You are not currently logged in.
Access your personal account or get JSTOR access through your library or other institution:
If You Use a Screen ReaderThis content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
The Clonal Ecology of Daphnia magna (Crustacea:Cladocera): I. Temporal Changes in the Clonal Structure of a Natural Population
G. R. Carvalho and D. J. Crisp
Journal of Animal Ecology
Vol. 56, No. 2 (Jun., 1987), pp. 453-468
Published by: British Ecological Society
Stable URL: http://www.jstor.org/stable/5060
Page Count: 16
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Preview not available
(1) Temporal changes in the frequencies of different clones (distinguished electrophoretically) of a natural shallow-lake population of Daphnia magna are described in relation to seasonal environmental changes monitored at six sites from July 1981 to July 1983. (2) Extensive, and sometimes rapid, changes occurred in the number of clones present and in clone size. Changes in clonal structure were remarkably uniform throughout the lake suggesting frequency changes in response to temporal environmental changes. There were no persistent aggregations of particular clones within spatially distinctive areas of the lake. Principal component analysis indicated that the abundance of certain clones was strongly influenced by seasonal variables, notably temperature and population density. (3) The population contained a few dominant, and many rare clonal groups. Three dominant clonal groups exhibited seasonal succession over two years, predominating respectively in summer, autumn and winter. Other genotypes either persisted throughout each year at variable densities, or were rare and apparently short-lived. (4) Clonal diversity, expressed as the Shannon-Wiener index and the number of clones recognized, was higher in summer and lower in winter, as was the total population density. (5) This study demonstrates rapid genetic changes, and suggests that ecological generalists, opportunists, and seasonal specialists may coexist within a single, primarily parthenogenetic Daphnia population. The manner in which such varied types of clone arise and fluctuate is discussed.
Journal of Animal Ecology © 1987 British Ecological Society