Density-dependent natural selection and trade-offs in life history traits.

Theories of density-dependent natural selection state that at extreme population densities evolution produces alternative life histories due to trade-offs. The trade-offs are presumed to arise because those genotypes with highest fitness at high population densities will not also have high fitness at low density and vice-versa. These predictions were tested by taking samples from six populations of Drosophila melanogaster kept at low population densities (r-populations) for nearly 200 generations and placing them in crowded cultures (K-populations). After 25 generations in the crowded cultures, the derived K-populations showed growth rate and productivity that at high densities were elevated relative to the controls, but at low density were depressed.

[1]  M. Asmussen.  Density-dependent selection incorporating intraspecific competition. II. A diploid model. , 1983, Genetics.

[2]  D. Hartl,et al.  The Experimental Assessment of Fitness in Drosophila. II. a Comparison of Competitive and Noncompetitive Measures. , 1983, Genetics.

[3]  D. Reznick.  Costs of reproduction: an evaluation of the empirical evidence , 1985 .

[4]  W. Bradshaw,et al.  Life-Historical Consequences of Density-Dependent Selection in the Pitcher-Plant Mosquito, Wyeomyia smithii , 1989, The American Naturalist.

[5]  R H Macarthur,et al.  SOME GENERALIZED THEOREMS OF NATURAL SELECTION. , 1962, Proceedings of the National Academy of Sciences of the United States of America.

[6]  J. Roughgarden.  Density‐Dependent Natural Selection , 1971 .

[7]  L. Mueller,et al.  Evolution of competitive ability in Drosophila by density-dependent natural selection. , 1988, Proceedings of the National Academy of Sciences of the United States of America.

[8]  L. Luckinbill.  r and K Selection in Experimental Populations of Escherichia coli , 1978, Science.

[9]  H. Barclay,et al.  An Experimental Test of Models Predicting Life-History Characteristics , 1981, The American Naturalist.

[10]  B. Clarke.  Density-Dependent Selection , 1972, The American Naturalist.

[11]  Brian Charlesworth,et al.  Selection in Density‐Regulated Populations , 1971 .

[12]  W. Anderson.  Genetic Equilibrium and Population Growth Under Density-Regulated Selection , 1971, The American Naturalist.

[13]  M. Rose.  Life History Evolution with Antagonistic Pleiotropy and Overlapping Generations , 1985 .

[14]  Laurence D. Mueller,et al.  Density-Dependent Population Growth and Natural Selection in Food-Limited Environments: The Drosophila Model , 1988, The American Naturalist.

[15]  W. Anderson,et al.  Density-Regulated Selection with Genotypic Interactions , 1983, The American Naturalist.