title: Cryptic lineages of a common alpine mayfly show strong life-history divergence.
abstract: Understanding ecological divergence of morphologically similar but genetically distinct species - previously considered as a single morphospecies - is of key importance in evolutionary ecology and conservation biology. Despite their morphological similarity, cryptic species may have evolved distinct adaptations. If such ecological divergence is unaccounted for, any predictions about their responses to environmental change and biodiversity loss may be biased. We used spatio-temporally replicated field surveys of larval cohort structure and population genetic analyses (using nuclear microsatellite markers) to test for life-history divergence between two cryptic lineages of the alpine mayfly Baetis alpinus in the Swiss Alps. We found that the more widespread and abundant cryptic lineage represents a 'generalist' with at least two cohorts per year, whereas the less abundant lineage is restricted to higher elevations and represents a 'specialist' with a single cohort per year. Importantly, our results indicate partial temporal segregation in reproductive periods between these lineages, potentially facilitating local coexistence and reproductive isolation. Taken together, our findings emphasize the need for a taxonomic revision: widespread and apparently generalist morphospecies can hide cryptic lineages with much narrower ecological niches and distribution ranges.
authors.affiliation: Department of Aquatic Ecology, EAWAG, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, 8600, Dübendorf, Switzerland.|Institute of Integrative Biology, ETH-Zurich, 8092, Zurich, Switzerland.
authors.forename: Marie
authors.identifier: http://orcid.org/0000-0002-0262-6416
authors.initials: M
authors.lastname: Leys
authors.affiliation: Department of Clinical Research, University of Bern and Swiss Institute of Bioinformatics, 3010, Bern, Switzerland.
authors.forename: Irene
authors.initials: I
authors.lastname: Keller
authors.affiliation: Department of Aquatic Ecology, EAWAG, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, 8600, Dübendorf, Switzerland.|Institute of Integrative Biology, ETH-Zurich, 8092, Zurich, Switzerland.
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Robinson
authors.affiliation: Department of Aquatic Ecology, EAWAG, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, 8600, Dübendorf, Switzerland.|Institute of Integrative Biology, ETH-Zurich, 8092, Zurich, Switzerland.
authors.forename: Katja
authors.initials: K
authors.lastname: Räsänen
mesh_terms: D000818:Animals; D005075:Biological Evolution; D065133:Ephemeroptera / Q000145:classification*; D014644:Genetic Variation; D005828:Genetics, Population; D018895:Microsatellite Repeats; D010802:Phylogeny; D062211:Spatio-Temporal Analysis
keywords: 
  Baetis alpinus
  ; cohort; morphospecies; population genetic structure; sympatry; voltinism