Sergey Gavrilets1,2,3, Urban Friberg4, William R Rice5. 1. Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, 37996, USA. sergey@nimbios.org. 2. Department of Mathematics, University of Tennessee, Knoxville, TN, USA. sergey@nimbios.org. 3. National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, TN, USA. sergey@nimbios.org. 4. IFM Biology, Linkoping University, Linkoping, Sweden. 5. Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, USA.