title: Strong asymmetry in the relative strengths of prezygotic and postzygotic barriers between two damselfly sister species.
abstract: One of the longest debates in biology has been over the relative importance of different isolating barriers in speciation. However, for most species, there are few data evaluating their relative contributions and we can only speculate on the general roles of pre- and postzygotic isolation. Here, we quantify the absolute and cumulative contribution of 19 potential reproductive barriers between two sympatric damselfly sister species, Ischnura elegans and I. graellsii, including both premating (habitat, temporal, sexual and mechanical isolation) and postmating barriers (prezygotic: sperm insemination success and removal rate, oviposition success, fertility, fecundity; postzygotic: hybrid viability, hybrid sterility and hybrid breakdown). In sympatry, total reproductive isolation between I. elegans females and I. graellsii males was 95.2%, owing mostly to a premating mechanical incompatibility (93.4%), whereas other barriers were of little importance. Isolation between I. graellsii females and I. elegans males was also nearly complete (95.8%), which was caused by the cumulative action of multiple prezygotic (n= 4, 75.4%) and postzygotic postmating barriers (n= 5, 7.4%). Our results suggest that premating barriers are key factors in preventing gene flow between species, and that the relative strengths of premating barriers is highly asymmetrical between the reciprocal crosses.
authors.affiliation: Grupo de Biología Evolutiva y Conservación, Departamento de Ecoloxía e Bioloxía Animal, EUET Forestal, Universidade de Vigo, 36005 Pontevedra, SpainCurrent Address: Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Apdo. Postal 70-275, Ciudad Universitaria, 04510, México D.F., México.Section for Animal Ecology, Department of Biology, Ecology Building, Lund University, SE-22362 Lund, SwedenE-mail: rguillen@uvigo.es.
authors.forename: Rosa Anna
authors.initials: RA
authors.lastname: Sánchez-Guillén
authors.affiliation: Grupo de Biología Evolutiva y Conservación, Departamento de Ecoloxía e Bioloxía Animal, EUET Forestal, Universidade de Vigo, 36005 Pontevedra, SpainCurrent Address: Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Apdo. Postal 70-275, Ciudad Universitaria, 04510, México D.F., México.Section for Animal Ecology, Department of Biology, Ecology Building, Lund University, SE-22362 Lund, SwedenE-mail: rguillen@uvigo.es.
authors.forename: Maren
authors.initials: M
authors.lastname: Wellenreuther
authors.affiliation: Grupo de Biología Evolutiva y Conservación, Departamento de Ecoloxía e Bioloxía Animal, EUET Forestal, Universidade de Vigo, 36005 Pontevedra, SpainCurrent Address: Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Apdo. Postal 70-275, Ciudad Universitaria, 04510, México D.F., México.Section for Animal Ecology, Department of Biology, Ecology Building, Lund University, SE-22362 Lund, SwedenE-mail: rguillen@uvigo.es.
authors.forename: Adolfo
authors.initials: A
authors.lastname: Cordero Rivera
mesh_terms: D000818:Animals; D005260:Female; D005298:Fertility; D049810:Genetic Speciation; D006824:Hybridization, Genetic; D007313:Insecta / Q000235:genetics*; D008297:Male; D010058:Oviposition; D060047:Reproductive Isolation; D012726:Sexual Behavior, Animal