title: Genetic divergence predicts reproductive isolation in damselflies.
abstract: Reproductive isolation is the defining characteristic of a biological species, and a common, but often untested prediction is a positive correlation between reproductive isolation and genetic divergence. Here, we test for this correlation in odonates, an order characterized by strong sexual selection. First, we measure reproductive isolation and genetic divergence in eight damselfly genera (30 species pairs) and test for a positive correlation. Second, we estimate the genetic threshold preventing hybrid formation and empirically test this threshold using wild populations of species within the Ischnura genus. Our results indicate a positive and strong correlation between reproductive isolation and genetic distance using both mitochondrial and nuclear genes cytochrome oxidase II (COII: r = 0.781 and 18S-28S: r = 0.658). Hybridization thresholds range from -0.43 to 1.78% for COII and -0.052-0.71% for 18S-28S, and both F1 -hybrids and backcrosses were detected in wild populations of two pairs of Ischnura species with overlapping thresholds. Our study suggests that threshold values are suitable to identify species prone to hybridization and that positive isolation-divergence relationships are taxonomically widespread.
authors.affiliation: Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México (UNAM), Mexico D.F, Mexico.|Grupo ECOEVO, Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, Pontevedra, Spain.
authors.forename: R A
authors.initials: RA
authors.lastname: Sánchez-Guillén
authors.affiliation: Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México (UNAM), Mexico D.F, Mexico.
authors.forename: A
authors.initials: A
authors.lastname: Córdoba-Aguilar
authors.affiliation: Grupo ECOEVO, Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, Pontevedra, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Cordero-Rivera
authors.affiliation: Department of Biology, Ecology Building, Lund University, Lund, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Wellenreuther
mesh_terms: D000818:Animals; D005260:Female; D049810:Genetic Speciation; D006824:Hybridization, Genetic; D008297:Male; D008969:Molecular Sequence Data; D063191:Odonata / Q000235:genetics*; D060047:Reproductive Isolation
keywords: hybridization; odonates; sexual and natural forces; speciation clock