title: Climatic niche evolution is faster in sympatric than allopatric lineages of the butterfly genusPyrgus.
abstract: Understanding how speciation relates to ecological divergence has long fascinated biologists. It is assumed that ecological divergence is essential to sympatric speciation, as a mechanism to avoid competition and eventually lead to reproductive isolation, while divergence in allopatry is not necessarily associated with niche differentiation. The impact of the spatial context of divergence on the evolutionary rates of abiotic dimensions of the ecological niche has rarely been explored for an entire clade. Here, we compare the magnitude of climatic niche shifts between sympatric versus allopatric divergence of lineages in butterflies. By combining next-generation sequencing, parametric biogeography and ecological niche analyses applied to a genus-wide phylogeny of PalaearcticPyrgusbutterflies, we compare evolutionary rates along eight climatic dimensions across sister lineages that diverged in large-scale sympatry versus allopatry. In order to examine the possible effects of the spatial scale at which sympatry is defined, we considered three sets of biogeographic assignments, ranging from narrow to broad definition. Our findings suggest higher rates of niche evolution along all climatic dimensions for sister lineages that diverge in sympatry, when using a narrow delineation of biogeographic areas. This result contrasts with significantly lower rates of climatic niche evolution found in cases of allopatric speciation, despite the biogeographic regions defined here being characterized by significantly different climates. Higher rates in allopatry are retrieved when biogeographic areas are too widely defined-in such a case allopatric events may be recorded as sympatric. Our results reveal the macro-evolutionary significance of abiotic niche differentiation involved in speciation processes within biogeographic regions, and illustrate the importance of the spatial scale chosen to define areas when applying parametric biogeographic analyses.
authors.affiliation: Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland camille.pitteloud@usys.ethz.ch.|Institute of Terrestrial Ecosystems, ETH Zürich, Zurich, Switzerland.|Swiss Federal Research Institute WSL, Birmensdorf, Switzerland.
authors.forename: Camille
authors.initials: C
authors.lastname: Pitteloud
authors.affiliation: Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.
authors.forename: Nils
authors.initials: N
authors.lastname: Arrigo
authors.affiliation: Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.|W. Szafer Institute of Botany, Polish Academy of Sciences, Kraków, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Suchan
authors.affiliation: CONACYT Research Fellow assigned to CONABIO, Comisión Nacional para el conocimiento y uso de la Biodiversidad, Mexico City, Mexico.
authors.forename: Alicia
authors.initials: A
authors.lastname: Mastretta-Yanes
authors.affiliation: Institute of Evolutionary Biology, CSIC-Universitat Pompeu Fabra, Barcelona, Spain.
authors.forename: Roger
authors.identifier: http://orcid.org/0000-0002-2447-4388
authors.initials: R
authors.lastname: Vila
authors.affiliation: Institute of Evolutionary Biology, CSIC-Universitat Pompeu Fabra, Barcelona, Spain.|Center for Biodiversity Genomics, Biodiversity Institute of Ontario, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Vlad
authors.initials: V
authors.lastname: Dincă
authors.affiliation: Institute of Evolutionary Biology, CSIC-Universitat Pompeu Fabra, Barcelona, Spain.|Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Hernández-Roldán
authors.affiliation: Laubacher Str. 4, Lich, Hessen, Germany.
authors.forename: Ernst
authors.initials: E
authors.lastname: Brockmann
authors.affiliation: Centre Suisse de Cartographie de la Faune, Neuchâtel, Switzerland.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Chittaro
authors.affiliation: Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czech Republic.
authors.forename: Irena
authors.initials: I
authors.lastname: Kleckova
authors.affiliation: Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.
authors.forename: Luca
authors.initials: L
authors.lastname: Fumagalli
authors.affiliation: Department of Life Sciences, Natural History Museum, Cromwell Road, London, UK.
authors.forename: Sven
authors.initials: S
authors.lastname: Buerki
authors.affiliation: Institute of Terrestrial Ecosystems, ETH Zürich, Zurich, Switzerland.|Swiss Federal Research Institute WSL, Birmensdorf, Switzerland.
authors.forename: Loïc
authors.initials: L
authors.lastname: Pellissier
authors.affiliation: Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland nadir.alvarez@unil.ch.
authors.forename: Nadir
authors.identifier: http://orcid.org/0000-0002-0729-166X
authors.initials: N
authors.lastname: Alvarez
mesh_terms: D000352:Africa, Northern; D000818:Animals; D001208:Asia; D005075:Biological Evolution; D002080:Butterflies / Q000235:genetics / Q000502:physiology*; D002980:Climate; D017753:Ecosystem; D005060:Europe; D049810:Genetic Speciation; D010802:Phylogeny; D061350:Sympatry
keywords: climatic niche; macro-evolutionary processes; next-generation sequencing; parametric biogeography