title: Spatiotemporal variation in local adaptation of a specialist insect herbivore to its long-lived host plant.
abstract: Local adaptation of interacting species to one another indicates geographically variable reciprocal selection. This process of adaptation is central in the organization and maintenance of genetic variation across populations. Given that the strength of selection and responses to it often vary in time and space, the strength of local adaptation should in theory vary between generations and among populations. However, such spatiotemporal variation has rarely been explicitly demonstrated in nature and local adaptation is commonly considered to be relatively static. We report persistent local adaptation of the short-lived herbivore Abrostola asclepiadis to its long-lived host plant Vincetoxicum hirundinaria over three successive generations in two studied populations and considerable temporal variation in local adaptation in six populations supporting the geographic mosaic theory. The observed variation in local adaptation among populations was best explained by geographic distance and population isolation, suggesting that gene flow reduces local adaptation. Changes in herbivore population size did not conclusively explain temporal variation in local adaptation. Our results also imply that short-term studies are likely to capture only a part of the existing variation in local adaptation.
authors.affiliation: Section of Ecology, Department of Biology, University of Turku, FI-20014, Turku, Finland. amk398@cornell.edu.|Current Address: Department of Ecology and Evolutionary Biology, Cornell University, Corson Hall, Ithaca, New York, 14853. amk398@cornell.edu.
authors.forename: Aino
authors.initials: A
authors.lastname: Kalske
authors.affiliation: Seed International, Oxford, United Kingdom.|Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, United Kingdom.
authors.forename: Roosa
authors.initials: R
authors.lastname: Leimu
authors.affiliation: Section of Ecology, Department of Biology, University of Turku, FI-20014, Turku, Finland.|Current Address: Plant Evolutionary Ecology, University of Tübingen, Auf der Morgenstelle 5, 72076, Tübingen, Germany.
authors.forename: J F
authors.initials: JF
authors.lastname: Scheepens
authors.affiliation: Institute of Integrative Biology, ETH-Zürich, ETH-Zentrum, CH-8092, Zürich, Switzerland.
authors.forename: Pia
authors.initials: P
authors.lastname: Mutikainen
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D005387:Finland; D005843:Geography; D060434:Herbivory; D008136:Longevity; D009036:Moths / Q000235:genetics / Q000502:physiology*; D011156:Population Density; D012621:Seasons; D012641:Selection, Genetic; D066047:Vincetoxicum / Q000235:genetics / Q000502:physiology*
keywords: Abrostola asclepiadis; Vincetoxicum hirundinaria; coevolution; geographic mosaic theory of coevolution; herbivory; plant-insect interactions