Chapter Forty Six - 1981 Testing density-dependent naural selection

Abstract

Once Roughgarden (1971; Chapter 34) had properly identified density-dependent rates of population growth as the appropriate target of natural selection then experimental tests became possible. Such a test would require an organism that could be raised under different density conditions and one which is amenable to measurements of population growth. Additionally, a species with a short generation time would be preferable. Mueller and Ayala (1981) did such a test with Drosophila melanogaster. They found that populations adapted to extreme densities reflected this adaptation in their population growth rates. Most interestingly there was a trade-off. The populations adapted to low density had lower growth rates under crowded conditions than the populations adapted to high density, and vice versa.