title: Polygamy slows down population divergence in shorebirds.
abstract: Sexual selection may act as a promotor of speciation since divergent mate choice and competition for mates can rapidly lead to reproductive isolation. Alternatively, sexual selection may also retard speciation since polygamous individuals can access additional mates by increased breeding dispersal. High breeding dispersal should hence increase gene flow and reduce diversification in polygamous species. Here, we test how polygamy predicts diversification in shorebirds using genetic differentiation and subspecies richness as proxies for population divergence. Examining microsatellite data from 79 populations in 10 plover species (Genus: Charadrius) we found that polygamous species display significantly less genetic structure and weaker isolation-by-distance effects than monogamous species. Consistent with this result, a comparative analysis including 136 shorebird species showed significantly fewer subspecies for polygamous than for monogamous species. By contrast, migratory behavior neither predicted genetic differentiation nor subspecies richness. Taken together, our results suggest that dispersal associated with polygamy may facilitate gene flow and limit population divergence. Therefore, intense sexual selection, as occurs in polygamous species, may act as a brake rather than an engine of speciation in shorebirds. We discuss alternative explanations for these results and call for further studies to understand the relationships between sexual selection, dispersal, and diversification.
authors.affiliation: Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, United Kingdom.|Organisms and Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, CF10 3AX, United Kingdom.
authors.forename: Josephine
authors.initials: J
authors.lastname: D'Urban Jackson
authors.affiliation: NERC-Biomolecular Analysis Facility, Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, United Kingdom.
authors.forename: Natalie
authors.initials: N
authors.lastname: Dos Remedios
authors.affiliation: Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, United Kingdom.
authors.forename: Kathryn H
authors.initials: KH
authors.lastname: Maher
authors.affiliation: Institut Supérieur de technologie de Menabe Morondava, Faculty of Sciences, University of Toliara, Madagascar.
authors.forename: Sama
authors.initials: S
authors.lastname: Zefania
authors.affiliation: U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, Oregon, 97331, USA.
authors.forename: Susan
authors.initials: S
authors.lastname: Haig
authors.affiliation: U.S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado, 80526, USA.
authors.forename: Sara
authors.initials: S
authors.lastname: Oyler-McCance
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, 40530, Sweden.
authors.forename: Donald
authors.initials: D
authors.lastname: Blomqvist
authors.affiliation: NERC-Biomolecular Analysis Facility, Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, United Kingdom.
authors.forename: Terry
authors.initials: T
authors.lastname: Burke
authors.affiliation: Organisms and Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, CF10 3AX, United Kingdom.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Bruford
authors.affiliation: Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, United Kingdom.
authors.forename: Tamás
authors.initials: T
authors.lastname: Székely
authors.affiliation: Institute of Zoology, Universitätsplatz 2, 8010, Graz, Austria.|Max Planck Institute for Ornithology, Eberhard Gwinner Str., 82319, Seewiesen, Germany.
authors.forename: Clemens
authors.initials: C
authors.lastname: Küpper
mesh_terms: D025041:Animal Migration; D000818:Animals; D046091:Charadriiformes / Q000235:genetics*; D051456:Gene Flow; D049810:Genetic Speciation; D014644:Genetic Variation; D018895:Microsatellite Repeats; D012726:Sexual Behavior, Animal
keywords: Dispersal; gene flow; mating systems; migration; sexual selection; shorebird; speciation