Intrinsic Cycles And Density And Frequency-Dependent Selection On Egg Size

University Of California-Santa Cruz, Santa Cruz CA

Investigators

Abstract

0108577 Sinervo Predicting population regulation is a fundamental goal of ecological and evolutionary studies. Population regulation must arise from effects of interactions between individuals on rate of reproduction and progeny survival. Interactions should be intense at high density, but weak at low density. The recent discovery of a genetic basis for population regulation of side-blotched lizards facilitates study of density effects. Lizards carry a genetic color marker for alternative reproductive strategies that have cascading effects on progeny survival. Population density and frequency of two genotypes will be manipulated in large-scale field experiments. Genetic change and population regulation will be studied across two generations on replicate field plots. Furthermore, laboratory breeding studies will determine whether the color marker and associated reproductive attributes are due to a single gene, or from many genes. Mechanisms of hormonal regulation are conserved among lizards, mammals, and birds. Thus, studies on lizards provide basic information on genes and hormones that control reproduction in many free-ranging and domestic species. Furthermore, experiments on density regulation in the wild provide basic information that is vital for predicting long-term changes in animal numbers. For example, predicting long-term effects of global climate change will require an understanding of the ecological and genetic causes of population regulation.