EVOLUTIONARY DYNAMICS OF HABITAT USE

I examine the evolution of alternate genotypes that use two habitats t hat differ in vegetative cover, focusing on the interplay between ecol ogical dynamics of the community and changes in selective advantage. F acultative habitat choice can stabilize a predator population that wou ld cycle if isolated in the more open habitat. This has important impl ications for the evolution of habitat use strategies. Local stability arising from facultative habitat use allows any number of behavioural genotypes to co-exist: selective use of the open habitat, selective us e of the dense habitat, opportunistic use of both habitats in proporti on to availability, and facultative switching between habitats to maxi mize energy gain. Go-existence occurs because the fitness landscape is hat at the ecological equilibrium imposed by the facultative genotype . In contrast, ecological instability favours the evolution of genotyp es with behavioural flexibility to avoid being in the wrong place at t he wrong time or selective exploitation of one of the habitats. Uncert ain information about habitat quality erodes the adaptive advantage of otherwise 'optimal' behaviours, favouring a bet-hedging behavioural s trategy synonymous with partial habitat preferences. These results sug gest that ecological dynamics could have a strong influence on behavio ural heterogeneity within forager populations and that a mixed ESS for habitat use should predominate.