ECOLOGICAL OPPORTUNITY AND PHENOTYPIC PLASTICITY INTERACT TO PROMOTE CHARACTER DISPLACEMENT AND SPECIES COEXISTENCE

摘要: We investigated the roles of resource availability and phenotypic plasticity in promoting ecological character displacement (i.e., trait evolution stemming from competition between species). Because generates new populations that differ use, this process should only occur when exploitable resources are available. tested hypothesis two species spadefoot toads (Spea bombifrons S. multiplicata) whose tadpoles use to develop into either an omnivore morph, which specializes on detritus, or a physically distinctive carnivore shrimp. Both grow best shrimp, but reared together, outcompetes multiplicata for shrimp detritus. found each occurred alone field, they produced similar proportions omnivores carnivores. When however, underwent larval development, with producing mostly omnivores, combined observations natural experiments evaluate whether such was possible both detritus were relatively abundant. Mixed-species ponds contained abundant contrast nearby pure-species ponds, deficient one resource. Experiments revealed competed poorly rare rare. In nature, these scarce, missing, perhaps through competitive exclusion by superior competitor remaining Thus, and, therefore, coexistence close competitors, diverse Finally, even if available, is not guaranteed transpire cannot utilize expeditiously. Phenotypic provides general important mechanism facilitating partitioning. shifts opportunity may often interact promote divergence competitors.