title: Rapid convergent evolution in wild crickets.
abstract: The earliest stages of convergent evolution are difficult to observe in the wild, limiting our understanding of the incipient genomic architecture underlying convergent phenotypes. To address this, we capitalized on a novel trait, flatwing, that arose and proliferated at the start of the 21st century in a population of field crickets (Teleogryllus oceanicus) on the Hawaiian island of Kauai. Flatwing erases sound-producing structures on male forewings. Mutant males cannot sing to attract females, but they are protected from fatal attack by an acoustically orienting parasitoid fly (Ormia ochracea). Two years later, the silent morph appeared on the neighboring island of Oahu. We tested two hypotheses for the evolutionary origin of flatwings in Hawaii: (1) that the silent morph originated on Kauai and subsequently introgressed into Oahu and (2) that flatwing originated independently on each island. Morphometric analysis of male wings revealed that Kauai flatwings almost completely lack typical derived structures, whereas Oahu flatwings retain noticeably more wild-type wing venation. Using standard genetic crosses, we confirmed that the mutation segregates as a single-locus, sex-linked Mendelian trait on both islands. However, genome-wide scans using RAD-seq recovered almost completely distinct markers linked with flatwing on each island. The patterns of allelic association with flatwing on either island reveal different genomic architectures consistent with the timing of two mutational events on the X chromosome. Divergent wing morphologies linked to different loci thus cause identical behavioral outcomes--silence--illustrating the power of selection to rapidly shape convergent adaptations from distinct genomic starting points.
authors.affiliation: Centre for Biological Diversity, University of St Andrews, St Andrews, Fife KY16 9TH, UK.
authors.forename: Sonia
authors.initials: S
authors.lastname: Pascoal
authors.affiliation: Edinburgh Genomics, University of Edinburgh, Edinburgh EH9 3JT, UK.
authors.forename: Timothee
authors.initials: T
authors.lastname: Cezard
authors.affiliation: Centre for Biological Diversity, University of St Andrews, St Andrews, Fife KY16 9TH, UK.
authors.forename: Aasta
authors.initials: A
authors.lastname: Eik-Nes
authors.affiliation: Edinburgh Genomics, University of Edinburgh, Edinburgh EH9 3JT, UK.
authors.forename: Karim
authors.initials: K
authors.lastname: Gharbi
authors.affiliation: Institute of Environmental Sciences, Jagiellonian University, Gronostajova 7, 30-387 Kraków, Poland.
authors.forename: Jagoda
authors.initials: J
authors.lastname: Majewska
authors.affiliation: Department of Biology, University of California, Riverside, CA 92521, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Payne
authors.affiliation: Centre for Biological Diversity, University of St Andrews, St Andrews, Fife KY16 9TH, UK.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Ritchie
authors.affiliation: Department of Biology, University of California, Riverside, CA 92521, USA; Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, MN 55108, USA.
authors.forename: Marlene
authors.initials: M
authors.lastname: Zuk
authors.affiliation: Centre for Biological Diversity, University of St Andrews, St Andrews, Fife KY16 9TH, UK. Electronic address: nwb3@st-andrews.ac.uk.
authors.forename: Nathan W
authors.initials: NW
authors.lastname: Bailey
mesh_terms: D000818:Animals; D005075:Biological Evolution; D006135:Gryllidae / Q000033:anatomy & histology* / Q000235:genetics* / Q000378:metabolism; D006254:Hawaii; D062312:Islands; D008297:Male; D009154:Mutation; D012726:Sexual Behavior, Animal; D014921:Wings, Animal / Q000033:anatomy & histology*