title: The alignment between phenotypic plasticity, the major axis of genetic variation and the response to selection.
abstract: Phenotypic plasticity is the ability of a genotype to produce more than one phenotype in order to match the environment. Recent theory proposes that the major axis of genetic variation in a phenotypically plastic population can align with the direction of selection. Therefore, theory predicts that plasticity directly aids adaptation by increasing genetic variation in the direction favoured by selection and reflected in plasticity. We evaluated this theory in the freshwater crustacean Daphnia pulex, facing predation risk from two contrasting size-selective predators. We estimated plasticity in several life-history traits, the G matrix of these traits, the selection gradients on reproduction and survival, and the predicted responses to selection. Using these data, we tested whether the genetic lines of least resistance and the predicted response to selection aligned with plasticity. We found predator environment-specific G matrices, but shared genetic architecture across environments resulted in more constraint in the G matrix than in the plasticity of the traits, sometimes preventing alignment of the two. However, as the importance of survival selection increased, the difference between environments in their predicted response to selection increased and resulted in closer alignment between the plasticity and the predicted selection response. Therefore, plasticity may indeed aid adaptation to new environments.
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK Animal Ecology, Department of Ecology and Genetics, Uppsala University, Uppsala 752 36, Sweden martin.i.lind@gmail.com.
authors.forename: Martin I
authors.initials: MI
authors.lastname: Lind
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
authors.forename: Kylie
authors.initials: K
authors.lastname: Yarlett
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
authors.forename: Julia
authors.initials: J
authors.lastname: Reger
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK Centro Nacional del Medio Ambiente, Universidad de Chile, Avenida Larrain 9975, La Reina, Santiago, Chile.
authors.forename: Mauricio J
authors.initials: MJ
authors.lastname: Carter
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
authors.forename: Andrew P
authors.identifier: http://orcid.org/0000-0002-4797-9143
authors.initials: AP
authors.lastname: Beckerman
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D003621:Daphnia / Q000033:anatomy & histology* / Q000235:genetics*; D020387:Food Chain; D014644:Genetic Variation; D010641:Phenotype; D012641:Selection, Genetic
keywords: Chaoborus flavicans; Daphnia pulex; Gasterosteus aculeatus; genetic accommodation; phenotypic plasticity; predation