genotypic frequencies have been observed over a 2-year period in a population of Daphnia magna polymorphic for two alleles of malate dehydrogenase. These changes were not the result of migration or random drift. Genotypic differences in both parthogenetic and sexual egg production were observed. There was a strong correlation between the parthogenetic fecundities of the genotypes and their frequencies 1 month later. Sexual egg production was enhanced among low fitness genotypes. These observations strongly suggest that populations of Daphnia magna consist of a limited number of ecologically differentiated clones. © 1974 The Genetical Society of Great Britain. All Rights Reserved.