title: Diversification in Hawaiian long-legged flies (Diptera: Dolichopodidae: Campsicnemus): biogeographic isolation and ecological adaptation.
abstract: Flies in the genus Campsicnemus have diversified into the second-largest adaptive radiation of Diptera in the Hawaiian Islands, with 179 Hawaiian endemic species currently described. Here we present the first phylogenetic analysis of Campsicnemus, with a focus on the Hawaiian fauna. We analyzed a combination of two nuclear (CAD, EF1α) and five mitochondrial (COI, COII, 12S, 16S, ND2) loci using Bayesian and maximum likelihood approaches to generate a phylogenetic hypothesis for the genus Campsicnemus. Our sampling included a total of 84 species (6 species from Europe, 1 from North America, 7 species from French Polynesia and 70 species from the Hawaiian Islands). The phylogenies were used to estimate divergence times, reconstruct biogeographic history, and infer ancestral ecological associations within this large genus. We found strong support for a South Pacific+Hawaiian clade, as well as for a monophyletic Hawaiian lineage. Divergence time estimates suggest that Hawaiian Islands were colonized approximately 4.6 million years ago, suggesting that most of the diversity within Campsicnemus evolved since the current high islands began forming ∼5 million years ago. We also observe a novel ecotype within the Pacific Campsicnemus; a widespread obligate water-skating form that has arisen multiple times across the Pacific Islands. Together, these analyses suggest that a combination of ecological, biogeographic and temporal factors have led to the impressive diversity of long-legged flies in Hawaii and elsewhere in the Pacific.
authors.affiliation: Department of Environmental Science, Policy and Management, 130 Mulford Hall, University of California, Berkeley, Berkeley, CA 94720-3114, United States. Electronic address: krgoodman@berkeley.edu.
authors.forename: Kari Roesch
authors.initials: KR
authors.lastname: Goodman
authors.affiliation: Hawaii Biological Survey, Bishop Museum, 1525 Bernice Street, Honolulu, HI 96817, United States. Electronic address: neale@bishopmuseum.org.
authors.forename: Neal L
authors.initials: NL
authors.lastname: Evenhuis
authors.affiliation: Biology Centre of the Academy of Sciences of the Czech Republic, Institute of Parasitology, Branišovská 31, České Budějovice 37005, Czech Republic. Electronic address: bartoska81@gmail.com.
authors.forename: Pavla
authors.initials: P
authors.lastname: Bartošová-Sojková
authors.affiliation: Department of Environmental Science, Policy and Management, 130 Mulford Hall, University of California, Berkeley, Berkeley, CA 94720-3114, United States. Electronic address: ogrady@drosophilaevolution.com.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: O'Grady
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D005075:Biological Evolution; D004272:DNA, Mitochondrial / Q000235:genetics; D004175:Diptera / Q000145:classification* / Q000235:genetics; D006254:Hawaii; D016013:Likelihood Functions; D008957:Models, Genetic; D010802:Phylogeny; D011114:Polynesia; D017422:Sequence Analysis, DNA
chemical_list: D004272:DNA, Mitochondrial
keywords: Adaptive radiation; Divergence dating; Dolichopodidae; Ecotype; Hawaiian Islands; Historical biogeography