Intraspecific Systematics of Gasterosteus Aculeatus Populations: Implications for Behavioral Ecology

Abstract

AbstractThe threespine stickleback is widespread in diverse coastal marine and freshwater habitats of the Holarctic. Extensive information on its behavior and evolution provide an exceptional background for behavioral ecology. The behavioral phenotype links studies of proximate and ultimate (evolutionary) causes of behavior. Analyses of the ultimate causes of behavior should be placed in a phylogenetic context. There have been four phases of interpretation of phenotypic variation in threespine stickleback: (1) taxonomic, (2) dispersalist-neutralist, (3) adaptationist, and (4) adaptationist-phylogenetic. Gasterosteus aculeatus should be treated as a highly variable species complex. Phylogenetic inferences based on geographical location and allozyme and nucleotide variation facilitate discrimination between ancestry and local adaptation as ultimate causes of phenotypic variation among populations. The phylogeny of threespine stickleback populations and the use of phylogenetic information to analyze causation of pelvic girdle variation among populations are reviewed. Criteria for selection of populations and behavioral traits for comparative studies are discussed.