Biological Journal of the Linnean Society, 2007, 90, 239–246. With 2 figures © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 90, 239–246 239 Original Article PHYLOGEOGRAPHY OF IPS TYPOGRAPHUS (SCOLYTINAE) A. SALLÉ ET AL. *Corresponding author. E-mail: carole.kerdelhue@pierroton. inra.fr. †Current address: Institut des Sciences de l’Evolution, Université Montpellier 2, Place Eugène Bataillon, F-34095 Montpellier cedex 05, France Phylogeography of a host-specific insect: genetic structure of Ips typographus in Europe does not reflect past fragmentation of its host A. SALLÉ 1† , W. ARTHOFER 2 , F. LIEUTIER 3 , C. STAUFFER 2 and C. KERDELHUÉ 4 * 1 INRA, Zoologie Forestière, BP 20619 Ardon, F-45166 Olivet cedex, France 2 Institute of Forest Entomology, Forest Pathology and Forest Protection, Department of Forest and Soil Sciences, Boku, University of Natural Resources and Applied Life Sciences, Vienna, 1190-Austria 3 Université d’Orléans, Laboratoire de Biologie des Ligneux et des Grandes Cultures, BP 6759, F-45067 Orléans cedex 2, France 4 INRA Centre de Pierroton, UMR BIOGECO, Entomologie et Biodiversité, 69 route d’Arcachon, F-33612 Cestas cedex, France Received 2 June 2005; accepted for publication 1 March 2006 The phylogeography of the bark beetle Ips typographus was assessed using five microsatellite markers. Twenty-eight populations were sampled throughout Europe on the host tree Picea abies. I. typographus showed very low levels of genetic diversity, and the study revealed a lack of genetic structure across Europe. No significant barrier to gene flow was found, even though P. abies has a fragmented distribution. A weak but significant effect of isolation by distance was found. These results suggest a high dispersal capacity of I. typographus, which leads to low genetic differentia- tion between populations. Its high dispersal capacity is likely to have prevented I. typographus from developing important local adaptations to its host, which would have influenced its genetic structure. The nuclear data was com- pared to previously published mitochondrial data that showed strong differentiation between Central–Northern European populations and Russian–Baltic populations, and a founder effect in Scandinavia, probably reflecting the postglacial history of I. typographus. Discrepancies between nuclear and mitochondrial markers could be due to the maternal inheritance of mitochondrial DNA, and to sex-biased dispersal in I. typographus. The overall low genetic diversity observed on both markers on a large geographical scale is discussed. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 90, 239–246. ADDITIONAL KEYWORDS: bottleneck – gene flow – glacial periods – host specialization – microsatellites – phylogeography – Scolytinae. INTRODUCTION Ips typographus (L.) (Coleoptera: Scolytinae) attacks Picea spp. stands throughout Eurasia. These bark beetles generally establish in decaying trees, where their brood completes larval development within the phloem. In Europe, the wide distribution range of I. typographus is closely related to that of P. abies (L.) Karsten, which includes Alpine, Hercynian- Carpathian and Baltic-Northern domains (Arbez, 1987). During the last ice ages, however, P. abies was restricted to the Dinaric Alps, the Carpathian Alps, the Apennines and the Northern area of Moscow (Lagercrantz & Ryman, 1990), from which Central and Northern Europe were recolonized after amelio- ration of temperature. P. abies still reveals high levels of population differentiation on a European scale (Vendramin et al., 2000; Gugerli et al., 2001) and the authors suggested three to four postglacial recoloniza- tion routes. Downloaded from https://academic.oup.com/biolinnean/article/90/2/239/2701026 by guest on 11 July 2022