hard selection

Szép E, Sachdeva H & Barton NH 2021 Polygenic local adaptation in metapopulations: a stochastic eco-evolutionary model. Evolution, in press.
doi:10.1111/evo.14210

• we assume hard selection
• population sizes are stochastic but influenced by mean fitness on the island plus local density-dependent regulation
• the size n*_i on island i, after selection and regulation, is a Poisson random variable with mean n_iW_ie^{r_i,0(1 − n_i/K_i)}
• r_i,0 is the baseline rate of growth
• K_i the baseline carrying capacity
• n_i the population size prior to selection
• W_i the mean genetic fitness on island i
• the n*_i offspring are formed by randomly sampling 2n*_i parents (with replacement) from the n_i individuals in proportion to individual fitness, and then creating offspring via free recombination of each pair of parent genotypes
• selection is density independent
• relative fitness of genotypes is independent of population size