Population genetics of an island invasion by Japanese Bush-Warblers in Hawaii, USA

Abstract

ABSTRACT Island bird populations often provide exemplary cases of evolution based on historical colonization and diversification events. However, capturing contemporary cases of evolution is rare. Introductions of nonnative birds into the Hawaiian Islands, USA, provide numerous potential opportunities to assess evolutionary changes over a relatively short time frame. One introduced species, the Japanese Bush-Warbler (Cettia diphone), has a well-established history in the Hawaiian Islands, with a documented introduction in 1929 to the island of Oahu and natural colonization of the other main islands by 1997. We sampled 143 Japanese Bush-Warblers from 5 of the main Hawaiian Islands and amplified 12 microsatellite loci (9 were variable) and sequenced portions of the cytochrome b and cytochrome c oxidase subunit I (COI) genes to assess the genetic structure and potential original source of these populations. As predicted, genetic diversity, measured by allelic richness and private alleles, was greatest on Oah...