COSTS INFLUENCE SEQUENTIAL MATE CHOICE IN STICKLEBACKS, GASTEROSTEUS-ACULEATUS

In nature females can usually choose among males only sequentially. Recent models of sequential choice predict that, with increasing costs of sampling, selectivity for preferred males should decline. In our tests female sticklebacks were highly selective in their sequential choice between dull and bright males when costs were low. With increasing time and energy costs of moving between males, they reduced their selectivity. In particular, when the females had to swim against a current, dull males when met became highly acceptable. The females' response to increased costs of sampling shows that they make the kind of economic decisions predicted by models of sequential choice. The strength of sexual selection by female choice therefore depends on the spatial structure of the population.