title: High genetic variation in resting-stage production in a metapopulation: Is there evidence for local adaptation?
abstract: Local adaptation is a key process for the maintenance of genetic diversity and population diversification. A better understanding of the mechanisms that allow (or prevent) local adaptation constitutes a key in apprehending how and at what spatial scale it occurs. The production of resting stages is found in many taxa and reflects an adaptation to outlast adverse environmental conditions. Daphnia magna (Crustacea) can alternate between asexual and sexual reproduction, the latter being linked to dormancy, as resting stages can only be produced sexually. In this species, on a continental scale, resting-stage production is locally adapted--that is, it is induced when the photoperiod indicates the imminence of habitat deterioration. Here, we aimed to explore whether selection is strong enough to maintain local adaptation at a scale of a few kilometers. We assessed life-history traits of 64 D. magna clones originating from 11 populations of a metapopulation with permanent and intermittent pool habitats. We found large within- and between-population variation for all dormancy-related traits, but no evidence for the hypothesized higher resting-stage production in animals from intermittent habitats. We discuss how gene flow, founder events, or other forms of selection might interfere with the process of local adaptation.
authors.affiliation: Zoological Institute, Basel University, Vesalgasse 1, 4051, Basel, Switzerland. anne.roulin@botinst.uzh.ch.|Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland. anne.roulin@botinst.uzh.ch.
authors.forename: Anne C
authors.initials: AC
authors.lastname: Roulin
authors.affiliation: MaIAGE-INRAUMR 1404, Domaine de Vilvert, 78352, Jouy en Josas, France.
authors.forename: Mahendra
authors.initials: M
authors.lastname: Mariadassou
authors.affiliation: Zoological Institute, Basel University, Vesalgasse 1, 4051, Basel, Switzerland.|School of Biological Sciences, Monash University, Melbourne, 3800, Australia.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Hall
authors.affiliation: Zoological Institute, Basel University, Vesalgasse 1, 4051, Basel, Switzerland.|Genetic Diversity Centre, Universitätstrasse 16, CHN E 55, 8092, Zürich, Switzerland.
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Walser
authors.affiliation: CNRS-UMR5175 CEFE, 1919, Route de Mende, 34293, Montpellier, France.
authors.forename: Christoph
authors.initials: C
authors.lastname: Haag
authors.affiliation: Zoological Institute, Basel University, Vesalgasse 1, 4051, Basel, Switzerland.|Tvärminne Zoological Station, Helsinki University, Hanko, Finland.
authors.forename: Dieter
authors.initials: D
authors.lastname: Ebert
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D000818:Animals; D003621:Daphnia / Q000235:genetics*; D017753:Ecosystem; D004956:Estivation / Q000235:genetics; D005260:Female; D005387:Finland; D014644:Genetic Variation; D008018:Life Cycle Stages / Q000235:genetics; D008297:Male; D010641:Phenotype; D012098:Reproduction / Q000502:physiology; D012100:Reproduction, Asexual
keywords: Daphnia magna; local adaptation; male production; metapopulation; resting-stage; sex-allocation